Central and Eastern United States 

Seismic Source Characterization 

for Nuclear Facilities 

Volume 6: Appendices G to L

U.S. Department of Energy

1000 Independence Avenue SW

Washington, DC 20585

Report # DOE/NE-0140

Electric Power Research Institute

3420 Hillview Avenue

Palo Alto, CA 94304

Report # 1021097

U.S. Nuclear Regulatory Commission

Offi ce of Nuclear Regulatory Research

Washington DC 20555

NUREG-2115

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Central and Eastern United States 

Seismic Source Characterization for 

Nuclear Facilities

Cosponsors

U.S. Department of Energy

1000 Independence Avenue SW

Washington, DC 20585

R. H. Lagdon, Jr.

Chief of Nuclear Safety

Office of the Under Secretary for Nuclear Security, S-5 

M.E. Shields

Project Manager

Office of Nuclear Energy, NE-72

Electric Power Research Institute

3420 Hillview Avenue

Palo Alto, CA 94304

J. F. Hamel 

Program Manager 

Advanced Nuclear Technology 

U.S. Nuclear Regulatory Commission

Office of Nuclear Regulatory Research

Washington DC 20555

R.G. Roche-Rivera

NRC Project Manager
DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITIES

EPRI DISCLAIMER

THIS DOCUMENT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED OR 

COSPONSORED BY THE ELECTRIC POWER RESEARCH INSTITUTE, INC. (EPRI). NEITHER 

EPRI, ANY MEMBER OF EPRI, ANY COSPONSOR BELOW, NOR ANY PERSON ACTING ON 

BEHALF OF ANY OF THEM:

(A) MAKES ANY WARRANTY OR REPRESENTATION WHATSOEVER, EXPRESS OR IMPLIED, (I) 

WITH RESPECT TO THE USE OF ANY INFORMATION, APPARATUS, METHOD, PROCESS, OR 

SIMILAR ITEM DISCLOSED IN THIS DOCUMENT, INCLUDING MERCHANTABILITY AND FITNESS 

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(INCLUDING ANY CONSEQUENTIAL DAMAGES, EVEN IF EPRI OR ANY EPRI REPRESENTATIVE 

HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES) RESULTING FROM YOUR 

SELECTION OR USE OF THIS DOCUMENT OR ANY INFORMATION, APPARATUS, METHOD, 

PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS DOCUMENT.

DOE DISCLAIMER

THIS REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY AN AGENCY OF 

THE UNITED STATES GOVERNMENT. NEITHER THE UNITED STATES GOVERNMENT NOR ANY 

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. 
This publication is a corporate document that should be cited in the literature in the following 

manner:

Technical Report: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities. EPRI, Palo Alto, CA, U.S. DOE, and U.S. NRC: 2012. 

iii

SPONSORS’ ACKNOWLEDGMENTS 

The project sponsors would like to acknowledge the following individuals for directing the 

project: 

Coppersmith Consulting, Inc. 

2121 N. California Blvd., #290 

Walnut Creek, CA 94596 

Technical Integration (TI) Lead

K.J. Coppersmith 

Savannah River Nuclear Solutions, LLC 

Savannah River Site 

Building 730-4B, Room 313 

Aiken, SC 29808 

CEUS SSC Project Manager

L.A. Salomone 

This document describes research sponsored by the Electric Power Research Institute (EPRI), 

U.S. Department of Energy (U.S. DOE) under Award Number DE-FG07-08ID14908, and the 

U.S. Nuclear Regulatory Commission (U.S. NRC) under Award Number NCR-04-09-144. 

v 

AUTHORS

This document was prepared by the following investigators: 

Technical Integration Lead Kevin J. Coppersmith

Project Manager Lawrence A. Salomone

Technical Integration Team Chris W. Fuller

Laura L. Glaser

Kathryn L. Hanson

Ross D. Hartleb

William R. Lettis

Scott C. Lindvall

Stephen M. McDuffie

Robin K. McGuire

Gerry L. Stirewalt

Gabriel R. Toro

Robert R. Youngs

Database Manager David L. Slayter

Technical Support Serkan B. Bozkurt

Randolph J. Cumbest

Valentina Montaldo Falero 

Roseanne C. Perman

Allison M. Shumway

Frank H. Syms

Martitia (Tish) P. Tuttle, Paleoliquefaction Data 

Resource

NUREG-2115 DOE/NE-0140 EPRI 1021097

vii 

This document has been

reproduced from the best available copy.

 

ix

ABSTRACT

This report describes a new seismic source characterization (SSC) model for the Central and 

Eastern United States (CEUS). It will replace the Seismic Hazard Methodology for the Central 

and Eastern United States, EPRI Report NP-4726 (July 1986) and the Seismic Hazard 

Characterization of 69 Nuclear Plant Sites East of the Rocky Mountains, Lawrence Livermore 

National Laboratory Model, (Bernreuter et al., 1989). The objective of the CEUS SSC Project is 

to develop a new seismic source model for the CEUS using a Senior Seismic Hazard Analysis 

Committee (SSHAC) Level 3 assessment process. The goal of the SSHAC process is to represent 

the center, body, and range of technically defensible interpretations of the available data, models, 

and methods. Input to a probabilistic seismic hazard analysis (PSHA) consists of both seismic 

source characterization and ground motion characterization. These two components are used to 

calculate probabilistic hazard results (or seismic hazard curves) at a particular site. This report 

provides a new seismic source model. 

Results and Findings

The product of this report is a regional CEUS SSC model. This model includes consideration of 

an updated database, full assessment and incorporation of uncertainties, and the range of diverse 

technical interpretations from the larger technical community. The SSC model will be widely 

applicable to the entire CEUS, so this project uses a ground motion model that includes generic 

variations to allow for a range of representative site conditions (deep soil, shallow soil, hard 

rock). Hazard and sensitivity calculations were conducted at seven test sites representative of 

different CEUS hazard environments. 

Challenges and Objectives

The regional CEUS SSC model will be of value to readers who are involved in PSHA work, and 

who wish to use an updated SSC model. This model is based on a comprehensive and traceable 

process, in accordance with SSHAC guidelines in NUREG/CR-6372, Recommendations for 

Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts. The model 

will be used to assess the present-day composite distribution for seismic sources along with their 

characterization in the CEUS and uncertainty. In addition, this model is in a form suitable for use 

in PSHA evaluations for regulatory activities, such as Early Site Permit (ESPs) and Combined 

Operating License Applications (COLAs).

Applications, Values, and Use

Development of a regional CEUS seismic source model will provide value to those who (1) have 

submitted an ESP or COLA for Nuclear Regulatory Commission (NRC) review before 2011; (2) 

will submit an ESP or COLA for NRC review after 2011; (3) must respond to safety issues 

resulting from NRC Generic Issue 199 (GI-199) for existing plants and (4) will prepare PSHAs 

to meet design and periodic review requirements for current and future nuclear facilities. This 

work replaces a previous study performed approximately 25 years ago. Since that study was 
x 

completed, substantial work has been done to improve the understanding of seismic sources and 

their characterization in the CEUS. Thus, a new regional SSC model provides a consistent, stable 

basis for computing PSHA for a future time span. Use of a new SSC model reduces the risk of 

delays in new plant licensing due to more conservative interpretations in the existing and future 

literature.

Perspective

The purpose of this study, jointly sponsored by EPRI, the U.S. Department of Energy (DOE), 

and the NRC was to develop a new CEUS SSC model. The team assembled to accomplish this 

purpose was composed of distinguished subject matter experts from industry, government, and 

academia. The resulting model is unique, and because this project has solicited input from the 

present-day larger technical community, it is not likely that there will be a need for significant 

revision for a number of years. See also Sponsors’ Perspective for more details.

Approach

The goal of this project was to implement the CEUS SSC work plan for developing a regional 

CEUS SSC model. The work plan, formulated by the project manager and a technical integration 

team, consists of a series of tasks designed to meet the project objectives. This report was 

reviewed by a participatory peer review panel (PPRP), sponsor reviewers, the NRC, the U.S. 

Geological Survey, and other stakeholders. Comments from the PPRP and other reviewers were 

considered when preparing the report. The SSC model was completed at the end of 2011. 

Keywords

Probabilistic seismic hazard analysis (PSHA)

Seismic source characterization (SSC)

Seismic source characterization model

Central and Eastern United States (CEUS)
xi

CONTENTS

Abstract........................................................................................................................................ ix

Contents....................................................................................................................................... xi

List of Figures ............................................................................................................................xxv

List of Tables........................................................................................................................... lxxvii

Executive Summary ................................................................................................................lxxxv

Participatory Peer Review Panel Final Report Dated October 24, 2011 ...................................xcv

Project Acknowledgements.........................................................................................................ciii

Sponsor’s Perspective ................................................................................................................ cv

Abbreviations ..............................................................................................................................cix

1 INTRODUCTION ....................................................................................................................1-1

1.1 Background and History..................................................................................................1-1

1.1.1 EPRI-SOG and LLNL Projects ................................................................................1-2

1.1.2 Development of the SSHAC Process .....................................................................1-2

1.1.3 Implementation of the SSHAC Methodology ..........................................................1-3

1.1.4 Regional SSC Model for Nuclear Facilities..............................................................1-3

1.1.5 Differences from USGS National Seismic Hazard Mapping Project........................1-4

1.2 Purpose of the CEUS SSC Project .................................................................................1-5

1.2.1 Implementation of SSHAC Level 3 Process ............................................................1-6

1.2.2 Goals: Stability and Longevity .................................................................................1-8

1.2.3 Interface with Ground Motion Models......................................................................1-8

1.3 Study Region.................................................................................................................1-10

1.4 Products of Project........................................................................................................1-10

1.4.1 Seismic Source Model for Study Region ...............................................................1-10

1.4.2 Hazard Input Document.........................................................................................1-12

1.4.3 Documentation of Technical Bases for All Assessments ......................................1-12

1.4.4 Other Key Products ...............................................................................................1-13

1.4.4.1 Data Evaluation and Data Summary Tables..................................................1-13
xii

1.4.4.2 Database of Geologic, Geophysical, and Seismological Data.......................1-13

1.4.4.3 Earthquake Catalog with Uniform Moment Magnitudes.................................1-13

1.4.4.4 Updated Paleoseismicity Data and Guidance................................................1-14

1.4.4.5 Recommendations for Future Applications of SSC Model.............................1-14

2 SSHAC LEVEL 3 ASSESSMENT PROCESS AND IMPLEMENTATION .............................2-1

2.1 Goals and Activities of a SSHAC Assessment Process..................................................2-2

2.1.1 Evaluation................................................................................................................2-4

2.1.2 Integration ...............................................................................................................2-4

2.2 Roles of CEUS SSC Project Participants........................................................................2-5

2.3 CEUS SSC Project Organization ....................................................................................2-7

2.4 Key Tasks and Activities .................................................................................................2-9

2.4.1 Database Development ...........................................................................................2-9

2.4.2 Identification of Significant Issues .........................................................................2-10

2.4.3 Workshop #1—Key Issues and Available Data .....................................................2-10

2.4.4 Workshop #2—Alternative Interpretations.............................................................2-12

2.4.5 Working Meetings..................................................................................................2-13

2.4.6 SSC Sensitivity Model Development .....................................................................2-14

2.4.7 Workshop #3—Feedback ......................................................................................2-15

2.4.8 SSC Preliminary Model Development ...................................................................2-16

2.4.9 Finalization and Review of SSC Draft and Final Model.........................................2-17

2.4.10 Documentation ....................................................................................................2-19

2.4.10.1 Development of the Hazard Input Document...............................................2-19

2.4.10.2 Development of Earlier Draft Report............................................................2-19

2.4.10.3 Draft Report Review.....................................................................................2-19

2.4.10.4 Final Report Development ...........................................................................2-20

2.5 Participatory Peer Review Panel...................................................................................2-20

2.5.1 Roles and Responsibilities ....................................................................................2-20

2.5.2 Reviews and Feedback ........................................................................................2-20

2.5.3 Fulfillment of SSHAC-Prescribed Scope of Review of Both Technical and 

Process Issues ..............................................................................................................2-21

2.6 Consistency of CEUS SSC Assessment Process with SSHAC Guidelines ..................2-22

3 EARTHQUAKE CATALOG....................................................................................................3-1

3.1 Goals for the Earthquake Catalog Development.............................................................3-1

3.1.1 Completeness..........................................................................................................3-1
xiii

3.1.2 Uniformity of Catalog Processing ............................................................................3-2

3.1.3 Catalog Review .......................................................................................................3-3

3.2 Catalog Compilation........................................................................................................3-4

3.2.1 Continental-Scale Catalogs .....................................................................................3-5

3.2.2 Regional Catalogs ...................................................................................................3-7

3.2.3 Catalogs from Special Studies ................................................................................3-7

3.2.4 Focal Depth Data.....................................................................................................3-8

3.2.5 Nontectonic Events..................................................................................................3-9

3.2.6 Identification of Unique Earthquake Entries ............................................................3-9

3.3 Development of a Uniform Moment Magnitude Earthquake Catalog............................3-11

3.3.1 Approach for Uniform Magnitude and Unbiased Recurrence Estimation ..............3-11

3.3.2 Estimation of E[M] for the CEUS SSC Project Catalog .........................................3-19

3.3.2.1 Effect of Magnitude Rounding on Statistical Tests ........................................3-19

3.3.2.2 Moment Magnitude Data................................................................................3-20

3.3.2.3 Estimation of E[M] from Body-Wave Magnitudes ..........................................3-22

3.3.2.4 Estimation of E[M] from ML Magnitudes.........................................................3-28

3.3.2.5 Estimation of E[M] from MS Magnitudes ........................................................3-29

3.3.2.6 Estimation of E[M] from MC and MD Magnitudes............................................3-30

3.3.2.7 Estimation of E[M] from the Logarithm of Felt Area.......................................3-32

3.3.2.8 Estimation of E[M] from the Maximum Intensity, I0 ........................................3-32

3.3.2.9 Uniform Moment Magnitude Catalog of E[M] and N* Values.........................3-36

3.4 Identification of Independent Earthquakes....................................................................3-37

3.5 Catalog Completeness..................................................................................................3-39

4 CONCEPTUAL SEISMIC SOURCE CHARACTERIZATION FRAMEWORK........................4-1

4.1 Needs for a Conceptual SSC Framework .......................................................................4-2

4.1.1 Logic Tree Approach to Representing Alternatives and Assessing 

Uncertainties........................................................................................................ 4-2

4.1.1.1 Examples of Logic Trees .................................................................................4-3

4.1.1.2 Assigning Weights to Logic Tree Branches .....................................................4-3

4.1.2 Data Identification and Evaluation ...........................................................................4-5

4.1.2.1 “Generic” Data Identification to Address Indicators of a Seismic Source ........4-5

4.1.2.2 Data Evaluation for Particular Seismic Sources: Data Evaluation and 

Data Summary Tables .................................................................................................4-7

4.1.3 Methodology for Identifying Seismic Sources..........................................................4-9
xiv

4.1.3.1 Hazard-Informed Approach ...........................................................................4-11

4.1.3.2 Conclusions Regarding the Hazard Significance of Various SSC Issues......4-13

4.1.3.3 Criteria for Defining Seismic Sources ............................................................4-14

4.2 Master Logic Tree .........................................................................................................4-18

4.2.1 Description of Logic Tree Elements.......................................................................4-18

4.2.2 RLME Source Logic Tree ......................................................................................4-20

4.2.3 Mmax Zones Logic Tree........................................................................................4-22

4.2.4 Seismotectonic Zones Branch...............................................................................4-24

5 SSC MODEL: OVERVIEW AND METHODOLOGY...............................................................5-1

5.1 Overview of Spatial and Temporal Models......................................................................5-1

5.1.1 Spatial Model Considerations..................................................................................5-1

5.1.2 Considerations Regarding Temporal Models ..........................................................5-3

5.1.3 Perspective on CEUS SSC Models.........................................................................5-4

5.2 Maximum Earthquake Magnitude Assessment...............................................................5-5

5.2.1 Approaches to Mmax Estimation in the CEUS........................................................5-6

5.2.1.1 Bayesian Mmax Approach...............................................................................5-8

5.2.1.2 Kijko Approach to Mmax Assessment ...........................................................5-17

5.2.1.3 Weights for the Alternative Mmax Approaches..............................................5-20

5.2.1.4 Example Mmax Distributions .........................................................................5-20

5.2.2 Other Mmax Issues ..............................................................................................5-21

5.3 Earthquake Recurrence Assessment............................................................................5-22

5.3.1 Smoothing to Represent Spatial Stationarity.........................................................5-22

5.3.2 Smoothing Approach.............................................................................................5-23

5.3.2.1 Development of Penalized-Likelihood Approach and Formulation ................5-23

5.3.2.2 Application of the Model and Specification of Model Parameters..................5-36

5.3.2.3 Exploration of Model Results in Parameter Space ........................................5-40

5.3.2.4 Consideration of Constant b-Value Kernel Approaches ................................5-42

5.3.2.5 Comparison to EPRI-SOG Approach.............................................................5-45

5.3.2.6 Assessment of the Lombardi Study ...............................................................5-46

5.3.3 Estimation of Recurrence for RLME Sources........................................................5-47

5.3.3.1 Estimation of Occurrence Rates for the Poisson Model ................................5-48

5.3.3.2 Estimation of Occurrence Rates for a Renewal Model ..................................5-51

5.3.3.3 Incorporating Uncertainty in the Input............................................................5-52

5.3.3.4 RLME Magnitude Distribution ........................................................................5-53
xv

5.4 Assessment of Future Earthquake Characteristics .......................................................5-54

5.4.1 Tectonic Stress Regime ........................................................................................5-55

5.4.2 Sense of Slip/Style of Faulting...............................................................................5-55

5.4.3 Strike and Dip of Ruptures ....................................................................................5-55

5.4.4 Seismogenic Crustal Thickness ...........................................................................5-56

5.4.5 Fault Rupture Area ................................................................................................5-57

5.4.6 Rupture Length-to-Width Aspect Ratio..................................................................5-57

5.4.7 Relationship of Rupture to Source Zone Boundaries ............................................5-58

5.5 Predicted Seismic Moment Rate...................................................................................5-58

6 SSC MODEL: RLME SOURCES AND MMAX ZONES BRANCH.........................................6-1

6.1 RLME Sources ................................................................................................................6-1

6.1.1 Charlevoix................................................................................................................6-3

6.1.1.1 Evidence for Temporal Clustering....................................................................6-4

6.1.1.2 Localizing Tectonic Features ...........................................................................6-4

6.1.1.3 Geometry and Style of Faulting .......................................................................6-5

6.1.1.4 RLME Magnitude .............................................................................................6-7

6.1.1.5 RLME Recurrence ...........................................................................................6-8

6.1.2 Charleston .............................................................................................................6-10

6.1.2.1 Evidence for Temporal Clustering..................................................................6-11

6.1.2.2 Localizing Feature .........................................................................................6-12

6.1.2.3 Geometry and Style of Faulting .....................................................................6-12

6.1.2.4 RLME Magnitude ...........................................................................................6-15

6.1.2.5 RLME Recurrence .........................................................................................6-17

6.1.3 Cheraw Fault ........................................................................................................6-22

6.1.3.1 Evidence for Temporal Clustering..................................................................6-23

6.1.3.2 Geometry and Style of Faulting .....................................................................6-24

6.1.3.3 RLME Magnitude ...........................................................................................6-25

6.1.3.4 RLME Recurrence .........................................................................................6-26

6.1.4 Meers Fault............................................................................................................6-28

6.1.4.1 Evidence for Temporal Clustering..................................................................6-29

6.1.4.2 Localizing Feature .........................................................................................6-29

6.1.4.3 Geometry and Style of Faulting .....................................................................6-30

6.1.4.4 RLME Magnitude ...........................................................................................6-31

6.1.4.5 RLME Recurrence .........................................................................................6-34
xvi

6.1.5 Reelfoot Rift–New Madrid Fault System ...............................................................6-35

6.1.5.1 Evidence for Temporal Clustering..................................................................6-40

6.1.5.2 Geometry and Style of Faulting .....................................................................6-42

6.1.5.3 RLME Magnitude ...........................................................................................6-44

6.1.5.4 RLME Recurrence .........................................................................................6-47

6.1.6 Reelfoot Rift—Eastern Rift Margin Fault ...............................................................6-50

6.1.6.1 Evidence for Temporal Clustering..................................................................6-53

6.1.6.2 Geometry and Style of Faulting .....................................................................6-53

6.1.6.3 RLME Magnitude ...........................................................................................6-54

6.1.6.4 RLME Recurrence .........................................................................................6-56

6.1.7 Reelfoot Rift—Marianna .......................................................................................6-57

6.1.7.1 Evidence for Temporal Clustering..................................................................6-58

6.1.7.2 Geometry and Style of Faulting .....................................................................6-59

6.1.7.3 RLME Magnitude ...........................................................................................6-60

6.1.7.4 RLME Recurrence .........................................................................................6-61

6.1.8 Reelfoot Rift—Commerce Fault Zone ..................................................................6-62

6.1.8.1 Evidence for Temporal Clustering..................................................................6-63

6.1.8.2 Geometry and Style of Faulting .....................................................................6-64

6.1.8.3 RLME Magnitude ...........................................................................................6-65

6.1.8.4 RLME Recurrence .........................................................................................6-66

6.1.9 Wabash Valley ......................................................................................................6-68

6.1.9.1 Evidence for Temporal Clustering..................................................................6-69

6.1.9.2 Geometry and Style of Faulting .....................................................................6-69

6.1.9.3 RLME Magnitude ...........................................................................................6-72

6.1.9.4 RLME Recurrence .........................................................................................6-73

6.2 Mmax Distributed Seismicity Source Zones..................................................................6-74

6.2.1 Definition of Mmax Zones .....................................................................................6-74

6.2.2 Criteria for Defining the MESE/NMESE Boundary ...............................................6-75

6.3 Maximum Magnitude Distributions for Mmax Distributed Seismicity Sources...............6-76

6.3.1 Maximum Observed Earthquake Magnitude .........................................................6-76

6.3.2 Mmax Distributions ................................................................................................6-77

6.4 Recurrence Parameters ................................................................................................6-78

6.4.1 Rate and b-Value Maps for Single Zone and Two Zones......................................6-78

6.4.2 Comparison of Recurrence Parameters to Catalog...............................................6-79
xvii

7 SSC MODEL: SEISMOTECTONIC ZONES BRANCH ..........................................................7-1

7.1 Approaches and Data Used to Define Seismotectonic Zones ........................................7-1

7.2 RLME Sources in the Seismotectonic Zones Branch......................................................7-4

7.3 Seismotectonic Source Zones.........................................................................................7-4

7.3.1 St. Lawrence Rift Zone (SLR) .................................................................................7-4

7.3.1.1 Background......................................................................................................7-5

7.3.1.2 Basis for Defining Seismotectonic Zone ........................................................7-11

7.3.1.3 Basis for Zone Geometry...............................................................................7-12

7.3.1.4 Basis for Zone Mmax.....................................................................................7-12

7.3.1.5 Future Earthquake Characteristics ................................................................7-13

7.3.2 Great Meteor Hotspot Zone (GMH) ......................................................................7-15

7.3.2.1 Background....................................................................................................7-16

7.3.2.2 Basis for Defining Seismotectonic Zone ........................................................7-18

7.3.2.3 Basis for Zone Geometry...............................................................................7-19

7.3.2.4 Basis for Zone Mmax.....................................................................................7-19

7.3.2.5 Future Earthquake Characteristics ................................................................7-20

7.3.3 Northern Appalachian Zone (NAP) .......................................................................7-21

7.3.3.1 Background....................................................................................................7-21

7.3.3.2 Basis for Defining Seismotectonic Zone ........................................................7-23

7.3.3.3 Basis for Zone Geometry...............................................................................7-24

7.3.3.4 Basis for Zone Mmax.....................................................................................7-24

7.3.3.5 Future Earthquake Characteristics ................................................................7-25

7.3.4 Paleozoic Extended Crust (PEZ)...........................................................................7-25

7.3.4.1 Background....................................................................................................7-26

7.3.4.2 Basis for Defining Seismotectonic Zone ........................................................7-32

7.3.4.3 Basis for Zone Geometry...............................................................................7-33

7.3.4.4 Basis for Zone Mmax.....................................................................................7-34

7.3.4.5 Future Earthquake Characteristics ...............................................................7-36

7.3.5 Ilinois Basin Extended Basement Zone (IBEB) .....................................................7-37

7.3.5.1 Background....................................................................................................7-38

7.3.5.2 Basis for Defining Seismotectonic Zone ........................................................7-38

7.3.5.3 Basis for Zone Geometry...............................................................................7-40

7.3.5.4 Basis for Zone Mmax.....................................................................................7-41

7.3.5.5 Future Earthquake Characteristics ................................................................7-41

7.3.6 Reelfoot Rift Zone (RR).........................................................................................7-42
xviii

7.3.6.1 Background....................................................................................................7-42

7.3.6.2 Basis for Defining Seismotectonic Zone ........................................................7-46

7.3.6.3 Basis for Zone Geometry...............................................................................7-46

7.3.6.4 Basis for Zone Mmax.....................................................................................7-47

7.3.6.5 Future Earthquake Characteristics ................................................................7-48

7.3.7 Extended Continental Crust–Atlantic Margin Zone (ECC-AM) ..............................7-48

7.3.7.1 Background....................................................................................................7-49

7.3.7.2 Basis for Defining Seismotectonic Zone ........................................................7-53

7.3.7.3 Basis for Geometry ........................................................................................7-54

7.3.7.4 Basis for Mmax ..............................................................................................7-54

7.3.7.5 Future Earthquake Characteristics ................................................................7-55

7.3.8 Atlantic Highly Extended Crust Zone (AHEX)........................................................7-55

7.3.8.1 Basis for Defining Seismotectonic Zone ........................................................7-56

7.3.8.2 Basis for Geometry ........................................................................................7-57

7.3.8.3 Basis for Mmax ..............................................................................................7-57

7.3.8.4 Future Earthquake Characteristics ................................................................7-57

7.3.9 Extended Continental Crust–Gulf Coast Zone (ECC-GC).....................................7-58

7.3.9.1 Basis for Defining Seismotectonic Zone ........................................................7-58

7.3.9.2 Basis for Zone Geometry...............................................................................7-59

7.3.9.3 Basis for Zone Mmax.....................................................................................7-62

7.3.9.4 Future Earthquake Characteristics ................................................................7-63

7.3.9.5 Possible Paleoliquefaction Features in Arkansas, Louisiana, and 

Mississippi .................................................................................................................7-64

7.3.10 Gulf Coast Highly Extended Crust Zone (GHEX)................................................7-65

7.3.10.1 Basis for Defining Seismotectonic Zone ......................................................7-66

7.3.10.2 Basis for Zone Geometry.............................................................................7-66

7.3.10.3 Basis for Zone Mmax...................................................................................7-66

7.3.10.4 Future Earthquake Characteristics ..............................................................7-67

7.3.11 Oklahoma Aulacogen Zone (OKA)......................................................................7-68

7.3.11.1 Basis for Defining Seismotectonic Zone ......................................................7-69

7.3.11.2 Basis for Zone Geometry.............................................................................7-69

7.3.11.3 Basis for Zone Mmax...................................................................................7-70

7.3.11.4 Future Earthquake Characteristics ..............................................................7-70

7.3.12 Midcontinent-Craton Zone (MidC) .......................................................................7-70

7.3.12.1 Background..................................................................................................7-71
xix

7.3.12.2 Basis for Defining Seismotectonic Zone ......................................................7-76

7.3.12.3 Basis for Zone Geometry.............................................................................7-77

7.3.12.4 Basis for Zone Mmax...................................................................................7-77

7.3.12.5 Future Earthquake Characteristics ..............................................................7-77

7.4 Maximum Magnitude Distributions for Seismotectonic Distributed Seismicity 

Sources ...............................................................................................................................7-78

7.4.1 Maximum Observed Earthquake Magnitude .........................................................7-78

7.4.2 Mmax Distributions ................................................................................................7-79

7.5 Recurrence Parameters ................................................................................................7-80

7.5.1 Rate and b-Value Maps for Single Zone and Two Zones......................................7-80

7.5.2 Comparison of Recurrence Parameters to Catalog...............................................7-80

8 DEMONSTRATION HAZARD CALCULATIONS...................................................................8-1

8.1 Background on Demonstration Hazard Calculations.......................................................8-1

8.2 Demonstration Hazard Calculations................................................................................8-2

8.2.1 Central Illinois Site...................................................................................................8-4

8.2.2 Chattanooga Site.....................................................................................................8-5

8.2.3 Houston Site............................................................................................................8-6

8.2.4 Jackson Site ............................................................................................................8-7

8.2.5 Manchester Site.......................................................................................................8-9

8.2.6 Savannah Site .........................................................................................................8-9

8.2.7 Topeka Site ...........................................................................................................8-10

9 USE OF THE CEUS SSC MODEL IN PSHA .........................................................................9-1

9.1 Overview .........................................................................................................................9-1

9.2 Hazard Input Document (HID).........................................................................................9-2

9.3 Implementation Instructions ............................................................................................9-2

9.3.1 Simplifications to Seismic Sources..........................................................................9-2

9.3.1.1 Charleston RLME.............................................................................................9-3

9.3.1.2 Charlevoix RLME.............................................................................................9-3

9.3.1.3 Cheraw RLME .................................................................................................9-4

9.3.1.4 Commerce Fault Zone RLME ..........................................................................9-5

9.3.1.5 Eastern Rift Margin North RLME .....................................................................9-5

9.3.1.6 Eastern Rift Margin South RLME.....................................................................9-5

9.3.1.7 Marianna RLME...............................................................................................9-6

9.3.1.8 Meers RLME....................................................................................................9-6
xx

9.3.1.9 New Madrid Fault System RLME.....................................................................9-7

9.3.1.10 Wabash Valley RLME....................................................................................9-7

9.3.1.11 Background Sources......................................................................................9-8

9.3.2 Accessing the SSC Model and Components from the Website ..............................9-8

9.3.3 Accessing Project Databases..................................................................................9-9

9.3.4 Use of SSC Model with Site-Specific Refinements ...............................................9-10

9.4 Hazard Significance ......................................................................................................9-10

9.4.1 Data Available to Evaluate the Precision of Seismic Hazard Estimates................9-10

9.4.2 Observed Imprecision in Seismic Hazard Estimates.............................................9-11

9.4.2.1 Area Seismic Sources....................................................................................9-11

9.4.2.2 RLME Seismic Sources .................................................................................9-12

9.4.2.3 Ground Motion Equations ..............................................................................9-15

9.4.2.4 Site Response ...............................................................................................9-19

9.4.3 Conclusions on the Precision in Seismic Hazard Estimates .................................9-19

10 REFERENCES ...................................................................................................................10-1

11 GLOSSARY OF KEY TERMS............................................................................................11-1

A DESCRIPTION OF THE CEUS SSC PROJECT DATABASE ............................................. A-1

A.1 Data Sources ................................................................................................................. A-2

A.2 Project Database Design and Management .................................................................. A-3

A.3 Workflow and Data Assessment.................................................................................... A-3

A.3.1 Workflow ................................................................................................................ A-3

A.3.2 Digital Data............................................................................................................. A-4

A.3.3 Nondigital Data ...................................................................................................... A-4

A.4 Use of Project Database in Model Development .......................................................... A-5

A.5 Metadata........................................................................................................................ A-5

A.6 Database Delivery Format ............................................................................................. A-6

B EARTHQUAKE CATALOG DATABASE ............................................................................. B-1

B.1 CEUS SSC Uniform Moment Magnitude Earthquake Catalog ...................................... B-1

B.2 Moment Magnitude Data................................................................................................ B-2

B.3 Approximate Moment Magnitude Data .......................................................................... B-3

B.4 CEUS SSC Project Data................................................................................................ B-3
xxi 

C DATA EVALUATION TABLES ............................................................................................. C-1 

Introduction .......................................................................................................................... C-2 

D DATA SUMMARY TABLES ................................................................................................. D-1 

Introduction .......................................................................................................................... D-2 

E CEUS PALEOLIQUEFACTION DATABASE, UNCERTAINTIES ASSOCIATED WITH 

PALEOLIQUEFACTION DATA, AND GUIDANCE FOR SEISMIC SOURCE 

CHARACTERIZATION.............................................................................................................. E-i

E.1 Development of the Paleoliquefaction Database........................................................... E-1 

E.1.1 Database Structure ................................................................................................ E-1 

E.1.2 Regional Data Sets ................................................................................................ E-4 

E.2 Uncertainties Associated with Paleoliquefaction Data ................................................ E-24

E.2.1 Collection of Paleoliquefaction Data ................................................................... E-24

E.2.2 Uncertainties Related to Interpretation of Paleoliquefaction Data........................ E-35

E.2.3 Recommendations for Future Research .............................................................. E-43 

 E.3 Guidance for the Use of Paleoliquefaction Data in Seismic Source

Characterization...................................................................................................................... E-44

E.4 Glossary....................................................................................................................... E-46

E.5 References .................................................................................................................. E-49

E.5.1 References Cited in Paleoliquefaction Database ................................................ E-49

E.5.2 References Cited in Appendix E .......................................................................... E-54

F WORKSHOP SUMMARIES ................................................................................................... F-1 

WORKSHOP 1: KEY ISSUES AND AVAILABLE DATA

DAY 1–TUESDAY, JULY 22, 2008 ....................................................................................... F-1 

DAY 2–WEDNESDAY, JULY 23, 2008............................................................................... F-10

REFERENCES .................................................................................................................... F-17

WORKSHOP 2: ALTERNATIVE INTERPRETATIONS

DAY 1–WEDNESDAY, FEBRUARY 18, 2009 .....................................................................F18

DAY 2–THURSDAY, FEBRUARY 19, 2009........................................................................ F-24

DAY 3–FRIDAY, FEBRUARY 20, 2009 .............................................................................. F-29

REFERENCES .................................................................................................................. F-34

WORKSHOP 3: FEEDBACK

DAY 1–TUESDAY, AUGUST 25, 2009............................................................................... F-42

DAY 2–WEDNESDAY, AUGUST 26, 2009......................................................................... F-49
xxii

G BIOGRAPHIES OF PROJECT TEAM..................................................................................G-1

EPRI MANAGEMENT ..........................................................................................................G-2

PROJECT MANAGER .........................................................................................................G-2

TI TEAM ...............................................................................................................................G-3

TECHNICAL SUPPORT.......................................................................................................G-7

DATABASE MANAGER.......................................................................................................G-9

PARTICIPATORY PEER REVIEW PANEL..........................................................................G-9

SPONSOR REVIEWERS...................................................................................................G-14

H CEUS SSC MODEL HAZARD INPUT DOCUMENT (HID)................................................... H-1

H.1 Introduction.................................................................................................................... H-1

H.2 Seismic Source Model Structure and Master Logic Tree .............................................. H-1

H.3 Mmax Zones Distributed Seismicity Sources ................................................................ H-2

H.3.1 Division of Study Region ....................................................................................... H-2

H.3.2 Location of Boundary of Mesozoic Extension ....................................................... H-2

H.3.3 Magnitude Interval Weights for Fitting Earthquake Occurrence Parameters ........ H-2

H.3.4 Mmax Zones ......................................................................................................... H-2

H.3.5 Seismogenic Crustal Thickness ............................................................................ H-2

H.3.6 Future Earthquake Rupture Characteristics .......................................................... H-3

H.3.7 Assessment of Seismicity Rates ........................................................................... H-3

H.3.8 Degree of Smoothing Applied in Defining Spatial Smoothing of Seismicity 

Rates ............................................................................................................................... H-3

H.3.9 Uncertainty in Earthquake Recurrence Rates........................................................ H-3

H.3.10 Uncertainty in Maximum Magnitude..................................................................... H-4

H.4 Seismotectonic Zones ................................................................................................... H-4

H.4.1 Alternative Zonation Models .................................................................................. H-4

H.4.2 Magnitude Interval Weights for Fitting Earthquake Occurrence Parameters ......... H-4

H.4.3 Seismotectonic Zones............................................................................................ H-5

H.4.4 Seismogenic Crustal Thickness............................................................................. H-5

H.4.5 Future Earthquake Rupture Characteristics .......................................................... H-5

H.4.6 Assessment of Seismicity Rates ........................................................................... H-5

H.4.7 Degree of Smoothing Applied in Defining Spatial Smoothing of Seismicity 

Rates .............................................................................................................................. H-5

H.4.8 Uncertainty in Earthquake Recurrence Rates ....................................................... H-5

H.4.9 Uncertainty in Maximum Magnitude ...................................................................... H-6

H.5 RLME Sources ....................................................................................................H-6
xxiii

H.5.1 Charlevoix RLME Seismic Source Model ............................................................. H-6

H.5.2 Charleston RLME Seismic Source Model.............................................................. H-7

H.5.3 Cheraw RLME Seismic Source Model................................................................... H-9

H.5.4 Meers RLME Seismic Source Model ................................................................... H-11

H.5.5 New Madrid Fault System RLME Seismic Source Model .................................... H-12

H.5.6 Eastern Rift Margin Fault RLME Seismic Source Model ..................................... H-14

H.5.7 Marianna Zone RLME Seismic Source Model ..................................................... H-15

H.5.8 Commerce Fault RLME Seismic Source Model................................................... H-16

H.5.9 Wabash Valley RLME Seismic Source Model ..................................................... H-18

I PPRP REVIEW COMMENTS...................................................................................................I-1

CORRESPONDENCE—CONTENTS ....................................................................................I-3

Participatory Peer Review Panel (PPRP) Letters..............................................................I-3

Technical Integration (TI) Team and Project Manager (PM) Response to PPRP 

Letters................................................................................................................................I-4

J MAGNITUDE-RECURRENCE MAPS FOR ALL REALIZATIONS AND ALL 

SOURCE-ZONE CONFIGURATIONS.......................................................................................J-1

K SCR DATABASE USED TO DEVELOP MMAX PRIOR DISTRIBUTIONS ......................... K-1

K.1 SCR Earthquake Catalog............................................................................................... K-1

K.2 SCR Crustal Domains.................................................................................................... K-3

L QUALITY ASSURANCE ........................................................................................................L-1

L.1 BACKGROUND...............................................................................................................L-1

L.2 CEUS SSC PROJECT ....................................................................................................L-2

L.2.1 Introduction..............................................................................................................L-2

L.3 BEST BUSINESS PRACTICES ......................................................................................L-3

L.3.1 General....................................................................................................................L-3

L.4 CEUS SSC EARTHQUAKE CATALOG DEVELOPMENT..............................................L-3

L.4.1 External Review of Earthquake Catalog..................................................................L-3

L.4.2 Simulation Testing...................................................................................................L-4

L.4.3 Checks for Consistency in Magnitude Conversion from Intensity ...........................L-4

L.4.4 Use of Verified Computer Programs........................................................................L-4

L.5 RECURRENCE ANALYSIS AND SPATIAL SMOOTHING.............................................L-4

L.5.1 Introduction..............................................................................................................L-4

L.5.2 Recurrence Comparisons at the Source-Zone Level ..............................................L-5
xxiv

L.5.3 Recurrence Comparisons for Portions of a Source Zone .......................................L-5

L.5.4 Examination of Recurrence Maps ..........................................................................L-5

L.5.5 Test with a Synthetic Catalog Homogeneous Seismicity .......................................L-5

L.5.6 Test for the Adequacy of Eight Maps to Represent Epistemic Uncertainty .............L-6

L.6 HAZARD CALCULATION SOFTWARE..........................................................................L-6

L.6.1 Introduction..............................................................................................................L-6

L.6.2 Test for the Treatment of Variable b........................................................................L-6

L.6.3 Test for the Treatment of Dipping Ruptures Within a Source Zone.........................L-6

L.6.4 Tests for Treatment of Epistemic Uncertainty from Sources that Make Small 

Contribution to Hazard......................................................................................................L-6
xxv

LIST OF FIGURES

Figure 1.3-1 Map showing the study area and test sites for the CEUS SSC Project...............1-15

Figure 2.3-1 CEUS SSC Project organization .........................................................................2-33

Figure 2.3-2 Lines of communication among the participants of the CEUS SSC Project........2-34

Figure 2.4-1 Essential activities associated with a SSHAC Level 3 or 4 project 

(Coppersmith et al., 2010)................................................................................................2-35

Figure 3.2-1 Areal coverage of the primary earthquake catalog sources. Top: GSC 

catalog (Halchuk, 2009); bottom: USGS seismic hazard mapping catalog (Petersen 

et al., 2008). Red line denotes boundary of study region. Blue line denotes portion 

of each catalog used for development of project catalog.................................................3-57

Figure 3.2-2 Histogram of ML magnitudes from the GSC SHEEF catalog for the time 

period 1600-1899 and the region east of longitude –105° and south of latitude 53° .......3-58

Figure 3.2-3 Histogram of ML magnitudes from the GSC SHEEF catalog for the time 

period 1900-1929 and the region east of longitude –105° and south of latitude 53° .......3-59

Figure 3.2-4 Histogram of ML magnitudes from the GSC SHEEF catalog for the time 

period 1930-1979 and the region east of longitude –105° and south of latitude 53° .......3-60

Figure 3.2-5 Histogram of ML magnitudes from the GSC SHEEF catalog for the time 

period 1980-2007 and the region east of longitude –105° and south of latitude 53° .......3-61

Figure 3.2-6 Histogram of ML magnitudes from the revised catalog with GSC as the 

source for the time period 1928-1979 ..............................................................................3-62

Figure 3.2-7 Map of the CEUS SSC Project catalog showing earthquakes of uniform 

moment magnitude E[M] 2.9 and larger. Colored symbols denote earthquakes not 

contained in the USGS seismic hazard mapping catalog. ...............................................3-63

Figure 3.3-1 Illustration of equivalence of the M* and γ2 corrections to remove bias in 

earthquake recurrence relationships estimated from magnitudes with uncertainty .........3-64

Figure 3.3-2 Approximate moment magnitudes from Atkinson (2004b) compared to 

values of M given in Table B-2 in Appendix B for earthquakes in common .....................3-65

Figure 3.3-3 Approximate moment magnitudes from Boatwright (1994) compared to 

values of M given in Table B-2 in Appendix B for earthquakes in common .....................3-66

Figure 3.3-4 Approximate moment magnitudes from Moulis (2002) compared to values 

of M given in Table B-2 in Appendix B for earthquakes in common.................................3-67

Figure 3.3-5 Difference between MN reported by the GSC and MN or mLg(f) reported by 

the Weston Observatory catalog as a function of time.....................................................3-68

Figure 3.3-6 Spatial distribution of earthquakes with body-wave (mb, mbLg, MN) and M 

magnitudes in the CEUS SSC Project catalog for the Midcontinent region. Color 

codes indicate the source of the body-wave magnitudes.................................................3-69

Figure 3.3-7 mb-M data for the earthquakes shown on Figure 3.3-6. Red curve shows the 

preferred offset fit M = mb – 0.28......................................................................................3-70
xxvi

Figure 3.3-8 Residuals from offset fit shown on Figure 3.3-7 plotted against earthquake 

year ..................................................................................................................................3-71

Figure 3.3-9 Spatial distribution of earthquakes with body wave (mb, mbLg, MN) and M 

magnitudes in the CEUS SSC Project catalog for the northeastern portion of the 

study region. Color codes indicate the source of the body-wave magnitudes. ................3-72

Figure 3.3-10 mb-M data for the earthquakes shown on Figure 3.3-9. Red curve shows 

the preferred offset fit M = mb – 0.42................................................................................3-73

Figure 3.3-11 Residuals from offset fit shown on Figure 3.3-10 plotted against 

earthquake year ...............................................................................................................3-74

Figure 3.3-12 Residuals for GSC data from offset fit shown on Figure 3.3-10 plotted 

against earthquake year...................................................................................................3-75

Figure 3.3-13 Residuals for WES data from offset fit shown on Figure 3.3-10 plotted 

against earthquake year...................................................................................................3-76

Figure 3.3-14 Residuals for data from sources other than GSC or WES from offset fit 

shown on Figure 3.3-10 plotted against earthquake year................................................3-77

Figure 3.3-15 Difference between body-wave magnitudes reported by LDO and those by 

other sources as a function of year..................................................................................3-78

Figure 3.3-16 Spatial distribution of earthquakes with reported GSC body-wave 

magnitudes. Red and blue symbols indicate earthquakes with both mb and M 

magnitudes for mb ≥ 3.5. Dashed line indicates the portion of the study region 

considered the “Northeast” for purposes of magnitude scaling........................................3-79

Figure 3.3-17 M-mb as a function of time for mb data from the GSC shown on Figure 3.3-

16 .....................................................................................................................................3-80

Figure 3.3-18 Plot of magnitude differences mbLg – m(3 Hz) for the OKO catalog...................3-81

Figure 3.3-19 Final mb-M data set. Vertical dashed lines indicate the magnitude range 

used to develop the scaling relationship. Diagonal line indicates a one-to-one 

correlation. .......................................................................................................................3-82

Figure 3.3-20 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

instrumental ML magnitudes.............................................................................................3-83

Figure 3.3-21 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

instrumental ML magnitudes and M magnitudes ..............................................................3-84

Figure 3.3-22 ML-M data from the CEUS SSC Project catalog and robust regression fit to 

the data ............................................................................................................................3-85

Figure 3.3-23 Relationship between MN and ML for the GSC data ..........................................3-86

Figure 3.3-24 Data from the northeastern portion of the study region with ML and MC or 

MD magnitude from catalog sources other than the GSC ................................................3-87

Figure 3.3-25 Data from the northeastern portion of the study region with ML and M 

magnitudes from sources other than the GSC.................................................................3-88

Figure 3.3-26 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

MS ≥ 3 magnitudes ...........................................................................................................3-89

Figure 3.3-27 MS-M data from the CEUS SSC Project catalog and quadratic polynomial 

fit to the data ....................................................................................................................3-90

Figure 3.3-28 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

MC ≥ 2.5 magnitudes ........................................................................................................3-91
xxvii

Figure 3.3-29 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

MC ≥ 2.5 and M magnitudes .............................................................................................3-92

Figure 3.3-30 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

MD ≥ 3 magnitudes ...........................................................................................................3-93

Figure 3.3-31 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

both MD and M magnitudes ..............................................................................................3-94

Figure 3.3-32 MC-M data from the CEUS SSC Project catalog and linear regression fit to 

the data ............................................................................................................................3-95

Figure 3.3-33 Spatial distribution of earthquakes with reported MC and MD magnitudes.........3-96

Figure 3.3-34 Comparison of MC and MD magnitudes for the LDO and WES catalogs ...........3-97

Figure 3.3-35 Comparison of MC with MD for at least one of the two magnitude types 

reported in the OKO catalog ............................................................................................3-98

Figure 3.3-36 Comparison of MC with MD for at least one of the two magnitude types 

reported in the CERI catalog............................................................................................3-99

Figure 3.3-37 Comparison of MC with MD for at least one of the two magnitude types 

reported in the SCSN catalog ........................................................................................3-100

Figure 3.3-38 Comparison of MC with MD for at least one of the two magnitude types 

reported in other catalogs for earthquakes in the Midcontinent portion of the study 

region .............................................................................................................................3-101

Figure 3.3-39 Relationship between M and MC, MD, or ML for the Midcontinent portion of 

the study region..............................................................................................................3-102

Figure 3.3-40 Comparison of MC and MD magnitudes with ML magnitudes for the region 

between longitudes 105°W and 100°W..........................................................................3-103

Figure 3.3-41 Comparison of mb magnitudes with ML magnitudes for the region between 

longitudes 105°W and 100°W ........................................................................................3-104

Figure 3.3-42 Comparison of mb magnitudes with MC and MD magnitudes for the region 

between longitudes 105°W and 100°W..........................................................................3-105

Figure 3.3-43 Spatial distribution of earthquake with ln(FA) in the CEUS SSC Project 

catalog............................................................................................................................3-106

Figure 3.3-44 Catalog ln(FA)–M data and fitted model..........................................................3-107

Figure 3.3-45 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

reported values of I0 .......................................................................................................3-108

Figure 3.3-46 I0 and M data for earthquakes in the CEUS SSC Project catalog. Curves 

show locally weighted least-squares fit (Loess) to the data and the relationship 

published by Johnston (1996b). .....................................................................................3-109

Figure 3.3-47 I0 and mb data from the NCEER91 catalog. Plotted are the relationships 

between I0 and mb developed by EPRI (1988) (EPRI-SOG) and Sibol et al. (1987)......3-110

Figure 3.3-48 Categorical model fits of I0 as a function and M for earthquakes in the 

CEUS SSC Project catalog ............................................................................................3-111

Figure 3.3-49 Results from proportional odds logistic model showing the probability of 

individual intensity classes as a function of M................................................................3-112

Figure 3.3-50 Comparison of I0 and mb data from the CEUS SSC Project catalog for 

those earthquakes with reported values of M (M set) and the full catalog (full set). 

Locally weighted least-squares fits to the two data sets are shown along with the 
xxviii

relationship use to develop the EPRI (1988) catalog and the Sibol et al. (1987) 

relationship used in the NCEER91 catalog. ...................................................................3-113

Figure 3.3-51 Linear fits to the data from Figure 3.3-50 for I0 ≥ V..........................................3-114

Figure 3.3-52 Comparison of I0 and mb data from the project, with mb adjusted for the 

difference in mb to M scaling .........................................................................................3-115

Figure 3.3-53 Linear fits to the data from Figure 3.3-52 for I0 ≥ V..........................................3-116

Figure 3.3-54 Composite I0–M data set used for assessment of I0 scaling relationship ........3-117

Figure 3.3-55 Linear and inverse sigmoid models fit to the project data for I0 > IV................3-118

Figure 3.4-1 Illustration of process used to identify clusters of earthquakes (from EPRI, 

1988, Vol. 1): (a) local and extended time and distance windows, (b) buffer window, 

and (c) contracted window .............................................................................................3-119

Figure 3.4-2 Identification of secondary (dependent) earthquakes inside the cluster 

region through Poisson thinning (from EPRI, 1988, Vol. 1)............................................3-120

Figure 3.4-3 Comparison of dependent event time and distance windows with results for 

individual clusters in the project catalog.........................................................................3-121

Figure 3.5-1 Earthquake catalog and catalog completeness regions used in EPRI-SOG 

(EPRI, 1988) ..................................................................................................................3-122

Figure 3.5-2 CEUS SSC Project earthquake catalog and modified catalog completeness 

regions ...........................................................................................................................3-123

Figure 3.5-3 Plot of year versus location for the CEUS SSC Project earthquake catalog. 

Red lines indicate the boundaries of the catalog completeness time periods................3-124

Figure 3.5-4 (1 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-125

Figure 3.5-4 (2 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-126

Figure 3.5-4 (3 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-127

Figure 3.5-4 (4 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-128

Figure 3.5-4 (5 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-129

Figure 3.5-4 (6 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-130

Figure 3.5-4 (7 of 7) “Stepp” plots of earthquake recurrence rate as a function of time for 

the individual catalog completeness regions shown on Figure 3.5-2.............................3-131

Figure 4.1.1-1 Example logic tree from the PEGASOS project (NAGRA, 2004) showing 

the assessment of alternative conceptual models on the logic tree. Each node of 

the logic tree represents an assessment that is uncertain. Alternative branches 

represent the alternative models or parameter values, and the weights associated 

with each branch reflect the TI Team’s relative degree of belief that each branch is 

the correct model or parameter value. .............................................................................4-40

Figure 4.1.1-2 Example logic tree from the PVHA-U (SNL, 2008) project showing the 

treatment of alternative conceptual models in the logic tree ............................................4-41
xxix

Figure 4.2.1-1 Master logic tree showing the Mmax zones and seismotectonic zones 

alternative conceptual models for assessing the spatial and temporal characteristics 

of future earthquake sources in the CEUS.......................................................................4-42

Figure 4.2.2-1 Example of a logic tree for RLME sources. Shown is the tree for the 

Marianna RLME source. ..................................................................................................4-43

Figure 4.2.2-2 Map showing RLME sources, some with alternative source geometries 

(discussed in Section 6.1). ...............................................................................................4-44

Figure 4.2.3-1 Logic tree for the Mmax zones branch of the master logic tree........................4-45

Figure 4.2.3-2 Subdivision used in the Mmax zones branch of the master logic tree. 

Either the region is considered one zone for purposes of Mmax or the region is 

divided into two zones as shown: a Mesozoic-and-younger extension (MESE) zone 

and a non-Mesozoic-and-younger zone (NMESE). In this figure the “narrow” MESE 

zone is shown ..................................................................................................................4-46

Figure 4.2.3-3 Subdivision used in the Mmax zones branch of the master logic tree. 

Either the region is considered one zone for purposes of Mmax or the region is 

divided into two zones as shown: a Mesozoic-and-younger extension (MESE) zone 

and a non-Mesozoic-and-younger zone (NMESE). In this figure the “wide” MESE 

zone is shown ..................................................................................................................4-47

Figure 4.2.4-1(a) Logic tree for the seismotectonic zones branch of the master logic tree .....4-48

Figure 4.2.4-1(b) Logic tree for the seismotectonic zones branch of the master logic tree .....4-49

Figure 4.2.4-2 Seismotectonic zones shown in the case where the Rough Creek Graben 

is not part of the Reelfoot Rift (RR), and the Paleozoic Extended Zone is narrow 

(PEZ-N) ...........................................................................................................................4-50

Figure 4.2.4-3 Seismotectonic zones shown in the case where the Rough Creek Graben 

is part of the Reelfoot Rift (RR-RCG), and the Paleozoic Extended Zone is narrow 

(PEZ-N)............................................................................................................................4-51

Figure 4.2.4-4 Seismotectonic zones shown in the case where the Rough Creek Graben 

is not part of the Reelfoot Rift (RR), and the Paleozoic Extended Crust is wide 

(PEZ-W) ...........................................................................................................................4-52

Figure 4.2.4-5 Seismotectonic zones shown in the case where the Rough Creek Graben 

is part of the Reelfoot Rift (RR-RCG), and the Paleozoic Extended Crust is wide 

(PEZ-W) ...........................................................................................................................4-53

Figure 5.2.1-1 Diagrammatic illustration of the Bayesian Mmax approach showing (a) the 

prior distribution, (b) the likelihood function, and (c) the posterior distribution. The 

posterior distribution is represented by a discrete distribution (d) for implementation 

in hazard analysis. ...........................................................................................................5-72

Figure 5.2.1-2 Diagrammatic illustration of the Bayesian Mmax approach showing (a) the 

prior distribution, (b) the likelihood function, and (c) the posterior distribution. The 

posterior distribution is represented by a discrete distribution (d) for implementation 

in hazard analysis. ...........................................................................................................5-73

Figure 5.2.1-3 Median values of mmax−obs as a function of maximum magnitude, mu

, and 

sample size N, the number of earthquakes ≥ M 4.5.........................................................5-74

Figure 5.2.1-4 Histograms of mmax−obs for extended and non-extended superdomains ..........5-75
xxx

Figure 5.2.1-5 Histograms of mmax−obs for Mesozoic-and-younger extended (MESE) 

superdomains and for older extended and non-extended (NMESE) superdomains........5-76

Figure 5.2.1-6 Histograms of mmax−obs for Mesozoic-and-younger extended (MESE) 

superdomains and for older extended and non-extended (NMESE) superdomains 

using age of most recent extension for the age classification..........................................5-77

Figure 5.2.1-7 Histograms of mmax−obs for Mesozoic-and-younger extended (MESE) 

superdomains and for older extended and non-extended (NMESE) superdomains 

using final sets indicated by asterisks in Tables 5.2.1-1 and 5.2.1-2 ...............................5-78

Figure 5.2.1-8 Histograms of mmax−obs for combined (COMB) superdomains using final 

sets indicated by asterisks in Table 5.2.1-3 .....................................................................5-79

Figure 5.2.1-9 Bias adjustments from mmax−obs to mu for the three sets of superdomain 

analysis results presented in Table 5.2.1-4......................................................................5-80

Figure 5.2.1-10 Results of simulations of estimates of Mmax using the Bayesian 

approach for earthquake catalogs ranging in size from 1 to 1,000 earthquakes. True 

Mmax is set at the mean of the prior distribution..............................................................5-81

Figure 5.2.1-11 Comparison of the Kijko (2004) estimates of mu for given values of 

mmax−obs and N, the number of earthquakes of magnitude ≥ 4.5. Also shown is the 

median value of mmax−obs for given mu obtained using Equation 5.2.1-2..........................5-82

Figure 5.2.1-12 Behavior of the cumulative probability function for mu (Equation 5.2.1-9) 

for the K-S-B estimator and a value of mmax−obs equal to 6..............................................5-83

Figure 5.2.1-13 Example Mmax distribution assessed for the Mesozoic-and-younger 

extended Mmax zone for the case where the zone is “narrow” (MESE-N). 

Distributions are shown for the Kijko approach and for the Bayesian approach using 

either the Mesozoic-and-younger extended prior distribution or the composite prior 

distribution. The final composite Mmax distribution, which incorporates the relative 

weights, is shown by the red probability distribution. .......................................................5-84

Figure 5.2.1-14 Example Mmax distribution assessed for the Northern Appalachian 

seismotectonic zone (NAP). Distributions are shown for the Kijko approach and for 

the Bayesian approach using either the Mesozoic-and-younger extended prior 

distribution or the composite prior distribution. Note that the Kijko results are shown 

in this example for illustration, even though they have zero weight. The final 

composite Mmax distribution, which incorporates the relative weights, is shown by 

the red probability distribution. .........................................................................................5-85

Figure 5.3.2-1 Likelihood function for rate per unit area in a Poisson process, for multiple 

values of the earthquake count N: (a) arithmetic scale, and (b) logarithmic scale 

used to illustrate decreasing COV as N increases...........................................................5-86

Figure 5.3.2-2 Likelihood function for b-value of an exponential magnitude distribution, 

for multiple values of the earthquake count N. The value of b is normalized by the 

maximum-likelihood estimate, which is derived from Equation 5.3.2-5............................5-87

Figure 5.3.2-3 Histogram of magnitudes in the earthquake catalog used in this section. 

The minimum magnitude shown (M 2.9) is the lowest magnitude used in these 

recurrence calculations. ...................................................................................................5-88
xxxi

Figure 5.3.2-4 Objectively determined values of the penalty function for ln(rate) for Case 

A magnitude weights. Source zones are sorted from smallest to largest. See list of 

abbreviations for full source-zone names. .......................................................................5-89

Figure 5.3.2-5 Objectively determined values of the penalty function for beta for Case A 

magnitude weights ...........................................................................................................5-90

Figure 5.3.2-6 Objectively determined values of the penalty function for ln(rate) for Case 

B magnitude weights........................................................................................................5-91

Figure 5.3.2-7 Objectively determined values of the penalty function for beta for Case B 

magnitude weights. Source zones are sorted from smallest to largest............................5-92

Figure 5.3.2-8 Objectively determined values of the penalty function for ln(rate) for Case 

E magnitude weights........................................................................................................5-93

Figure 5.3.2-9 Objectively determined values of the penalty function for beta for Case E 

magnitude weights. Source zones are sorted from smallest to largest............................5-94

Figure 5.3.2-10 Mean map of rate and b-value for ECC-AM calculated using Case A 

magnitude weights ...........................................................................................................5-95

Figure 5.3.2-11 Mean map of rate and b-value for ECC-GC calculated using Case A 

magnitude weights ...........................................................................................................5-96

Figure 5.3.2-12 Mean map of rate and b-value for ECC-AM calculated using Case B 

magnitude weights ...........................................................................................................5-97

Figure 5.3.2-13 Mean map of rate and b-value for ECC-GC calculated using Case B 

magnitude weights ...........................................................................................................5-98

Figure 5.3.2-14 Mean map of rate and b-value for ECC-AM calculated using Case E 

magnitude weights ...........................................................................................................5-99

Figure 5.3.2-15 Mean map of rate and b-value for ECC-GC calculated using Case E 

magnitude weights .........................................................................................................5-100

Figure 5.3.2-16 Sensitivity of seismic hazard at Manchester site to the strength of the 

prior on b ........................................................................................................................5-101

Figure 5.3.2-17 Sensitivity of seismic hazard at Topeka site to the strength of the prior 

on b ................................................................................................................................5-102

Figure 5.3.2-18 Sensitivity of seismic hazard at Manchester site to the choice of 

magnitude weights .........................................................................................................5-103

Figure 5.3.2-19 Sensitivity of seismic hazard at Topeka site to the choice of magnitude 

weights ...........................................................................................................................5-104

Figure 5.3.2-20 Sensitivity of seismic hazard from source NAP at Manchester site to the 

eight alternative recurrence maps for Case B magnitude weights.................................5-105

Figure 5.3.2-21 Sensitivity of seismic hazard from source MID-C–A at Topeka site to the 

eight alternative recurrence maps for Case B magnitude weights.................................5-106

Figure 5.3.2-22 Mean recurrence-parameter map for the study region under the highest 

weighted source-zone configuration in the master logic tree. See Sections 6.3 and 

7.5 for all mean maps.....................................................................................................5-107

Figure 5.3.2-23 Map of the uncertainty in the estimated recurrence parameters, 

expressed as the coefficient of variation of the rate (left) and the standard deviation 

of the b-value (right) for the study region, under the highest weighted source-zone 

configuration in the master logic tree. See Appendix J for all maps of uncertainty........5-108
xxxii

Figure 5.3.2-24 First of eight equally likely realizations of the recurrence-parameter map 

for the study region under the highest weighted source-zone configuration in the 

master logic tree. See Appendix J for maps of all realizations for all source-zone 

configurations.................................................................................................................5-109

Figure 5.3.2-25 Eighth of eight equally likely realizations of the recurrence-parameter 

map for the study region under the highest weighted source-zone configuration in 

the master logic tree. See Appendix J for maps of all realizations for all source-zone 

configurations.................................................................................................................5-110

Figure 5.3.2-26 Map of geographic areas considered in the exploration of model results.....5-111

Figure 5.3.2-27 Comparison of model-predicted earthquake counts for the USGS 

Eastern Tennessee area using Case A magnitude weights. The error bars 

represent the 16%–84% uncertainty associated with the data, computed using the 

Weichert (1980) procedure. ...........................................................................................5-112

Figure 5.3.2-28 Comparison of model-predicted earthquake counts for the USGS 

Eastern Tennessee area using Case B magnitude weights...........................................5-113

Figure 5.3.2-29 Comparison of model-predicted earthquake counts for the USGS 

Eastern Tennessee area using Case E magnitude weights...........................................5-114

Figure 5.3.2-30 Comparison of model-predicted earthquake counts for the central New 

England area using Case A magnitude weights ............................................................5-115

Figure 5.3.2-31 Comparison of model-predicted earthquake counts for the central New 

England area using Case B magnitude weights ............................................................5-116

Figure 5.3.2-32 Comparison of model-predicted earthquake counts for the central New 

England area using Case E magnitude weights ............................................................5-117

Figure 5.3.2-33 Comparison of model-predicted earthquake counts for the Nemaha 

Ridge area using Case A magnitude weights ................................................................5-118

Figure 5.3.2-34 Comparison of model-predicted earthquake counts for the Nemaha 

Ridge area using Case B magnitude weights ................................................................5-119

Figure 5.3.2-35 Comparison of model-predicted earthquake counts for the Nemaha 

Ridge area using Case E magnitude weights ................................................................5-120

Figure 5.3.2-36 Comparison of model-predicted earthquake counts for the Miami, FL, 

area using Case A magnitude weights...........................................................................5-121

Figure 5.3.2-37 Comparison of model-predicted earthquake counts for the Miami, FL, 

area using Case B magnitude weights...........................................................................5-122

Figure 5.3.2-38 Comparison of model-predicted earthquake counts for the Miami, FL, 

area using Case E magnitude weights...........................................................................5-123

Figure 5.3.2-39 Comparison of model-predicted earthquake counts for the St. Paul, MN, 

area using Case A magnitude weights...........................................................................5-124

Figure 5.3.2-40 Comparison of model-predicted earthquake counts for the St. Paul, MN, 

area using Case B magnitude weights...........................................................................5-125

Figure 5.3.2-41 Comparison of model-predicted earthquake counts for the St. Paul, MN, 

area using Case E magnitude weights...........................................................................5-126

Figure 5.3.2-42 Recurrence parameters for the ECC-AM, MID-C–A, and NAP 

seismotectonic source zones and Case A magnitude weights computed using an 

objective adaptive kernel approach................................................................................5-127
xxxiii

Figure 5.3.3-1 Likelihood distribution for rate parameter λ derived using Equation 5.3.3-1 

for N = 2 and T = 2,000 years. Top: normalized probability density function for λ. 

Bottom: resulting cumulative distribution function. Dashed lines show the 

cumulative probability levels for the Miller and Rice (1983) discrete approximation of 

a continuous probability distribution. ..............................................................................5-128

Figure 5.3.3-2 Uncertainty distributions for the age of Charleston RLMEs............................5-129

Figure 5.4.4-1 Spatial distribution of earthquakes in the CEUS SSC Project catalog. 

Solid lines indicate the boundaries of the seismotectonic source zones (narrow 

interpretation).................................................................................................................5-130

Figure 5.4.4-2 Spatial distribution of earthquakes in the CEUS SSC Project catalog with 

good quality depth determinations used for assessing crustal thickness. Solid lines 

indicate the boundaries of the seismotectonic source zones (narrow interpretation).....5-131

Figure 5.4.4-3 Distribution of better-quality focal depths in Mmax source zones...................5-132

Figure 5.4.4-4 (1 of 3) Distribution of better-quality focal depths in seismotectonic source 

zones..............................................................................................................................5-133

Figure 5.4.4-4 (2 of 3) Distribution of better-quality focal depths in seismotectonic source 

zones..............................................................................................................................5-134

Figure 5.4.4-4 (3 of 3) Distribution of better-quality focal depths in seismotectonic source 

zones..............................................................................................................................5-135

Figure 6.1-1 Map showing the RLME sources characterized in the CEUS SSC model. 

Detailed alternatives to the source geometries are shown on figures associated with 

each RLME discussion...................................................................................................6-111

Figure 6.1-2a Map showing the RLME sources and seismicity from the CEUS SSC 

earthquake catalog. Some of the RLMEs occur in regions of elevated seismicity, but 

others do not. .................................................................................................................6-112

Figure 6.1-2b Close-up of the Wabash Valley and New Madrid/Reelfoot Rift RLME 

sources and seismicity from the CEUS SSC earthquake catalog. Some of the 

RLMEs occur in regions of elevated seismicity, but others do not.................................6-113

Figure 6.1.1-1 Logic tree for the Charlevoix RLME source....................................................6-114

Figure 6.1.1-2 Seismicity and tectonic features of the Charlevoix RLME ..............................6-115

Figure 6.1.1-3 Magnetic and gravity anomaly maps of the Charlevoix RLME .......................6-116

Figure 6.1.2-1a Logic tree for the Charleston RLME source .................................................6-117

Figure 6.1.2-1b Logic tree for the Charleston RLME source .................................................6-118

Figure 6.1.2-2 Charleston RLME source zones with (a) total magnetic anomaly and (b) 

residual isostatic gravity data ......................................................................................6-119

Figure 6.1.2-3 Postulated faults and tectonic features in the Charleston region .................6-120

Figure 6.1.2-4 Postulated faults and tectonic features in the local Charleston area ............6-121

Figure 6.1.2-5a Postulated faults and tectonic features in the Charleston region with 

Charleston RLME source zones ...................................................................................6-122

Figure 6.1.2-5b Postulated faults and tectonic features in the local Charleston area with 

Charleston RLME source zones ....................................................................................6-123

Figure 6.1.2-6 Schematic diagram showing contemporary, maximum, and minimum 

constraining age sample locations .................................................................................6-124
xxxiv

Figure 6.1.2-7 Charleston space-time diagram of earthquakes interpreted from 

paleoliquefaction, contemporary-ages-only scenario ....................................................6-125

Figure 6.1.2-8 Charleston space-time diagram of earthquakes interpreted from 

paleoliquefaction, all-ages scenario .............................................................................6-126

Figure 6.1.2-9 Distribution of liquefaction from earthquake A, contemporary-ages-only 

scenario ........................................................................................................................6-127

Figure 6.1.2-10 Distribution of liquefaction from earthquake B, contemporary-ages-only 

scenario ........................................................................................................................6-128

Figure 6.1.2-11 Distribution of liquefaction from earthquake C, contemporary-ages-only 

scenario ........................................................................................................................6-129

Figure 6.1.2-12 Distribution of liquefaction from earthquake D, contemporary-ages-only 

scenario ........................................................................................................................6-130

Figure 6.1.2-13 Distribution of liquefaction from earthquake E, contemporary-ages-only 

scenario ........................................................................................................................6-131

Figure 6.1.2-14 Distribution of liquefaction from earthquake A, all-ages scenario ...............6-132

Figure 6.1.2-15 Distribution of liquefaction from earthquake B, all-ages scenario ...............6-133

Figure 6.1.2-16 Distribution of liquefaction from earthquake C, all-ages scenario ...............6-134

Figure 6.1.2-17 Distribution of liquefaction from earthquake D, all-ages scenario ...............6-135

Figure 6.1.2-18 Distribution of liquefaction from earthquake E, all-ages scenario.................6-136

Figure 6.1.2-19 Uncertainty distributions for the age of Charleston RLMEs..........................6-137

Figure 6.1.3-1 Logic tree for the Cheraw fault RLME source.................................................6-138

Figure 6.1.3-2 Map (c) and hillshade relief images (a, b, and d) showing location of 

mapped Cheraw fault, possible northeast extension, and paleoseismic locality............6-139

Figure 6.1.3-3 Cheraw RLME source relative to (a) total magnetic anomaly and (b) 

residual isostatic gravity data .........................................................................................6-140

Figure 6.1.4-1 Meers fault location ........................................................................................6-141

Figure 6.1.4-2 Logic tree for the Meers fault source ..............................................................6-142

Figure 6.1.5-1 Logic tree for the NMFS RLME source .........................................................6-143

Figure 6.1.5-2 Map showing seismicity and major subsurface structural features in the 

New Madrid region .......................................................................................................6-144

Figure 6.1.5-3 Map showing geomorphic and near-surface tectonic features in the New 

Madrid region and locations of NMFS RLME fault sources ..........................................6-145

Figure 6.1.5-4 Rupture segments (a) and models (b) for the New Madrid faults from 

Johnston and Schweig (1996) and (c) the NMFS RLME fault sources ........................6-146

Figure 6.1.5-5 Map of NMSZ showing estimated ages and measured sizes of 

liquefaction features .......................................................................................................6-147

Figure 6.1.5-6 Earthquake chronology for NMSZ from dating and correlation of 

liquefaction features at sites (listed at top) along N-S transect across region................6-148

Figure 6.1.5-7 Probability distributions for the age of the AD 900 and AD 1450 NMFS 

RLMEs ...........................................................................................................................6-149

Figure 6.1.5-8 Liquefaction fields for the 1811-1812, AD 1450, and AD 900 earthquakes 

as interpreted from spatial distribution and stratigraphy of sand blows..........................6-150
xxxv

Figure 6.1.6-1a Logic tree for the Reelfoot Rift–Eastern Rift Margin South RLME source. 

Two options for the southern extent of the ERM-S are considered: ERM-SCC 

includes the Crittenden County fault zone, and ERM-SRP includes the postulated 

zone of deformation based on fault picks identified in a high-resolution seismic 

profile along the Mississippi River..................................................................................6-151

Figure 6.1.6-1b Logic tree for the Reelfoot Rift–Eastern Rift Margin North RLME source.....6-152

Figure 6.1.6-2 Map showing structural features and paleoseismic investigation sites 

along the eastern margin of the Reelfoot rift. The inset map shows the locations of 

inferred basement faults that border and cross the Reelfoot rift (Csontos et al., 

2008) and the inferred Joiner Ridge–Meeman-Shelby fault (JR-MSF; Odum et al., 

2010). ............................................................................................................................6-153

Figure 6.1.6-3 Maps showing surficial geology and locations of subsurface investigations 

at (a) Meeman-Shelby Forest State Park locality and (b) Union City site (MSF and 

UC on Figure 6.1.6-2). Modified from Cox et al. (2006) and Odum et al. (2010). ..........6-154

Figure 6.1.6-4 Figure showing the timing of events along the eastern Reelfoot rift margin. 

Modified from Cox (2009)...............................................................................................6-155

Figure 6.1.7-1 Logic tree for the Reelfoot rift–Marianna RLME source .................................6-156

Figure 6.1.7-2 Map showing tectonic features and locations of paleoliquefaction sites in 

the vicinity of Marianna, Arkansas .................................................................................6-157

Figure 6.1.7-3 Map showing liquefaction features near Daytona Beach lineament 

southwest of Marianna, Arkansas ..................................................................................6-158

Figure 6.1.8-1 Logic tree for the Commerce Fault Zone RLME source .................................6-159

Figure 6.1.8-2 Map showing tectonic features, seismicity, and paleoseismic localities 

along the Commerce Fault Zone RLME source.............................................................6-160

Figure 6.1.8-3 Location of the Commerce geophysical lineament and Commerce Fault 

Zone RLME source relative to the (a) regional magnetic anomaly map and (b) 

regional gravity anomaly map ........................................................................................6-161

Figure 6.1.8-4 Space-time diagram showing constraints on the location and timing of late 

Pleistocene and Holocene paleoearthquakes that may be associated with the 

Commerce Fault Zone RLME source.............................................................................6-162

Figure 6.1.9-1 Logic tree for the Wabash Valley RLME source.............................................6-163

Figure 6.1.9-2 Map showing seismicity, subsurface structural features, paleoearthquake 

energy centers, and postulated neotectonic deformation in the Wabash Valley 

region of southern Illinois and southern Indiana ..........................................................6-164

Figure 6.1.9-3 Wabash Valley RLME source relative to (a) magnetic anomaly, and (b) 

residual isostatic gravity data .......................................................................................6-165

Figure 6.2-1 Map showing the two Mmax zones for the “narrow” interpretation of the 

Mesozoic-and-younger extended zone ..........................................................................6-166

Figure 6.2-2 Map showing the two Mmax zones for the “wide” interpretation of the 

Mesozoic-and-younger extended zone ..........................................................................6-167

Figure 6.3.1-1 Distributions for m max-obs for the Mmax distributed seismicity source zones ..6-168

Figure 6.3.2-1 Mmax distributions for the study region treated as a single Mmax zone........6-169

Figure 6.3.2-2 Mmax distributions for the MESE-N Mmax zone............................................6-170
xxxvi

Figure 6.3.2-3 Mmax distributions for the MESE-W Mmax zone ...........................................6-171

Figure 6.3.2-4 Mmax distributions for the NMESE-N Mmax zone .........................................6-172

Figure 6.3.2-5 Mmax distributions for the NMESE-W Mmax zone ........................................6-173

Figure 6.4.1-1 Mean map of rate and b-value for the study region under the source-zone 

configuration, with no separation of Mesozoic extended and non-extended; Case A 

magnitude weights .........................................................................................................6-174

Figure 6.4.1-2 Mean map of rate and b-value for the study region under the source-zone 

configuration, with no separation of Mesozoic extended and non-extended; Case B 

magnitude weights .........................................................................................................6-175

Figure 6.4.1-3 Mean map of rate and b-value for the study region under the source-zone 

configuration, with no separation of Mesozoic extended and non-extended; Case E 

magnitude weights .........................................................................................................6-176

Figure 6.4.1-4 Mean map of rate and b-value for the study region under the source-zone 

configuration, with separation of Mesozoic extended and non-extended, narrow 

geometry for MESE; Case A magnitude weights ...........................................................6-177

Figure 6.4.1-5 Mean map of rate and b-value for the study region under the source-zone 

configuration, with separation of Mesozoic extended and non-extended, narrow 

geometry for MESE; Case B magnitude weights ...........................................................6-178

Figure 6.4.1-6 Mean map of rate and b-value for the study region under the source-zone 

configuration, with separation of Mesozoic extended and non-extended, narrow 

geometry for MESE; Case E magnitude weights ...........................................................6-179

Figure 6.4.1-7 Mean map of rate and b-value for the study region under the source-zone 

configuration, with separation of Mesozoic extended and non-extended, wide 

geometry for MESE; Case A magnitude weights ...........................................................6-180

Figure 6.4.1-8 Mean map of rate and b-value for the study region under the source-zone 

configuration, with separation of Mesozoic extended and non-extended, wide 

geometry for MESE; Case B magnitude weights ...........................................................6-181

Figure 6.4.1-9 Mean map of rate and b-value for the study region under the source-zone 

configuration, with separation of Mesozoic extended and non-extended, wide 

geometry for MESE; Case E magnitude weights ...........................................................6-182

Figure 6.4.2-1 Comparison of model-predicted earthquake counts for study region using 

Case A magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-183

Figure 6.4.2-2 Comparison of model-predicted earthquake counts for study region using 

Case B magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-184

Figure 6.4.2-3 Comparison of model-predicted earthquake counts for study region using 

Case E magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-185

Figure 6.4.2-4 Comparison of model-predicted earthquake counts for MESE-N using 

Case A magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-186

Figure 6.4.2-5 Comparison of model-predicted earthquake counts for MESE-N using 

Case B magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-187
xxxvii

Figure 6.4.2-6 Comparison of model-predicted earthquake counts for MESE-N using 

Case E magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-188

Figure 6.4.2-7 Comparison of model-predicted earthquake counts for MESE-W using 

Case A magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-189

Figure 6.4.2-8 Comparison of model-predicted earthquake counts for MESE-W using 

Case B magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-190

Figure 6.4.2-9 Comparison of model-predicted earthquake counts for MESE-W using 

Case E magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-191

Figure 6.4.2-10 Comparison of model-predicted earthquake counts for NMESE-N using 

Case A magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-192

Figure 6.4.2-11 Comparison of model-predicted earthquake counts for NMESE-N using 

Case B magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-193

Figure 6.4.2-12 Comparison of model-predicted earthquake counts for NMESE-N using 

Case E magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-194

Figure 6.4.2-13 Comparison of model-predicted earthquake counts for NMESE-W using 

Case A magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-195

Figure 6.4.2-14 Comparison of model-predicted earthquake counts for NMESE-W using 

Case B magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-196

Figure 6.4.2-15 Comparison of model-predicted earthquake counts for NMESE-W using 

Case E magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure....................6-197

Figure 7.1-1 Seismotectonic zones shown in the case where the Rough Creek graben is 

not part of the Reelfoot rift (RR) and the Paleozoic Extended Crust is narrow (PEZN) ....................................................................................................................................7-83

Figure 7.1-2 Seismotectonic zones shown in the case where the Rough Creek graben is 

part of the Reelfoot rift (RR_RCG) and the Paleozoic Extended Crust is narrow 

(PEZ-N)............................................................................................................................7-84

Figure 7.1-3 Seismotectonic zones shown in the case where the Rough Creek graben is 

not part of the Reelfoot rift (RR) and the Paleozoic Extended Crust is wide (PEZ-W).....7-85

Figure 7.1-4 Seismotectonic zones shown in the case where the Rough Creek graben is 

part of the Reelfoot rift (RR_RCG) and the Paleozoic Extended Crust is wide (PEZW).....................................................................................................................................7-86

Figure 7.1-5 Example of comparing seismotectonic zones with magnetic map developed 

as part of the CEUS SSC Project.....................................................................................7-87

Figure 7.1-6 Example of comparing seismotectonic zones with isostatic gravity map 

developed as part of the CEUS SSC Project . ................................................................7-88
xxxviii

Figure 7.1-7 Map of seismicity based on the earthquake catalog developed for the CEUS 

SSC Project......................................................................................................................7-89

Figure 7.1-8 Map showing example comparison of seismotectonic zones with seismicity. 

Note the non-uniform spatial distribution of seismicity within the zones. Spatial 

smoothing of a- and b-values accounts for these spatial variations.................................7-90

Figure 7.3-1 Logic tree for the seismotectonic zones branch of the master logic tree.............7-91

Figure 7.3.1-1 Significant earthquakes and paleoseismology of the SLR seismotectonic 

zone .................................................................................................................................7-92

Figure 7.3.1-2 Tectonic features of the SLR seismotectonic zone ..........................................7-93

Figure 7.3.1-3 Magnetic and gravity anomaly maps of the SLR seismotectonic zone ............7-94

Figure 7.3.2-1 Significant earthquakes and paleoseismic study area in the region of the 

GMH seismotectonic zone ...............................................................................................7-95

Figure 7.3.2-2 Igneous rocks attributed to the GMH seismotectonic zone ..............................7-96

Figure 7.3.2-3 Relocated hypocentral depths and crustal depth of the GMH 

seismotectonic zone.........................................................................................................7-97

Figure 7.3.2-4 Magnetic and gravity anomaly maps of the GMH seismotectonic zone ..........7-98

Figure 7.3.3-1 Seismicity of the NAP seismotectonic zone .....................................................7-99

Figure 7.3.3-2 Magnetic and gravity anomaly maps of the NAP seismotectonic zone ..........7-100

Figure 7.3.4-1 Seismicity and tectonic features of the PEZ seismotectonic zone..................7-101

Figure 7.3.4-2 Magnetic and gravity anomaly maps of the PEZ seismotectonic zone ..........7-102

Figure 7.3.5-1 Map showing seismicity, subsurface Paleozoic and basement structures, 

and postulated energy centers for prehistoric earthquakes ...........................................7-103

Figure 7.3.5-2 Map showing alternative boundaries for Precambrian (proto-Illinois basin) 

rift basins........................................................................................................................7-104

Figure 7.3.5-3 Maps showing the IBEB source zone boundaries, seismicity, and 

prehistoric earthquake centers relative to (a) regional magnetic anomalies and (b) 

regional gravity anomalies .............................................................................................7-105

Figure 7.3.6-1 Map of seismicity and geomorphic features and faults showing evidence 

for Quaternary neotectonic deformation and reactivation. Inset map shows 

basement structures associated with the Reelfoot rift. ..................................................7-106

Figure 7.3.6-2 Maps showing geophysical anomalies in the Reelfoot rift region ...................7-107

Figure 7.3.7-1 Mesozoic basins within the ECC-AM zone ....................................................7-108

Figure 7.3.7-2 Seismicity within the ECC-AM and AHEX zones............................................7-109

Figure 7.3.7-3 Magnetic and gravity data for ECC-AM and AHEX zones..............................7-110

Figure 7.3.7-4 Estimated locations of the 1755 M 6.1 Cape Ann earthquake .......................7-111

Figure 7.3.8-1 Correlation of interpreted transitional crust with the East Coast magnetic 

anomaly..........................................................................................................................7-112

Figure 7.3.9-1 The ECC-GC seismotectonic zone.................................................................7-113

Figure 7.3.10-1 The GHEX seismotectonic zone...................................................................7-114

Figure 7.3.11-1 The OKA seismotectonic zone and regional gravity and magnetic data ......7-115

Figure 7.3.12-1 Simplified tectonic map showing the distribution of principal basement 

faults, rifts, and sutures in the Midcontinent...................................................................7-116
xxxix

Figure 7.3.12-2 Maps showing major basement structural features relative to (a) regional 

magnetic anomalies and (b) regional gravity anomalies ................................................7-117

Figure 7.3.12-3 Seismic zones and maximum observed earthquakes in the MidC zone ......7-118

Figure 7.3.12-4 Alternative MidC source zone configurations ...............................................7-119

Figure 7.4.1-1 (1 of 3) Distributions for mmax−obs for the seismotectonic distributed 

seismicity source zones .................................................................................................7-120

Figure 7.4.1-1 (2 of 3) Distributions for mmax−obs for the seismotectonic distributed 

seismicity source zones .................................................................................................7-121

Figure 7.4.1-1 (3 of 3) Distributions for mmax−obs for the seismotectonic distributed 

seismicity source zones .................................................................................................7-122

Figure 7.4.2-1 Mmax distributions for the AHEX seismotectonic zone ..................................7-123

Figure 7.4.2-2 Mmax distributions for the ECC_AM seismotectonic zone.............................7-124

Figure 7.4.2-3 Mmax distributions for the ECC_GC seismotectonic zone.............................7-125

Figure 7.4.2-4 Mmax distributions for the GHEX seismotectonic zone..................................7-126

Figure 7.4.2-5 Mmax distributions for the GMH seismotectonic zone....................................7-127

Figure 7.4.2-6 Mmax distributions for the IBEB seismotectonic zone....................................7-128

Figure 7.4.2-7 Mmax distributions for the MidC-A seismotectonic zone................................7-129

Figure 7.4.2-8 Mmax distributions for the MidC-B seismotectonic zone................................7-130

Figure 7.4.2-9 Mmax distributions for the MidC-C seismotectonic zone................................7-131

Figure 7.4.2-10 Mmax distributions for the MidC-D seismotectonic zone..............................7-132

Figure 7.4.2-11 Mmax distributions for the NAP seismotectonic zone ..................................7-133

Figure 7.4.2-12 Mmax distributions for the OKA seismotectonic zone ..................................7-134

Figure 7.4.2-13 Mmax distributions for the PEZ_N seismotectonic zone ..............................7-135

Figure 7.4.2-14 Mmax distributions for the PEZ_W seismotectonic zone..............................7-136

Figure 7.4.2-15 Mmax distributions for the RR seismotectonic zone.....................................7-137

Figure 7.4.2-16 Mmax distributions for the RR_RCG seismotectonic zone...........................7-138

Figure 7.4.2-17 Mmax distributions for the SLR seismotectonic zone...................................7-139

Figure 7.5.1-1 Mean map of rate and b-value for the study region under the source-zone 

configuration with narrow interpretation of PEZ, Rough Creek graben associated 

with Midcontinent; Case A magnitude weights...............................................................7-140

Figure 7.5.1-2 Mean map of rate and b-value for the study region under the source-zone 

configuration with narrow interpretation of PEZ, Rough Creek graben associated 

with Midcontinent; Case B magnitude weights...............................................................7-141

Figure 7.5.1-3 Mean map of rate and b-value for the study region under the source-zone 

configuration with narrow interpretation of PEZ, Rough Creek graben associated 

with Midcontinent; Case E magnitude weights...............................................................7-142

Figure 7.5.1-4 Mean map of rate and b-value for the study region under the source-zone 

configuration with narrow interpretation of PEZ, Rough Creek graben associated 

with Reelfoot rift; Case A magnitude weights.................................................................7-143
xl

Figure 7.5.1-5 Mean map of rate and b-value for the study region under the source-zone 

configuration with narrow interpretation of PEZ, Rough Creek graben associated 

with Reelfoot rift; Case B magnitude weights.................................................................7-144

Figure 7.5.1-6 Mean map of rate and b-value for the study region under the source-zone 

configuration with narrow interpretation of PEZ, Rough Creek graben associated 

with Reelfoot rift; Case E magnitude weights.................................................................7-145

Figure 7.5.1-7 Mean map of rate and b-value for the study region under the source-zone 

configuration with wide interpretation of PEZ, Rough Creek graben associated with 

Midcontinent; Case A magnitude weights ......................................................................7-146

Figure 7.5.1-8 Mean map of rate and b-value for the study region under the source-zone 

configuration with wide interpretation of PEZ, Rough Creek graben associated with 

Midcontinent; Case B magnitude weights ......................................................................7-147

Figure 7.5.1-9 Mean map of rate and b-value for the study region under the source-zone 

configuration with wide interpretation of PEZ, Rough Creek graben associated with 

Midcontinent; Case E magnitude weights ......................................................................7-148

Figure 7.5.1-10 Mean map of rate and b-value for the study region under the sourcezone configuration with wide interpretation of PEZ, Rough Creek graben associated 

with Reelfoot rift; Case A magnitude weights.................................................................7-149

Figure 7.5.1-11 Mean map of rate and b-value for the study region under the sourcezone configuration with wide interpretation of PEZ, Rough Creek graben associated 

with Reelfoot rift; Case B magnitude weights.................................................................7-150

Figure 7.5.1-12 Mean map of rate and b-value for the study region under the sourcezone configuration with wide interpretation of PEZ, Rough Creek graben associated 

with Reelfoot rift; Case E magnitude weights.................................................................7-151

Figure 7.5.2-1 Comparison of model-predicted earthquake counts for AHEX using Case 

A magnitude weights. No earthquake counts are shown because this source zone 

contains no seismicity. . ...............................................................................................7-152

Figure 7.5.2-2 Comparison of model-predicted earthquake counts for AHEX using Case 

B magnitude weights. No earthquake counts are shown because this source zone 

contains no seismicity.. .................................................................................................7-153

Figure 7.5.2-3 Comparison of model-predicted earthquake counts for AHEX using Case 

E magnitude weights. No earthquake counts are shown because this source zone 

contains no seismicity. ..................................................................................................7-154

Figure 7.5.2-4 Comparison of model-predicted earthquake counts for ECC_AM using 

Case A magnitude weights. The error bars represent the 16%–84% uncertainty 

associated with the data, computed using the Weichert (1980) procedure. ..................7-155

Figure 7.5.2-5 Comparison of model-predicted earthquake counts for ECC_AM using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-156

Figure 7.5.2-6 Comparison of model-predicted earthquake counts for ECC_AM using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-157

Figure 7.5.2-7 Comparison of model-predicted earthquake counts for ECC_GC using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-158

Figure 7.5.2-8 Comparison of model-predicted earthquake counts for ECC_GC using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-159

Figure 7.5.2-9 Comparison of model-predicted earthquake counts for ECC_GC using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-160
xli

Figure 7.5.2-10 Comparison of model-predicted earthquake counts for GHEX using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-161

Figure 7.5.2-11 Comparison of model-predicted earthquake counts for GHEX using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-162

Figure 7.5.2-12 Comparison of model-predicted earthquake counts for GHEX using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-163

Figure 7.5.2-13 Comparison of model-predicted earthquake counts for GMH using Case 

A magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-164

Figure 7.5.2-14 Comparison of model-predicted earthquake counts for GMH using Case 

B magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-165

Figure 7.5.2-15 Comparison of model-predicted earthquake counts for GMH using Case 

E magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-166

Figure 7.5.2-16 Comparison of model-predicted earthquake counts for IBEB using Case 

A magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-167

Figure 7.5.2-17 Comparison of model-predicted earthquake counts for IBEB using Case 

B magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-168

Figure 7.5.2-18 Comparison of model-predicted earthquake counts for IBEB using Case 

E magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-169

Figure 7.5.2-19 Comparison of model-predicted earthquake counts for MidC-A using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-170

Figure 7.5.2-20 Comparison of model-predicted earthquake counts for MidC-A using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-171

Figure 7.5.2-21 Comparison of model-predicted earthquake counts for MidC-A using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-172

Figure 7.5.2-22 Comparison of model-predicted earthquake counts for MidC–B using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-173

Figure 7.5.2-23 Comparison of model-predicted earthquake counts for MidC-B using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-174

Figure 7.5.2-24 Comparison of model-predicted earthquake counts for MidC–B using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-175

Figure 7.5.2-25 Comparison of model-predicted earthquake counts for MidC–C using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-176

Figure 7.5.2-26 Comparison of model-predicted earthquake counts for MidC–C using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-177

Figure 7.5.2-27 Comparison of model-predicted earthquake counts for MidC–C using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-178

Figure 7.5.2-28 Comparison of model-predicted earthquake counts for MidC–D using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-179

Figure 7.5.2-29 Comparison of model-predicted earthquake counts for MidC–D using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-180

Figure 7.5.2-30 Comparison of model-predicted earthquake counts for MidC–D using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-181

Figure 7.5.2-31 Comparison of model-predicted earthquake counts for NAP using Case 

A magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-182
xlii

Figure 7.5.2-32 Comparison of model-predicted earthquake counts for NAP using Case 

B magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-183

Figure 7.5.2-33 Comparison of model-predicted earthquake counts for NAP using Case 

E magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-184

Figure 7.5.2-34 Comparison of model-predicted earthquake counts for OKA using Case 

A magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-185

Figure 7.5.2-35 Comparison of model-predicted earthquake counts for OKA using Case 

B magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-186

Figure 7.5.2-36 Comparison of model-predicted earthquake counts for OKA using Case 

E magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-187

Figure 7.5.2-37 Comparison of model-predicted earthquake counts for PEZ_N using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-188

Figure 7.5.2-38 Comparison of model-predicted earthquake counts for PEZ_N using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-189

Figure 7.5.2-39 Comparison of model-predicted earthquake counts for PEZ_N using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-190

Figure 7.5.2-40 Comparison of model-predicted earthquake counts for PEZ_W using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-191

Figure 7.5.2-41 Comparison of model-predicted earthquake counts for PEZ_W using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-192

Figure 7.5.2-42 Comparison of model-predicted earthquake counts for PEZ_W using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-193

Figure 7.5.2-43 Comparison of model-predicted earthquake counts for RR using Case A 

magnitude weights. Error bars as in Figure 7.5.2-4. .....................................................7-194

Figure 7.5.2-44 Comparison of model-predicted earthquake counts for RR using Case B 

magnitude weights. Error bars as in Figure 7.5.2-4. .....................................................7-195

Figure 7.5.2-45 Comparison of model-predicted earthquake counts for RR using Case E 

magnitude weights. Error bars as in Figure 7.5.2-4. .....................................................7-196

Figure 7.5.2-46 Comparison of model-predicted earthquake counts for RR_RCG using 

Case A magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-197

Figure 7.5.2-47 Comparison of model-predicted earthquake counts for RR_RCG using 

Case B magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-198

Figure 7.5.2-48 Comparison of model-predicted earthquake counts for RR_RCG using 

Case E magnitude weights. Error bars as in Figure 7.5.2-4. .........................................7-199

Figure 7.5.2-49 Comparison of model-predicted earthquake counts for SLR using Case

A magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-200

Figure 7.5.2-50 Comparison of model-predicted earthquake counts for SLR using Case 

B magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-201

Figure 7.5.2-51 Comparison of model-predicted earthquake counts for SLR using Case 

E magnitude weights. Error bars as in Figure 7.5.2-4. ..................................................7-202

Figure 8.1-1 Map showing the study area and seven test sites for the CEUS SSC Project ....8-28

Figure 8.1-2 Mean VS profile for shallow soil site....................................................................8-29

Figure 8.1-3 Mean VS profile for deep soil site........................................................................8-30
xliii

Figure 8.1-4 Mean amplification factors for shallow soil site....................................................8-31

Figure 8.1-5 Mean amplification factors for deep soil site........................................................8-32

Figure 8.2-1a Central Illinois 10 Hz rock hazard: mean and fractile total hazard.....................8-33

Figure 8.2-1b Central Illinois 1 Hz rock hazard: mean and fractile total hazard.......................8-34

Figure 8.2-1c Central Illinois PGA rock hazard: mean and fractile total hazard.......................8-35

Figure 8.2-1d Central Illinois 10 Hz rock hazard: total and contribution by RLME and 

background ......................................................................................................................8-36

Figure 8.2-1e Central Illinois 1 Hz rock hazard: total and contribution by RLME and 

background ......................................................................................................................8-37

Figure 8.2-1f Central Illinois PGA rock hazard: total and contribution by RLME and 

background ......................................................................................................................8-38

Figure 8.2-1g Central Illinois 10 Hz rock hazard: contribution by background source.............8-39

Figure 8.2-1h Central Illinois 1 Hz rock hazard: contribution by background source...............8-40

Figure 8.2-1i Central Illinois PGA rock hazard: contribution by background source................8-41

Figure 8.2-1j Central Illinois 10 Hz rock hazard: comparison of three source models.............8-42

Figure 8.2-1k Central Illinois 1 Hz rock hazard: comparison of three source models ..............8-43

Figure 8.2-1l Central Illinois PGA rock hazard: comparison of three source models...............8-44

Figure 8.2-1m Central Illinois 10 Hz shallow soil hazard: total and total and contribution 

by RLME and background................................................................................................8-45

Figure 8.2-1n Central Illinois 1 Hz shallow soil hazard: total and contribution by RLME 

and background ...............................................................................................................8-46

Figure 8.2-1o Central Illinois PGA shallow soil hazard: total and contribution by RLME 

and background ...............................................................................................................8-47

Figure 8.2-1p Central Illinois 10 Hz deep soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-48

Figure 8.2-1q Central Illinois 1 Hz deep soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-49

Figure 8.2-1r Central Illinois PGA deep soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-50

Figure 8.2-1s Central Illinois 10 Hz hazard: comparison of three site conditions ....................8-51

Figure 8.2-1t Central Illinois 1 Hz hazard: comparison of three site conditions .......................8-52

Figure 8.2-1u Central Illinois PGA hazard: comparison of three site conditions......................8-53

Figure 8.2-1v Central Illinois 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones................................................................................................................................8-54

Figure 8.2-1w Central Illinois 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones................................................................................................................................8-55

Figure 8.2-1x Central Illinois 10 Hz rock hazard: sensitivity to Mmax for source IBEB............8-56

Figure 8.2-1y Central Illinois 1 Hz rock hazard: sensitivity to Mmax for source IBEB..............8-57

Figure 8.2-1z Central Illinois 10 Hz rock hazard: sensitivity to smoothing options ..................8-58

Figure 8.2-1aa Central Illinois 1 Hz rock hazard: sensitivity to smoothing options ..................8-59

Figure 8.2-1bb Central Illinois 10 Hz rock hazard: sensitivity to eight realizations for 

source IBEB, Case A .......................................................................................................8-60
xliv

Figure 8.2-1cc Central Illinois 10 Hz rock hazard: sensitivity to eight realizations for 

source IBEB, Case B .......................................................................................................8-61

Figure 8.2-1dd Central Illinois 10 Hz rock hazard: sensitivity to eight realizations for 

source IBEB, Case E .......................................................................................................8-62

Figure 8.2-1ee Central Illinois 1 Hz rock hazard: sensitivity to eight realizations for 

source IBEB, Case A .......................................................................................................8-63

Figure 8.2-1ff Central Illinois 1 Hz rock hazard: sensitivity to eight realizations for source 

IBEB, Case B ...................................................................................................................8-64

Figure 8.2-1gg Central Illinois 1 Hz rock hazard: sensitivity to eight realizations for 

source IBEB, Case E .......................................................................................................8-65

Figure 8.2-2a Chattanooga 10 Hz rock hazard: mean and fractile total hazard ......................8-66

Figure 8.2-2b Chattanooga 1 Hz rock hazard: mean and fractile total hazard.........................8-67

Figure 8.2-2c Chattanooga PGA rock hazard: mean and fractile total hazard ........................8-68

Figure 8.2-2d Chattanooga 10 Hz rock hazard: total and contribution by RLME and 

background ......................................................................................................................8-69

Figure 8.2-2e Chattanooga 1 Hz rock hazard: total and contribution by RLME and 

background ......................................................................................................................8-70

Figure 8.2-2f Chattanooga PGA rock hazard: total and contribution by RLME and 

background ......................................................................................................................8-71

Figure 8.2-2g Chattanooga 10 Hz rock hazard: contribution by background source...............8-72

Figure 8.2-2h Chattanooga 1 Hz rock hazard: contribution by background source.................8-73

Figure 8.2-2i Chattanooga PGA rock hazard: contribution by background source..................8-74

Figure 8.2-2j Chattanooga 10 Hz rock hazard: comparison of three source models...............8-75

Figure 8.2-2k Chattanooga is 1 Hz rock hazard: comparison of three source models ............8-76

Figure 8.2-2l Chattanooga PGA rock hazard: comparison of three source models.................8-77

Figure 8.2-2m Chattanooga 10 Hz shallow soil hazard: total and contribution by RLME 

and background ...............................................................................................................8-78

Figure 8.2-2n Chattanooga 1 Hz shallow soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-79

Figure 8.2-2o Chattanooga PGA shallow soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-80

Figure 8.2-2p Chattanooga 10 Hz deep soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-81

Figure 8.2-2q Chattanooga 1 Hz deep soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-82

Figure 8.2-2r Chattanooga PGA deep soil hazard: total and contribution by RLME and 

background ......................................................................................................................8-83

Figure 8.2-2s Chattanooga 10 Hz hazard: comparison of three site conditions ......................8-84

Figure 8.2-2t Chattanooga 1 Hz hazard: comparison of three site conditions .........................8-85

Figure 8.2-2u Chattanooga PGA hazard: comparison of three site conditions........................8-86

Figure 8.2-2v Chattanooga 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones................................................................................................................................8-87
xlv

Figure 8.2-2w Chattanooga 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones................................................................................................................................8-88

Figure 8.2-2x Chattanooga 10 Hz rock hazard: sensitivity to Mmax for source PEZ-N...........8-89

Figure 8.2-2y Chattanooga 1 Hz rock hazard: sensitivity to Mmax for source PEZ-N.............8-90

Figure 8.2-2z Chattanooga 10 Hz rock hazard: sensitivity to smoothing options ....................8-91

Figure 8.2-2aa Chattanooga 1 Hz rock hazard: sensitivity to smoothing options ....................8-92

Figure 8.2-2bb Chattanooga 10 Hz rock hazard: sensitivity to eight realizations for 

source PEZ-N, Case A.....................................................................................................8-93

Figure 8.2-2cc Chattanooga 10 Hz rock hazard: sensitivity to eight realizations for 

source PEZ-N, Case B.....................................................................................................8-94

Figure 8.2-2dd Chattanooga 10 Hz rock hazard: sensitivity to eight realizations for 

source PEZ-N, Case E.....................................................................................................8-95

Figure 8.2-2ee Chattanooga 1 Hz rock hazard: sensitivity to eight realizations for source 

PEZ-N, Case A.................................................................................................................8-96

Figure 8.2-2ff Chattanooga 1 Hz rock hazard: sensitivity to eight realizations for source 

PEZ-N, Case B.................................................................................................................8-97

Figure 8.2-2gg Chattanooga 1 Hz rock hazard: sensitivity to eight realizations for source 

PEZ-N, Case E.................................................................................................................8-98

Figure 8.2-3a Houston 10 Hz rock hazard: mean and fractile total hazard..............................8-99

Figure 8.2-3b Houston 1 Hz rock hazard: mean and fractile total hazard..............................8-100

Figure 8.2-3c Houston PGA rock hazard: mean and fractile total hazard..............................8-101

Figure 8.2-3d Houston 10 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-102

Figure 8.2-3e Houston 1 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-103

Figure 8.2-3f Houston PGA rock hazard: total and contribution by RLME and background..8-104

Figure 8.2-3g Houston 10 Hz rock hazard: contribution by background source ....................8-105

Figure 8.2-3h Houston 1 Hz rock hazard: contribution by background source ......................8-106

Figure 8.2-3i Houston PGA rock hazard: contribution by background source .......................8-107

Figure 8.2-3j Houston 10 Hz rock hazard: comparison of three source models ....................8-108

Figure 8.2-3k Houston is 1 Hz rock hazard: comparison of three source models..................8-109

Figure 8.2-3l Houston PGA rock hazard: comparison of three source models......................8-110

Figure 8.2-3m Houston 10 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-111

Figure 8.2-3n Houston 1 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-112

Figure 8.2-3o Houston PGA shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-113

Figure 8.2-3p Houston 10 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-114

Figure 8.2-3q Houston 1 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-115
xlvi

Figure 8.2-3r Houston PGA deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-116

Figure 8.2-3s Houston 10 Hz hazard: comparison of three site conditions............................8-117

Figure 8.2-3t Houston 1 Hz hazard: comparison of three site conditions ..............................8-118

Figure 8.2-3u Houston PGA hazard: comparison of three site conditions .............................8-119

Figure 8.2-3v Houston 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones ....8-120

Figure 8.2-3w Houston 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones .....8-121

Figure 8.2-3x Houston 10 Hz rock hazard: sensitivity to Mmax for source GHEX.................8-122

Figure 8.2-3y Houston 1 Hz rock hazard: sensitivity to Mmax for source GHEX...................8-123

Figure 8.2-3z Houston 10 Hz rock hazard: sensitivity to smoothing options..........................8-124

Figure 8.2-3aa Houston 1 Hz rock hazard: sensitivity to smoothing options .........................8-125

Figure 8.2-3bb Houston 10 Hz rock hazard: sensitivity to eight realizations for source 

GHEX, Case A ...............................................................................................................8-126

Figure 8.2-3cc Houston 10 Hz rock hazard: sensitivity to eight realizations for source 

GHEX, Case B ...............................................................................................................8-127

Figure 8.2-3dd Houston 10 Hz rock hazard: sensitivity to eight realizations for source 

GHEX, Case E ...............................................................................................................8-128

Figure 8.2-3ee Houston 1 Hz rock hazard: sensitivity to eight realizations for source 

GHEX, Case A ...............................................................................................................8-129

Figure 8.2-3ff Houston 1 Hz rock hazard: sensitivity to eight realizations for source 

GHEX, Case B ...............................................................................................................8-130

Figure 8.2-3gg Houston 1 Hz rock hazard: sensitivity to eight realizations for source 

GHEX, Case E ...............................................................................................................8-131

Figure 8.2-4a Jackson 10 Hz rock hazard: mean and fractile total hazard............................8-132

Figure 8.2-4b Jackson 1 Hz rock hazard: mean and fractile total hazard..............................8-133

Figure 8.2-4c Jackson PGA rock hazard: mean and fractile total hazard..............................8-134

Figure 8.2-4d Jackson 10 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-135

Figure 8.2-4e Jackson 1 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-136

Figure 8.2-4f Jackson PGA rock hazard: total and contribution by RLME and background ..8-137

Figure 8.2-4g Jackson 10 Hz rock hazard: contribution by background source ....................8-138

Figure 8.2-4h Jackson 1 Hz rock hazard: contribution by background source ......................8-139

Figure 8.2-4i Jackson PGA rock hazard: contribution by background source .......................8-140

Figure 8.2-4j Jackson 10 Hz rock hazard: comparison of three source models ....................8-141

Figure 8.2-4k Jackson is 1 Hz rock hazard: comparison of three source models..................8-142

Figure 8.2-4l Jackson PGA rock hazard: comparison of three source models ......................8-143

Figure 8.2-4m Jackson 10 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-144

Figure 8.2-4n Jackson 1 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-145
xlvii

Figure 8.2-4o Jackson PGA shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-146

Figure 8.2-4p Jackson 10 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-147

Figure 8.2-4q Jackson 1 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-148

Figure 8.2-4r Jackson PGA deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-149

Figure 8.2-4s Jackson 10 Hz hazard: comparison of three site conditions............................8-150

Figure 8.2-4t Jackson 1 Hz hazard: comparison of three site conditions ..............................8-151

Figure 8.2-4u Jackson PGA hazard: comparison of three site conditions .............................8-152

Figure 8.2-4v Jackson 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones ....8-153

Figure 8.2-4w Jackson 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones .....8-154

Figure 8.2-4x Jackson 10 Hz rock hazard: sensitivity to Mmax for source ECC-GC.............8-155

Figure 8.2-4y Jackson 1 Hz rock hazard: sensitivity to Mmax for source ECC-GC...............8-156

Figure 8.2-4z Jackson 10 Hz rock hazard: sensitivity to smoothing options..........................8-157

Figure 8.2-4aa Jackson 1 Hz rock hazard: sensitivity to smoothing options..........................8-158

Figure 8.2-4bb Jackson 10 Hz rock hazard: sensitivity to eight realizations for source 

ECC-GC, Case A ...........................................................................................................8-159

Figure 8.2-4cc Jackson 10 Hz rock hazard: sensitivity to eight realizations for source 

ECC-GC, Case B ...........................................................................................................8-160

Figure 8.2-4dd Jackson 10 Hz rock hazard: sensitivity to eight realizations for source 

ECC-GC, Case E ...........................................................................................................8-161

Figure 8.2-4ee Jackson 1 Hz rock hazard: sensitivity to eight realizations for source 

ECC-GC, Case A ...........................................................................................................8-162

Figure 8.2-4ff Jackson 1 Hz rock hazard: sensitivity to eight realizations for source ECCGC, Case B....................................................................................................................8-163

Figure 8.2-4gg Jackson 1 Hz rock hazard: sensitivity to eight realizations for source 

ECC-GC, Case E ...........................................................................................................8-164

Figure 8.2-5a Manchester 10 Hz rock hazard: mean and fractile total hazard ......................8-165

Figure 8.2-5b Manchester 1 Hz rock hazard: mean and fractile total hazard ........................8-166

Figure 8.2-5c Manchester PGA rock hazard: mean and fractile total hazard ........................8-167

Figure 8.2-5d Manchester 10 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-168

Figure 8.2-5e Manchester 1 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-169

Figure 8.2-5f Manchester PGA rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-170

Figure 8.2-5g Manchester 10 Hz rock hazard: contribution by background source...............8-171

Figure 8.2-5h Manchester 1 Hz rock hazard: contribution by background source.................8-172

Figure 8.2-5i Manchester PGA rock hazard: contribution by background source..................8-173

Figure 8.2-5j Manchester 10 Hz rock hazard: comparison of three source models...............8-174
xlviii

Figure 8.2-5k Manchester is 1 Hz rock hazard: comparison of three source models ............8-175

Figure 8.2-5l Manchester PGA rock hazard: comparison of three source models.................8-176

Figure 8.2-5m Manchester 10 Hz shallow soil hazard: total and contribution by RLME 

and background .............................................................................................................8-177

Figure 8.2-5n Manchester 1 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-178

Figure 8.2-5o Manchester PGA shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-179

Figure 8.2-5p Manchester 10 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-180

Figure 8.2-5q Manchester 1 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-181

Figure 8.2-5r Manchester PGA deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-182

Figure 8.2-5s Manchester 10 Hz hazard: comparison of three site conditions ......................8-183

Figure 8.2-5t Manchester 1 Hz hazard: comparison of three site conditions.........................8-184

Figure 8.2-5u Manchester PGA hazard: comparison of three site conditions........................8-185

Figure 8.2-5v Manchester 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones..............................................................................................................................8-186

Figure 8.2-5w Manchester 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones..............................................................................................................................8-187

Figure 8.2-5x Manchester 10 Hz rock hazard: sensitivity to Mmax for source NAP ..............8-188

Figure 8.2-5y Manchester 1 Hz rock hazard: sensitivity to Mmax for source NAP ................8-189

Figure 8.2-5z Manchester 10 Hz rock hazard: sensitivity to smoothing options ....................8-190

Figure 8.2-5aa Manchester 1 Hz rock hazard: sensitivity to smoothing options....................8-191

Figure 8.2-5bb Manchester 10 Hz rock hazard: sensitivity to eight realizations for source 

NAP, Case A..................................................................................................................8-192

Figure 8.2-5cc Manchester 10 Hz rock hazard: sensitivity to eight realizations for source 

NAP, Case B..................................................................................................................8-193

Figure 8.2-5dd Manchester 10 Hz rock hazard: sensitivity to eight realizations for source 

NAP, Case E..................................................................................................................8-194

Figure 8.2-5ee Manchester 1 Hz rock hazard: sensitivity to eight realizations for source 

NAP, Case A..................................................................................................................8-195

Figure 8.2-5ff Manchester 1 Hz rock hazard: sensitivity to eight realizations for source 

NAP, Case B..................................................................................................................8-196

Figure 8.2-5gg Manchester 1 Hz rock hazard: sensitivity to eight realizations for source 

NAP, Case E..................................................................................................................8-197

Figure 8.2-6a Savannah 10 Hz rock hazard: mean and fractile total hazard.........................8-198

Figure 8.2-6b Savannah 1 Hz rock hazard: mean and fractile total hazard...........................8-199

Figure 8.2-6c Savannah PGA rock hazard: mean and fractile total hazard...........................8-200

Figure 8.2-6d Savannah 10 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-201
xlix

Figure 8.2-6e Savannah 1 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-202

Figure 8.2-6f Savannah PGA rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-203

Figure 8.2-6g Savannah 10 Hz rock hazard: contribution by background source .................8-204

Figure 8.2-6h Savannah 1 Hz rock hazard: contribution by background source ...................8-205

Figure 8.2-6i Savannah PGA rock hazard: contribution by background source ....................8-206

Figure 8.2-6j Savannah 10 Hz rock hazard: comparison of three source models .................8-207

Figure 8.2-6k Savannah is 1 Hz rock hazard: comparison of three source models...............8-208

Figure 8.2-6l Savannah PGA rock hazard: comparison of three source models ...................8-209

Figure 8.2-6m Savannah 10 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-210

Figure 8.2-6n Savannah 1 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-211

Figure 8.2-6o Savannah PGA shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-212

Figure 8.2-6p Savannah 10 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-213

Figure 8.2-6q Savannah 1 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-214

Figure 8.2-6r Savannah PGA deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-215

Figure 8.2-6s Savannah 10 Hz hazard: comparison of three site conditions.........................8-216

Figure 8.2-6t Savannah 1 Hz hazard: comparison of three site conditions............................8-217

Figure 8.2-6u Savannah PGA hazard: comparison of three site conditions ..........................8-218

Figure 8.2-6v Savannah 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax 

zones..............................................................................................................................8-219

Figure 8.2-6w Savannah 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones ..8-220

Figure 8.2-6x Savannah 10 Hz rock hazard: sensitivity to Mmax for source ECC-AM..........8-221

Figure 8.2-6y Savannah 1 Hz rock hazard: sensitivity to Mmax for source ECC-AM............8-222

Figure 8.2-6z Savannah 10 Hz rock hazard: sensitivity to smoothing options.......................8-223

Figure 8.2-6aa Savannah 1 Hz rock hazard: sensitivity to smoothing options ......................8-224

Figure 8.2-6bb Savannah 10 Hz rock hazard: sensitivity to eight realizations for source 

ECC-AM, Case A ...........................................................................................................8-225

Figure 8.2-6cc Savannah 10 Hz rock hazard: sensitivity to eight realizations for source 

ECC-AM, Case B ...........................................................................................................8-226

Figure 8.2-6dd Savannah 10 Hz rock hazard: sensitivity to eight realizations for source 

ECC-AM, Case E ...........................................................................................................8-227

Figure 8.2-6ee Savannah 1 Hz rock hazard: sensitivity to eight realizations for source 

ECC-AM, Case A ...........................................................................................................8-228

Figure 8.2-6ff Savannah 1 Hz rock hazard: sensitivity to eight realizations for source 

ECC-AM, Case B ...........................................................................................................8-229
l

Figure 8.2-6gg Savannah 1 Hz rock hazard: sensitivity to eight realizations for source 

ECC-AM, Case E ...........................................................................................................8-230

Figure 8.2-7a Topeka 10 Hz rock hazard: mean and fractile total hazard .............................8-231

Figure 8.2-7b Topeka 1 Hz rock hazard: mean and fractile total hazard ...............................8-232

Figure 8.2-7c Topeka PGA rock hazard: mean and fractile total hazard ...............................8-233

Figure 8.2-7d Topeka 10 Hz rock hazard: total and contribution by RLME and 

background ....................................................................................................................8-234

Figure 8.2-7e Topeka 1 Hz rock hazard: total and contribution by RLME and background...8-235

Figure 8.2-7f Topeka PGA rock hazard: total and contribution by RLME and background ...8-236

Figure 8.2-7g Topeka 10 Hz rock hazard: contribution by background source......................8-237

Figure 8.2-7h Topeka 1 Hz rock hazard: contribution by background source........................8-238

Figure 8.2-7i Topeka PGA rock hazard: contribution by background source ........................8-239

Figure 8.2-7j Topeka 10 Hz rock hazard: comparison of three source models......................8-240

Figure 8.2-7k Topeka is 1 Hz rock hazard: comparison of three source models...................8-241

Figure 8.2-7l Topeka PGA rock hazard: comparison of three source models .......................8-242

Figure 8.2-7m Topeka 10 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-243

Figure 8.2-7n Topeka 1 Hz shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-244

Figure 8.2-7o Topeka PGA shallow soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-245

Figure 8.2-7p Topeka 10 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-246

Figure 8.2-7q Topeka 1 Hz deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-247

Figure 8.2-7r Topeka PGA deep soil hazard: total and contribution by RLME and 

background ....................................................................................................................8-248

Figure 8.2-7s Topeka 10 Hz hazard: comparison of three site conditions.............................8-249

Figure 8.2-7t Topeka 1 Hz hazard: comparison of three site conditions................................8-250

Figure 8.2-7u Topeka PGA hazard: comparison of three site conditions ..............................8-251

Figure 8.2-7v Topeka 10 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones .....8-252

Figure 8.2-7w Topeka 1 Hz rock hazard: sensitivity to seismotectonic vs. Mmax zones.......8-253

Figure 8.2-7x Topeka 10 Hz rock hazard: sensitivity to Mmax for source MidC-A ................8-254

Figure 8.2-7y Topeka 1 Hz rock hazard: sensitivity to Mmax for source MidC-A ..................8-255

Figure 8.2-7z Topeka 10 Hz rock hazard: sensitivity to smoothing options...........................8-256

Figure 8.2-7aa Topeka 1 Hz rock hazard: sensitivity to smoothing options...........................8-257

Figure 8.2-7bb Topeka 10 Hz rock hazard: sensitivity to eight realizations for source 

MidC-A, Case A .............................................................................................................8-258

Figure 8.2-7cc Topeka 10 Hz rock hazard: sensitivity to eight realizations for source 

MidC-A, Case B .............................................................................................................8-259
li

Figure 8.2-7dd Topeka 10 Hz rock hazard: sensitivity to eight realizations for source 

MidC-A, Case E .............................................................................................................8-260

Figure 8.2-7ee Topeka 1 Hz rock hazard: sensitivity to eight realizations for source 

MidC-A, Case A .............................................................................................................8-261

Figure 8.2-7ff Topeka 1 Hz rock hazard: sensitivity to eight realizations for source MidCA, Case B.......................................................................................................................8-262

Figure 8.2-7gg Topeka 1 Hz rock hazard: sensitivity to eight realizations for source 

MidC-A, Case E .............................................................................................................8-263

Figure 9.3-1 1 Hz sensitivity to rupture orientation at Savannah for the Charleston 

regional source.................................................................................................................9-24

Figure 9.3-2 10 Hz sensitivity to rupture orientation at Savannah for the Charleston 

regional source.................................................................................................................9-25

Figure 9.3-3 1 Hz sensitivity to seismogenic thickness at Manchester for the Charlevoix 

area source ......................................................................................................................9-26

Figure 9.3-4 10 Hz sensitivity to seismogenic thickness at Manchester for the Charlevoix 

area source ......................................................................................................................9-27

Figure 9.3-5 1 Hz sensitivity to rupture orientation (dip) at Manchester for the Charlevoix 

area source ......................................................................................................................9-28

Figure 9.3-6 10 Hz sensitivity to rupture orientation (dip) at Manchester for the 

Charlevoix area source ....................................................................................................9-29

Figure 9.3-7 1 Hz sensitivity to seismogenic thickness at Topeka for the Cheraw fault 

source ..............................................................................................................................9-30

Figure 9.3-8 10 Hz sensitivity to seismogenic thickness at Topeka for the Cheraw fault 

source ..............................................................................................................................9-31

Figure 9.3-9 1 Hz sensitivity to rupture orientation (dip) at Topeka for the Cheraw fault 

source ..............................................................................................................................9-32

Figure 9.3-10 10 Hz sensitivity to rupture orientation at Topeka for the Cheraw fault 

source ..............................................................................................................................9-33

Figure 9.3-11 1 Hz sensitivity to seismogenic thickness at Jackson for the Commerce 

area source ......................................................................................................................9-34

Figure 9.3-12 10 Hz sensitivity to seismogenic thickness at Jackson for the Commerce 

area source ......................................................................................................................9-35

Figure 9.3-13 1 Hz sensitivity to seismogenic thickness at Jackson for the ERM-N area 

source ..............................................................................................................................9-36

Figure 9.3-14 10 Hz sensitivity to seismogenic thickness at Jackson for the ERM-N area 

source ..............................................................................................................................9-37

Figure 9.3-15 1 Hz sensitivity to seismogenic thickness at Jackson for the ERM-S area 

source ..............................................................................................................................9-38

Figure 9.3-16 10 Hz sensitivity to seismogenic thickness at Jackson for the ERM-S area 

source ..............................................................................................................................9-39

Figure 9.3-17 1 Hz sensitivity to seismogenic thickness at Jackson for the Marianna area 

source ..............................................................................................................................9-40

Figure 9.3-18 10 Hz sensitivity to seismogenic thickness at Jackson for the Marianna 

area source ......................................................................................................................9-41
lii

Figure 9.3-19 1 Hz sensitivity to seismogenic thickness at Topeka for the Meers fault 

and OKA area sources.....................................................................................................9-42

Figure 9.3-20 1 Hz sensitivity to seismogenic thickness at Houston for the Meers fault 

and OKA area sources.....................................................................................................9-43

Figure 9.3-21 10 Hz sensitivity to seismogenic thickness at Topeka for the Meers fault 

and OKA area sources.....................................................................................................9-44

Figure 9.3-22 10 Hz sensitivity to seismogenic thickness at Houston for the Meers fault 

and OKA area sources.....................................................................................................9-45

Figure 9.3-23 1 Hz sensitivity to rupture orientation at Houston for the OKA area source ......9-46

Figure 9.3-24 10 Hz sensitivity to rupture orientation at Houston for the OKA area source ....9-47

Figure 9.3-25 1 Hz sensitivity to rupture orientation (dip) at Topeka for the OKA area 

source ..............................................................................................................................9-48

Figure 9.3-26 1 Hz sensitivity to rupture orientation (dip) at Houston for the OKA area 

source ..............................................................................................................................9-49

Figure 9.3-27 10 Hz sensitivity to rupture orientation (dip) at Topeka for the OKA area 

source ..............................................................................................................................9-50

Figure 9.3-28 10 Hz sensitivity to rupture orientation (dip) at Houston for the OKA area 

source ..............................................................................................................................9-51

Figure 9.3-29 1 Hz sensitivity to rupture orientation (dip) at Topeka for the Meers fault 

source ..............................................................................................................................9-52

Figure 9.3-30 1 Hz sensitivity to rupture orientation (dip) at Houston for the Meers fault 

source ..............................................................................................................................9-53

Figure 9.3-31 10 Hz sensitivity to rupture orientation (dip) at Topeka for the Meers fault 

source ..............................................................................................................................9-54

Figure 9.3-32 10 Hz sensitivity to rupture orientation (dip) at Houston for the Meers fault 

source ..............................................................................................................................9-55

Figure 9.3-33 1 Hz sensitivity to seismogenic thickness at Jackson for the NMFS fault 

sources.............................................................................................................................9-56

Figure 9.3-34 10 Hz sensitivity to seismogenic thickness at Jackson for the NMFS fault 

sources.............................................................................................................................9-57

Figure 9.3-35 1 Hz sensitivity to seismogenic thickness at Central Illinois for the Wabash 

Valley area source ...........................................................................................................9-58

Figure 9.3-36 10 Hz sensitivity to seismogenic thickness at Central Illinois for the 

Wabash Valley area source .............................................................................................9-59

Figure 9.3-37 1 Hz sensitivity to rupture orientation (dip) at Central Illinois for the 

Wabash Valley area source .............................................................................................9-60

Figure 9.3-38 10 Hz sensitivity to rupture orientation (dip) at Central Illinois for the 

Wabash Valley area source .............................................................................................9-61

Figure 9.3-39 1 Hz sensitivity to fault ruptures vs. point source for the Central Illinois site 

from the Mid C–A background source..............................................................................9-62

Figure 9.3-40 10 Hz sensitivity to fault ruptures vs. point source for the Central Illinois 

site from the Mid C–A background source .......................................................................9-63

Figure 9.4-1 COVMH from EPRI (1989) team sources vs. ground motion amplitude for 

seven test sites: PGA (top), 10 Hz SA (middle), and 1 Hz SA (bottom)...........................9-64
liii

Figure 9.4-2 COVMH from EPRI (1989) team sources vs. seismic hazard (i.e., annual 

frequency of exceedance) for seven test sites: PGA (top), 10 Hz SA (middle), and 1 

9-Hz SA (bottom) .............................................................................................................9-65

Figure 9.4-3 COVMH from seismic source experts (PEGASOS project) vs. amplitude (top) 

and annual frequency (bottom) ........................................................................................9-66

Figure 9.4-4 COVK and COVMH from Charleston alternatives for PGA, plotted vs. PGA 

amplitude (top) and hazard (bottom). COVMH is the total COV of mean hazard; see 

Table 9.4-2 for other labels for curves. ............................................................................9-67

Figure 9.4-5 COVK and COVMH from Charleston alternatives for 10 Hz, plotted vs. 10 Hz 

amplitude (top) and hazard (bottom). COVMH is the total COV of mean hazard; see 

Table 9.4-2 for other labels for curves. ............................................................................9-68

Figure 9.4-6 COVK and COVMH from Charleston alternatives for 1 Hz, plotted vs. 1 Hz 

amplitude (top) and hazard (bottom). COVMH is the total COV of mean hazard; see 

Table 9.4-2 for other labels for curves.. ...........................................................................9-69

Figure 9.4-7 COVK and COVMH of total hazard from New Madrid for 1 Hz, plotted vs. 1 

Hz amplitude (top) and hazard (bottom). COVMH is the total COV; see the text for 

other labels for curves......................................................................................................9-70

Figure 9.4-8 PGA hazard curves for Manchester test site .......................................................9-71

Figure 9.4-9 COVMH of PGA hazard at Manchester site from ground motion equation vs. 

PGA..................................................................................................................................9-72

Figure 9.4-10 COV of PGA hazard at Manchester site from ground motion equation vs. 

hazard ..............................................................................................................................9-73

Figure 9.4-11 COV of 10 Hz hazard at Manchester site from ground motion equations 

vs. hazard.........................................................................................................................9-74

Figure 9.4-12 COV of 1 Hz hazard at Manchester site from ground motion equations vs. 

hazard ..............................................................................................................................9-75

Figure 9.4-13 1 Hz spectral acceleration hazard curves for Manchester test site ...................9-76

Figure 9.4-14 COVMH of PGA hazard at Chattanooga from ground motion equation vs. 

hazard ..............................................................................................................................9-77

Figure 9.4-15 COVMH of 10 Hz hazard at Chattanooga from ground motion equation vs. 

hazard ..............................................................................................................................9-78

Figure 9.4-16 COVMH of 1 Hz hazard at Chattanooga site from ground motion equation 

vs. hazard.........................................................................................................................9-79

Figure 9.4-17 PGA hazard curves for Savannah test site........................................................9-80

Figure 9.4-18 COVMH of PGA hazard at Savannah site from ground motion equations vs. 

hazard ..............................................................................................................................9-81

Figure 9.4-19 COVMH of 10 Hz hazard at Savannah site from ground motion equations 

vs. hazard.........................................................................................................................9-82

Figure 9.4-20 COVMH of 1 Hz hazard at Savannah site from ground motion equations vs. 

hazard ..............................................................................................................................9-83

Figure 9.4-21 PGA hazard curves for Columbia site ...............................................................9-84

Figure 9.4-22 COVMH of PGA hazard at Columbia from ground motion equations vs. 

hazard ..............................................................................................................................9-85
liv

Figure 9.4-23 COVMH of 10 Hz hazard at Columbia from ground motion equations vs. 

hazard ..............................................................................................................................9-86

Figure 9.4-24 COVMH of 1 Hz hazard at Columbia from ground motion equations vs. 

hazard ..............................................................................................................................9-87

Figure 9.4-25 COVMH of PGA hazard at Chattanooga (New Madrid only) vs. hazard .............9-88

Figure 9.4-26 COVMH of 10 Hz hazard at Chattanooga (New Madrid only) vs. hazard............9-89

Figure 9.4-27 COVMH of 1 Hz hazard at Chattanooga (New Madrid only) vs. hazard..............9-90

Figure 9.4-28 COVMH for PGA and 1 Hz SA vs. ground motion amplitude resulting from 

alternative ground motion experts, PEGASOS project.....................................................9-91

Figure 9.4-29 COVMH for PGA and 1 Hz SA vs. mean hazard from alternative ground 

motion experts, PEGASOS project ..................................................................................9-92

Figure 9.4-30 COVHAZ from ground motion equations vs. mean hazard for Chattanooga .......9-93

Figure 9.4-31 COVMH from ground motion equations vs. mean hazard for Central Illinois ......9-94

Figure 9.4-32 COVMH from soil experts vs. PGA and 1 Hz SA, PEGASOS project .................9-95

Figure 9.4-33 COVMH from soil experts vs. mean hazard for PGA and 1 Hz SA, 

PEGASOS project............................................................................................................9-96

Figure 9.4-34 COVMH resulting from site response models vs. mean hazard for four sites, 

1 Hz (top) and 10 Hz (bottom)..........................................................................................9-97

Figure 11-1 Geologic time scale (Walker and Geissman, 2009) ...........................................11-10

Figure A-1 GEBCO elevation data for the CEUS study area (BODC, 2009). ........................ A-22

Figure A-2 CEUS SSC independent earthquake catalog ....................................................... A-24

Figure A-3 Bedrock geology and extended crust after Kanter (1994)..................................... A-26

Figure A-4 Crustal provinces after Rohs and Van Schmus (2007)......................................... A-28

Figure A-5 Geologic map of North America ............................................................................ A-31

Figure A-6 Locations of geologic cross sections in the CEUS................................................ A-33

Figure A-7 Precambrian crustal boundary after Van Schmus et al. (1996) ............................ A-35

Figure A-8a Precambrian geology and features after Reed (1993)........................................ A-37

Figure A-8b Explanation of Precambrian geology and features after Reed (1993) ................ A-38

Figure A-9 Precambrian provinces after Van Schmus et al. (2007)........................................ A-40

Figure A-10 Precambrian units after Whitmeyer and Karlstrom (2007) .................................. A-42

Figure A-11 Surficial materials in the conterminous United States after Soller et al. 

(2009).............................................................................................................................. A-44

Figure A-12 Basement and sediment thickness in the USGS Crustal Database for North 

America. Symbol size represents overlying sediment thickness (km); symbol color 

represents basement thickness (km). ............................................................................. A-46

Figure A-13 Top of basement P-wave seismic velocity in the USGS Crustal Database for 

North America ................................................................................................................. A-47

Figure A-14 Sediment thickness for North America and neighboring regions ........................ A-49

Figure A-15 Physiographic divisions of the conterminous United States after Fenneman 

and Johnson (1946) ........................................................................................................ A-51

Figure A-16 CEUS SSC free-air gravity anomaly grid. Shaded relief with 315-degree 

azimuth and 30-degree inclination applied...................................................................... A-54
lv

Figure A-17 CEUS SSC free-air gravity anomaly grid. Shaded relief with 180-degree 

azimuth and 30-degree inclination applied...................................................................... A-55

Figure A-18 CEUS SSC complete Bouguer gravity anomaly grid with free-air gravity 

anomaly in marine areas. Shaded relief with 315-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-56

Figure A-19 CEUS SSC complete Bouguer gravity anomaly grid with free-air gravity 

anomaly in marine areas. Shaded relief with 180-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-57

Figure A-20 CEUS SSC residual isostatic gravity anomaly grid. Shaded relief with 315-

degree azimuth and 30-degree inclination applied. ........................................................ A-58

Figure A-21 CEUS SSC residual isostatic gravity anomaly grid Shaded relief with 180-

degree azimuth and 30-degree inclination applied. ........................................................ A-59

Figure A-22 CEUS SSC regional isostatic gravity anomaly grid............................................. A-60

Figure A-23 CEUS SSC first vertical derivative of residual isostatic gravity anomaly grid...... A-61

Figure A-24 CEUS SSC first vertical derivative of Bouguer gravity anomaly grid with 

free-air anomaly in marine areas .................................................................................... A-62

Figure A-25 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

low pass filtered at 240 km.............................................................................................. A-63

Figure A-26 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

high pass filtered at 240 km. Shaded relief with 315-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-64

Figure A-27 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

high pass filtered at 240 km. Shaded relief with 180-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-65

Figure A-28 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

high pass filtered at 120 km. Shaded relief with 315-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-66

Figure A-29 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

high pass filtered at 120 km. Shaded relief with 180-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-67

Figure A-30 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

upward continued to 40 km ............................................................................................. A-68

Figure A-31 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

minus the complete Bouguer (with marine free-air) gravity anomaly upward 

continued to 40 km. Shaded relief with 315-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-69

Figure A-32 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

minus the complete Bouguer (with marine free-air) gravity anomaly upward 

continued to 40 km. Shaded relief with 180-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-70

Figure A-33 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

upward continued to 100 km ........................................................................................... A-71

Figure A-34 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

minus the complete Bouguer (with marine free-air) gravity anomaly anomaly 
lvi

upward continued to 100 km. Shaded relief with 315-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-72

Figure A-35 CEUS SSC complete Bouguer (with marine free-air) gravity anomaly grid 

minus the complete Bouguer (with marine free-air) gravity anomaly upward 

continued to 100 km. Shaded relief with 180-degree azimuth and 30-degree 

inclination applied............................................................................................................ A-73

Figure A-36 CEUS SSC horizontal derivative of residual isostatic gravity anomaly grid ........ A-74

Figure A-37 CEUS SSC horizontal derivative of first vertical derivative of residual 

isostatic gravity anomaly grid .......................................................................................... A-75

Figure A-38 Corrected heat flow values from the SMU Geothermal Laboratory Regional 

Heat Flow Database (2008) ............................................................................................ A-77

Figure A-39 CEUS SSC total intensity magnetic anomaly grid (Ravat et al., 2009). 

Shaded relief with 315-degree azimuth and 30-degree inclination applied..................... A-80

Figure A-40 CEUS SSC total intensity magnetic anomaly grid (Ravat et al., 2009). 

Shaded relief with 180-degree azimuth and 30-degree inclination applied..................... A-81

Figure A-41 CEUS SSC differentially reduced to pole magnetic anomaly grid (Ravat, 

2009). Shaded relief with 315-degree azimuth and 30-degree inclination applied.......... A-82

Figure A-42 CEUS SSC differentially reduced to pole magnetic anomaly grid (Ravat, 

2009). Shaded relief with 180-degree azimuth and 30-degree inclination applied.......... A-83

Figure A-43 CEUS SSC tilt derivative of differentially reduced to pole magnetic anomaly 

grid (degrees) (Ravat, 2009)........................................................................................... A-84

Figure A-44 CEUS SSC horizontal derivative of tilt derivative of differentially reduced to 

pole magnetic anomaly grid (radians) (Ravat, 2009) ...................................................... A-85

Figure A-45 CEUS SSC tilt derivative of differentially reduced to pole magnetic anomaly 

grid (Ravat, 2009) ........................................................................................................... A-86

Figure A-46 CEUS SSC amplitude of analytic signal magnetic anomaly grid (Ravat, 

2009)............................................................................................................................... A-87

Figure A-47 CEUS SSC paleoliquefaction database .............................................................. A-89

Figure A-48 CEUS SSC compilation of seismic reflection and seismic refraction lines.......... A-91

Figure A-49 USGS National Seismic Hazard Maps (Petersen et al., 2008) ........................... A-93

Figure A-50 USGS NSHM ground motion hazard at spectral acceleration of 1 hz with 2% 

probability of exceedance in 50 years (Petersen et al., 2008) ........................................ A-94

Figure A-51 USGS NSHM ground motion hazard at spectral acceleration of 1 hz with 5% 

probability of exceedance in 50 years (Petersen et al., 2008) ........................................ A-95

Figure A-52 USGS NSHM ground motion hazard at spectral acceleration of 1 hz with 

10% probability of exceedance in 50 years (Petersen et al., 2008) ................................ A-96

Figure A-53 USGS NSHM ground motion hazard at spectral acceleration of 3 hz with 2% 

probability of exceedance in 50 years (Petersen et al., 2008) ........................................ A-97

Figure A-54 USGS NSHM ground motion hazard at spectral acceleration of 3 hz with 5% 

probability of exceedance in 50 years (Petersen et al., 2008) ........................................ A-98

Figure A-55 USGS NSHM ground motion hazard at spectral acceleration of 3 hz with 

10% probability of exceedance in 50 years (Petersen et al., 2008) ................................ A-99

Figure A-56 USGS NSHM ground motion hazard at spectral acceleration of 5 hz with 2% 

probability of exceedance in 50 years (Petersen et al., 2008) ...................................... A-100
lvii

Figure A-57 USGS NSHM ground motion hazard at spectral acceleration of 5 hz with 5% 

probability of exceedance in 50 years (Petersen et al., 2008) ...................................... A-101

Figure A-58 USGS NSHM ground motion hazard at spectral acceleration of 5 hz with 

10% probability of exceedance in 50 years (Petersen et al., 2008).............................. A-102

Figure A-59 USGS NSHM peak ground acceleration with 2% probability of exceedance 

in 50 years (Petersen et al., 2008)................................................................................ A-103

Figure A-60 USGS NSHM peak ground acceleration with 5% probability of exceedance 

in 50 years (Petersen et al., 2008)................................................................................ A-104

Figure A-61 USGS NSHM peak ground acceleration with 10% probability of exceedance 

in 50 years (Petersen et al., 2008)................................................................................ A-105

Figure A-62 Deformation of the North American Plate interior using GPS station data 

(Calais et al., 2006)....................................................................................................... A-107

Figure A-63 Stress measurement update for the CEUS (Hurd, 2010).................................. A-110

Figure A-64 CEUS SSC Project study area boundary.......................................................... A-112

Figure A-65 USGS Quaternary fault and fold database (USGS, 2006)................................ A-114

Figure A-66 Quaternary features compilation for the CEUS (Crone and Wheeler, 2000; 

Wheeler, 2005; USGS, 2010) ....................................................................................... A-116

Figure A-67 CEUS Mesozoic rift basins after Benson (1992)............................................... A-118

Figure A-68 CEUS Mesozoic rift basins after Dennis et al. (2004)....................................... A-120

Figure A-69 CEUS Mesozoic rift basins after Schlische (1993)............................................ A-122

Figure A-70 CEUS Mesozoic rift basins after Withjack et al. (1998)..................................... A-124

Figure A-71 RLME zones for the CEUS ............................................................................... A-126

Figure A-72 Mesozoic and non-Mesozoic zones for the CEUS, wide interpretation............. A-128

Figure A-73 Mesozoic and non-Mesozoic zones for the CEUS, narrow interpretation......... A-129

Figure A-74 CEUS seismotectonic zones model A............................................................... A-130

Figure A-75 CEUS seismotectonic zones model B............................................................... A-131

Figure A-76 CEUS seismotectonic zones model C .............................................................. A-132

Figure A-77 CEUS seismotectonic zones model D .............................................................. A-133

Figure E-1 Map of CEUS showing locations of regional data sets included in the CEUS 

SSC Project paleoliquefaction database, including New Madrid seismic zone and 

surrounding region; Marianna, Arkansas, area; St. Louis region; Wabash Valley 

seismic zone and surrounding region; Arkansas-Louisiana-Mississippi region; 

Charleston seismic zone; Atlantic Coastal region and the Central Virginia seismic 

zone; Newburyport, Massachusetts, and surrounding region; and Charlevoix 

seismic zone and surrounding region. ............................................................................ E-68

Figure E-2 Diagram illustrating size parameters of liquefaction features, including sand 

blow thickness, width, and length; dike width; and sill thickness, as well as some of 

the diagnostic characteristics of these features. ............................................................. E-69

Figure E-3 Diagram illustrating sampling strategy for dating of liquefaction features as 

well as age data, such as 14C maximum and 14C minimum, used to calculate 

preferred age estimates and related uncertainties of liquefaction features..................... E-70

Figure E-4 GIS map of New Madrid seismic zone and surrounding region showing 

portions of rivers searched for earthquake-induced liquefaction features by M. 
lviii

Tuttle, R. Van Arsdale, and J. Vaughn and collaborators (see explanation); 

information contributed for this report. Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................... E-71

Figure E-5 GIS map of New Madrid seismic zone and surrounding region showing 

locations of liquefaction features for which there are and are not radiocarbon data. 

Map projection is USA Contiguous Albers Equal Area Conic, North America Datum 

1983. ............................................................................................................................... E-72

Figure E-6 GIS map of New Madrid seismic zone and surrounding region showing 

locations of liquefaction features that are thought to be historical or prehistoric in 

age or whose ages are poorly constrained. Map projection is USA Contiguous 

Albers Equal Area Conic, North America Datum 1983. .................................................. E-73

Figure E-7 GIS map of New Madrid seismic zone and surrounding region showing 

preferred age estimates of liquefaction features; features whose ages are poorly 

constrained are excluded. Map projection is USA Contiguous Albers Equal Area 

Conic, North America Datum 1983. ................................................................................ E-74

Figure E-8 GIS map of New Madrid seismic zone and surrounding region showing 

measured thicknesses of sand blows. Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................... E-75

Figure E-9 GIS map of New Madrid seismic zone and surrounding region showing 

preferred age estimates and measured thicknesses of sand blows. Map projection 

is USA Contiguous Albers Equal Area Conic, North America Datum 1983. ................... E-76

Figure E-10 GIS map of New Madrid seismic zone and surrounding region showing 

measured widths of sand dikes. Map projection is USA Contiguous Albers Equal 

Area Conic, North America Datum 1983......................................................................... E-77

Figure E-11 GIS map of New Madrid seismic zone and surrounding region showing 

preferred age estimates and measured widths of sand dikes. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................... E-78

Figure E-12 GIS map of New Madrid seismic zone and surrounding region illustrating 

preferred age estimates and measured thicknesses of sand blows as well as 

preferred age estimates and measured widths of sand dikes for sites where sand 

blows do not occur. Map projection is USA Contiguous Albers Equal Area Conic, 

North America Datum 1983............................................................................................. E-79

Figure E-13 GIS map of Marianna, Arkansas, area showing seismicity and locations of 

paleoliquefaction features relative to mapped traces of Eastern Reelfoot rift margin 

fault, White River fault zone, Big Creek fault zone, Marianna escarpment, and 

Daytona Beach lineament. Map projection is USA Contiguous Albers Equal Area 

Conic, North America Datum 1983. ................................................................................ E-80

Figure E-14 (A) Trench log and (B) ground-penetrating radar profile, showing vertical 

sections of sand blows and sand dikes at Daytona Beach SE2 site along the 

Daytona Beach lineament southwest of Marianna, Arkansas. Vertical scale of GPR 

profile is exaggerated (modified from Al-Shukri et al., 2009). ......................................... E-81

Figure E-15 GIS map of Marianna, Arkansas, area showing locations of liquefaction 

features for which there are and are not radiocarbon data. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................... E-82

Figure E-16 GIS map of Marianna, Arkansas, area showing locations of liquefaction 

features that are thought to be historical or prehistoric in age or whose ages are 

poorly constrained. To date, no liquefaction features thought to have formed during 
lix

1811-1812 earthquakes have been found in area. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................... E-83

Figure E-17 GIS map of Marianna, Arkansas, area showing preferred age estimates of 

liquefaction features; features whose ages are poorly constrained are excluded. 

Map projection is USA Contiguous Albers Equal Area Conic, North America Datum 

1983. ............................................................................................................................... E-84

Figure E-18 GIS map of Marianna, Arkansas, area showing measured thicknesses of 

sand blows. Map projection is USA Contiguous Albers Equal Area Conic, North 

America Datum 1983. ..................................................................................................... E-85

Figure E-19 GIS map of Marianna, Arkansas, area showing preferred age estimates and 

measured thicknesses of sand blows. Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................... E-86

Figure E-20 GIS map of Marianna, Arkansas, area showing measured widths of sand 

dikes. Map projection is USA Contiguous Albers Equal Area Conic, North America 

Datum 1983..................................................................................................................... E-87

Figure E-21 GIS map of Marianna, Arkansas, area showing preferred age estimates and 

measured widths of sand dikes. Map projection is USA Contiguous Albers Equal 

Area Conic, North America Datum 1983......................................................................... E-88

Figure E-22 GIS map of St. Louis, Missouri, region showing seismicity and portions of 

rivers searched for earthquake-induced liquefaction features by Tuttle and 

collaborators; information contributed for this report. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................... E-89

Figure E-23 GIS map of St. Louis, Missouri, region showing locations of liquefaction 

features, including several soft-sediment deformation structures, for which there are 

and are not radiocarbon data. Map projection is USA Contiguous Albers Equal Area 

Conic, North America Datum 1983. ................................................................................ E-90

Figure E-24 GIS map of St. Louis, Missouri, region showing locations of liquefaction 

features that are thought to be historical or prehistoric in age or whose ages are 

poorly constrained. Map projection is USA Contiguous Albers Equal Area Conic, 

North America Datum 1983............................................................................................. E-91

Figure E-25 GIS map of St. Louis, Missouri, region showing preferred age estimates of 

liquefaction features; features whose ages are poorly constrained, including several 

that are prehistoric in age, are not shown. Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................... E-92

Figure E-26 GIS map of St. Louis, Missouri, region showing measured thicknesses of 

sand blows at similar scale as used in Figure E-8 of sand blows in New Madrid 

seismic zone. Note that few sand blows have been found in St. Louis region. Map 

projection is USA Contiguous Albers Equal Area Conic, North America Datum 

1983. ............................................................................................................................... E-93

Figure E-27 GIS map of St. Louis, Missouri, region showing preferred age estimates and 

measured thicknesses of sand blows. Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................... E-94

Figure E-28 GIS map of St. Louis, Missouri, region showing measured widths of sand 

dikes at similar scale as that used in Figure E-10 for sand dikes in New Madrid 

seismic zone. Map projection is USA Contiguous Albers Equal Area Conic, North 

America Datum 1983. ..................................................................................................... E-95
lx

Figure E-29 GIS map of St. Louis, Missouri, region showing measured widths of sand 

dikes at similar scale as that used in Figures E-42 and E-48 for sand dikes in the 

Newburyport and Charlevoix regions, respectively. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................... E-96

Figure E-30 GIS map of St. Louis, Missouri, region showing preferred age estimates and 

measured widths of sand dikes. Map projection is USA Contiguous Albers Equal 

Area Conic, North America Datum 1983......................................................................... E-97

Figure E-31 GIS map of Wabash Valley seismic zone and surrounding region showing 

portions of rivers searched for earthquake-induced liquefaction features (digitized 

from McNulty and Obermeier, 1999). Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................... E-98

Figure E-32 GIS map of Wabash Valley seismic zone and surrounding region showing 

measured widths of sand dikes at similar scale as that used in Figures E-10 and E11 for sand dikes in New Madrid seismic zone. Map projection is USA Contiguous 

Albers Equal Area Conic, North America Datum 1983. .................................................. E-99

Figure E-33 GIS map of Wabash Valley region of Indiana and Illinois showing preferred 

age estimates and paleoearthquake interpretation. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................. E-100

Figure E-34 GIS map of Arkansas-Louisiana-Mississippi (ALM) region showing 

paleoliquefaction study locations. Map projection is USA Contiguous Albers Equal 

Area Conic, North America Datum 1983....................................................................... E-101

Figure E-35 GIS map of Charleston, South Carolina, region showing locations of 

paleoliquefaction features for which there are and are not radiocarbon dates. Map 

projection is USA Contiguous Albers Equal Area Conic, North America Datum 

1983. ............................................................................................................................. E-102

Figure E-36 GIS map of Charleston, South Carolina, region showing locations of 

historical and prehistoric liquefaction features. Map projection is USA Contiguous 

Albers Equal Area Conic, North America Datum 1983. ................................................ E-103

Figure E-37 Map of Atlantic coast region showing areas searched for paleoliquefaction 

features by Gelinas et al. (1998) and Amick, Gelinas, et al. (1990). Rectangles 

indicate 7.5-minute quadrangles in which sites were investigated for presence of 

paleoliquefaction features. The number of sites investigated is shown within that 

quadrangle, if known. Orange and yellow indicate quadrangles in which 

paleoliquefaction features were recognized.................................................................. E-104

Figure E-38 Map of Central Virginia seismic zone region showing portions of rivers 

searched for earthquake-induced liquefaction features by Obermeier and McNulty 

(1998)............................................................................................................................ E-105

Figure E-39 GIS map of Newburyport, Massachusetts, and surrounding region showing 

seismicity and portions of rivers searched for earthquake-induced liquefaction 

features (Gelinas et al., 1998; Tuttle, 2007, 2009). Solid black line crossing map 

represents Massachusetts–New Hampshire border. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................. E-106

Figure E-40 GIS map of Newburyport, Massachusetts, and surrounding region showing 

locations of liquefaction features for which there are and are not radiocarbon dates. 

Map projection is USA Contiguous Albers Equal Area Conic, North America Datum 

1983. ............................................................................................................................. E-107
lxi

Figure E-41 GIS map of Newburyport, Massachusetts, and surrounding region showing 

locations of liquefaction features that are thought to be historical or prehistoric in 

age or whose ages are poorly constrained. Map projection is USA Contiguous 

Albers Equal Area Conic, North America Datum 1983. ................................................ E-108

Figure E-42 GIS map of Newburyport, Massachusetts, and surrounding region showing 

measured widths of sand dikes. Map projection is USA Contiguous Albers Equal 

Area Conic, North America Datum 1983....................................................................... E-109

Figure E-43 GIS map of Newburyport, Massachusetts, and surrounding region showing 

preferred age estimates and measured widths of sand dikes. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................. E-110

Figure E-44 Map of Charlevoix seismic zone and adjacent St. Lawrence Lowlands 

showing mapped faults and portions of rivers along which reconnaissance and 

searches for earthquake-induced liquefaction features were performed. Charlevoix 

seismic zone is defined by concentration of earthquakes and locations of historical 

earthquakes northeast of Quebec City. Devonian impact structure in vicinity of 

Charlevoix seismic zone is outlined by black dashed line. Taconic thrust faults are 

indicated by solid black lines with sawteeth on upper plate; Iapetan rift faults are 

shown by solid black lines with hachure marks on downthrown side (modified from 

Tuttle and Atkinson, 2010). ........................................................................................... E-111

Figure E-45 GIS map of Charlevoix seismic zone and surrounding region showing 

locations of liquefaction features, including several soft-sediment deformation 

structures, for which there are and are not radiocarbon data. Note the location of 

1988 M 5.9 Saguenay earthquake northwest of the Charlevoix seismic zone. Map 

projection is USA Contiguous Albers Equal Area Conic, North America Datum 

1983. ............................................................................................................................. E-112

Figure E-46 GIS map of Charlevoix seismic zone and surrounding region showing 

locations of liquefaction features that are modern, historical, or prehistoric in age, or 

whose ages are poorly constrained. Map projection is USA Contiguous Albers 

Equal Area Conic, North America Datum 1983............................................................. E-113

Figure E-47 GIS map of Charlevoix seismic zone and surrounding region showing 

preferred age estimates of liquefaction features; features whose ages are poorly 

constrained are excluded. Map projection is USA Contiguous Albers Equal Area 

Conic, North America Datum 1983. .............................................................................. E-114

Figure E-48 GIS map of Charlevoix seismic zone and surrounding region showing 

measured widths of sand dikes. Map projection is USA Contiguous Albers Equal 

Area Conic, North America Datum 1983....................................................................... E-115

Figure E-49 GIS map of Charlevoix seismic zone and surrounding region showing 

preferred age estimates and measured widths of sand dikes. Map projection is USA 

Contiguous Albers Equal Area Conic, North America Datum 1983. ............................. E-116

Figure E-50 Photograph of moderate-sized sand blow (12 m long, 7 m wide, and 14 cm 

thick) that formed about 40 km from epicenter of 2001 M 7.7 Bhuj, India, 

earthquake (from Tuttle, Hengesh, et al., 2002), combined with schematic vertical 

section illustrating structural and stratigraphic relations of sand blow, sand dike, and 

source layer (modified from Sims and Garvin, 1995).................................................... E-117

Figure E-51 Tree trunks buried and killed by sand blows, vented during 1811-1812 New 

Madrid earthquakes (from Fuller, 1912)........................................................................ E-118
lxii

Figure E-52 Large sand-blow crater that formed during 2002 M 7.7 Bhuj, India, 

earthquake. Backpack for scale. Photograph: M. Tuttle (2001). ................................... E-119

Figure E-53 Sand-blow crater that formed during 1886 Charleston, South Carolina, 

earthquake. Photograph: J.K. Hillers (from USGS Photograph Library). ...................... E-120

Figure E-54 Photograph of sand blow and related sand dikes exposed in trench wall and 

floor in New Madrid seismic zone. Buried soil horizon is displaced downward 

approximately 1 m across two dikes. Clasts of soil horizon occur within dikes and 

overlying sand blow. Degree of soil development above and within sand blow 

suggests that it is at least several hundred years old and formed prior to 1811-1812 

New Madrid earthquakes. Organic sample (location marked by red flag) from crater 

fill will provide close minimum age constraint for formation of sand blow. For scale, 

each colored intervals on shovel handle represents 10 cm. Photograph: M. Tuttle...... E-121

Figure E-55 Sand dikes, ranging up to 35 cm wide, originate in pebbly sand layer and 

intrude overlying diamicton, These features were exposed in cutbank along 

Cahokia Creek about 25 km northeast of downtown St. Louis (from Tuttle, 2000)....... E-122

Figure E-56 Photograph of small diapirs of medium sand intruding base of overlying 

deposit of interbedded clayey silt and very fine sand, and clasts of clayey silt in 

underlying medium sand, observed along Ouelle River in Charlevoix seismic zone. 

Sand diapirs and clasts probably formed during basal erosion and foundering of 

clayey silt due to liquefaction of the underlying sandy deposit. Red portion of shovel 

handle represents 10 cm (modified from Tuttle and Atkinson, 2010)............................ E-123

Figures E-57 (A) Load cast formed in laminated sediments of Van Norman Lake during 

1952 Kern County, California, earthquake. Photograph: J. Sims (from Sims, 1975). 

(B) Load cast, pseudonodules, and related folds formed in laminated sediment 

exposed along Malbaie River in Charlevoix seismic zone. Sand dikes crosscutting 

these same laminated sediments occur at a nearby site. For scale, each painted 

interval of the shovel handle represents 10 cm (modified from Tuttle and Atkinson, 

2010). ............................................................................................................................ E-124

Figure E-58 Log of sand blow and uppermost portions of related sand dikes exposed in 

trench wall at Dodd site in New Madrid seismic zone. Sand dikes were also 

observed in opposite wall and trench floor. Sand blow buries pre-event A horizon, 

and a subsequent A horizon has developed in top of sand blow. Radiocarbon dating 

of samples collected above and below sand blow brackets its age between 490 and 

660 yr BP. Artifact assemblage indicates that sand blow formed during late 

Mississippian (300–550 yr BP or AD 1400–1670) (modified from Tuttle, Collier, et 

al., 1999). ...................................................................................................................... E-125

Figures E-59 (A) Photograph of earthquake-induced liquefaction features found in 

association with cultural horizon and pit exposed in trench wall near Blytheville, 

Arkansas, in New Madrid seismic zone. Photograph: M. Tuttle. (B) Trench log of 

features shown in (A). Sand dike formed in thick Native American occupation 

horizon containing artifacts of early Mississippian cultural period (950–1,150 yr BP). 

Cultural pit dug into top of sand dike contains artifacts and charcoal used to 

constrain minimum age of liquefaction features (modified from Tuttle and Schweig, 

1995). ............................................................................................................................ E-126

Figure E-60 In situ tree trunks such as this one buried and killed by sand blow in New 

Madrid seismic zone offer opportunity to date paleoearthquakes to the year and 

season of occurrence. Photograph: M. Tuttle. .............................................................. E-127
lxiii

Figure E-61 Portion of dendrocalibration curve illustrating conversion of radiocarbon age 

to calibrated date in calendar years. In example, 2-sigma radiocarbon age of 2,280–

2,520 BP is converted to calibrated date of 770–380 BC (from Tuttle, 1999)............... E-128

Figure E-62 Empirical relation developed between A horizon thickness of sand blows 

and years of soil development in New Madrid region. Horizontal bars reflect 

uncertainties in age estimates of liquefaction features; diamonds mark midpoints of 

possible age ranges (from Tuttle et al., 2000)............................................................... E-129

Figure E-63 Diagram illustrating earthquake chronology for New Madrid seismic zone for 

past 5,500 years based on dating and correlation of liquefaction features at sites 

(listed at top) across region from north to south. Vertical bars represent age 

estimates of individual sand blows, and horizontal bars represent event times of 

138 yr BP (AD 1811-1812); 500 yr BP ± 150 yr; 1,050 yr BP ± 100 yr; and 4,300 yr 

BP ± 200 yr (modified from Tuttle, Schweig, et al., 2002; Tuttle et al., 2005). .............. E-130

Figure E-64 Diagram illustrating earthquake chronology for New Madrid seismic zone for 

past 2,000 years, similar to upper portion of diagram shown in Figure E-63. As in 

Figure E-63, vertical bars represent age estimates of individual sand blows, and 

horizontal bars represent event times. Analysis performed during CEUS SSC 

Project derived two possible uncertainty ranges for timing of paleoearthquakes, 

illustrated by the darker and lighter portions of the colored horizontal bars, 

respectively: 503 yr BP ± 8 yr or 465 yr BP ± 65 yr, and 1,110 yr BP ± 40 yr or 1055 

± 95 yr (modified from Tuttle, Schweig, et al., 2002)..................................................... E-131

Figure E-65 Maps showing spatial distributions and sizes of sand blows and sand dikes 

attributed to 500 and 1,050 yr BP events. Locations and sizes of liquefaction 

features that formed during AD 1811-1812 (138 yr BP) New Madrid earthquake 

sequence shown for comparison (modified from Tuttle, Schweig, et al., 2002)............ E-132

Figure E-66 Liquefaction fields for 138 yr BP (AD 1811-1812); 500 yr BP (AD 1450); and 

1,050 yr BP (AD 900) events as interpreted from spatial distribution and 

stratigraphy of sand blows (modified from Tuttle, Schweig, et al., 2002). Ellipses 

define areas where similar-age sand blows have been mapped. Overlapping 

ellipses indicate areas where sand blows are composed of multiple units that 

formed during sequence of earthquakes. Dashed ellipse outlines area where 

historical sand blows are composed of four depositional units. Magnitudes of 

earthquakes in 500 yr BP and 1,050 yr BP are inferred from comparison with 1811-

1812 liquefaction fields. Magnitude estimates of December (D), January (J), and 

February (F) main shocks and large aftershocks taken from several sources; 

rupture scenario from Johnston and Schweig (1996; modified from Tuttle, Schweig, 

et al., 2002). .................................................................................................................. E-133

Figure E-67 Empirical relation between earthquake magnitude and epicentral distance to 

farthest known sand blows induced by instrumentally recorded earthquakes 

(modified from Castilla and Audemard, 2007)............................................................... E-134

Figure E-68 Distances to farthest known liquefaction features indicate that 500 and 

1,050 yr BP New Madrid events were at least of M 6.7 and 6.9, respectively, when 

plotted on Ambraseys (1988) relation between earthquake magnitude and 

epicentral distance to farthest surface expression of liquefaction. Similarity in size 

distribution of historical and prehistoric sand blows, however, suggests that 

paleoearthquakes were comparable in magnitude to 1811-1812 events or M ~7.6 

(modified from Tuttle, 2001). ......................................................................................... E-135

Figure H-1-1 Region covered by the CEUS SSC model......................................................... H-44
lxiv

Figure H-2-1 Master logic tree for the CEUS SSC model....................................................... H-45

Figure H-3-1 Logic tree for the Mmax zones branch of the master logic tree......................... H-46

Figure H-3-2 Mesozoic extended (MESE-W) and non-extended (NMESE-W) Mmax 

zones for the “wide” interpretation................................................................................... H-47

Figure H-3-3 Mesozoic extended (MESE-N) and non-extended (NMESE-N) Mmax zones 

for the “narrow” interpretation.......................................................................................... H-48

Figure H-4-1(a) Logic tree for the seismotectonic zones branch of the master logic tree....... H-49

Figure H-4-1(b) Logic tree for the seismotectonic zones branch of the master logic tree....... H-50

Figure H-4-2 Seismotectonic zones shown in the case where the Rough Creek Graben 

is not part of the Reelfoot Rift (RR) and the Paleozoic Extended zone is narrow 

(PEZ-N)........................................................................................................................... H-51

Figure H-4-3 Seismotectonic zones shown in the case where the Rough Creek Graben 

is part of the Reelfoot Rift (RR-RCG) and the Paleozoic Extended zone is narrow 

(PEZ-N)........................................................................................................................... H-52

Figure H-4-4 Seismotectonic zones shown in the case where the Rough Creek Graben 

is not part of the Reelfoot Rift (RR) and the Paleozoic Extended zone is wide (PEZW).................................................................................................................................... H-53

Figure H-4-5 Seismotectonic zones shown in the case where the Rough Creek Graben 

is part of the Reelfoot Rift (RR-RCG) and the Paleozoic Extended zone is wide 

(PEZ-W) .......................................................................................................................... H-54

Figure H-5-1 Logic tree for the RLME source branch of the master logic tree........................ H-55

Figure H-5-2 Location of RLME sources in the CEUS SSC model......................................... H-56

Figure H-5.1-1 Logic tree for Charlevoix RLME source .......................................................... H-57

Figure H-5.1-2 Charlevoix RLME source geometry ................................................................ H-58

Figure H-5.2-1(a) Logic tree for Charleston RLME source ..................................................... H-59

Figure H-5.2-1(b) Logic tree for Charleston RLME source ..................................................... H-60

Figure H-5.2-2 Charleston RLME alternative source geometries ........................................... H-61

Figure H-5.3-1 Logic tree for Cheraw RLME source............................................................... H-62

Figure H-5.3-2 Cheraw RLME source geometry..................................................................... H-63

Figure H-5.4-1 Logic tree for Meers RLME source ................................................................. H-64

Figure H-5.4-2 Meers RLME source geometries .................................................................... H-65

Figure H-5.5-1 Logic tree for NMFS RLME source................................................................. H-66

Figure H-5.5-2 New Madrid South (NMS) fault alternative RMLE source geometries: 

Blytheville Arch-Bootheel Lineament (BA-BL) and Blytheville Arch-Blytheville fault 

zone (BA-BFZ) ................................................................................................................ H-67

Figure H-5.5-3 New Madrid North (NMN) fault alternative RMLE source geometries: New 

Madrid North (NMN_S) and New Madrid North plus extension (NMN_L)....................... H-68

Figure H-5.5-4 Reelfoot Thrust (RFT) fault alternative RMLE source geometries: 

Reelfoot thrust (RFT_S) and Reelfoot thrust plus extensions (RFT_L)........................... H-69

Figure H-5.6-1 Logic tree for ERM-S RLME source ............................................................... H-70

Figure H-5.6-2 Logic tree for ERM-N RLME source ............................................................... H-71

Figure H-5.6-3 ERM-S RLME source geometries................................................................... H-72
lxv

Figure H-5.6-4 ERM-N RLME source geometry ..................................................................... H-73

Figure H-5.7-1 Logic tree for Marianna RLME source ............................................................ H-74

Figure H-5.7-2 Marianna RLME source geometry .................................................................. H-75

Figure H-5.8-1 Logic tree for Commerce Fault Zone RLME source ....................................... H-76

Figure H-5.8-2 Commerce RLME source geometry ............................................................... H-77

Figure H-5.9-1 Logic tree for Wabash Valley RLME source ................................................... H-78

Figure H-5.9-2 Wabash Valley RLME source geometry ......................................................... H-79

Figure J-1 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 1 ........................................................................................................J-2

Figure J-2 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 2 ........................................................................................................J-3

Figure J-3 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 3 ........................................................................................................J-4

Figure J-4 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 4 ........................................................................................................J-5

Figure J-5 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 5 ........................................................................................................J-6

Figure J-6 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 6 ........................................................................................................J-7

Figure J-7 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 7 ........................................................................................................J-8

Figure J-8 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 8 ........................................................................................................J-9

Figure J-9 Map of the coefficient of variation of the rate and the standard deviation of the 

b-value for the study region under the Mmax zonation, with no separation of 

Mesozoic extended and non-extended; Case A magnitude weights................................J-10

Figure J-10 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 1 ......................................................................................................J-11

Figure J-11 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 2 ......................................................................................................J-12

Figure J-12 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 3 ......................................................................................................J-13
lxvi

Figure J-13 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 4 ......................................................................................................J-14

Figure J-14 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 5 ......................................................................................................J-15

Figure J-15 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 6 ......................................................................................................J-16

Figure J-16 Map of the rate and b-value for the study region under the Mmax zonation,

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 7 ......................................................................................................J-17

Figure J-17 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 8 ......................................................................................................J-18

Figure J-18 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with no separation of 

Mesozoic extended and non-extended; Case B magnitude weights................................J-19

Figure J-19 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 1 ......................................................................................................J-20

Figure J-20 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 2 ......................................................................................................J-21

Figure J-21 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 3 ......................................................................................................J-22

Figure J-22 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 4 ......................................................................................................J-23

Figure J-23 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 5 ......................................................................................................J-24

Figure J-24 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 6 ......................................................................................................J-25

Figure J-25 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 7 ......................................................................................................J-26

Figure J-26 Map of the rate and b-value for the study region under the Mmax zonation, 

with no separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 8 ......................................................................................................J-27

Figure J-27 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with no separation of 

Mesozoic extended and non-extended; Case E magnitude weights................................J-28
lxvii

Figure J-28 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 1 ......................................................................................................J-29

Figure J-29 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 2 ......................................................................................................J-30

Figure J-30 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 3 ......................................................................................................J-31

Figure J-31 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 4 ......................................................................................................J-32

Figure J-32 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 5 ......................................................................................................J-33

Figure J-33 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 6 ......................................................................................................J-34

Figure J-34 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 7 ......................................................................................................J-35

Figure J-35 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 8 ......................................................................................................J-36

Figure J-36 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with separation of 

Mesozoic extended and non-extended; Case A magnitude weights................................J-37

Figure J-37 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 1 ......................................................................................................J-38

Figure J-38 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 2 ......................................................................................................J-39

Figure J-39 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 3 ......................................................................................................J-40

Figure J-40 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 4 ......................................................................................................J-41

Figure J-41 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 5 ......................................................................................................J-42

Figure J-42 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 6 ......................................................................................................J-43
lxviii

Figure J-43 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 7 ......................................................................................................J-44

Figure J-44 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 8 ......................................................................................................J-45

Figure J-45 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with separation of 

Mesozoic extended and non-extended; Case B magnitude weights................................J-46

Figure J-46 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 1 ......................................................................................................J-47

Figure J-47 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 2 ......................................................................................................J-48

Figure J-48 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 3 ......................................................................................................J-49

Figure J-49 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 4 ......................................................................................................J-50

Figure J-50 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 5 ......................................................................................................J-51

Figure J-51 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 6 ......................................................................................................J-52

Figure J-52 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 7 ......................................................................................................J-53

Figure J-53 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 8 ......................................................................................................J-54

Figure J-54 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with separation of 

Mesozoic extended and non-extended; Case E magnitude weights................................J-55

Figure J-55 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 1 ......................................................................................................J-56

Figure J-56 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 2 ......................................................................................................J-57

Figure J-57 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 3 ......................................................................................................J-58
lxix

Figure J-58 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 4 ......................................................................................................J-59

Figure J-59 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 5 ......................................................................................................J-60

Figure J-60 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 6 ......................................................................................................J-61

Figure J-61 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 7 ......................................................................................................J-62

Figure J-62 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case A magnitude 

weights: Realization 8 ......................................................................................................J-63

Figure J-63 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with separation of 

Mesozoic extended and non-extended; Case A magnitude weights................................J-64

Figure J-64 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 1 ......................................................................................................J-65

Figure J-65 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 2 ......................................................................................................J-66

Figure J-66 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 3 ......................................................................................................J-67

Figure J-67 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 4 ......................................................................................................J-68

Figure J-68 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 5 ......................................................................................................J-69

Figure J-69 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 6 ......................................................................................................J-70

Figure J-70 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 7 ......................................................................................................J-71

Figure J-71 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case B magnitude 

weights: Realization 8 ......................................................................................................J-72

Figure J-72 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with separation of 

Mesozoic extended and non-extended; Case B magnitude weights................................J-73
lxx

Figure J-73 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 1 ......................................................................................................J-74

Figure J-74 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 2 ......................................................................................................J-75

Figure J-75 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 3 ......................................................................................................J-76

Figure J-76 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 4 ......................................................................................................J-77

Figure J-77 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 5 ......................................................................................................J-78

Figure J-78 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 6 ......................................................................................................J-79

Figure J-79 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 7 ......................................................................................................J-80

Figure J-80 Map of the rate and b-value for the study region under the Mmax zonation, 

with separation of Mesozoic extended and non-extended; Case E magnitude 

weights: Realization 8 ......................................................................................................J-81

Figure J-81 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the Mmax zonation, with separation of 

Mesozoic extended and non-extended; Case E magnitude weights................................J-82

Figure J-82 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

1 .......................................................................................................................................J-83

Figure J-83 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

2 .......................................................................................................................................J-84

Figure J-84 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

3 .......................................................................................................................................J-85

Figure J-85 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

4 .......................................................................................................................................J-86

Figure J-86 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

5 .......................................................................................................................................J-87

Figure J-87 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

6 .......................................................................................................................................J-88
lxxi

Figure J-88 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

7 .......................................................................................................................................J-89

Figure J-89 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

8 .......................................................................................................................................J-90

Figure J-90 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with narrow 

interpretation of PEZ; Case A magnitude weights ...........................................................J-91

Figure J-91 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

1 .......................................................................................................................................J-92

Figure J-92 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

2 .......................................................................................................................................J-93

Figure J-93 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

3 .......................................................................................................................................J-94

Figure J-94 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

4 .......................................................................................................................................J-95

Figure J-95 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

5 .......................................................................................................................................J-96

Figure J-96 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

6 .......................................................................................................................................J-97

Figure J-97 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

7 .......................................................................................................................................J-98

Figure J-98 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

8 .......................................................................................................................................J-99

Figure J-99 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with narrow 

interpretation of PEZ; Case B magnitude weights .........................................................J-100

Figure J-100 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

1 .....................................................................................................................................J-101

Figure J-101 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

2 .....................................................................................................................................J-102

Figure J-102 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

3 .....................................................................................................................................J-103
lxxii

Figure J-103 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

4 .....................................................................................................................................J-104

Figure J-104 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

5 .....................................................................................................................................J-105

Figure J-105 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

6 .....................................................................................................................................J-106

Figure J-106 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

7 .....................................................................................................................................J-107

Figure J-107 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

8 .....................................................................................................................................J-108

Figure J-108 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with narrow 

interpretation of PEZ; Case E magnitude weights .........................................................J-109

Figure J-109 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

1 .....................................................................................................................................J-110

Figure J-110 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

2 .....................................................................................................................................J-111

Figure J-111 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

3 .....................................................................................................................................J-112

Figure J-112 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

4 .....................................................................................................................................J-113

Figure J-113 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

5 .....................................................................................................................................J-114

Figure J-114 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

6 .....................................................................................................................................J-115

Figure J-115 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

7 .....................................................................................................................................J-116

Figure J-116 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case A magnitude weights: Realization 

8 .....................................................................................................................................J-117

Figure J-117 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with narrow 

interpretation of PEZ; Case A magnitude weights .........................................................J-118
lxxiii

Figure J-118 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

1 .....................................................................................................................................J-119

Figure J-119 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

2 .....................................................................................................................................J-120

Figure J-120 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

3 .....................................................................................................................................J-121

Figure J-121 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

4 .....................................................................................................................................J-122

Figure J-122 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

5 .....................................................................................................................................J-123

Figure J-123 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

6 .....................................................................................................................................J-124

Figure J-124 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

7 .....................................................................................................................................J-125

Figure J-125 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case B magnitude weights: Realization 

8 .....................................................................................................................................J-126

Figure J-126 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with narrow 

interpretation of PEZ; Case B magnitude weights .........................................................J-127

Figure J-127 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

1 .....................................................................................................................................J-128

Figure J-128 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

2 .....................................................................................................................................J-129

Figure J-129 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

3 .....................................................................................................................................J-130

Figure J-130 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

4 .....................................................................................................................................J-131

Figure J-131 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

5 .....................................................................................................................................J-132

Figure J-132 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

6 .....................................................................................................................................J-133
lxxiv

Figure J-133 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

7 .....................................................................................................................................J-134

Figure J-134 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with narrow interpretation of PEZ; Case E magnitude weights: Realization 

8 .....................................................................................................................................J-135

Figure J-135 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with narrow 

interpretation of PEZ; Case E magnitude weights .........................................................J-136

Figure J-136 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 1 ... J-137

Figure J-137 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 2 ... J-138

Figure J-138 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 3 ... J-139

Figure J-139 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 4 ... J-140

Figure J-140 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 5 ... J-141

Figure J-141 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 6 ... J-142

Figure J-142 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 7 ... J-143

Figure J-143 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 8 ... J-144

Figure J-144 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with wide

interpretation of PEZ; Case A magnitude weights .........................................................J-145

Figure J-145 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 1 ... J-146

Figure J-146 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 2 ... J-147

Figure J-147 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 3 ... J-148

Figure J-148 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 4 ... J-149

Figure J-149 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 5 ... J-150

Figure J-150 Map of the rate and b-value for the study region under the seismotectonic

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 6 ... J-151

Figure J-151 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 7 ... J-152

Figure J-152 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 8 ... J-153
lxxv

Figure J-153 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with wide 

interpretation of PEZ; Case B magnitude weights .........................................................J-154

Figure J-154 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 1 ... J-155

Figure J-155 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 2 ... J-156

Figure J-156 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 3 ... J-157

Figure J-157 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 4 ... J-158

Figure J-158 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 5 ... J-159

Figure J-159 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 6 ... J-160

Figure J-160 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 7 ... J-161

Figure J-161 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 8 ... J-162

Figure J-162 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with wide 

interpretation of PEZ; Case E magnitude weights .........................................................J-163

Figure J-163 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 1 ... J-164

Figure J-164 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 2 ... J-165

Figure J-165 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 3 ... J-166

Figure J-166 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 4 ... J-167

Figure J-167 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 5 ... J-168

Figure J-168 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 6 ... J-169

Figure J-169 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 7 ... J-170

Figure J-170 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case A magnitude weights: Realization 8 ... J-171

Figure J-171 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with wide 

interpretation of PEZ; Case A magnitude weights .........................................................J-172

Figure J-172 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 1 ... J-173
lxxvi

Figure J-173 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 2 ... J-174

Figure J-174 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 3 ... J-175

Figure J-175 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 4 ... J-176

Figure J-176 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 5 ... J-177

Figure J-177 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 6 ... J-178

Figure J-178 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 7 ... J-179

Figure J-179 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case B magnitude weights: Realization 8 ... J-180

Figure J-180 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with wide 

interpretation of PEZ; Case B magnitude weights .........................................................J-181

Figure J-181 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 1 ... J-182

Figure J-182 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 2 ... J-183

Figure J-183 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 3 ... J-184

Figure J-184 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 4 ... J-185

Figure J-185 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 5 ... J-186

Figure J-186 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 6 ... J-187

Figure J-187 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 7 ... J-188

Figure J-188 Map of the rate and b-value for the study region under the seismotectonic 

zonation, with wide interpretation of PEZ; Case E magnitude weights: Realization 8 ... J-189

Figure J-189 Map of the coefficient of variation of the rate and the standard deviation of 

the b-value for the study region under the seismotectonic zonation, with wide 

interpretation of PEZ; Case E magnitude weights .........................................................J-190

Figure K-1 Comparison of relationships between number of reporting stations and 

moment magnitude presented in Johnston et al. (1994) and Johnston (1996b)............. K-41

Figure K-2 Comparison of relationships between isoseismal areas and moment 

magnitude presented in Johnston et al. (1994) and Johnston (1996b)........................... K-42
lxxvii

LIST OF TABLES

Table 2.2-1 Technical Meetings Conducted as Part of the CEUS SSC Project.......................2-29

Table 2.2-2 Contributors to the CEUS SSC Project.................................................................2-30

Table 3.2-1 Summary of Earthquakes Added–USGS Earthquake Catalog by Time 

Period...............................................................................................................................3-44

Table 3.2-2 Summary of Earthquakes Added–USGS Earthquake Catalog by Source............3-45

Table 3.3-1 Conversion Relationships Used–Develop Uniform Moment Magnitudes E[M].....3-46

Table 3.4-1 Comparison of CEUS SSC Catalog Declustering Results Obtained Using the 

EPRI (1988) Approach with the Gardner Knopoff (1974) Approach ................................3-47

Table 3.5-1 Probability of Detection and Equivalent Periods of Completeness for the 

CEUS for Magnitude Weighting Case A ..........................................................................3-48

Table 3.5-2 Probability of Detection and Equivalent Periods of Completeness for the 

CEUS for Magnitude Weighting Case B ..........................................................................3-51

Table 3.5-3 Probability of Detection and Equivalent Periods of Completeness for the 

CEUS for Magnitude Weighting Case E ..........................................................................3-54

Table 4.1.2-1 Sample table indicating particular types of data that can be considered in 

the identification and characterization of seismic sources (Table 2, ANSI/ANS-2.27-

2008)................................................................................................................................4-26

Table 4.1.2-2 Sample table identifying the types of data that can be considered for 

characterizing different types of seismic sources, and an evaluation of the relative 

usefulness or credibility of the various data types (Budnitz et al., 1997)..........................4-27

Table 4.1.2-3 Table showing the “generic” (not source-specific) evaluation of data to 

address indicators of a unique seismic source. The table indicates the TI Team’s 

assessment of the types of data that can be used to address the indicators and 

their relative usefulness. ..................................................................................................4-28

Table 4.1.2-4 Example of Data Evaluation Table for the Illinois Basin–Extended 

Basement Zone (IBEB) ....................................................................................................4-34

Table 4.1.2-5 Example of Data Summary Table for the Extended Continental Crust–

Atlantic Margin (ECC-AM) and Atlantic Highly Extended Crust (AHEX) Zones ...............4-35

Table 4.1.3-1 Criteria Used to Define the Seismotectonic Zones and Mmax Zones ...............4-37

Table 4.2.2-1 RLME Sources...................................................................................................4-38

Table 4.2.4-1 Seismotectonic Zones .......................................................................................4-39

Table 5.2.1-1 Mesozoic-and-Younger Extended Superdomains (MESE)................................5-60

Table 5.2.1-2 Older Extended and Non-Extended Superdomains (NMESE) ..........................5-61

Table 5.2.1-3 Composite SCR Superdomains (COMP)...........................................................5-62

Table 5.2.1-4 Results of Analyses of Updated SCR Superdomains........................................5-63
lxxviii

Table 5.2.1-5 Source Zones, P(mu > 81⁄4) Values, and Weights on Kijko (2004) K-S-B 

Estimates .........................................................................................................................5-64

Table 5.2.1-6 Mmax Distributions for the Two Example Seismic Sources...............................5-65

Table 5.3.2-1 Alternative Cases Considered for the Magnitude-Dependent Weights..............5-65

Table 5.3.3-1 Miller and Rice (1983) Discrete 5-Point Approximation to a Continuous 

Probability Distribution and the Modified Form Used in This Study .................................5-65

Table 5.4-1 Assessment of Default Characteristics of Future Earthquakes in the CEUS........5-66

Table 5.4-2 Characteristics of Future Earthquakes for Individual Seismic Sources ................5-68

Table 5.4-3 Estimates of D90 for Individual Seismic Source Zones..........................................5-71

Table 6.1-1 Summary of Data Used to Assess RLME Recurrence Frequencies.....................6-80

Table 6.1.1-1 Charlevoix RLME Recurrence Frequency .........................................................6-83

Table 6.1.2-1 Summary of Interpreted Charleston Earthquake Ages and Sizes from 

“Contemporary Ages Only” Scenario ...............................................................................6-84

Table 6.1.2-2 Summary of Interpreted Charleston Earthquake Ages and Sizes from “All 

Ages” Scenario.................................................................................................................6-84

Table 6.1.2-3 Charleston Liquefaction Feature Ages Used to Assess Ages of Prehistoric 

Earthquakes .....................................................................................................................6-85

Table 6.1.2-4 Charleston RLME Recurrence Frequency for Poisson Model ...........................6-86

Table 6.1.2-5 Charleston RLME Recurrence Frequency for Renewal Model..........................6-87

Table 6.1.3-1 Range of Cheraw Fault Estimated Magnitudes (M)...........................................6-88

Table 6.1.3-2 Cheraw RLME In-Cluster Recurrence Frequency .............................................6-89

Table 6.1.3-3 Cheraw RLME In-Cluster Slip Rates .................................................................6-89

Table 6.1.3-4 Cheraw RLME Out-of-Cluster Recurrence Frequency ......................................6-90

Table 6.1.3-5 Cheraw RLME Out-of-Cluster Slip Rates ..........................................................6-90

Table 6.1.4-1 Range of Estimated Meers Fault Earthquake Magnitudes (M)..........................6-91

Table 6.1.4-2 Meers RLME In-Cluster Recurrence Frequency................................................6-91

Table 6.1.4-3 Meers RLME Out-of-Cluster Recurrence Frequency.........................................6-91

Table 6.1.5-1 Preferred Ages for Paleoearthquakes in the New Madrid Region1

...................6-92

Table 6.1.5-2 Magnitude Comparisons for New Madrid 1811-1812 Earthquake 

Sequence .........................................................................................................................6-93

Table 6.1.5-3 Liquefaction Constraints on Age of AD 1450 NMFS RLME...............................6-94

Table 6.1.5-4 Liquefaction Constraints on Age of AD 900 NMFS RLME.................................6-95

Table 6.1.5-5 NMFS In-Cluster RLME Recurrence Frequency—Poisson Model ....................6-96

Table 6.1.5-6 NMFS In-Cluster RLME Recurrence Frequency—Renewal Model ...................6-96

Table 6.1.5-7 NMFS Out-of-Cluster RLME Recurrence Frequency—Poisson Model .............6-96

Table 6.1.6-1 Range of ERM-S Estimated Magnitudes (M).....................................................6-97

Table 6.1.6-2 Range of ERM-N Estimated Magnitudes (M) ....................................................6-98

Table 6.1.6-3 ERM-S RLME Recurrence Frequency...............................................................6-98

Table 6.1.6-4 ERM-N RLME Recurrence Frequency ..............................................................6-99

Table 6.1.7-1 Marianna RLME Recurrence Frequency ...........................................................6-99
lxxix

Table 6.1.8-1 Range of Commerce Fault Zone RLME Estimated Magnitudes (M)................6-100

Table 6.1.8-2 Commerce Fault Zone RLME Recurrence Frequency.....................................6-101

Table 6.1.9-1 Liquefaction Evidence for Prehistoric Earthquakes in the Southern Illinois 

Basin ..............................................................................................................................6-102

Table 6.1.9-2 Wabash RLME Recurrence Frequency ...........................................................6-109

Table 6.2-1 Alternative Mmax Zonation Models ....................................................................6-109

Table 6.3.2-1 Maximum Magnitude Distributions for Mmax Distributed Seismicity 

Sources ..........................................................................................................................6-110

Table 7.1-1 Data Summary and Data Evaluation Tables for Seismotectonic Zones in 

Appendices C and D ........................................................................................................7-81

Table 7.4.2-1 Maximum Magnitude Distributions for Seismotectonic Distributed 

Seismicity Sources...........................................................................................................7-82

Table 8.1-1 Description of Seven Test Sites............................................................................8-13

Table 8.2.1-1 Mean and Select Fractiles for Rock Hazard at Central Illinois: Digital Data

for Figures 8.2-1a through 8.2-1c.....................................................................................8-14

Table 8.2.2-1 Mean and Select Fractiles for Rock Hazard at Chattanooga: Digital Data 

for Figures 8.2-2a through 8.2-2c.....................................................................................8-16

Table 8.2.3-1 Mean and Select Fractiles for Rock Hazard at Houston: Digital Data for 

Figures 8.2-3a through 8.2-3c..........................................................................................8-18

Table 8.2.4-1 Mean and Select Fractiles for Rock Hazard at Jackson: Digital Data for 

Figures 8.2-4a through 8.2-4c..........................................................................................8-20

Table 8.2.5-1 Mean and Select Fractiles for Rock Hazard at Manchester: Digital Data for 

Figures 8.2-5a through 8.2-5c..........................................................................................8-22

Table 8.2.6-1 Mean and Select Fractiles for Rock Hazard at Savannah: Digital Data for 

Figures 8.2-6a through 8.2-6c..........................................................................................8-24

Table 8.2.7-1 Mean and Select Fractiles for Rock Hazard at Topeka: Digital Data for 

Figures 8.2-7a through 8.2-7c..........................................................................................8-26

Table 9.4-1 Available Information for Determining the Precision of Mean Hazard ..................9-21

Table 9.4-2 Summary of an Example Logic Tree Representing Uncertainties for the 

Charleston Seismic Zone .................................................................................................9-21

Table 9.4-3 Basic Weights Given in EPRI (2004) for Ground Motion Equations .....................9-22

Table 9.4-4 Ground Motion Equations and Weights Used in USGS 2008 National Hazard 

Map for CEUS..................................................................................................................9-23

Table 9.4-5 Minimum COVMH Values Observed in Seismic Hazard ........................................9-23

Table A-1 CEUS SSC GIS Database ....................................................................................... A-7

Table B-1 Earthquake Catalog.................................................................................................. B-6

Table B-2 Moment Magnitude Data ...................................................................................... B-312

Table B-3 Approximate Moment Magnitude Data................................................................. B-324

Table C-5.4 Data Evaluation Future Earthquake Characteristics ............................................. C-3

Table C-6.1.1 Data Evaluation Charlevoix RLME..................................................................... C-9

Table C-6.1.2 Data Evaluation Charleston RLME .................................................................. C-14

Table C-6.1.3 Data Evaluation Cheraw Fault RLME .............................................................. C-30
lxxx 

Table C-6.1.4 Data Evaluation Oklahoma Aulacogen RLME ................................................. C-36 

Table C-6.1.5 Data Evaluation Reelfoot Rift–New Madrid Fault System RLMEs ................... C-42 

Table C-6.1.6 Data Evaluation Reelfoot Rift–Eastern Margin Fault(s) RLMEs ....................... C-51 

Table C-6.1.7 Data Evaluation Reelfoot Rift–Marianna RLME ............................................... C-62 

Table C-6.1.8 Data Evaluation Reelfoot Rift–Commerce Fault Zone RLME .......................... C-67 

Table C-6.1.9 Data Evaluation Wabash Valley RLME ............................................................ C-75 

Table C-7.3.1 Data Evaluation St. Lawrence Rift Zone ......................................................... C-83 

Table C-7.3.2 Data Evaluation Great Meteor Hotspot Zone ................................................... C-92 

Table C-7.3.3 Data Evaluation Northern Appalachian Zone ................................................... C-99 

Table C-7.3.4 Data Evaluation Paleozoic Extended Crust Zone .......................................... C-105 

Table C-7.3.5 Data Evaluation Illinois Basin-Extended Basement Zone .............................. C-112 

Table C-7.3.6 Data Evaluation Reelfoot Rift Zone ................................................................ C-124 

Tables C-7.3.7/7.3.8 Data Evaluation Extended Continental Crust—Atlantic ....................... C-131 

Tables C-7.3.9/7.3.10 Data Evaluation Extended Continental Crust–Gulf Coast ................ C-138 

Table C-7.3.12 Data Evaluation Midcontinent-Craton Zone ................................................ C-146 

Table D-5.4 Data Summary Future Earthquake Characteristics ............................................... D-3 

Table D-6.1.1 Data Summary Charlevoix RLME .................................................................... D-10 

Table D-6.1.2 Data Summary Charleston RLME .................................................................... D-17 

Table D-6.1.3 Data Summary Cheraw Fault RLME ................................................................ D-35 

Table D-6.1.4 Data Summary Oklahoma Aulacogen RLME ................................................... D-38 

Table D-6.1.5 Data Summary Reelfoot Rift–New Madrid Seismic Zone (NMSZ) Region ....... D-44 

Table D-6.1.9 Data Summary Wabash Valley RLME ............................................................. D-92 

Table D-7.3.1 Data Summary St. Lawrence Rift Zone (SLR) ............................................... D-121 

Table D-7.3.2 Data Summary Great Meteor Hotspot Zone (GMH) ....................................... D-141 

Table D-7.3.3 Data Summary Northern Appalachian Zone (NAP) ....................................... D-151 

Table D-7.3.4 Data Summary Paleozoic Extended Crust Zone ............................................ D-163 

Table D-7.3.7 Data Summary Extended Continental Crust Zone–Atlantic Margin (ECCAM) ................................................................................................................................ D-191 

Table D-7.3.9 Data Summary Extended Continental Crust Zone–Gulf Coast (ECC-GC) ..... D-225 

Table D-7.3.12 Data Summary Midcontinent-Craton Zone (MidC) ....................................... D-240 

Table E-1.2-1. Summary of Information on Liquefaction Features in Regional Data Sets........ E-5 

Table E-1.2-2 Summary of Type and Prevalence of Paleoliquefaction Features ..................... E-7 

Table E-2.1.3. Summary of Dating Techniques Used in Paleoliquefaction Studies................ E-30 

Table E-2.2. Uncertainties Related to Interpretation of Paleoearthquake Parameters ........... E-36 

Table 1: Key Questions and Topics That Workshop 2 Presenters Were Asked to 

Address ............................................................................................................................ F-35 

Table H-3-1 Weighted Alternative Seismogenic Crustal Thickness Values for Mmax 

Zones .............................................................................................................................. H-20 

Table H-3-2 Aleatory Distributions for Characterization of Future Earthquake Ruptures 

for Mmax Zones .............................................................................................................. H-20 
lxxxi

Table H-3-3 Maximum Magnitude Distributions for Mmax Distributed Seismicity Sources .... H-20

Table H-4-1 Seismotectonic Source Zones ............................................................................ H-21

Table H-4-2 Weighted Alternative Seismogenic Crustal Thickness Values for 

Seismotectonic Zones..................................................................................................... H-21

Table H-4-3 Aleatory Distributions for Characterization of Future Earthquake Ruptures 

for Seismotectonic Zones................................................................................................ H-22

Table H-4-4 Maximum Magnitude Distributions for Seismotectonic Distributed Seismicity 

Sources ........................................................................................................................... H-24

Table H-5.1-1 Charlevoix RLME Magnitude Distribution ........................................................ H-25

Table H-5.1-2 Annual Frequencies for Charlevoix RLME Events Data Set 1: 1870 and 

1663 ................................................................................................................................ H-25

Table H-5.1-3 Annual Frequencies for Charlevoix RLME Events Data Set 2: 3 

Earthquakes in 6–7 kyr BP.............................................................................................. H-25

Table H-5.1-4 Annual Frequencies for Charlevoix RLME Events Data Set 3: 4 

Earthquakes in 9.5–10.2 kyr BP...................................................................................... H-26

Table H-5.2-1 Charleston RLME Magnitude Distribution........................................................ H-26

Table H-5.2-2 Annual Frequencies for Charleston RLME Events Poisson Model, 2,000-

Year Time Period Earthquakes 1886, A, B, and C.......................................................... H-26

Table H-5.2-3 Annual Frequencies for Charleston RLME Events Poisson Model, 5,500-

Year Time Period Earthquakes 1886, A, B, and C.......................................................... H-27

Table H-5.2-4 Annual Frequencies for Charleston RLME Events Poisson Model, 5,500-

Year Time Period Earthquakes 1886, A, B, C, and D ..................................................... H-27

Table H-5.2-5 Annual Frequencies for Charleston RLME Events Poisson Model, 5,500-

Year Time Period Earthquakes 1886, A, B, C, and E ..................................................... H-27

Table H-5.2-6 Annual Frequencies for Charleston RLME Events Poisson Model, 5,500-

Year Time Period Earthquakes 1886, A, B, C, D, and E................................................. H-28

Table H-5.2-7 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.3, 2,000-Year Time Period Earthquakes 1886, A, B, and C ..................................... H-28

Table H-5.2-8 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.5, 2,000-Year Time Period Earthquakes 1886, A, B, and C ..................................... H-28

Table H-5.2-9 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.7, 2,000-Year Time Period Earthquakes 1886, A, B, and C ..................................... H-29

Table H-5.2-10 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.3, 5,500-Year Time Period Earthquakes 1886, A, B, and C ..................................... H-29

Table H-5.2-11 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.5, 5,500-Year Time Period Earthquakes 1886, A, B, and C ..................................... H-29

Table H-5.2-12 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.7, 5,500-Year Time Period Earthquakes 1886, A, B, and C ..................................... H-30

Table H-5.2-13 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.3, 5,500-Year Time Period Earthquakes 1886, A, B, C, and D................................. H-30

Table H-5.2-14 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.5, 5,500-Year Time Period Earthquakes 1886, A, B, C, and D................................. H-30
lxxxii

Table H-5.2-15 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.7, 5,500-Year Time Period Earthquakes 1886, A, B, C, and D................................. H-31

Table H-5.2-16 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.3, 5,500-Year Time Period Earthquakes 1886, A, B, C, and E................................. H-31

Table H-5.2-17 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.5, 5,500-Year Time Period Earthquakes 1886, A, B, C, and E................................. H-31

Table H-5.2-18 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.7, 5,500-Year Time Period Earthquakes 1886, A, B, C, and E................................. H-32

Table H-5.2-19 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.3, 5,500-Year Time Period Earthquakes 1886, A, B, C, D, and E ............................ H-32

Table H-5.2-20 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.5, 5,500-Year Time Period Earthquakes 1886, A, B, C, D, and E ............................ H-32

Table H-5.2-21 Annual Frequencies for Charleston RLME Events BPT Renewal Model, α

= 0.7, 5,500-Year Time Period Earthquakes 1886, A, B, C, D, and E ............................ H-33

Table H-5.3-1 Cheraw RLME Magnitude Distribution............................................................. H-33

Table H-5.3-2 Annual Frequencies for Cheraw RLME Events In-Cluster Case, Data Set: 

2 Earthquakes in 20–25 kyr ............................................................................................ H-33

Table H-5.3-3 Annual Frequencies for Cheraw RLME Events In-Cluster Case, Data Set: 

3 Earthquakes in 20–25 kyr ............................................................................................ H-34

Table H-5.3-4 Slip Rates for Cheraw Fault In-Cluster Case, Data Set: 3.2–4.1 m in 20–

25 kyr .............................................................................................................................. H-34

Table H-5.3-5 Annual Frequencies for Cheraw RLME Events Out-of-Cluster Case, Time 

Between Clusters ............................................................................................................ H-34

Table H-5.3-6 Slip Rates for Cheraw Fault Out-of-Cluster Case, Data Set: 7–8 m in 0.4–

2.0 myr ............................................................................................................................ H-35

Table H-5.4-1 Meers RLME Magnitude Distribution ............................................................... H-35

Table H-5.4-2 Annual Frequencies for Meers RLME Events In-Cluster Case........................ H-35

Table H-5.4-3 Annual Frequencies for Meers RLME Events Out-of-Cluster Case................. H-36

Table H-5.5-1 NMFS RLME Magnitude Distribution ............................................................... H-36

Table H-5.5-2 Annual Frequencies for NMFS RLME Events In-Cluster Case, Poisson 

Model .............................................................................................................................. H-36

Table H-5.5-3 Annual Frequencies for NMFS RLME Events In-Cluster Case, BPT Model, 

α = 0.3 ............................................................................................................................. H-37

Table H-5.5-4 Annual Frequencies for NMFS RLME Events In-Cluster Case, BPT Model, 

α = 0.5 ............................................................................................................................. H-37

Table H-5.5-5 Annual Frequencies for NMFS RLME Events In-Cluster Case, BPT Model, 

α = 0.7 ............................................................................................................................. H-37

Table H-5.5-6 Annual Frequencies for NMFS RLME Events Out-of-Cluster Case, 

Poisson Model................................................................................................................. H-38

Table H-5.6-1 ERM-S RLME Magnitude Distribution.............................................................. H-38

Table H-5.6-2 ERM-N RLME Magnitude Distribution ............................................................. H-38

Table H-5.6-3 Annual Frequencies for ERM-S RLME Events Data Set: 2 Earthquakes in 

17.7–21.7 kyr .................................................................................................................. H-39
lxxxiii

Table H-5.6-4 Annual Frequencies for ERM-S RLME Events Data Set: 3 Earthquakes in 

17.7–21.7 kyr .................................................................................................................. H-39

Table H-5.6-5 Annual Frequencies for ERM-S RLME Events Data Set: 4 Earthquakes in 

17.7–21.7 kyr .................................................................................................................. H-39

Table H-5.6-6 Annual Frequencies for ERM-N RLME Events Data Set: 1 Earthquake in 

12–35 kyr ........................................................................................................................ H-40

Table H-5.6-7 Annual Frequencies for ERM-N RLME Events Data Set: 2 Earthquakes in 

12–35 kyr ........................................................................................................................ H-40

Table H-5.7-1 Marianna RLME Magnitude Distribution .......................................................... H-40

Table H-5.7-2 Annual Frequencies for Marianna RLME Events Data Set: 3 Earthquakes 

in 9.6–10.2 kyr................................................................................................................. H-41

Table H-5.7-3 Annual Frequencies for Marianna RLME Events Data Set: 4 Earthquakes 

in 9.6–10.2 kyr................................................................................................................. H-41

Table H-5.8-1 Commerce RLME Magnitude Distribution........................................................ H-41

Table H-5.8-2 Annual Frequencies for Commerce RLME Events Data Set: 2 

Earthquakes in 18.9–23.6 kyr ......................................................................................... H-42

Table H-5.8-3 Annual Frequencies for Commerce RLME Events Data Set: 3 

Earthquakes in 18.9–23.6 kyr ......................................................................................... H-42

Table H-5.9-1 Wabash RLME Magnitude Distribution ............................................................ H-42

Table H-5.9-2 Annual Frequencies for Wabash RLME Events Data Set: 2 Earthquakes 

in 11–13 kyr..................................................................................................................... H-43

PPRP Comment Response Table ...............................................................................(Appendix I)

Table K-1 SCR Earthquake Catalog ......................................................................................... K-5

Table K-2 SCR Domains Updated from Johnston et al. (1994).............................................. K-34

EXECUTIVE SUMMARY 

The Central and Eastern United States Seismic Source Characterization for Nuclear Facilities 

(CEUS SSC) Project was conducted over the period from April 2008 to December 2011 to 

provide a regional seismic source model for use in probabilistic seismic hazard analyses 

(PSHAs) for nuclear facilities. The study replaces previous regional seismic source models 

conducted for this purpose, including the Electric Power Research Institute–Seismicity Owners 

Group (EPRI-SOG) model (EPRI, 1988, 1989) and the Lawrence Livermore National 

Laboratory model (Bernreuter et al., 1989). Unlike the previous studies, the CEUS SSC Project 

was sponsored by multiple stakeholders—namely, the EPRI Advanced Nuclear Technology 

Program, the Office of Nuclear Energy and the Office of the Chief of Nuclear Safety of the U.S. 

Department of Energy (DOE), and the Office of Nuclear Regulatory Research of the Nuclear 

Regulatory Commission (NRC). The study was conducted using Senior Seismic Hazard Analysis 

Committee (SSHAC) Study Level 3 methodology to provide high levels of confidence that the 

data, models, and methods of the larger technical community have been considered and the 

center, body, and range of technically defensible interpretations have been included. 

The regional seismic source characterization (SSC) model defined by this study can be used for 

site-specific PSHAs, provided that appropriate site-specific assessments are conducted as 

required by current regulations and regulatory guidance for the nuclear facility of interest. This 

model has been designed to be compatible with current and anticipated ground-motion 

characterization (GMC) models. The current recommended ground-motion models for use at 

nuclear facilities are those developed by EPRI (2004, 2006a, 2006b). The ongoing Next 

Generation Attenuation–East (NGA-East) project being supported by the NRC, DOE, and EPRI 

will provide ground-motion models that are appropriate for use with the CEUS SSC model. The 

methodology for a SSHAC Level 3 project as applied to the CEUS SSC Project is explained in 

the SSHAC report (Budnitz et al., 1997), which was written to discuss the evolution of expert 

assessment methodologies conducted during the previous three decades for purposes of 

probabilistic risk analyses. The methodological guidance provided in the SSHAC report was 

intended to build on the lessons learned from those previous studies and, specifically, to arrive at 

processes that would make it possible to avoid the issues encountered by the previous studies 

(NRC, 2011).

The SSHAC assessment process, which differs only slightly for Level 3 and 4 studies, is a 

technical process accepted in the NRC’s seismic regulatory guidance (Regulatory Guide 1.208) 

for ensuring that uncertainties in data and scientific knowledge have been properly represented in 

seismic design ground motions consistent with the requirements of the seismic regulation 

10 CFR Part 100.23 (―Geologic and Seismic Siting Criteria‖). Therefore, the goal of the SSHAC 

assessment process is the proper and complete representation of knowledge and uncertainties in 

the SSC and GMC inputs to the PSHA (or similar hazard analysis). As discussed extensively in 

lxxxv
Executive Summary 

the SSHAC report (Budnitz et al., 1997) and affirmed in NRC (2011), a SSHAC assessment 

process consists of two important sequential activities, evaluation and integration. For a Level 3 

assessment, these activities are conducted by the Technical Integration (TI) Team under the 

leadership of the TI Lead. As described in NRC (2011), 

The fundamental goal of a SSHAC process is to carry out properly and document completely the 

activities of evaluation and integration, defined as: 

Evaluation: The consideration of the complete set of data, models, and methods proposed by 

the larger technical community that are relevant to the hazard analysis. 

Integration: Representing the center, body, and range of technically defensible interpretations 

in light of the evaluation process (i.e., informed by the assessment of existing data, models, 

and methods). 

Each of the assessment and model-building activities of the CEUS SSC Project is associated with 

the evaluation and integration steps in a SSHAC Level 3 process. Consistent with the 

requirements of a SSHAC process, the specific roles and responsibilities of all project 

participants were defined in the Project Plan, and adherence to those roles was the responsibility 

of the TI Lead and the Project Manager. The technical assessments are made by the TI Team, 

who carry the principal responsibility of evaluation and integration, under the technical 

leadership of the TI Lead. The Database Manager and other technical support individuals assist 

in the development of work products. Resource and proponent experts participate by presenting 

their data, models, and interpretations at workshops and through technical interchange with the 

TI Team throughout the project. The Participatory Peer Review Panel (PPRP) is responsible for a 

continuous review of both the SSHAC process being followed and the technical assessments 

being made. The project management structure is headed by the Project Manager, who serves as 

the liason with the sponsors and the PPRP and manages the activities of all participants. The 

SSHAC Level 3 assessment process and implementation is discussed in depth in Chapter 2 of 

this report. 

Each of the methodology steps in the SSHAC guidelines (Budnitz, 1997) was addressed 

adequately during the CEUS SSC Project. Furthermore, the project developed a number of 

enhancements to the process steps for conducting a SSHAC Study Level 3 project. For example, 

the SSHAC guidelines call for process steps that include developing a preliminary assessment 

model, calculating hazard using that model in order to identify the key issues, and finalizing the 

model in light of the feedback provided from the hazard calculations and sensitivity analyses. 

Because of the regional nature of the project and the multitude of assessments required, four 

rounds of model-building and three rounds of feedback were conducted. These activities ensured 

that all significant issues and uncertainties were identified and that the appropriate effort was 

devoted to the issues of most significance to the hazard results. A comparison of the activities 

conducted during the CEUS SSC Project with those recommended in the SSHAC guidelines 

themselves (Section 2.6) led to the conclusion that the current standards of practice have been 

met for a SSHAC Study Level 3 process—both those that are documented in the SSHAC report 

and those that resulted from precedents set by projects conducted since the SSHAC report was 

issued. 

lxxxvi
Executive Summary 

The catalog of past earthquakes that have occurred in a region is an important source of 

information for the quantification of future seismic hazards. This is particularly true in stable 

continental regions (SCRs) such as the CEUS where the causative mechanisms and structures for 

the occurrence of damaging earthquakes are generally poorly understood, and the rates of crustal 

deformation are low such that surface and near-surface indications of stresses in the crust and the 

buildup and release of crustal strains are difficult to quantify. Because the earthquake catalog is 

used in the characterization of the occurrence of future earthquakes in the CEUS, developing an 

updated earthquake catalog for the study region was an important focus of the CEUS SSC 

Project. The specific goals for earthquake catalog development and methods used to attain those 

goals are given in Chapter 3. 

The earthquake catalog development consists of four main steps: catalog compilation, 

assessment of a uniform size measure to apply to each earthquake, identification of dependent 

earthquakes (catalog declustering), and assessment of the completeness of the catalog as a 

function of location, time, and earthquake size. An important part of the catalog development 

process was review by seismologists with extensive knowledge and experience in catalog 

compilation. The result is an earthquake catalog covering the entire study region for the period 

from 1568 through the end of 2008. Earthquake size is defined in terms of the moment 

magnitude scale (Hanks and Kanamori, 1979), consistent with the magnitude scale used in 

modern ground-motion prediction equations (GMPEs) for CEUS earthquakes. A significant 

contribution of the CEUS SSC Project is the work conducted to develop an updated and 

consistent set of conversion relationships between various earthquake size measures 

(instrumental magnitudes and intensity) and moment magnitude. 

The conceptual SSC framework described in Chapter 4 was developed early in the CEUS SSC 

Project in order to provide a consistent approach and philosophy to SSC by the TI Team. This 

framework provides the basic underpinnings of the SSC model developed for the project, and it

led to the basic structure and elements of the master logic tree developed for the SSC model. In 

considering the purpose of the CEUS SSC Project, the TI Team identified three attributes that are 

needed for a conceptual SSC framework: 

1. A systematic, documented approach to treating alternatives using logic trees, including 

alternative conceptual models for future spatial distributions of seismicity (e.g., stationarity); 

alternative methods for expressing the future temporal distribution of seismicity (e.g., 

renewal models, Poisson models); and alternative data sets for characterizing seismic sources 

(e.g., paleoseismic data, historical seismicity data). 

2. A systematic approach to identifying applicable data for the source characterization, 

evaluating the usefulness of the data, and documenting the consideration given to the data by 

the TI Team. 

3. A methodology for identifying seismic sources based on defensible criteria for defining a 

seismic source, incorporating the lessons learned in SSC over the past two decades, and 

identifying the range of approaches and models that can be shown to be significant to hazard. 

Each of these needs was addressed by the methodology used in the project. For example, the 

need for a systematic approach to identifying and evaluating the data and information that 

underlie the source characterization assessments was met by the development of Data Summary 

lxxxvii
Executive Summary 

and Data Evaluation tables. These tables were developed for each seismic source to document 

the information available at the time of the CEUS SSC assessments (the Data Summary tables) 

and the way those data were used in the characterization process (the Data Evaluation tables). 

Given the evolution of approaches to identifying seismic sources, it is appropriate to provide a 

set of criteria and the logic for their application in the CEUS SSC Project. In the project, unique 

seismic sources are defined to account for distinct differences in the following criteria: 

Earthquake recurrence rate 

Maximum earthquake magnitude (Mmax) 

Expected future earthquake characteristics (e.g., style of faulting, rupture orientation, depth 

distribution) 

Probability of activity of tectonic feature(s) 

Rather than treat these criteria as operating simultaneously or without priority, the CEUS SSC 

methodology works through them sequentially. Further, because each criterion adds complexity 

to the seismic source model, it is applied only if its application would lead to hazard-significant 

changes in the model. In this way, the model becomes only as complex as required by the 

available data and information. 

The CEUS SSC master logic tree is tied to the conceptual SSC framework that establishes the 

context for the entire seismic source model. The master logic tree depicts the alternative 

interpretations and conceptual models that represent the range of defensible interpretations, and 

the relative weights assessed for the alternatives. By laying out the alternatives initially, the 

subsequent detailed source evaluations were conducted within a framework that ensures 

consistency across the sources. Important elements of the master logic tree are as follows: 

Representation of the sources defined based on paleoseismic evidence for the occurrence of 

repeated large-magnitude earthquakes (RLMEs, defined as two or more earthquakes with 

M ≥ 6.5). 

Alternatives to the spatial distribution of earthquakes based on differences in maximum 

magnitudes (Mmax zones approach). 

Representation of uncertainty in spatial stationarity of observed seismicity based on 

smoothing of recurrence parameters. 

Representation of possible differences in future earthquake characteristics (e.g., style, 

seismogenic thickness, and orientation of ruptures), which lead to definition of 

seismotectonic zones in the logic tree (seismotectonic zones approach). 

The methodologies used by the project to make the SSC assessments are discussed in Chapter 5. 

The heart of any SSC model for PSHA is a description of the future spatial and temporal 

distribution of earthquakes. Continued analysis of the historical seismicity record and network 

monitoring by regional and local seismic networks has led to acceptance within the community 

that the general spatial patterns of observed small- to moderate-magnitude earthquakes provide 

predictive information about the spatial distribution of future large-magnitude earthquakes. The 

analyses leading to this conclusion have focused on whether the observed patterns of earthquakes 

lxxxviii
Executive Summary 

have varied through time; therefore, in effect, this is an assessment of uncertainty in whether 

small- to moderate-magnitude earthquakes have been relatively stationary through time.

However, the available data on larger-magnitude earthquakes and their relationship to the spatial 

distribution of smaller earthquakes based on the observed record are quite limited. These data are 

not sufficient to allow confidence in the predictions generated by empirical spatial models. For 

this reason, geologic and geophysical data are needed to specify the locations of future 

earthquakes in addition to the observed patterns of seismicity. 

Detailed studies in the vicinity of large historical and instrumental earthquakes, and liquefaction 

phenomena associated with them, coupled with field and laboratory studies of geotechnical 

properties, are leading to a stronger technical basis for (1) placing limits on the locations of 

paleoearthquakes interpreted by the distribution of liquefaction phenomena and (2) defining their 

magnitudes. In some cases, the paleoseismic evidence for RLMEs is compelling, and the TI 

Team has included the RLME source in the SSC model. The locations of RLME sources 

notwithstanding, the spatial distribution of distributed seismicity sources has advanced in PSHA 

largely because of the assumption of spatial stationarity, and the SSC and hazard community 

uses approaches to ―smooth‖ observed seismicity to provide a map that expresses the future 

spatial pattern of recurrence rates. The CEUS SSC model is based largely on the assumption, 

typical in PSHA studies, that spatial stationarity of seismicity is expected to persist for a period 

of approximately 50 years. 

Estimating Mmax in SCRs such as the CEUS is highly uncertain despite considerable interest 

and effort by the scientific community over the past few decades. Mmax is defined as the upper 

truncation point of the earthquake recurrence curve for individual seismic sources, and the 

typically broad distribution of Mmax for any given source reflects considerable epistemic 

uncertainty. Because the maximum magnitude for any given seismic source in the CEUS occurs 

rarely relative to the period of observation, the use of the historical seismicity record provides 

important but limited constraints on the magnitude of the maximum event. Because of the 

independent constraints on earthquake size, those limited constraints are used to estimate the 

magnitudes of RLME. For distributed seismicity source zones, two approaches are used to assess 

Mmax: the Bayesian approach and the Kijko approach. In the Bayesian procedure (Johnston et 

al., 1994), the prior distribution is based on the magnitudes of earthquakes that occurred 

worldwide within tectonically analogous regions. As part of the CEUS SSC Project, the TI Team 

pursued the refinement and application of the Bayesian Mmax approach becauses it provides a 

quantitative and repeatable process for assessing Mmax. 

The TI Team also explored alternative approaches for the assessment of Mmax that provide 

quantitative and repeatable results, and the team identified the approach developed by Kijko 

(2004) as a viable alternative. While the Kijko approach requires fewer assumptions than the 

Bayesian approach in that it uses only the observed earthquake statistics for the source, this is 

offset by the need for a relatively larger data sample in order to get meaningful results. Both 

approaches have the positive attribute that they are repeatable given the same data and they can 

be readily updated given new information. The relative weighting of the two approaches for 

inclusion in the logic tree is source-specific, a function of the numbers of earthquakes that are 

present within the source upon which to base the Mmax assessment: sources with fewer 

earthquakes are assessed to have little or no weight for the Kijko approach, while those with 

lxxxix
Executive Summary 

larger numbers of events are assessed higher weight for the Kijko approach. In all cases, because 

of the stability of the Bayesian approach and the preference for ―analogue‖ approaches within the 

larger technical community, the Bayesian approach is assessed higher weight than the Kijko 

approach for all sources. 

A major effort was devoted to updating the global set of SCR earthquakes and to assessing 

statistically significant attributes of those earthquakes following the approach given in Johnston 

et al. (1994). In doing so, it was found that the only significant attribute defining the prior 

distribution is the presence or absence of Mesozoic-or-younger extension. The uncertainty in this 

assessment is reflected in the use of two alternative priors: one that takes into account the 

presence or absence of crustal domains having this attribute, and another that combines the entire 

CEUS region as a single SCR crustal domain with a single prior distribution. The use of the 

Bayesian—and Kijko—approach requires a definition of the largest observed magnitude within 

each source, and this assessment, along with the associated uncertainty, was incorporated into the 

Mmax distributions for each seismic source. Consideration of global analogues led to the 

assessment of an upper truncation to all Mmax distributions at 81⁄4 and a lower truncation at 51⁄2. 

The broad distributions of Mmax for the various seismic source zones reflect the current 

epistemic uncertainty in the largest earthquake magnitude within each seismic source. 

The CEUS SSC model is based to a large extent on an assessment that spatial stationarity of 

seismicity will persist for time periods of interest for PSHA (approximately the next 50 years). 

Stationarity in this sense does not mean that future locations and magnitudes of earthquakes will 

occur exactly where they have occurred in the historical and instrumental record. Rather, the 

degree of spatial stationarity varies as a function of the type of data available to define the 

seismic source. RLME sources are based largely on paleoseismic evidence for repeated largemagnitude (M ≥ 6.5) earthquakes that occur in approximately the same location over periods of a 

few thousand years. On the other hand, patterns of seismicity away from the RLME sources 

within the Mmax and seismotectonic zones are defined from generally small- to moderatemagnitude earthquakes that have occurred during a relatively short (i.e., relative to the repeat 

times of large events) historical and instrumental record. Thus, the locations of future events are 

not as tightly constrained by the locations of past events as for RLME sources. The spatial 

smoothing operation is based on calculations of earthquake recurrence within one-quarter-degree 

or half-degree cells, with allowance for ―communication‖ between the cells. Both a- and bvalues are allowed to vary, but the degree of variation has been optimized such that b-values 

vary little across the study region. 

The approach used to smooth recurrence parameters is a refinement of the penalized-likelihood 

approach used in EPRI-SOG (EPRI, 1988), but it is designed to include a number of elements 

that make the formulation more robust, realistic, and flexible. These elements include the 

reformulation in terms of magnitude bins, the introduction of magnitude-dependent weights, 

catalog incompleteness, the effect of Mmax, spatial variation of parameters within the source 

zone, and the prior distributions of b. A key assessment made by the TI Team was the weight 

assigned to various magnitude bins in the assessment of smoothing parameters (Cases A, B, 

and E). This assessment represents the uncertainty in the interpretation that smaller magnitudes 

define the future locations and variation in recurrence parameters. Appropriately, the penalizedlikelihood approach results in higher spatial variation (less smoothing) when the low-magnitude 

xc
Executive Summary 

bins are included with high weight, and much less variation (higher smoothing) in the case where 

the lower-magnitude bins are given low or zero weight. The variation resulting from the final set 

of weights reflects the TI Team’s assessment of the epistemic uncertainty in the spatial variation 

of recurrence parameters throughout the SSC model. 

The earthquake recurrence models for the RLME sources are somewhat simpler than those for 

distributed seismicity sources because the magnitude range for individual RLMEs is relatively 

narrow and their spatial distribution is limited geographically such that spatial variability is not a 

concern. This limits the problem to one of estimating the occurrence rate in time of a point 

process. The data that are used to assess the occurrence rates are derived primarily from 

paleoseismic studies and consist of two types: data that provide estimated ages of the 

paleoearthquakes such that the times between earthquakes can be estimated, and data that 

provide an estimate of the number of earthquakes that have occurred after the age of a particular 

stratigraphic horizon. These data are used to derive estimates of the RLME occurrence rates and 

their uncertainty. 

The estimation of the RLME occurrence rates is dependent on the probability model assumed for 

the temporal occurrence of these earthquakes. The standard model applied for most RLME 

sources in this study is the Poisson model, in which the probability of occurrence of an RLME in 

a specified time period is completely characterized by a single parameter, λ, the rate of RLME 

occurrence. The Poisson process is ―memoryless‖—that is, the probability of occurrence in the 

next time interval is independent of when the most recent earthquake occurred, and the time 

between earthquakes is exponentially distributed with a standard deviation equal to the mean 

time between earthquakes. For two RLME sources (Reelfoot Rift–New Madrid fault system and 

the Charleston source), the data are sufficient to suggest that the occurrence of RLMEs is more 

periodic in nature (the standard deviation is less than the mean time between earthquakes). For 

these RLME sources a simple renewal model can also be used to assess the probability of 

earthquake occurrence. In making an estimate of the probability of occurrence in the future, this 

model takes into account the time that has elapsed since the most recent RLME occurrence. 

The CEUS SSC model has been developed for use in future PSHAs. To make this future use 

possible, the SSC model must be combined with a GMC model. At present, the GMPEs in use 

for SCRs such as the CEUS include limited information regarding the characteristics of future 

earthquakes. In anticipation of the possible future development of GMPEs for the CEUS that will 

make it possible to incorporate similar types of information, a number of characteristics of future 

earthquakes in the CEUS are assessed. In addition to characteristics that might be important for 

ground motion assessments, there are also assessed characteristics that are potentially important 

to the modeling conducted for hazard analysis. Future earthquake characteristics assessed include 

the tectonic stress regime, sense of slip/style of faulting, strike and dip of ruptures, seismogenic 

crustal thickness, fault rupture area versus magnitude relationship, rupture length-to-width aspect 

ratio, and relationship of ruptures to source boundaries. 

Chapters 6 and 7 include discussions of the seismic sources that are defined by the Mmax zones 

and the seismotectonic zones branches of the master logic tree. Because of convincing evidence 

for their existence, both approaches include RLME sources. The rarity of repeated earthquakes 

relative to the period of historical observation means that evidence for repeated events comes 

xci
Executive Summary 

largely from the paleoseismic record. By identifying the RLMEs and including them in the SSC 

model, there is no implication that the set of RLMEs included is in fact the total set of RLMEs 

that might exist throughout the study region. This is because the presently available studies that 

locate and characterize the RLMEs have been concentrated in certain locations and are not 

systematic across the entire study region. Therefore, the evidence for the existence of the RLMEs 

is included in the model where it exists, but the remaining parts of the study region are also 

assessed to have significant earthquake potential, which is evidenced by the inclusion of 

moderate-to-large magnitudes in the Mmax distributions for every Mmax zone or seismotectonic 

zone. 

In Chapter 6, each RLME source is described in detail by the following factors: (1) evidence for 

temporal clustering, (2) geometry and style of faulting, (3) RLME magnitude, and (4) RLME 

recurrence. The descriptions document how the data have been evaluated and assessed to arrive 

at the various elements of the final SSC model, including all expressions of uncertainty. The 

Data Summary and Data Evaluation tables (Appendices C and D) complement the discussions in 

the text, documenting all the data that were considered in the course of data evaluation and 

integration process for each particular seismic source. 

Alternative models for the distributed seismicity zones that serve as background zones to the 

RLME sources are either Mmax zones or seismotectonic zones. The Mmax zones are described 

in Chapter 6 and are defined according to constraints on the prior distributions for the Bayesian 

approach to estimating Mmax. The seismotectonic zones are described in Chapter 7 and are 

identified based on potential differences in Mmax as well as future earthquake characteristics. 

Each seismotectonic zone in the CEUS SSC model is described according to the following 

attributes: (1) background information from various data sets; (2) bases for defining the 

seismotectonic zone; (3) basis for the source geometry; (4) basis for the zone Mmax (e.g., largest 

observed earthquake); and (5) future earthquake characteristics. Uncertainties in the 

seismotectonic zone characteristics are described and are represented in the logic trees developed 

for each source. 

For purposes of demonstrating the CEUS SSC model, seismic hazard calculations were 

conducted at seven demonstration sites throughout the study region, as described in Chapter 8. 

The site locations were selected to span a range of seismic source types and levels of seismicity. 

The results from the seismic hazard calculations are intended for scientific use to demonstrate the 

model, and they should not be used for engineering design. Mean hazard results are given for a 

range of spectral frequencies (PGA, 10 Hz, and 1 Hz) and for a range of site conditions. All 

calculations were made using the EPRI (2004, 2006) ground-motion models such that results 

could be compared to understand the SSC effects alone. Sensitivity analyses were conducted to 

provide insight into the dominant seismic sources and the important characteristics of the 

dominant seismic source at each site. The calculated mean hazard results are compared with the 

results using the SSC model from the 2008 U.S. Geological Survey national seismic hazard maps 

and the SSC model from the Combined Operating License applications for new nuclear power 

reactors. The hazard results using the CEUS SSC model given in Chapter 8 are reasonable and 

readily understood relative to the results from other studies, and sensitivities of the calculated 

hazard results can be readily explained by different aspects of the new model. The TI Team 

concludes that the SSC model provides reasonable and explainable calculated seismic hazard 

xcii
Executive Summary 

results, and the most important aspects of the SSC model to the calculated hazard (e.g., 

recurrence rates of RLME sources, recurrence parameters for distributed seismicity sources, 

Mmax) and their uncertainties have all been appropriately addressed. 

Presumably, the GMC model input to the PSHA calculations will be replaced in the future by the 

results of the ongoing NGA-East project. The calculated hazard at the demonstration sites in 

Chapter 8 comes from the regional CEUS SSC model and does not include any local refinements 

that might be necessary to account for local seismic sources. Depending on the regulatory 

guidance that is applicable for the facility of interest, additional site-specific studies may be 

required to provide local refinements to the model. 

To assist future users of the CEUS SSC model, Chapter 9 presents a discussion on the use of the 

model for PSHA. The basic elements of the model necessary for hazard calculations are given in 

the Hazard Input Document (HID). This document provides all necessary parameter values and 

probability distributions for use in a modern PSHA computer code. The HID does not, however, 

provide any justification for the values, since that information is given in the text of this report. 

Chapter 9 also describes several simplifications to seismic sources that can be made to increase 

efficiency in seismic hazard calculations. These simplifications are recommended on the basis of 

sensitivity studies of alternative hazard curves that represent a range of assumptions on a 

parameter’s value. Sensitivities are presented using the test sites in this study. For applications of 

the seismic sources from this study, similar sensitivity studies should be conducted for the 

particular site of interest to confirm these results and to identify additional simplifications that 

might be appropriate. For the seismic sources presented, only those parameters that can be 

simplified are discussed and presented graphically. The sensitivity studies consisted of 

determining the sensitivity of hazard to logic tree branches for each node of the logic tree 

describing that source. The purpose was to determine which nodes of the logic tree could be 

collapsed to a single branch in order to achieve more efficient hazard calculations without 

compromising the accuracy of overall hazard results. 

Finally, this report provides a discussion of the level of precision that is associated with seismic 

hazard estimates in the CEUS. This discussion addresses how seismic hazard estimates might 

change if the analysis were repeated by independent experts having access to the same basic 

information (geology, tectonics, seismicity, ground-motion equations, site characterization). It 

also addresses how to determine whether the difference in hazard would be significant if this 

basic information were to change and that change resulted in a difference in the assessed seismic 

hazard. This analysis was performed knowing that future data and models will continue to be 

developed and that a mechanism for evaluating the significance of that information is needed. 

Based on the precision model evaluated, if an alternative assumption or parameter is used in a 

seismic hazard study, and it potentially changes the calculated hazard (annual frequency of 

exceedence) by less than 25 percent for ground motions with hazards in the range 10–4

to 10–6, 

that potential change is within the level of precision at which one can calculate seismic hazard. It 

should be noted, however, that a certain level of precision does not relieve users from performing 

site-specific studies to identify potential capable seismic sources within the site region and 

vicinity as well as to identify newer models and data. Also, this level of precision does not 

relieve users from fixing any errors that are discovered in the CEUS SSC model as it is 

xciii
Executive Summary 

implemented for siting critical facilities. In addition, NRC has not defined a set value for 

requiring or not requiring siting applicants to revise or update PSHAs. 

Included in the report are appendices that summarize key data sets and analyses: the earthquake 

catalog, the Data Summary and Data Evaluation tables, the paleoliquefaction database, the HID, 

and documentation important to the SSHAC process. These data and analyses will assist future 

users of the CEUS SSC model in the implementation of the model for purposes of PSHA. The 

entire report and database will be provided on a website after the Final Project Report is issued. 

The TI Team, Project Manager, and Sponsors determined the approach for quality assurance on 

the CEUS SSC Project in 2008, taking into account the SSHAC assessment process and national 

standards. The approach was documented in the CEUS SSC Project Plan dated June 2008 and 

discussed in more detail in the CEUS SSC Report (Appendix L). Beyond the assurance of quality 

arising from the external scientific review process, it is the collective, informed judgment of the 

TI Team (via the process of evaluation and integration) and the concurrence of the PPRP (via the 

participatory peer review process), as well as adherence to the national standard referred to in 

Appendix L, that ultimately lead to the assurance of quality in the process followed and in the 

products that resulted from the SSHAC hazard assessment framework. 

xciv
October 24, 2011 

Cliff Munson 

Senior Technical Advisor 

Office of New Reactors 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555 

Robert Roche 

Project Manager 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555 

 

Richard H. Lagdon, Jr. 

Chief of Nuclear Safety 

Office of the Under Secretary for Nuclear 

Security, S-5 

U.S. Department of Energy 

1000 Independence Avenue SW 

Washington, DC 20585 

Thomas P. Miller 

Senior Technical Advisor 

Office of Nuclear Energy, NE-72/GTN 

U.S. Department of Energy 

1000 Independence Avenue SW 

Washington, DC 20585 

 

Jeffrey F. Hamel 

Advanced Nuclear Technology Program 

Manager 

Electric Power Research Institute 

3420 Hillview Avenue 

Palo Alto, CA 94304 

Gentlemen: 

Reference: Central and Eastern United States Seismic Source Characterization for Nuclear 

Facilities Project: Participatory Peer Review Panel Final Report

Introduction 

This letter constitutes the final report of the PPRP1

 (“the Panel”) for the Central and Eastern 

United States Seismic Source Characterization for Nuclear Facilities Project (the “CEUS SSC 

Project” or “the Project”). The eight Panel members (Jon P. Ake, Walter J. Arabasz, William J. 

Hinze, Annie M. Kammerer, Jeffrey K. Kimball, Donald P. Moore, Mark D. Petersen, J. Carl 

Stepp) participated in the Project in a manner fully consistent with the SSHAC Guidance.2

 The 

Panel was actively engaged in all phases and activities of the Project’s implementation, including 

final development of the Project Plan and planning of the evaluation and integration activities, 

which are the core of the SSHAC assessment process. 

                                                       

1

 Participatory Peer Review Panel 

2

 Budnitz, R. J., G. Apostolakis, D. M. Boore, L. S. Cluff, K. L. Coppersmith, C. A. Cornell, and P. A. 

Morris, 1997. Recommendations for Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty

and the Use of Experts (known as the “Senior Seismic Hazard Analysis Committee Report,” or the

“SSHAC Guidance”). NUREG/CR-6372, U. S. Nuclear Regulatory Commission. TIC; 235076. 

Washington, DC. 

xix 

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PPRP Final Report, CEUS SSC PROJECT October 24, 2011 

xx

The Panel’s involvement, described more fully later in this letter, also included review of 

analyses performed by the Project to support the evaluation and integration processes, review of 

interim evaluation and integration products, and review of the interim draft project report and the 

final project report. Additionally, panel members participated in specific analyses as resource 

experts, and panel members were observers in or participated as resource experts in eight of the 

eleven Technical Integrator Team (TI Team) working meetings held to implement the integration 

phase of the assessment process. We want to express our appreciation for the opportunity to 

participate in the CEUS SSC Project in this way. 

In the remainder of this letter we provide our observations and conclusions on key elements of 

the project implementation process, and we summarize our reviews of the draft and final project 

reports. As we explain in our comments, assurance that the center, body, and range of the 

technically-defensible interpretations (“CBR of the TDI”)3 have been properly represented in the 

CEUS SSC Model fundamentally comes from implementing the structure and rigor of the 

SSHAC Guidance itself. We are aware that the SSHAC Guidance is accepted by the Nuclear 

Regulatory Commission and the Department of Energy for developing seismic hazard models 

that provide reasonable assurance, consistent with the seismic safety decision-making practices 

of these agencies, of compliance with their seismic safety policies and regulatory requirements. 

For these reasons, we describe aspects of the SSHAC Guidance to provide context for our 

observations and conclusions. 

Project Plan: Conformity to the SSHAC Assessment Process 

The SSHAC Guidance recognizes that observed data, available methods, models, and 

interpretations all contain uncertainties. These uncertainties lead to alternative scientific 

analyses and interpretations. In other words, experts in the broad technical community do not 

hold a single interpretation. Accepting this scientific situation, the SSHAC assessment process is 

designed to engage the scientific community in an orderly assessment of relevant data, methods, 

models, and interpretations that constitute current scientific knowledge as the basis for 

development of a seismic hazard model that represents the CBR of the TDI. 

The assessment process is carried out by means of two main activities: evaluation and

integration.

4

 In implementation, the evaluation activities are structured to inform the integration 

activities. The evaluations are carried out by means of workshops in which the TI Team engages 

proponents of alternative interpretations that represent the range of relevant current community 

knowledge. Resource experts in the various relevant data sets are also engaged. The workshops 

have the dual purposes of, first, evaluating the degree to which alternative interpretations are 

supported by observed data and, second, defining uncertainties in the degree to which the 

interpretations are defensible, given the observed data. Integration is carried out by individual 

evaluator experts or evaluator expert teams (Level 4 process) or by a Technical Integrator (TI) 

Team (Level 3 process) who, informed by the evaluation activities, characterize the range of 

                                                       

3 See Section 2.1 in the CEUS SSC Final Report for discussion of concepts relating to the center, body, 

and range of the “technically-defensible interpretations” vs. the center, body, and range of the “informed 

technical community.” 

4 For an excellent discussion of this two-stage process, see Practical Implementation Guidelines for 

SSHAC Level 3 and 4 Hazard Studies, USNRC NUREG-XXXX, Draft for Review, Office of Nuclear 

Regulatory Research, May 2011. 

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PPRP Final Report, CEUS SSC PROJECT October 24, 2011 

 xxi 

defensible alternative interpretations in an integrated hazard model and assess the scientific 

uncertainty distribution. Based on our review of the Project Plan and our subsequent discussions 

with the Project Team, we concurred that the Plan conformed with the SSHAC Guidance,

incorporating lessons learned from fourteen years experience using the Guidance, and that the 

planned implementation was structured to properly carry out the SSHAC assessment process for 

development of the CEUS SSC Model. 

SSHAC Level 3 Assessment Process 

The SSHAC Guidance describes implementation processes for four levels of assessment 

depending on the scientific complexity of the assessment and the intended use of the assessed 

hazard model. For an assessment such as the regional SSC model for the Central and Eastern 

United States, which will be used at many sites for making safety and licensing decisions for 

nuclear facilities, the SSHAC Guidance recommends using an assessment Level 3 or Level 4. 

There are process differences between a Level 3 and Level 4 implementation, but the objective is 

the same: to obtain from multiple proponent experts information that supports an informed 

assessment of the range of existent relevant interpretations and associated uncertainties that 

together represent current community knowledge and to perform an informed assessment of the 

CBR of the TDI. We understand that within the SSHAC assessment process “technically 

defensible” means that observed data are sufficient to support evaluation of the interpretation and 

the corresponding uncertainty. 

In a Level 4 assessment process a TI Team facilitates the assessment, identifying and engaging 

proponent and resource experts, performing supporting analyses, and conducting knowledge 

evaluation workshops and assessment integration working meetings. Multiple experts or teams 

of experts perform as evaluators of the range of existent interpretations and as integrators of the 

hazard model. The individual evaluator experts or evaluator expert teams take ownership of 

their individual or team assessments. In a Level 3 assessment all of these activities are 

consolidated under a single TI Team consisting of a TI Lead, multiple evaluator experts 

representing the scope of required scientific expertise, and experienced data and hazard analysts. 

As we noted earlier in this report, assurance that the CBR of the TDI is properly represented in a 

hazard model comes from rigorously implementing the SSHAC assessment process itself. We 

note that an important lesson learned from multiple implementations of the SSHAC Guidance

over the past fourteen years is that the Level 3 and Level 4 assessment processes provide 

comparably high assurance that the relevant scientific knowledge and the community uncertainty 

distribution are properly assessed and represented in the hazard model. The Level 3 assessment 

is significantly more integrated and cohesive and is more efficient to implement. These 

considerations led us to endorse use of the Level 3 assessment for implementation of the CEUS 

SSC Project in our Workshop No. 1 review letter. During the course of the Project we observed

that the higher level of cohesiveness inherent in the Level 3 assessment process leads to 

significantly improved communication, facilitating the experts’ performance of their technical 

work. 

xcvii
PPRP Final Report, CEUS SSC PROJECT October 24, 2011 

xxii

Overall Project Organization 

A complex project with multiple sponsors such as the CEUS SSC Project cannot be successful 

unless it is well organized and energetically managed so that the various participants understand 

the interconnectedness of their activities and perform their technical work as a cohesive group. 

In this regard the adopted project management structure allowed the Project Manager to provide 

integrated overall project leadership, manage the database development activities, and effectively 

maintain communication with the PPRP and project sponsors while allowing TI Team lead to 

concentrate on the structural and technical activities of the assessment as the Project unfolded. 

We conclude that the project organization was effective overall and particularly so with regard to 

facilitating the TI Team’s implementation of the assessment process. 

Implementing the SSHAC Level 3 Assessment Process 

Irrespective of the level of implementation, evaluation and integration are the main activities of a 

SSHAC assessment. The evaluation activities aim to identify and evaluate all relevant available 

data, models, methods, and scientific interpretations as well as uncertainties associated with each 

of them. The integration activities, informed by the evaluations, aim to represent the CBR of the 

TDI in a fully integrated SSC model. 

Evaluation 

Consistent with the SSHAC Guidance the evaluation phase of the CEUS SSC project 

accomplished a comprehensive evaluation of the data, models, methods, and scientific 

interpretations existent in the larger technical community that are relevant to the SSC model. In 

significant part the process was carried out in three structured workshops, each focusing on 

accomplishing a specific step in the evaluation process. 

The first workshop (WS-1) focused on evaluations of relevant geological, geophysical, and 

seismological datasets (including data quality and uncertainties) and on identification of hazardsignificant data and hazard-significant SSC assessment issues. It became clear that a number of 

issues relating to the earthquake catalog, the paleoliquefaction data set, the potential-field 

geophysical data, updating procedures for assessing maximum earthquake magnitude, and 

development of procedures for assessing earthquake recurrence would require focused analyses. 

These analyses were appropriately carried out within the TI Team working interactively with 

appropriate resource experts recognized by the larger scientific and technical community. 

WS-2 focused on evaluations of the range of alternative scientific interpretations, methods, and 

models within the larger scientific community and on corresponding uncertainties. WS-3 

focused on evaluations of hazard feedback derived at seven representative test locations using a 

preliminary CEUS SSC model. Specifically, the workshop focused on the identification of the 

key issues of most significance to completing the SSC model assessment. 

Experience has shown that evaluations to gain understanding of the quality of various data sets 

and uncertainties associated with them are essential for fully informing an SSC assessment. We 

observed that in WS-1 resource experts for the various data sets did a high-quality job of 

describing the data sets and giving their perspective about the data quality and associated 

uncertainties. We conclude that the understanding of data quality and uncertainties gained in 

WS-1 together with continued interactions between the TI Team and data resource experts 

xcviii
PPRP Final Report, CEUS SSC PROJECT October 24, 2011 

 

significantly informed the TI Team’s evaluations. The TI Team’s evaluations of the data quality 

and uncertainties are well documented in the innovative “Data Summary Tables” and “Data 

Evaluation Tables” included in the Project Report. Importantly, the TI Team continued to 

effectively engage data resource experts in productive analyses of potential-field geophysical 

data, the earthquake catalog, development of the paleoearthquake data set (including an 

integrated assessment of the paleoliquefaction data in order to extend the earthquake catalog), the 

development of methods for assessing maximum earthquakes, and the development of 

earthquake recurrence analyses. All of these focused analyses strongly informed the assessment 

process. Moreover, documentation of the analyses resulted in stand-alone products of the Project 

that will serve future users of the CEUS SSC Model.

The compilation and evaluation of potentially relevant methods, models, and alternative 

scientific interpretations representing the community knowledge and corresponding uncertainties 

must be considered the core process activity of any SSHAC assessment. This step was largely 

carried out in WS-2. Success in defining the community knowledge depends on fully engaging 

proponent experts representing the range of methods, models, and interpretations existent at the 

time. Full engagement means that the proponent experts completely and clearly describe their 

interpretations and the data that support them and provide their individual evaluations of 

corresponding uncertainties. We observed that the actions taken by the Project and TI Team to 

explain the workshop goals and to guide participants toward meeting those goals was very 

productive. We conclude that the workshop was highly successful in meeting the stated goals 

and that it fully met the expectation of the SSHAC Guidance with respect to evaluating the range 

of alternative scientific interpretations. The discussions during the workshop and between the TI 

Team and Panel following the workshop evolved the “SSC Framework” concept, which 

provided transparent criteria that framed the TI Team’s systematic identification and assessment 

of seismic sources throughout the CEUS. 

Feedback from hazard calculations and sensitivity analyses is an important step in a SSHAC 

assessment to understand the importance of elements of the model and inform the final 

assessments. For development of a regional SSC model to be used for site-specific probabilistic 

seismic hazard analyses (PSHAs) at many geographically distributed sites, feedback based on the 

preliminary model is particularly important. Following WS-2 a preliminary SSC model termed 

“the SSC sensitivity model,” was developed and used for hazard sensitivity calculations that 

were evaluated in WS-3. While the SSC sensitivity model was clearly preliminary, the 

evaluation of sensitivity results that took place in WS-3 provided important feedback for 

completing analyses and for supporting the TI Team’s development of the preliminary CEUS 

SSC model. The Panel was able to review the preliminary model and provide feedback in a 

subsequent project briefing meeting on March 24, 2010. 

Together the three workshops provided the TI Team interactions with the appropriate range of 

resource and proponent experts. These experts were carefully identified to present, discuss, and 

debate the data, models, and methods that together form the basis for assuring that the CBR of 

the TDI have been properly represented in the hazard model. Experts representing academia, 

government, and private industry participated. The TI Team also reached out to a wide range of 

experts as they developed the database and performed the integration activities to develop the 

SSC model. The Panel participated throughout this process, and is satisfied that the TI Team 

fully engaged appropriate experts to accomplish the goals of a SSHAC Guidance. 

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PPRP Final Report, CEUS SSC PROJECT October 24, 2011 

xxiv

Integration 

Consistent with the SSHAC Guidance, integration is the process of assessing the CBR of the TDI 

and representing the assessment in the SSC model. Informed by the evaluation process, the 

integration process includes representation of the range of defensible methods, models, and 

interpretations of the larger technical community together with new models and methods 

developed by analyses during the evaluation and integration process. 

For the CEUS SSC Project, development of the earthquake catalog, methods for assessing and 

representing maximum earthquake magnitudes, and methods for earthquake recurrence 

assessment continued during the integration process. The Panel reviewed all the analyses at 

various stages of development and provided comments and recommendations. The TI Team 

performed the integration process by means of eleven working meetings. Members of the Panel 

participated in most of these working meetings as observers or resource experts. The full Panel 

participated in the discussions during both feedback meetings and provided formal comments 

and recommendations following the meetings. We observed that the integration process was

thorough and that it acceptably complied with the SSHAC Guidance. Based on our participation 

and observations we conclude that the integrated CEUS SSC Model appropriately represents the 

center, body, and range of current methods, models and technically defensible interpretations. 

PPRP Engagement 

Consistent with the SSHAC Guidance, the Panel was fully engaged in peer-review interactions 

with the TI Team and the Project Manager of the CEUS SSC Project throughout the entire 

project period—from development of the Project Plan in early to mid 2008 through production of 

the Final Project Report in mid to late 2011.5 The Panel provided both written and oral peerreview comments on both technical and process aspects at many stages of the Project’s 

evolution. Key PPRP activities, leading up to this final report, have included: 

• Review of the Project Plan. 

• Formulation of a PPRP implementation plan, specifically for the CEUS SSC Project, to 

ensure adherence to the general guidance provided by SSHAC and NUREG-1563 for the 

scope and goals of a PPRP review. 

• Involvement in each of the three Project workshops, including advising in the planning 

stage; participating collectively as a review panel during the workshop (and individually 

as resource experts when requested by the TI Team), providing timely comments on 

technical and process issues; and submitting a written report of the Panel’s observations 

and recommendations following each workshop. 

• Development and implementation of a process, together with the TI Team, to document 

the resolution of recommendations made in PPRP formal communications. 

• Participation as observers (and occasionally as resource experts when requested by the TI 

Team) in eight of the TI Team’s 11 working meetings. 

• Peer-review and written comments, including several informal reports, on the TI Team’s 

intermediate work products, particularly early versions of the CEUS SSC Model. 

                                                       

5

 See CEUS SSC Final Report: Section 2.5, Table 2.2-1, and Appendix I 

c
PPRP Final Report, CEUS SSC PROJECT October 24, 2011 

 

• Direct interaction with the TI Team and Project Manager in more than 20 teleconferences 

and four face-to-face briefings—in addition to the three workshops and eight working 

meetings of the TI Team noted above. 

• Extensive, critical peer-review of the Project’s 2010 Draft Report and 2011 Final Report. 

The Panel, collectively and individually, fully understood the SSHAC Guidance for a structured 

participatory peer review and the requirements for a Level 3 assessment process; had full and 

frequent access to information and interacted extensively with the TI Team and Project Manager 

throughout the entire project; provided peer-review comments at numerous stages; and, as 

documented within the Final Project Report, was fully engaged to meet its peer-review 

obligations in an effective way. 

Project Report 

The SSHAC Guidance makes clear that adequate documentation of process and results is crucial 

for their understanding and use by others in the technical community, by later analysis teams, 

and by the project sponsors. The Panel understood what was needed to conform to the SSHAC 

requirements, and it was committed to ensuring that the documentation of technical details 

associated with the CEUS SSC Model in the Project Report was clear and complete. The Panel 

was equally committed to ensuring the transparency of process aspects of the project, both in 

implementation and in description in the Project Report. 

The Panel provided lengthy compilations of review comments (see Appendix I of the Project 

Report) for both the 2010 Draft Report and the 2011 Final Report. These included hundreds of 

comments, categorized as general, specific, relating to clarity and completeness, or editorial. 

The massive amount of detail provided by the TI Team in the Project Report and the 

intensiveness of the Panel’s review comments both reflect great diligence and a mutual 

understanding by the TI Team and the PPRP of the thoroughness and high quality of 

documentation expected in the Project Report. 

The Project Manager and the TI Lead provided review criteria to the Panel for both the draft and 

final versions of the Project Report. The criteria for reviewing the Draft Report6

 covered the 

range of technical and process issues consistent with requirements of the SSHAC Guidance, 

including draft implementation guidance (see footnote #4). Key criteria, among others, include 

sufficiency of explanatory detail; adequate consideration of the full range of data, models, and 

methods—and the views of the larger technical community; adequate justification of the data 

evaluation process, logic-tree weights, and other technical decisions; proper treatment of 

uncertainties; and conformance to a SSHAC Level 3 assessment process. To be clear, the PPRP 

is charged with judging the adequacy of the documented justification for the CEUS SSC Model 

and its associated logic-tree weights. The TI Team “owns” the Model and logic-tree weights. 

Criteria for reviewing the Final Report focused on reaching closure to comments made on the 

Draft Report and ensuring that no substantive issues remained unresolved. To that end, among 

its many review comments on the Final Report the Panel identified “mandatory” comments, 

which the TI Team was required to address in the final version of the Project Report. 

                                                       

6

 See PPRP report dated October 4, 2010, in Appendix I of CEUS SSC Final Report 

ci
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cii
PROJECT ACKNOWLEDGMENTS 

This study was sponsored by the Electric Power Research Institute (EPRI) Advanced Nuclear 

Technology Action Plan Committee, the U.S. Department of Energy (DOE) Office of Nuclear 

Energy and Office of the Chief of Nuclear Safety, and the U.S. Nuclear Regulatory Commission 

(NRC) Office of Nuclear Regulatory Research. Technical experts from the DOE, NRC, U.S. 

Geological Survey, Defense Nuclear Facility Safety Board, industry, and academia participated 

in the study as part of the Technical Integration (TI) Team or as members of the Participatory 

Peer Review Panel (PPRP). Any statements, opinions, findings, conclusions, or 

recommendations expressed in this material are those of the authors and do not necessarily 

reflect those of the participating or sponsoring agencies. 

Jeffrey F. Hamel was the EPRI Advanced Nuclear Technology Program Manager. Lawrence A. 

Salomone of Savannah River Nuclear Solutions, LLC, served as the Project Manager for the 

study. Kevin J. Coppersmith of Coppersmith Consulting Inc., served as the lead for the TI Team. 

J. Carl Stepp of Earthquake Hazards Solutions, and Walter J. Arabasz, Research Professor 

Emeritus of Geology and Geophysics at the University of Utah, served as Co-chairmen for the 

PPRP. The entire Central and Eastern United States Seismic Source Characterization Project 

Team and their roles are discussed in Section 2 and are shown on the project oganization chart 

(Figure 2.3-1) of the report. 

The authors of the report wish to acknowledge the contributions of the following people: the 

resource experts who participated in Workshop 1, the proponent experts who participated in 

Workshop 2, and the technical experts who provided valuable insights, perspective, and 

references throughout the study. The names of all these contributors are listed in Table 2.2-2. 

In addition, the authors of the report appreciate the support of Geraldine Moore-Butler as 

administrative assistant and Nancy L. Sutherland as technical editor for the project. This report 

was assembled at AMEC. 

ciii
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SPONSORS’ PERSPECTIVE 

This report describes a new seismic source characterization model for the Central and Eastern 

United States (CEUS) for use in probabilistic seismic hazard analysis (PSHA) for nuclear 

facilities. PSHA has become a generally accepted procedure for supporting seismic design, 

seismic safety and decision making for both industry and government. Input to a PSHA consists 

of seismic source characterization (SSC) and ground motion characterization (GMC); these two 

components are necessary to calculate probabilistic hazard results (or seismic hazard curves) at a 

particular geographic location. 

The 1986 Electric Power Research Institute and Seismicity Owners Group (EPRI-SOG) study 

included both an SSC and GMC component. Recent applications for new commercial reactors 

have followed U.S. Nuclear Regulatory Commission (NRC) regulatory guidance (RG 1.208) by 

using the EPRI-SOG source model as a starting point and updating it as appropriate on a sitespecific basis. This CEUS SSC Project has developed a new SSC model for the CEUS to replace 

the SSC component of the EPRI-SOG study. 

The CEUS SSC Project was conducted using a Senior Seismic Hazard Analysis Committee 

(SSHAC) Level 3 process, as described in the NRC publication, Recommendations for 

Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts 

(NUREG/CR-6372). The goal of the SSHAC process is to represent the center, body, and range 

of technically defensible interpretations of the available data, models, and methods. The CEUS 

SSC model is applicable to any site within the CEUS and can be used with the EPRI 2004/2006 

GMC model to calculate seismic hazard at any site of interest. Long-term efforts to replace the 

EPRI 2004/2006 GMC model with the Next Generation Attenuation Relationships for Central 

and Eastern North America obtained from the NGA-East Project is scheduled for completion in 

2014. 

The updated CEUS SSC model provides industry and government with the following: a new 

model for the commercial nuclear industry to perform PSHAs for future reactor license 

applications; the NRC to support its review of early site permit (ESP) and construction and 

operating license (COL) applications; and the U.S. Department of Energy (DOE) to support 

modern PSHAs to meet design and periodic review requirements for its current and future 

nuclear facilities. Specific benefits of the model are as follows: 

Consistency: For many sites, seismic sources at distances up to 300 km (186 mi.) or more 

significantly contribute to hazard at some spectral frequencies. Consequently, seismic hazard 

models for many sites have significant geologic overlap. If done separately, there is a 

likelihood of conflicting assessments for the same regions. A regional source model allows 

for consistent input into a PSHA. An updated conceptual SSC framework that provides a 

cv
Sponsors’ Perspective

consistent basis for identifying and characterizing seismic sources in the CEUS has been 

developed. The NRC will no longer need to review each time each applicant’s regional SSC

model when the accepted CEUS SSC model is used. This will avoid lengthy review of the 

regional SSC model in ESP and COL applications for sites within the CEUS that use the 

accepted regional CEUS SSC model to develop its site-specific SSC model. 

Stability: This CEUS SSC model was developed using the accepted state-of-practice 

SSHAC methodology that involved the following tasks: 

o Development of a comprehensive database and new tools for documenting the data 

consideration process. 

o Multiple workshops to identify applicable data, debate alternative hypotheses, and 

discuss feedback. 

o Multiple working meetings by the Technical Integration (TI) Team to develop the SSC 

model and fully incorporate uncertainties. 

o Technical advancements in a number of areas, such as developing a uniform earthquake 

catalog, developing an updated approach for assessing maximum magnitude, compiling 

data evaluation tables, incorporating paleoseismic data, and using spatial smoothing 

tools.

o Participatory peer review, including four panel briefings, multiple interactions, and 

periodic formal feedback. 

o Proper documentation of all process and technical aspects of the project. 

Experience has shown that stability is best achieved through proper and thorough 

characterization of our knowledge and uncertainties, coupled with the involvement of the 

technical community, regulators, and oversight groups. 

Greater Longevity: An explicit goal of the SSHAC methodology is to represent the center, 

body, and range of the technically defensible interpretations of the available data, models,

and methods. Using the SSHAC process provides reasonable assurance that this goal has 

been achieved. Representing the center, body, and range of interpretations at the time of the 

study means that as new information is acquired and various interpretations evolve as a 

result, the current thinking at any point is more likely to be addressed in the study. As new 

information becomes available, an existing SSC will require periodic reviews to evaluate the 

implications of the new findings. The need for updates to a particular study is now better 

understood as a result of findings of the CEUS SSC Project sensitivity studies to determine 

the significance of source characteristics. 

Cost and Schedule Savings: The CEUS SSC model can be used to perform a PSHA at any 

geographic location within the CEUS. It is applicable at any point within the CEUS, subject 

to site-specific refinements required by facility-specific regulations or regulatory guidance. 

Having stable, consistent input into a regional PSHA will reduce the time and cost required 

to complete a commercial nuclear site’s ESP or COL licensing application, prepare a DOE 

site’s PSHA, and develop design input for new commercial and DOE mission-critical nuclear 

facilities.

cvi
Sponsors’ Perspective 

cvii 

 Advancement of Science: The CEUS SSC Project provides new data, models, and methods. 

This information was shared at three workshops with international observers as a means to 

provide technology transfer for application in other regions. The CEUS SSC earthquake 

catalog, which merges and reconciles several catalogs and provides a uniform moment 

magnitude for all events, and the CEUS SSC paleoliquefaction database provide a new 

baseline for future research and updates. New approaches used in this project for spatial 

smoothing of recurrence parameters, assessment of maximum magnitude, and systematical 

documentation of all data considered and evaluated also benefit future research and PSHA 

updates. 

The sponsors of the CEUS SSC Project are utilities and vendors on the EPRI Advanced Nuclear 

Technology Action Plan Committee, the DOE Office of Nuclear Energy, the DOE Office of the 

Chief of Nuclear Safety, and the NRC Office of Nuclear Regulatory Research. Technical experts 

from the DOE, NRC, U.S. Geological Survey (USGS), and Defense Nuclear Facility Safety 

Board (DNFSB) participated in the study as part of the TI Team or as members of the 

Participatory Peer Review Panel (PPRP). 

The product of the CEUS SSC Project is a robust peer-reviewed regional CEUS SSC model for 

use in PSHAs. This model will be applicable to the entire CEUS, providing an important 

baseline for future research and updates. The CEUS SSC Project demonstrates that a SSHAC 

Level 3 approach can achieve the goals of considering the knowledge and uncertainties of the 

larger technical community within a robust and transparent framework. The value of the new 

CEUS SSC model has been enhanced by the participation of key stakeholders from industry, 

government, and academia who were part of the CEUS SSC Project Team. 

Looking forward, the NRC will publish NUREG-2117 (2012), Practical Implementation 

Guidelines for SSHAC Level 3 and 4 Hazard Studies that provides SSHAC guidance on the need 

to update a regional model. The guidance covers updating both regional and site-specific 

assessments. It addresses the “refinement” process of starting with a regional model and refining 

it for site-specific applications. 
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ABBREVIATIONS 

AD anno domini (in the year of the Lord) 

AFE annual frequency of exceedance 

AIC Akaike information criterion 

ALM Alabama-Louisiana-Mississippi (zone of possible paleoseismic features) 

AM Atlantic Margin (seismotectonic zone) 

AHEX Atlantic Highly Extended Crust (seismotectonic zone) 

ANSS U.S. Advanced National Seismic System 

ANT Advanced Nuclear Technology 

APC Action Plan Comittee 

BA Blytheville arch 

BC before Christ 

BCFZ Big Creek fault zone 

BFZ Blytheville fault zone 

BL Bootheel lineament 

BMA Brunswick magnetic anomaly 

BP before present 

BPT Brownian passage time 

BTP Branch Technical Position 

CAD computer-aided design

cix
Abbreviations 

CBR center, body, and range 

CCFZ Crittenden County fault zone 

CDZ Commerce deformation zone 

CENA Central and Eastern North America

CERI Center for Earthquake Research and Information 

CEUS Central and Eastern United States 

CFZ Commerce fault zone 

CFR Code of Federal Regulations 

CGL Commerce geophysical lineament 

CGRGC Cottonwood Grove–Rough Creek graben 

CI confidence interval 

CNWRA Center for Nuclear Waste Regulatory Analysis 

COCORP Consortium for Continental Reflection Profiling 

COCRUST Consortium for Crustal Reconnaissance Using Seismic Techniques 

COL combined construction and operating license 

COLA combined operating license application 

COMP composite prior, composite superdomain 

CON contemporary (with earthquake occurrence) 

COV coefficient of variation 

CPT cone penetration test 

CVSZ Central Virginia seismic zone 

D&G Dewey and Gordon (1984 catalog) 

DEM digital elevation model 

cx
Abbreviations 

DNFSB Defense Nuclear Facilities Safety Board 

DOE U.S. Department of Energy 

DWM Division of Waste Management 

ECC Extended Continental Crust 

ECC-AM Extended Continental Crust–Atlantic Margin (seismotectonic zone) 

ECC-GC Extended Continental Crust–Gulf Coast (seismotectonic zone) 

ECFS East Coast fault system 

ECFS-C East Coast fault system—central segment 

ECFS-N East Coast fault system—northern segment 

ECFS-S East Coast fault system—southern segment 

EC-SFS East Coast–Stafford fault system 

ECMA East Coast magnetic anomaly 

ECRB East Continent rift basin 

ECTM Eastern Canada Telemetered Network 

E[M] expected moment magnitude listed in the CEUS SSC catalog for an earthquake 

ENA eastern North America 

EP Eau Plain shear zone 

EPRI Electric Power Research Institute 

EPRI-SOG Electric Power Research Institute–Seismicity Owners Group 

ERM Eastern rift margin 

ERM-N Eastern rift margin—north

ERM-RP Eastern rift margin—river (fault) picks 

ERM-S Eastern rift margin—south

cxi
Abbreviations 

ERM-SCC Eastern rift margin—south/Crittenden County 

ERM-SRP Eastern rift margin—south/river (fault) picks 

ERRM Eastern Reelfoot Rift Margin 

ESP early site permit 

ESRI Environmental Systems Research Institute 

ETSZ Eastern Tennessee seismic zone 

EUS Eastern United States 

FAFC Fluorspar Area fault complex 

FGDC Federal Geographic Data Committee 

ft foot or feet 

FTP file transfer protocol 

ft/s feet per second 

ft/yr feet per year 

FWLA Fugro William Lettis & Associates 

FWR Fort Wayne rift 

Ga billion years ago 

GC Gulf Coast 

GCVSZ Giles County, Virginia, seismic zone 

GHEX Gulf Coast Highly Extended Crust (seismotectonic zone) 

GIS geographic information system 

GLTZ Great Lakes tectonic zone 

GMC ground-motion characterization (model) 

GMH Great Meteor Hotspot (seismotectonic zone) 

cxii
Abbreviations 

GMPE ground-motion prediction equation 

GMRS ground-motion response spectra 

GPR ground-penetrating radar 

GPS global positioning system 

GSC Geological Survey of Canada 

Gyr gigayears (109 years) 

HF Humboldt fault 

HID hazard input document 

I0 maximum intensity 

IAEA International Atomic Energy Agency

IBEB Illinois Basin Extended Basement (seismotectonic zone) 

IPEEE Individual Plant Examination for External Events 

IRM Iapetan rifted margin 

ISC International Seismological Centre 

ITC informed technical community 

ka thousand years ago 

K-Ar potassium-argon 

km kilometer(s) 

km2 square kilometer(s) 

km/sec kilometers per second 

K-S Kijko-Sellevoll 

K-S-B Kijko-Sellevoll-Bayes 

kyr thousand years 

cxiii
Abbreviations 

LDO Lamont-Doherty Earth Observatory (catalog) 

LHS Latin hypercube sampling 

LLNL Lawrence Livermore National Laboratory 

ln(FA) logarithm of felt area (with felt area measured in km2) 

LS least squares 

LSA La Salle anticlinal belt 

LWLS locally weighted least squares 

m meter(s) 

M magnitude 

M, MW moment magnitudes 

Ma million years ago 

MAR Marianna (RLME source) 

mb body-wave magnitude (short period) 

mbLg body-wave magnitude determined from higher-mode (Lg) surface waves

MC coda magnitude 

MCMC Markov Chain Monte Carlo 

MD duration magnitude 

MESE Mesozoic and younger extended crust 

MESE-N Mesozoic-and-younger extended crust or Mmax zone that is ―narrow‖

MESE-W Mesozoic-and-younger extended crust or Mmax zone that is ―wide‖

mi. mile(s) 

mi.2 square mile(s) 

MIDC midcontinent 

cxiv
Abbreviations 

MidC Midcontinent-Craton (seismotectonic zone) 

Mfa felt-area magnitude 

ML local magnitude 

Mmax, Mmax maximum magnitude 

MMI modified Mercalli intensity 

mm/yr millimeters per year 

MN Nuttli magnitude 

Mo Scalar seismic moment 

MRS Midcontinent rift system 

m/s meters per second 

MS surface-wave magnitude 

MSF Meeman-Shelby fault 

Mw 

Myr million years 

NAD83 North American Datum of 1983 

NAP Northern Appalachian (seismotectonic zone) 

Nd neodymium 

NEDB National Earthquake Database 

NEI Nuclear Energy Institute 

NEIC National Earthquake Information Center 

NF Niagara fault zone 

NMESE Non-Mesozoic and younger extended crust

NMESE-N Mesozoic-and-younger extended crust or Mmax zone that is ―narrow‖

cxv
Abbreviations 

NMESE-W Mesozoic-and-younger extended crust or Mmax zone that is ―wide‖

NMFS New Madrid fault system 

NMN New Madrid North fault 

NMS New Madrid South fault 

NMSZ New Madrid seismic zone 

NN New Madrid north (fault segment as designated by Johnston and Schweig, 1996) 

NOAA National Oceanic and Atmospheric Administration 

NPP nuclear power plant(s) 

NR Nemaha Ridge 

NRC U.S. Nuclear Regulatory Commission 

NRHF Nemaha Ridge–Humboldt fault

NSHMP National Seismic Hazard Mapping Project 

NW New Madrid west (fault segment as designated by Johnston and Schweig, 1996) 

OKA Oklahoma aulacogen (seismotectonic zone) 

OKO Oklahoma Geological Survey Leonard Geophysical Observatory (catalog) 

OSL optically stimulated luminescence 

Pa probability of activity (of being seismogenic) 

PEZ Paleozoic Extended Crust (seismotectonic zone) 

PGA peak ground acceleration 

PM Project Manager 

PPRP Participatory Peer Review Panel 

PSHA probabilistic seismic hazard analysis 

PVHA probabilistic volcanic hazard analysis 

cxvi
Abbreviations 

RCG Rough Creek graben 

RF Reelfoot fault 

RFT Reelfoot thrust (fault) 

RLME repeated large-magnitude earthquake (source) 

RR Reelfoot rift zone 

RS Reelfoot South (fault segment) 

SA spectral acceleration 

SCL St. Charles lineament 

SCML south-central magnetic lineament 

SCR stable continental region 

SCSN South Carolina Seismic Network 

SEUS Southeastern United States (catalog) 

SEUSSN Southeastern United States Seismic Network 

SGFZ Ste. Genevieve fault zone 

SHmax maximum horizontal stress, compression, or principal stress 

SLR St. Lawrence rift (seismotectonic zone) 

SLTZ Spirit Lake tectonic zone 

SLU Saint Louis University (catalog) 

SNM Sanford et al. (2002 catalog) 

SOG Seismicity Owners Group 

SPT standard penetration test 

SRA Stover, Reagor, and Algermissen (1984 catalog) 

SRTM Shuttle Radar Topography Mission 

cxvii
Abbreviations 

SSC seismic source characterization 

SSE safe shutdown earthquake 

SSHAC Senior Seismic Hazard Analysis Committee 

Str&Tur Street and Turcotte (1977 catalog) 

SUSN Southeastern United States Network 

TC technical community 

TFI technical facilitator/integrator 

TI technical integration 

USGS U.S. Geological Survey 

USNSN U.S. National Seismograph Network 

UTC Coordinated Universal Time 

VP/VS ratio of P-wave velocity to S-wave velocity 

WES Weston Observatory (catalog) 

WIPP Waste Isolation Pilot Project 

WQSZ Western Quebec seismic zone 

WRFZ White River fault zone 

WUS Western United States 

WVFS Wabash Valley fault system 

WVSZ Wabash Valley seismic zone 

WWSSN World-Wide Standardized Seismograph Network 

cxviii
NUREG-2115 DOE/NE-0140 EPRI 1021097

APPENDIX G 

Biographies of Project Team 

G

APPENDIX 

BIOGRAPHIES OF PROJECT TEAM 

Biographies for CEUS SSC Project team members are provided in this appendix. As described in 

Section 2.3 and shown on Figure 2.3-1, there are several organizational levels of project 

participants. In this appendix, biographies for the CEUS SSC Project management team are 

presented first. These are followed by the biographies for individual members of the TI Team, 

Technical Support, Database Manager, Participatory Peer Review Panel, and Sponsor Reviewers, 

in alphabetical order for each organizational level. 

G-1
EPRI MANAGEMENT 

Robert P. Kassawara, PhD, is EPRI Senior Project Manager for the Structural Reliability and 

Integrity group at EPRI. Dr. Kassawara is responsible for the technical, financial, and 

administrative planning and management of EPRI’s research and development for seismic 

engineering for commercial nuclear power plants. Projects include all aspects of the discipline 

from seismic hazard to equipment qualification. Before joining EPRI in 1985, he managed the 

engineering analysis section of the Plant Engineering Division of IMPELL in Melville, New 

York. In this position, he was responsible for performing structural engineering analyses 

predominantly for the nuclear power industry. Between 1970 and 1981, he managed and 

contributed to nuclear power plant design and analysis at Combustion Engineering in Windsor, 

Connecticut. Dr. Kassawara has a BS in civil engineering from the Polytechnic Institute of 

Brooklyn (1966), and an MS (1968) and PhD (1970) in civil engineering from the University of 

Illinois. 

Jeffrey F. Hamel is EPRI ANT Program Manager in the ANT program within the nuclear sector 

at EPRI. His current research activities focus on supporting deployment of advanced nuclear 

plants in the near term, while promoting areas of research to support long-term nuclear 

sustainability and growth. Specifically, Mr. Hamel oversees research on near-term deployment of 

advanced light-water-reactor nuclear plants, development of the Next Generation Nuclear Plant 

GEN IV technology, and technical and commercial support for an integrated spent-fuel 

management strategy. Before joining EPRI in 2007, he worked at General Electric as the 

manager of special projects and was responsible for managing and leading new growth for GE’s

nuclear business, particularly in pressurized water reactor and spent-fuel services. In addition, 

while at GE, he supported the commercial development of new nuclear power plant projects both 

domestically and internationally, including development of key engineering, mechanical and 

electrical equipment necessary for project execution. Mr. Hamel received a BS in marine 

transportation from the Massachusetts Maritime Academy in Buzzards Bay, Mass., along with a 

U.S. Coast Guard Merchant Marine license and U.S. Navy Reserve commission. He received his 

MBA from Santa Clara University in Santa Clara, California. 

PROJECT MANAGER 

Lawrence A. Salomone, PE, is the Project Manager for the CEUS SSC Project. He is a 

registered Professional Engineer with 40 years of experience in the environmental and earth 

sciences. He is the Site Chief Geotechnical Engineer at the Savannah River Site (SRS) in Aiken, 

S.C., where he has developed and managed a $100 million geological, seismological, and 

geotechnical (GSG) characterization program to integrate geotechnical and geo-environmental 

work for mission-critical nuclear facilities at the SRS. He has directed 35-person and 70-person 

multidisciplinary groups. As an Associate with Dames and Moore, he directed the licensing, site 

preparation, and foundation operations for a nuclear power plant. As a research civil engineer for 

the National Bureau of Standards (now National Institute of Standards and Technology), he 

performed research to advance geotechnical, earthquake engineering, and energy technology. 

Mr. Salomone was nominated by the National Capital Section of the American Society of Civil 

Engineers for the Walter L. Huber Civil Engineering Research Prize for his work in the area of 

thermal soil mechanics. His work was used to study backfills for the Yucca Mountain high level 

waste repository, design underground electric transmission lines and develop mesoscale (severe) 

G-2
weather forecasting models. He currently serves as a consultant to the U.S. House of 

Representatives and the U.S. Senate on national energy policy issues. 

Mr. Salomone established the industry-government partnership to develop a new SSC model for 

the CEUS. He served as the Department of Energy (DOE) representative supporting the 

NEI/EPRI New Plant Seismic Issue Resolution Program and interacted with the NRC for its 

update of seismic regulatory guidance. Currently, he is a member of the Seismic Lessons 

Learned Panel that advises the DOE Nuclear Facility Safety Program, and he is the EPRI 

representative on the Joint Management Committee for the Next Generation Attenuation–East 

Project. He participated in the Pacific Engineering Research Center (PEER) workshops for the 

Next Generation Attenuation–West Project. He has provided support for the DOE Nuclear Power 

2010 program and now serves on the New Carolina Nuclear Power Policy Subcommittee. He is 

the author or co-author of over 40 published papers and many technical reports. Mr. Salomone 

earned his BCE in civil engineering from Manhattan College in Riverdale, N.Y., and his MS in 

geotechnical engineering from the University of California, Los Angeles. 

TI TEAM

Kevin J. Coppersmith, PhD, of Coppersmith Consulting, Inc., is the Technical Integrator (TI) 

lead for the CEUS SSC Project. He has more than 30 years of consulting experience, with 

primary emphasis in probabilistic hazard analyses (seismic, volcanic, and related geohazards) for 

design and review of critical facilities within regulated environments. He has pioneered 

approaches to characterizing earth sciences data and their associated uncertainties for 

probabilistic seismic hazard analyses (PSHAs) for a range of critical facility sites, including 

nuclear power plant sites, high-level waste repositories, dams, offshore platforms, pipelines, and 

bridges. Dr. Coppersmith was a member of SSHAC, which provided PSHA methodology 

guidance to the NRC, DOE, and EPRI. As a co-principal investigator, he recently completed a 

study for the NRC on reviewing lessons learned from the application of SSHAC Study Level 3 

and 4 methodologies over the past 10 years. He is currently working with NRC research staff to 

develop a nuclear regulatory (NUREG) series document on detailed implementation guidance for 

SSHAC Level 3 and 4 studies. 

Dr. Coppersmith has extensive experience in leading SSHAC Level 3 and 4 studies for nuclear 

facilities. He served as the SSC technical facilitator/integrator (TFI) for SSHAC Level 4 seismic 

hazard studies at the Yucca Mountain, Nevada, high-level waste repository, and he was the SSC 

TFI for the PEGASOS SSHAC Level 4 study for four nuclear power plants in Switzerland. He 

was also the TFI for the probabilistic volcanic hazard analysis conducted in 1996 for Yucca 

Mountain, as well as for the update to that study completed in 2008. He is the SSC TI lead for 

SSHAC Level 3 seismic hazard studies for licensing of a nuclear power plant at Thyspunt, South 

Africa. He also serves on the peer review panel for BC Hydro’s SSHAC Level 3 seismic hazard 

analysis for 41 sites in the service area in British Columbia, Canada. Dr. Coppersmith received 

his BS in geology from Washington & Lee University in 1974 and his PhD from the University 

of California, Santa Cruz, in 1979. 

Chris Fuller, PhD, is a Senior Geologist with Fugro William Lettis & Associates, Inc., 

specializing in earthquake geology. Dr. Fuller’s work has focused on performing regional and 

site-specific investigations to assess geologic and seismic hazards for nuclear power plants 

throughout the United States, and he has utilized SSHAC processes to develop seismic source 

G-3
characterizations for Turkey, the Meers fault, and the Gulf Coastal region. Dr. Fuller earned his 

BS (2000), MS (2002), and PhD (2006) in geological sciences from the University of 

Washington. 

Laura Glaser is a Project Geologist for AMEC Geomatrix, Inc., with 4 years of experience in 

regional and site-specific seismic source characterization for PSHAs. Her project work includes 

SSHAC Level 2 studies for several sites in the CEUS, eastern Canada, and the United Kingdom. 

Ms. Glaser is a member of the TI staff for the SSHAC Level 3 seismic hazard studies for the 

licensing of a nuclear power plant at Thuyspunt, South Africa, performing regional source 

characterization and site-specific field investigations. Prior to this, Ms. Glaser performed 

geochemical research, including developing the geochronology of alluvial terraces of the Wind 

River Range from U-series dating of pedogenic carbonate and determining watershed-scale 

erosion rates from cosmogenic nuclides and soil–mass balance relationships. Ms. Glaser earned a 

BA in earth and planetary science from the University of California, Berkeley. 

Kathryn L. Hanson is a Principal Geologist with AMEC Geomatrix, Inc. She has over 30 years 

of applied research and consulting experience, conducting and directing investigations to 

quantitatively assess geologic hazards to critical facilities in the United States and abroad. Her 

work has involved integrating earth sciences data and the uncertainty in these data into 

assessments of seismic, volcanic, and related geohazards in a variety of tectonic environments, 

both onshore and offshore. She has conducted both probabilistic and deterministic geohazard 

assessments to support successful siting, engineering, and design of nuclear facilities, dams, 

pipelines, and other critical facilities. Her consulting experience has emphasized regional and 

site-specific geologic, seismologic, and geophysical studies to identify and evaluate geohazards 

such as potential earthquake ground motions and surface faulting. Her work incorporates stateof-the-art methods in the use of geologic data to understand fault behavior and characterize 

seismic sources. Her recent work involves seismic source characterization and surface faulting 

investigations in support of Early Site Permits (ESPs) and Combined Construction and Operating 

License (COL) applications for several potential nuclear power plant sites in central and eastern 

United States. In addition to writing numerous major consulting reports and abstracts 

summarizing technical studies, Ms. Hanson was the senior author for NRC NUREG/CR 5503 

and has published over 20 papers in peer-reviewed journals and proceedings volumes. She has a 

BS in geology from Iowa State University and an MS from the University of Oregon. 

Ross Hartleb, PhD, is a Senior Geologist with Fugro William Lettis & Associates, Inc., 

specializing in earthquake geology. He has conducted paleoseismologic studies and postearthquake surveys in California and Turkey. He has experience performing regional and site 

investigations to assess geologic and seismic hazards for nuclear power plants throughout the 

CEUS and has utilized SSHAC processes to develop seismic source characterizations for the 

Charleston, South Carolina, and northern Caribbean regions. For the CEUS SSC Project, Dr. 

Hartleb served as a member of the TI team and participated in the development of a 

paleoliquefaction database and a report on uncertainties related to the collection and 

interpretation of paleoliquefaction data. Dr. Hartleb earned his BA in geology from Amherst 

College (1992), his MS in earth science from the University of California, Santa Barbara (1998), 

and his PhD in earth sciences from the University of Southern California (2006.) 

William R. Lettis, PhD, is President of Fugro William Lettis & Associates, Inc. (FWLA). He 

has over 30 years experience performing regional and site investigations to assess geologic and 

G-4
seismic hazards for large engineered facilities including bridges, dams, nuclear and fossil fuel 

plants, pipelines, and liquid natural gas terminals. With over 100 publications, he is a recognized 

authority on the assessment of seismic hazards, both in the United States and throughout the 

world. As peer reviewer, Dr. Lettis was chosen to observe the SSHAC Level 3 assessment of 

potential seismic sources and attenuation models for potential nuclear power plant sites in the 

United Arab Emirates. He provided recommendations to ensure that the results from the SSHAC 

meeting formed a solid basis for developing the ground motion response spectra and would be 

acceptable during regulatory review of the construction license application. He is also the TI for 

a Level 3 SSHAC assessment of seismic sources for the BC Hydro project and directed the 

development of the tectonic framework. FWLA has completed studies for 18 of the current COL 

applications in the United States, and Dr. Lettis was in the lead position of oversight, providing 

direction and input for the seismic source applications, on all of these projects. Dr. Lettis earned 

his BS in geology from Humboldt State University (1977) and his MS (1979) and PhD (1982) in 

geology from the University of California, Berkeley. 

Scott Lindvall is a Senior Principal Geologist with Fugro William Lettis & Associates, Inc., 

specializing in earthquake hazards and paleoseismology. He has been active in paleoseismic 

research to quantify the past behavior and timing of past earthquakes on active faults and has 

also performed detailed mapping of surface ruptures as part of several post-earthquake 

investigations in southern California and abroad. He has directed the geologic and seismic 

evaluations for multiple ESP and COL applications for new nuclear power plants in the CEUS. 

These studies have focused on geologic and seismic source characterizations, implementation of 

the SSHAC process, independent technical review, and support for the NRC licensing process. 

For the CEUS SSC Project, Mr. Lindvall served as a member of the TI team to develop the 

seismic source model and participated in the development of a paleoliquefaction database and 

accompanying report. Mr. Lindvall earned his BS in geology from Stanford University (1984) 

and his MS in geological sciences from San Diego State University (1988). 

Stephen (Steve) McDuffie, PhD, has served as a Seismic Engineer for the Chief of Nuclear 

Safety (CNS) at DOE since September 2008. In this position he helps the CNS and the Under 

Secretary for Energy fulfill their Central Technical Authority responsibilities by overseeing 

seismic hazard characterization and design activities at DOE facilities. Previously, Dr. McDuffie 

worked for DOE’s Richland Operations Office as a facility representative at the Hanford Site for 

10 years. In that position he served as a representative of DOE management, overseeing 

contractor cleanup activities in the field, with a focus on nuclear safety, worker safety, and 

environmental protection. Before coming to DOE, Dr. McDuffie worked for nearly 6 years for 

the NRC in Rockville, Maryland. During this time, he held several positions, including serving 

as a geologist reviewing volcanic hazards, seismic hazards, and groundwater flow at the 

proposed high-level nuclear waste repository at Yucca Mountain. He also managed NRC 

licensing casework for, and performed inspections of, fabricators and users of spent nuclear fuel 

and other radioactive material packagings. Dr. McDuffie earned a BA in geology from Whitman 

College (1987), an MA (1990) and PhD (1992) in earth and planetary sciences from Johns 

Hopkins University. He also received an MBA (2002) from Washington State University. 

Robin K. McGuire, PhD, is the founder of Risk Engineering, Inc., of Boulder, Colorado, and is 

currently Vice President of Fugro William Lettis & Associates, Inc. For 30 years he has 

consulted in seismic hazard analysis, earthquake engineering, and the application of probabilistic 

methods to engineering problems. He has conducted seismic hazard analyses at sites of major 

G-5
engineering facilities at over 100 locations within the United States and at over 30 locations in 

foreign countries, in a range of technical environments. In addition, he has developed earthquake 

hazard software that is used around the world in engineering, insurance, risk management, 

government, and research for seismic hazard estimation. Dr. McGuire is the author of over 100 

papers and articles on these topics that have been published in technical journals or as technical 

reports, as well as Seismic Hazard and Risk Analysis, a monograph published by the Earthquake 

Engineering Research Institute (EERI) in 2004. He is a past president of the Seismological 

Society of America (SSA) and has served on the Board of Directors of both SSA and EERI. Dr. 

McGuire was elected to the National Academy of Engineering in 2007. He holds degrees in 

structural engineering from MIT (SB and PhD) and the University of California, Berkeley (MS).

Gerry L. Stirewalt, PhD, PG, is a Senior Geologist with the NRC Office of New Reactors, 

Division of Site and Environmental Reviews, Geoscience and Geotechnical Engineering Branch 

2. He is a registered Professional Geologist and certified Engineering Geologist with extensive 

practical knowledge of the standard practices required for characterization of site-specific, area, 

and regional geology, geomorphology, hydrology, paleoseismicity, seismicity, and 

seismotectonic settings at nuclear power plant sites, including site-specific geophysical and 

geotechnical in situ and laboratory testing procedures. Dr. Stirewalt has extensive experience in 

applying this knowledge under regulatory standards and guidelines for surface and subsurface 

geologic, hydrologic, paleoseismic, seismic, geophysical, and geotechnical field investigations 

and geologic hazards analysis at nuclear power plant sites. He also has considerable experience 

with review of applicant Safety Analysis Reports and preparation of NRC Safety Evaluation 

Reports for nuclear power plants; 3-D geospatial modeling of high-level radioactive waste 

(HLW) and non-HLW sites for the NRC; technical, regulatory, and programmatic review of 

DOE plans and technical reports for the civilian HLW management program; and geologic, 

hydrologic, and geophysical site characterization and public outreach activities for the DOE 

civilian HLW management program. Dr. Stirewalt earned a BA in geology and mathematics 

from Catawba College, North Carolina (1964), a PhD in structural geology from the University 

of North Carolina (1970), and did postdoctoral study in structural geology at Lamont-Doherty 

Geological Observatory (1969–1971), and the University of British Columbia (1971–1973). 

Gabriel R. Toro, PhD, Senior Principal Engineer with Fugro William Lettis & Associates, Inc., 

has more than 30 years of experience in PSHA for critical facilities and other applications of 

probabilistic and statistical methods to the engineering analysis of natural hazards. His project 

experience includes a number of significant studies that have advanced the state of practice in 

PSHA. In the EPRI-SOG study, Dr. Toro designed and developed the software for the PSHA 

calculations and was a key member of the group selecting the ground motion models. As a 

member of the SSHAC staff, he was a major contributor to the chapter on ground motions, as 

well as contributing to the chapter on source characterization and to four appendices. He also 

directed and coordinated the PSHA calculations for the Yucca Mountain and PEGASOS Level 4 

PSHA studies. Dr. Toro has made significant contributions to multiple areas of PSHA, including 

the development of ground motion models for regions with limited data such as the CEUS, the 

treatment of uncertainty in PSHA inputs, models for temporal clustering in the New Madrid 

region, and the probabilistic modeling of soil profiles for use in site-response calculations. He 

has also served as reviewer for PSHA and risk studies in Asia, Africa, and the Americas. Awards 

he has received include the Fulbright Travel Grant, the OMAE Award from ASME, and the 

G-6
EERI Outstanding Paper Award. Dr. Toro has a civil engineer’s degree from the National 

University of Colombia, and a Master’s and PhD in civil engineering from M.I.T. 

Robert R. Youngs, PhD, a Principal Engineer at AMEC Geomatrix, Inc., has more than 35 

years of consulting experience, with primary emphasis in hazard and decision analysis. He has 

pioneered approaches for incorporating earth sciences data and their associated uncertainties into 

probabilistic hazard analyses. The focus of this work has been on developing quantitative 

evaluations of hazard by combining statistical data and expert judgment. Dr. Youngs has 

considerable experience in assessing earthquake hazards in central and eastern North America 

and implementing SSHAC processes. He was a member of the research teams that developed 

EPRI’s seismic hazard assessment for nuclear power plants in the CEUS and EPRI-sponsored 

research projects to assess ground motions (1993) and maximum magnitudes (1994) for the 

CEUS. He was also a member of the project team for the NRC project to develop response 

spectral shapes for analysis of nuclear facilities (NUREG/CR-6728) in 2001 and the EPRI 

project to characterize ground motions in the CEUS for analysis of nuclear facilities in 2004. Dr. 

Youngs has completed seismic hazard analyses of existing and proposed nuclear power plants 

throughout the United States (including in Alabama, Florida, Louisiana, Michigan, and North 

Carolina) and internationally, including in Ontario, Canada and Switzerland (PEGASOS 

project). He earned his BS in civil engineering at California State Polytechnical University, 

Pomona (1969), and his MS and PhD in geotechnical engineering at the University of California, 

Berkeley (1982). 

TECHNICAL SUPPORT 

Serkan Bozkurt, MCP, is a Senior GIS Analyst and Information Manager at AMEC Geomatrix, 

Inc. He has 14 years of work experience in GIS, information management, and Internet 

technologies. The focus of his work has been the utilization of spatial models; 3-D 

visualizations; and GIS analysis and remote sensing technologies to support geosciences projects 

such as geohazards analysis for oil facilities, offshore platforms, pipelines, nuclear power plants, 

bridges dams, levees, and other critical facilities. Some of his recent project work includes GIS 

and information management services for SSHAC Level 2 studies and for sites in the United 

States, Canada, and the United Kingdom. Prior to joining AMEC, Mr. Bozkurt worked at the 

U.S. Geological Survey on the Earthquake Hazards Team as a GIS analyst and Web developer. 

He has contributed to more than 50 scientific publications related to seismic hazard studies. He 

earned a BS in urban and regional planning from Istanbul Mimar Sinan University (1996) and an 

M.C.P in GIS and city planning from the Istanbul Mimar Sinan University (2000). 

Randolph J. Cumbest, PhD, is a Principal Geologist with Fugro William Lettis & Associates, 

Inc. (FWLA). He has 15 years experience with Westinghouse Savannah River Co., where he was 

engaged in various geological and geophysical characterization activities and was technical lead 

for the Savannah River Site fault characterization program. Dr. Cumbest has been with FWLA 

since 2007 and has been involved with studies for licensing commercial reactors. He earned his 

BS in geology from Auburn University (1976), his MS in geology from the University of 

Georgia (1987), and his PhD in geological sciences from Virginia Polytechnic Institute (1988). 

In addition, he has had postdoctoral positions as a research associate at Princeton University and 

as visiting scientist at the Institute of Advanced Studies, The Australian National University. 

G-7
Valentina Montaldo Falero, PhD, is a Project Scientist for AMEC Geomatrix, Inc., with 10 

years of research and consulting experience in probabilistic seismic hazard analysis. The focus of 

her work has been development and analysis of earthquake catalogs; assessment of recurrence 

parameters; and quantification of hazard. She has been involved in performing SSHAC Level 2 

seismic hazard analyses for nuclear power plants in the CEUS, eastern Canada, and Europe, and 

in conducting probabilistic seismic hazard studies for dams and other facilities located in western 

North America (Oregon, Washington, Idaho, and British Columbia). Before joining AMEC 

Geomatrix, Dr. Montaldo Falero helped develop the national seismic hazard map of Italy and 

coauthored several scientific publications. She earned a BS/MS in geological sciences from the 

University of Milan, Italy (2000), and a PhD from the University of Milan-Bicocca, Italy (2006). 

Roseanne C. Perman, PhD, a Senior Geologist at AMEC Geomatrix, Inc., has more than 30 

years of experience as a consulting geologist with an emphasis on geologic hazards. She has 

managed and participated in a variety of multidisciplinary studies to evaluate potential geologic 

hazards to critical facilities for public agencies and private organizations and has assisted in 

developing hazard methodology and policy recommendations for state, federal, and professional 

organizations. For more than a decade, Dr. Perman’s work was focused primarily on DOE 

studies for DOE to characterize uncertainties surrounding complex technical issues associated 

with the proposed high-level radioactive waste repository at Yucca Mountain. For the many 

DOE studies that involved expert elicitation, Dr. Perman had key roles in methodology 

development, coordination, and documentation. These included SSHAC Level 4 studies to 

complete a PSHA in 1998, a probabilistic volcanic hazard analysis conducted in 1996, and the 

update to that study completed in 2008. More recently, Dr. Perman has been involved in seismic 

source characterization for nuclear facilities located throughout the CEUS and in the Ontario 

region of Canada. For the CEUS SSC Project she had responsibilities for documentation, 

including coordination of report production. Dr. Perman earned a B.A. in both geography (1976) 

and earth science (1981), and an M.A. (1985) and Ph.D. (1988) in paleontology, all from the 

University of California, Berkeley. 

Allison Shumway is a Senior Staff Geologist who joined Fugro William Lettis & Associates, 

Inc., in 2007. Ms. Shumway’s experience in PSHA comes from working collaboratively with 

Risk Engineering, Inc., for the past 2 years on projects for the nuclear power industries. She 

earned her BA in geological sciences from the State University of New York at Geneseo (2005) 

and her MS in earth sciences from the University of Memphis (2007), where her graduate work 

focused on seismic hazard in the New Madrid seismic zone. 

Frank H. Syms, PhD, is a Principal Engineering Geologist with Fugro William Lettis & 

Associates, Inc. He has been practicing in geology respective to nuclear applications for over 20 

years. Much of this experience has been in the southeast respective to the DOE Savannah River 

site as well as serving in a review capacity for studies conducted for new facilities at Oak Ridge, 

Tennessee. During the past 4 years, Dr. Syms has concentrated on studies for the licensing of 

new commercial nuclear power reactors in the United States. His contributions to the CEUS SSC 

Project included the initial development of the database structure, selection of the data screening 

criteria, and participation in Workshop 1. Dr. Syms received his BS (1987), MS (1997), and PhD 

(2002) in geology from the University of South Carolina. 

Martitia (Tish) Tuttle, PhD, is Director and Principal Investigator with M. Tuttle & Associates. 

She has been active in paleoseismology and earthquake hazards research since 1985, conducting 

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studies of the geologic record of past earthquakes in the central, northeastern, and western United 

States; northeastern Caribbean; southeastern Canada; western Australia; and western Portugal. 

She has conducted paleoliquefaction studies in the central United States, including the New 

Madrid seismic zone and surrounding region since 1992, where she has played a pivotal role in 

identifying and dating earthquake-induced liquefaction features and assessing the earthquake 

potential of the region. Dr. Tuttle has participated in post-earthquake surveys of liquefaction 

features and related ground failures in California, Quebec, and India, and has collaborated in 

geotechnical studies of liquefaction sites in Massachusetts, Quebec, and the central United 

States. For the CEUS SSC Project, she served as a resource expert in earthquake-induced 

liquefaction and paleoseismology and participated in the development of a paleoliquefaction 

database and a report on uncertainties related to the collection and interpretation of 

paleoliquefaction data. Dr. Tuttle earned a BS in soil science from Oregon State University 

(1979), a BS in earth sciences from Portland State University (1983), an MS in earth sciences 

from University of California, Santa Cruz (1985), and PhD in geology from University of 

Maryland (1999). 

DATABASE MANAGER 

David L. Slayter, PG, is a Senior GIS Analyst at Fugro William Lettis & Associates, Inc. He 

has 19 years of experience in several roles involving the geologic and natural sciences, as a 

geologist and a GIS scientist. His professional background includes consulting and research, as 

well as local, state, and federal government experience on projects ranging from spatial analysis 

to GIS project design. Mr. Slayter has worked on the development of GIS databases for several 

proposed nuclear power plant license applications. He has also been involved in the development 

of quality assurance standards for GIS databases and quality control and validation of GIS 

software. He is a registered Professional Geologist in California and a certified GIS Professional. 

He currently serves on the Education Committee of the Geospatial Information & Technology 

Association and the Review Committee of the GIS Certification Institute. Mr. Slayter earned his 

BS in geology from California State University, Sacramento (1991), and his MA in geography 

from the University of Oklahoma (2003). 

PARTICIPATORY PEER REVIEW PANEL 

Jon P. Ake, PhD, is currently Senior Seismologist in the Office of Research, Division of 

Engineering of the NRC. His duties include overseeing research on a broad range of seismic 

related issues for hazard assessment and integration with risk analyses. Dr. Ake began his career 

conducting research on explosively generated ground motions, the dynamic response of earth 

media, and applications of signal analysis to ground shock problems. He subsequently worked as 

a consulting geophysicist with responsibility for operating a 21-station seismic network in central 

Colorado and performing high-resolution seismic refraction and reflection studies and other 

engineering geophysical investigations (magnetic, electrical, and gravity). In 1989 he joined the 

U.S. Bureau of Reclamation, where his responsibilities included conducting, reviewing, and 

coordinating probabilistic seismic hazard studies, integrating the results with engineering 

analyses, and incorporating them into quantitative risk assessments. Dr. Ake served as a member 

of the expert panel that characterized seismic sources for a PSHA for the proposed high-level 

waste repository at Yucca Mountain. He also served in a liaison role to the DOE on seismic 

hazard issues for the Yucca Mountain Project, in which he assisted in the coordination and 

G-9
preparation of documents on disruptive events that became part of the license application to the 

NRC. 

Dr. Ake has served on the Dam Safety Advisory Team to the U.S. Bureau of Reclamation; the 

Federal Interagency Committee on Dam Safety; the U.S.-Japan Panel on Wind and Seismic 

Effects; the Consortium of Strong Motion Operators (COSMOS); and ANS/ANSI Committees 

2.27 (Criteria for Investigations of Nuclear Facilities Sites for Seismic Hazard Assessments), 

2.29 (Probabilistic Seismic Hazard Analysis), and 2.20 (Seismic Instrumentation for Nuclear 

Facilities). He has acted as a peer reviewer for the University of California Campus Earthquake 

Safety Program, BC Hydro, U.S. Army Corps of Engineers, DOE, California Department of 

Water Resources, Federal Energy Regulatory Commission, and the USGS, among others. He is 

currently a member of the DOE Seismic Lessons Learned Panel and Next Generation 

Attenuation–East projects. Dr. Ake obtained a BA in geology and physics from Western State 

College in Colorado and an MS and PhD in geophysics from the New Mexico Institute of 

Mining and Technology. 

Walter J. Arabasz, PhD, is Co-Chairman of the PPRP for the CEUS SSC Project. He has 

worked since 1974 as a seismologist at the University of Utah, where he is now Research 

Professor Emeritus of Geology and Geophysics. From 1985 to June 2010 he was Director of the 

University of Utah Seismograph Stations. He has more than 40 years of professional experience 

in research, project management, consulting, and occasional teaching in seismology, 

seismotectonics, and earthquake hazard assessment. He is the author or co-author of 46 

published papers, 94 published abstracts, and many technical reports. In addition, he has served 

on numerous national and state advisory and policy-making committees for earthquake risk 

reduction and U.S. network seismology. 

Since 1977 Dr. Arabasz has routinely provided professional consulting services and peer review 

on earthquake hazard assessments for dams, nuclear facilities, and other critical construction, 

including services for engineering firms, the International Atomic Energy Agency, DOE, the 

U.S. Bureau of Reclamation, EPRI, Los Alamos National Laboratory, and the state of Utah, 

among others. He has had broad experience in implementing PSHA, beginning with participation 

as a member of the PSHA methodology team in the original EPRI seismic hazard 

characterization of the CEUS (1985–1987). As a member of the National Research Council’s 

Panel on Seismic Hazard Evaluation (1992–1996), he observed the development of and formally 

reviewed recommendations for PSHA made by the Senior Seismic Hazard Analysis Committee 

(SSHAC). Honors include the U.S. Geological Survey’s John Wesley Powell Award, the 

Western States Seismic Policy Council Lifetime Achievement Award in Earthquake Risk 

Reduction, and the [Utah] Governor’s Medal for Science and Technology. Dr. Arabasz earned a 

BS in geology at Boston College (1964), an MS in geology at the California Institute of 

Technology (1966), and a PhD in geology and geophysics at the California Institute of 

Technology (1971). 

William J. Hinze, PhD, is Emeritus Professor of Geophysics at Purdue University. Before 

coming to Purdue, where he taught for 26 years, he served at the U.S. Army Engineering 

Research and Development Laboratory, worked as an industrial exploration geophysicist, and 

later taught at Michigan State University for 13 years. He has supervised approximately 100 

graduate students during his professional career. In addition to having extensive university 

teaching experience, Dr. Hinze has experience in research and industrial consulting on the 

G-10
geological and engineering applications of gravity and magnetic fields. He has authored or coauthored more than 130 journal publications and has co-edited or co-authored four books. He has 

been a member of numerous government and scientific panels dealing with gravity and magnetic 

fields, geophysics and geology of continents, continental drilling, digital geoscience data, 

seismotectonics, and nuclear waste disposal. From 1990 to 1996, he served as associate editor of 

geophysics and then senior editor of the Journal of Geophysical Research–Solid Earth. He 

served on the NRC’s Advisory Committee on Nuclear Waste from 1989 to 1997 and from 2005 

to 2008. He is recipient of the Institute on Lake Superior Geology’s Goldich Medal and the 

American Geophysical Union’s Kaula Award. Dr. Hinze is a member of the Society of 

Exploration Geophysicists and the American Geophysical Union, and he is a Fellow of the 

Geological Society of America. Currently he serves as Earth Science Consultant to the NRC’s 

Advisory Committee on Reactor Safeguards. He obtained a PhD in geophysics from the 

University of Wisconsin–Madison. 

Ann Marie (Annie) Kammerer, PhD, is currently a Senior Seismologist and Earthquake 

Engineer in the Office of Nuclear Regulatory Research at the NRC, where she coordinates and 

manages the Seismic Research Program. In this role, she is responsible for overseeing research 

on a broad range of seismic topics ranging from seismic hazard to seismic risk assessments for 

nuclear facilities. She is project manager for the NRC research project titled “Practical 

Procedures for the Implementation of the SSHAC Guidelines and for Updating Hazards,” which 

will result in a new NUREG-series report intended as a companion document to the original 

SSHAC report. She is also the NRC project manager and representative on the Joint 

Management Committee for the Next Generation Attenuation–East project, which is developing 

ground-motion prediction equations for Central and Eastern North America for use with the 

CEUS SSC for Nuclear Facilities model. 

In addition to her experience at the NRC, Dr. Kammerer has 15 years of experience in private 

consulting on seismic topics. Before joining the NRC in 2006, she was a consultant with the 

international design firm, Arup. As seismic hazard lead for the Americas, she was responsible for 

consulting in a wide variety of areas, including geotechnical earthquake engineering, seismology, 

and risk assessment. Dr. Kammerer has authored two dozen publications, including technical 

reports, journal articles, a book chapter, conference proceedings and papers, and an ASCE 

special publication. She was the project manager and a principal author of Regulatory Guide 

1.208 and is assisting the International Atomic Energy Agency with the update of Safety Guide 

NS-G-3.5. She is also the project manager for the updates to regulatory guides on liquefaction 

assessments and determination of floor spectra and is responsible for the development of a new 

regulatory guidance on technology-neutral performance-based engineering of nuclear power 

plants. Dr. Kammerer holds three degrees, with minors in seismology and structural engineering, 

from the University of California, Berkeley: a BS in civil engineering, an MS in geotechnical 

engineering, and a PhD in geotechnical earthquake engineering. 

Jeffrey K. Kimball is a Technical Specialist (Seismologist) on the staff of the Defense Nuclear 

Facilities Safety Board. He is responsible for technical issues involving natural phenomena 

hazards, nuclear facility safety and design, and general oversight of defense nuclear facilities. He 

has 30 years of experience with the evaluation and characterization of natural phenomena 

hazards and the design of critical facilities to resist these hazards. He has full knowledge of a 

wide range of nuclear facility regulations, regulatory guides, standards, manuals, guides, and 

review plans associated with nuclear facility design and evaluation. From 1990 to 2006, Mr. 

G-11
Kimball was the group lead for engineering design in the DOE National Nuclear Security 

Administration. He supervised technical staff responsible for technical review of nuclear facility 

designs and safety analysis. He led the development of seismic site characterization at numerous 

DOE sites, including the definition of the design basis earthquake, and led preparation of DOE 

standards and guides to define requirements and procedures to complete assessment of natural 

phenomena hazards. 

Mr. Kimball was the DOE sponsor for the program that led to the “Recommendations for 

Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts,”

commonly referred to as the SSHAC guidelines. From 1987 to 1990, he was a geophysicist in the 

DOE Office of Radioactive Waste, responsible for establishing the baseline site characterization 

plan for the Yucca Mountain high-level waste repository site. Before that, from 1984 to 1987, he 

was a senior geophysicist with Roy F. Weston Inc., participating in the review and development 

of environmental assessments for nine candidate high-level waste sites, and comparing and 

ranking sites for site characterization. From 1980 to 1984, he was a geophysicist with the NRC, 

participating in the review of safety analysis reports and developing appropriate sections of those 

reports. Mr. Kimball holds a BS in atmospheric and oceanic sciences and an MS in geosciences 

(geophysics/seismology), both from the University of Michigan. 

Donald P. Moore, PE, is a Consulting Engineer with Southern Nuclear Operating Company. He

has over 40 years experience in seismic analysis, seismic design, seismic qualification, and 

seismic hazard assessment of nuclear power plant structures, systems, and components. He has 

provided technical leadership through EPRI and NEI in many areas, such as implementation of 

seismic margin assessment methodology, the resolution of USI A-46 on equipment seismic 

qualification, the methodology for response to individual plant examination of external events 

(IPEEE) for seismic activity, and seismic analysis of unanchored spent fuel dry casks at 

independent spent-fuel storage facilities. He has participated in the development of industry 

codes and standards for nuclear facilities, such as ASCE-4, ASCE/SEI 43-05, IEEE-344, and 

ASME code revisions. 

Mr. Moore was a member of the EPRI industry task group that provided NRC comments on new 

regulations and regulatory guides for ESPs and COLs. He also participated in the peer review of 

the seismic analysis of Westinghouse AP600, and in NRC research on the seismic response of 

unanchored spent-fuel casks. He is a member of the NEI Seismic Issues Task Force and the 

EPRI Technical Review and Advisory Group, which are involved in resolving seismic issues 

with ESPs and COLs. Mr. Moore has been a member of the Technical Advisory Group for a 

number of COL applicants for the Site Safety Analysis Report section 2.5 (Geology, Seismology, 

and Geotechnical Engineering). He has co-authored a number of technical papers on seismic 

analysis and design. He is currently the Technical Interface for Southern Nuclear for the seismic 

portion of the Vogtle ESP and COL. Mr. Moore holds a BS in civil engineering from University 

of Alabama and an MS in engineering from The University of Alabama at Birmingham. He is a 

licensed Professional Engineer. 

Mark D. Petersen, PhD, is currently the Chief of the U.S. National Seismic Hazard Mapping 

Project of the U.S. Geological Survey in Golden, Colo., and also serves as a National 

Coordinator for the USGS Earthquake Hazards Program. Dr. Petersen was lead in developing the 

1996 California state hazard maps (California Geological Survey) and the 2008 National Seismic 

Hazard Maps (USGS). He is responsible for the USGS seismic hazard maps that are applied in 

G-12
many modern building codes, implemented in earthquake insurance rates, and considered for 

public policy decisions. Dr. Petersen has served on several scientific committees, including the 

Working Group on California Earthquake Probabilities (1999, 2002, 2008); the Working Group 

on Utah Earthquake Probabilities (2010); the Science Advisory Board for the California 

Earthquake Authority (2003–2005); the Utah Seismic Safety Commission (2002–2010); the 

Global Earthquake Model (GEM) Modeling Advisory Group (2009–2010); the Advisory Board 

for the Swiss Seismological Service (2009); PEER Next Generation Attenuation Relations 

groups (2003–2010); and the PPRP for the CEUS SSC Project (2008–2010). In addition to the 

U.S. hazard analyses, he has conducted seismic hazard assessments for Europe (Turkey); central 

Asia; Southeast Asia (India, Thailand, Cambodia, Vietnam, Laos, Indonesia, Singapore, 

Malaysia); Central America and the Caribbean (Panama, Puerto Rico, Virgin Islands); and South 

America (all countries). Dr. Petersen has a BS and MS in geology from Brigham Young 

University, and an MPhil and PhD from Columbia University’s Lamont-Doherty Earth 

Observatory. 

J. Carl Stepp, PhD, of Earthquake Hazards Solutions, is Co-Chairman of the Participatory Peer 

Review Panel (PPRP) for the CEUS SSC Project. Dr. Stepp has more than 40 years experience 

developing PSHA methods and developing probabilistic seismic design bases, primarily for 

nuclear power generation plants and other critical facilities. During his professional career he has 

been a research seismologist for the U.S. Coast and Geodetic Survey for approximately 10 years; 

he was chief of the Geology, Seismology, and Geotechnical Engineering Branch at the NRC, in 

charge of the application of seismic hazard assessment in nuclear facilities seismic regulation for 

7 years; he headed research and development of seismic hazard, seismic design, and seismic 

regulation technologies for 10 years as director of the Seismic Center at EPRI; and he provided 

consulting services in seismic hazard assessment and seismic safety regulation for approximately 

20 years. At the NRC, he supervised early implementation of the nuclear seismic regulation 10 

CFR, Part 100, Appendix A for reviews of 53 nuclear power plant construction and operating 

license applications, and the development of geology, seismology, and geotechnical engineering 

sections of the NRC’s Standard Review Plan. At EPRI, Dr. Stepp managed a broad program of 

nuclear plant seismic safety research and technology development, including methods for 

probabilistic seismic hazard assessment and for predicting earthquake-generated ground motion. 

He was technical lead for EPRI, interacting with both the NRC and industry to incorporate the 

integrated results of EPRI’s seismic research and technology development into seismic 

regulations, including the 10 CFR Part 100.23 rule making and the development of Regulatory 

Guide 1.165 and Revision 3 of the related Standard Review Plan sections. 

Dr. Stepp directed development of the PSHA for the Yucca Mountain, Nevada, high-level 

nuclear waste site; he chaired the development of Preclosure Seismic Design Methodology for a 

Geologic Repository at Yucca Mountain, and he chaired the Seismic Review Panel for 

development of the Yucca Mountain license application. He served as a member of the EPRI 

Technical Review and Advisory Group, supporting the NEI/EPRI New Plant Seismic Issue 

Resolution Program and interacting with the NRC to update Regulatory Guide 1.208 and the 

related sections of the Standard Review Plan. Currently he is Chairman of the PPRP for the BC 

Hydro PSHA Project and a member of the Seismic Lessons Learned Panel that advises the DOE

Nuclear Facility Safety Program. Dr. Stepp holds a BS in geology from Oklahoma State 

University, an MS in geophysics from the University of Utah, and a PhD in geophysics from 

Pennsylvania State University. 

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SPONSOR REVIEWERS 

Brent Gutierrez, PhD, PE, CEM, is the Natural Phenomena Hazards Engineering Manager for 

DOE’s Savannah River Operations Office located in Aiken, S.C. He has more than 22 years of 

engineering experience in the mitigation of natural phenomena hazards for nuclear facilities 

inclusive of hazard evaluation and geotechnical, structural, and mechanical engineering. His 

current responsibilities include developing mitigation policy for the Natural Phenomena Hazards 

Department and promulgating this policy into Savannah River’s engineering standards and 

practice. Dr. Gutierrez received a BS and MS in mechanical engineering from Mississippi State 

University and a PhD in mechanical engineering from the University of South Carolina. 

Clifford G. Munson, PhD, is Senior Technical Advisor in the Division of Site and 

Environmental Reviews, Office of New Reactors for the NRC. He is the principal reviewer of 

new nuclear plant siting applications in the areas of geology, seismology, and geotechnical 

engineering for the NRC. He has developed and updated several regulatory guidance documents 

pertaining to siting, including Chapter 2.5 of NUREG-0800, “Standard Review Plan for the 

Review of Safety Analysis Reports for Nuclear Power Plants”; Regulatory Guide 1.206, 

“Combined License Applications for Nuclear Power Plants (LWR Edition)”; and Regulatory 

Guide 1.208, “A Performance-Based Approach to Define the Site-Specific Earthquake Ground 

Motion.” Dr. Munson joined the NRC in 1995 as a geophysicist, becoming a senior geophysicist 

in 2003, then a branch chief in 2008 until he took his current position in November 2009. He has 

a BS in statistics (1987) from Brigham Young University and an MS (1991) and PhD in 

geophysics (1995) from the University of Wisconsin–Madison. 

G-14
NUREG-2115 DOE/NE-0140 EPRI 1021097

APPENDIX H 

CEUS SSC Model Hazard Input Document (HID) 

H 

APPENDIX 

CEUS SSC MODEL HAZARD INPUT DOCUMENT (HID) 

H.1 Introduction

This appendix describes the CEUS SSC Model in the main report. The purpose of this document is 

to provide the necessary information so that an analyst experienced in PSHA can implement the 

seismic source model. The appendix contains the logic tree structure and descriptions of the 

parameters that define the frequency and spatial distribution of potential future earthquakes. The 

reader is referred to the main report for detailed descriptions of methods and rationale used to 

develop the model parameters. The digital files that contain the input parameters described in this 

appendix are contained on the project website. The area covered by this model is shown on Figure 

H-1-1 along with the locations of the test sites used for hazard sensitivity calculations presented in 

Chapter 8. 

H.2 Seismic Source Model Structure and Master Logic Tree 

The structure of the CEUS SSC model is described in Section 4. The CEUS SSC Model contains 

two general types of seismic sources. The first type of seismic source uses the recorded history of 

seismicity to model the frequency and spatial distribution of moderate to large earthquakes (M ≥ 5).

These sources are denoted as distributed seismicity sources. They cover the entire region shown on 

Figure H-1-1. The second type of seismic source uses the paleo-earthquake record to model the 

frequency and spatial distribution of repeated large magnitude earthquakes (RLMEs) at specific 

locations. 

Figure H-2-1 shows the master logic tree for the CEUS SSC model. The basis for this logic tree is 

described in Section 4.2. The first node addresses the conceptual approach used to characterize the 

distributed seismicity sources. Two approaches are used. The first is an approach in which 

distributed seismicity is modeled using seismicity rates that smoothly vary across the entire study 

region. The study region is subdivided only on the basis of differences in maximum magnitudes. 

The first branch is designated as the Mmax Zones approach. The second approach uses seismic 

source zones defined on a seismotectonic basis to model distributed seismicity. The second branch 

is designated as the Seismotectonic Zones approach. In both approaches specific seismic sources are 

used to model individual sources of RLMEs. The RLME sources represent additional sources of 

seismic hazard that are added to the hazard from the distributed seismicity sources. 

The models developed for the various types of seismic sources are described in subsequent sections 

of this appendix. 

H-1
Appendix H 

H.3 Mmax Zones Distributed Seismicity Sources 

Figure H-3-1 shows the logic tree structure to be used for the distributed seismicity sources on the 

Mmax Zones branch of the master logic tree. This logic tree is discussed in Section 4.2.3 of the 

main report.

H.3.1 Division of Study Region 

The first node addresses whether or not the study region is divided into two zones that have 

different Mmax distributions. If ―No‖ then the entire study region, shown on Figure H-1-1, is 

treated as a single source. If ―Yes‖ then the study region is divided into Mesozoic and younger 

extended regions (MESE) and those regions that do not display such evidence (NMESE). 

H.3.2 Location of Boundary of Mesozoic Extension 

The second node of the Mmax Zones logic tree, which applies only to the Mesozoic and younger 

separation branch, addresses the alternative boundaries between the MESE and NMSES regions. 

Two alternatives are used. The first, labeled the ―Wide Interpretation‖ has a broad interpretation of 

the extent of Mesozoic extension. Figure H-3-2 shows the location of this boundary. The second, 

labeled the ―Narrow Interpretation‖ makes a narrow interpretation of the extent of Mesozoic 

extension. Figure H3-3 shows the location of this boundary. 

H.3.3 Magnitude Interval Weights for Fitting Earthquake Occurrence Parameters 

The third node addresses the issue of the weight assigned to smaller magnitudes in the estimation of 

seismicity parameters for the seismic source zones. Three cases are used, Cases A, B, and E. The 

weights assigned to individual magnitude intervals are discussed in Section 5.3.2.2. 

H.3.4 Mmax Zones 

The next element of the Mmax Zones logic tree (which is not a node but a listing) identifies the 

Mmax zone designations for each case. The vertical bar without a dot at the branching point 

designates the addition of hazard from all of the listed sources, as opposed to weighted alternatives 

that appear with a dot on the logic tree. The coordinates defining the boundaries of the Mmax Zones 

are contained in the file Source_Zones_Geometry.zip on the project web site. The boundary for 

each zone is contained in an ASCII file named for the source with the extension ―zon‖ (e.g. 

―MESE-N.zon‖ for the MESE-N Mmax zone). 

H.3.5 Seismogenic Crustal Thickness 

The fifth node of the logic tree represents the uncertainty distribution for seismogenic crustal 

thickness. The distribution used for each Mmax zone is listed in Table H-3-1. These are epistemic 

uncertainties representing weighted alternative assessments of the seismogenic crustal thickness for 

each Mmax zone. 

H-2
Appendix H 

H.3.6 Future Earthquake Rupture Characteristics

The sixth node addresses the uncertainty distributions for the rupture characteristics of future 

earthquakes. In the CEUS SSC model a single aleatory distribution is applied to each Mmax zone. 

These aleatory distributions are listed in Table H-3-2. 

The area of individual earthquake ruptures is modeled using the relationship: 

log10(A in km2) = M – 4.366 (H-1) 

The rupture aspect ratio is 1:1 until the rupture reaches maximum rupture width. For larger ruptures 

the width is fixed and the length is increased to obtain the area given by Equation H-1. This model 

is used for all earthquake sources described in this HID. 

H.3.7 Assessment of Seismicity Rates 

The seventh node of the Mmax Zones logic tree on Figure H-3-1 addresses the approach used for 

assessing seismicity rates and their spatial distribution. Allowing both the a-value and the b-value to 

vary spatially is the selected approach. The approach is described in Section 5.3.2. Seismicity 

parameters are estimated for 1⁄2° longitude by 1⁄2° latitude cells or partial cells. 

H.3.8 Degree of Smoothing Applied in Defining Spatial Smoothing of Seismicity 

Rates 

The eighth node of the logic tree addresses the degree of smoothing applied in the seismicity 

parameter estimation in each source region. A single approach, the ―Objective‖ approach, is used to 

select the degree of smoothing. This is discussed in Section 5.3.2.2 of the main report. 

H.3.9 Uncertainty in Earthquake Recurrence Rates

The ninth node of the logic tree addresses the epistemic uncertainty in earthquake recurrence 

parameters. The recurrence parameter distributions are represented by eight alternative spatial 

distributions developed from the fitted parameter distributions. These alternatives are described in

Section 5.3.2. The result is eight equally weighted alternative sets of recurrence parameters for each 

Mmax Zone. The recurrence parameters are contained in the file ―CEUS_SSC_All_xyab_Files.zip‖

on the project web site. The recurrence parameters are contained in ASCII files for each Mmax zone 

using the following file naming convention. 

Zone_Case_Realization.ext 

The “Zone‖ portion of the file name is the Mmax Zone name, MESE-W, MESE-N, NMESE-W, 

NMESE-N, and STUDY_R for the case when the entire study region is considered a single Mmax 

Zone. The ―Case‖ portion of the file name refers to Case A, Case B, or Case E on Figure H-4. The 

―Realization‖ portion of the file name takes on the values ―01‖, ―02‖, ―03‖, ―04‖, ―05‖, ―06‖, ―07‖, 

and ―08‖ to indicate the eight equally weighted alternative sets of recurrence parameters. The ―ext‖ 

portion of the file name takes on two values. An extension of ―xyab‖ indicates a file containing 

recurrence parameters for PSHA calculations that integrate over magnitude starting from a 

minimum magnitude, m0, of M 5.0. An extension of ―xyab4‖ indicates a file containing recurrence 

parameters for PSHA calculations that integrate over magnitude starting from a minimum 

H-3
Appendix H 

magnitude, m0, of M 4.0, which would typically be used for PSHA calculations incorporating the 

Cumulative Absolute Velocity (CAV) filter. 

Each recurrence parameter file contains a header with the case description. The second record 

provides the number of individual cells and the nominal cell size in degrees (e.g 0.5 for 1⁄2° 

longitude by 1⁄2° latitude cells). The remaining records contain the following information in five 

columns: 

Longitude and latitude of the center of the cell or partial cell, in degrees. 

Recurrence rate of earthquakes of magnitude m0 and larger per equatorial degrees2. For the 

files with extension ―xyab‖ this is the rate of M 5 and larger earthquakes and for files with 

extension ―xyab4‖ this is the rate of M 4 and larger earthquakes. 

Beta value. This is the b-value expressed in natural log units {β = b x ln(10)}. 

Area of the cell in equatorial degrees2

. The absolute value of recurrence rate is the product 

of the values in the third and fifth columns. 

H.3.10 Uncertainty in Maximum Magnitude 

The tenth node of the logic tree addresses the uncertainty in the maximum magnitude for each 

Mmax Zone. These epistemic distributions are listed in Table H-3-3. 

H.4 Seismotectonic Zones 

Figure H-4-1 shows the logic tree structure for the seismotectonic source zones component of the 

master logic tree. The components of the source model logic tree are described below. Table H-4-1 

lists the seismotectonic source zones. 

H.4.1 Alternative Zonation Models

The first two nodes address the alternative zonation models. The first node addresses the uncertainty 

in the western boundary of the Paleozoic Extended Crust seismotectonic zone. The two alternatives 

are the narrow interpretation (0.8) and the wide interpretation (0.2). The second node of the logic 

tree addresses the uncertainty in the eastern extent of the Reelfoot Rift zone (RR) —whether or not 

it includes the Rough Creek Graben (RCG). These two logic tree levels lead to the four alternative 

seismotectonic zonation configurations shown on Figures H-4-2 through H-4-5. The discussion of 

this assessment and the associated weights is given in Section 7.3.6.3 of the main report. As shown 

on Figures H-4-1 though H-4-5, the alternative zonation models produce alternative versions of the 

Mid-Continent source zone. These are designated MidC-A, MidC-B, MidC-C, and MidC-D.

H.4.2 Magnitude Interval Weights for Fitting Earthquake Occurrence Parameters 

The third node addresses the issue of the weight assigned to smaller magnitudes in the estimation of 

seismicity parameters for the seismic source zones. As in the Mmax Zones model, three cases are 

used, Cases A, B, and E. The weights assigned to individual magnitude intervals are discussed in 

Section 5.3.2.2. 

H-4
Appendix H 

H.4.3 Seismotectonic Zones 

The next element of the logic tree is again a listing of the individual seismotectonic source zones for 

each zonation model. The vertical bar without a dot at the branching point designates the addition of 

hazard from all of the listed sources. The coordinates defining the boundaries of the source are 

contained in the file Source_Zones_Geometry.zip on the project web site. The boundary for each 

zone is contained in an ASCII file named for the source with the extension ―zon‖ (e.g. ―AHEX.zon‖ 

for the AHEX seismotectonic source zone). 

H.4.4 Seismogenic Crustal Thickness 

The fifth node of the logic tree represents the uncertainty distribution for seismogenic crustal 

thickness. The distribution used for each seismotectonic zone is listed in Table H-4-2. These are 

epistemic uncertainties representing weighted alternatives. 

H.4.5 Future Earthquake Rupture Characteristics

The sixth node addresses the uncertainty distributions for the rupture characteristics of future 

earthquakes. In the CEUS SSC model a single aleatory distribution is applied to each 

seismotectonic zone. These aleatory distributions are listed in Table H-4-3. 

The area of individual earthquake ruptures is modeled using the relationship given in Equation H-1 

above. The rupture aspect ratio is 1:1 until the rupture reaches maximum rupture width. For larger 

ruptures the width is fixed and the length is increased to obtain the area given by Equation H-1. This 

model is used for all earthquake sources described in this HID. 

H.4.6 Assessment of Seismicity Rates 

The seventh node of the logic tree on Figure H-4-1 addresses the approach used for assessing 

seismicity rates and their spatial distribution. Allowing both the a-value and the b-value to vary 

spatially is the selected approach. The approach is described in Section 5.3.2. Seismicity parameters 

are estimated for 1⁄4° longitude by 1⁄4° latitude cells or partial cells for all sources except the MidContinent sources, for which the cell size 1⁄2° longitude by 1⁄2° latitude is used. 

H.4.7 Degree of Smoothing Applied in Defining Spatial Smoothing of Seismicity 

Rates 

The eighth node of the logic tree addresses the degree of smoothing applied in the seismicity 

parameter estimation in each source region. A single approach is used to select the degree of 

smoothing for each source. This is discussed in Section 5.3.2.2 of the main report. For all sources 

but the St. Lawrence Rift zone (SLR) the ―Objective‖ approach is used. 

H.4.8 Uncertainty in Earthquake Recurrence Rates 

The ninth node of the logic tree addresses the epistemic uncertainty in earthquake recurrence 

parameters. As was the case for the Mmax zones, the recurrence parameter distributions are 

represented by eight alternative spatial distributions developed from the fitted parameter 

distributions. These alternatives are described in Section 5.3.2. The result is eight equally weighted 

alternative sets of recurrence parameters for each Seismotectonic Zone. The recurrence parameters 

H-5
Appendix H 

are contained in the file ―CEUS_SSC_All_xyab_Files.zip‖ on the project web site. The recurrence 

parameters are contained in ASCII files for each seismotectonic zone using the naming convention 

and file format described in Section H.3.9. 

H.4.9 Uncertainty in Maximum Magnitude 

The tenth node of the logic tree addresses the uncertainty in the maximum magnitude for each 

seismotectonic zone. These distributions are listed in Table H-4-4. 

H.5 RLME Sources 

This section describes the models for the RLME sources. As shown on Figure H-2-1, these sources 

are considered to be additional sources superimposed on the distributed seismicity sources on the 

seismotectonic branch of the master logic tree or on the Mmax Zones on the Mmax Zone branch of 

the master logic tree. Figure H-5-1 shows the overall structure of the RLME sources model. There 

are 10 RLME sources. Each source has a logic tree defining the uncertainty in characterization. 

Discussion of the each of the individual RLME sources is contained in Section H.5 of the main 

report. The locations of the RLME sources are shown on Figure H-5-2. The parameters for each of 

the RLME sources present in the following sections are contained in files located on the CEUS SSC 

Project website in the RLME directory. 

H.5.1 Charlevoix RLME Seismic Source Model 

The Charlevoix RLME source is described in Section 6.1.1 of the main text. The logic tree for the 

Charlevoix RLME source is shown on Figure H-5.1-1. The parameters are located on the CEUS 

SSC Project web site in the file ―Charlevoix_RLME.xls.‖

H.5.1.1 Temporal Clustering 

The first node of the logic tree addresses the issue of temporal clustering of earthquakes in the 

present tectonic stress regime. This node of the logic tree is not applicable to the Charlevoix RLME 

source. 

H.5.1.2 Localizing Tectonic Features 

Because the occurrence of RLMEs in the Charlevoix zone cannot be associated with a specific 

feature, future RLMEs are modeled as occurring randomly within the RLME source zone, as 

indicated on the second node of the logic tree (Figure H-5.1-1). 

H.5.1.3 Geometry and Style of Faulting 

The geometry of the Charlevoix RLME source is shown on Figure H-5.1-2. A single source zone 

geometry is used. The coordinates are contained on the ―Geometry‖ tab of the file 

―Charlevoix_RLME.xls.‖ Given the small source size and uncertain fault locations, the boundaries 

of the Charlevoix RLME source are leaky, allowing ruptures to extend beyond the source boundary 

by 50 percent. 

The thickness of seismogenic crust is modeled with equal weight on 25 and 30 km (16 and 19 mi.), 

as shown on the fourth node of the logic tree (Figure H-5.1-1). 

H-6
Appendix H 

Future earthquake ruptures are modeled as reverse faulting earthquakes. Rupture geometry is 

modeled by a single aleatory distribution as shown by the fifth node of the logic tree. Strikes of 

ruptures are to be uniformly distributed over azimuths of 0 to 360 degrees. Fault dips are uniformly 

distributed between 45 and 60 degrees. 

H.5.1.4 RLME Magnitude 

Table H-5.1-1 lists the epistemic uncertainty distribution for the expected magnitude of future 

earthquakes associated with the Charlevoix RLME source. Aleatory variability in the size of an 

individual Charlevoix RLME is modeled as a uniform distribution of ±0.25 M units centered on the 

expected RLME magnitude value listed in Table H-5.1-1. 

H.5.1.5 RLME Recurrence 

The remaining nodes of the Charlevoix RLME logic tree address uncertainties in the specification 

of the annual frequency of RLMEs. 

Recurrence Methods and Data 

Two approaches are used to assess RLME recurrence. The ―Earthquake Recurrence Intervals‖ 

approach is assigned a weight of 0.2. This approach leads to data set 1. The ―Earthquake Count in a 

Time Interval‖ approach is assigned a weight of 0.8. There are two data sets associated with this 

branch. Data set 2 is assigned a conditional weight of 0.75 and data set 3 is assigned a conditional 

weight of 0.25. 

Earthquake Recurrence Model 

The Poisson model is used as the earthquake recurrence model, with a weight of 1.0. 

RLME Annual Frequency 

The final node of the logic tree addresses the uncertainty distributions for the annual frequency of 

RLMEs. These distributions are listed in Tables H-5.1-2, H-5.1-3, and H-5.1-4. The data are 

contained in the file ―Charlevoix_RLME.xls.‖

H.5.2 Charleston RLME Seismic Source Model 

Charleston RLME source is described in Section 6.1.2 of the main text. Figure H-5.2-1 shows the 

logic tree for the Charleston RLME source. The parameters are located on the CEUS SSC Project 

web site in the file “Charleston_RLME.xls.”

H.5.2.1 Temporal Clustering 

The first node of the logic tree (Figure H-5.2-1) addresses the issue of temporal clustering of 

earthquakes on the Charleston RLME source. The Charleston RLME seismic source is modeled as 

“in” a temporal cluster with a weight of 0.9 and “out” of a temporal cluster with a weight of 0.1. For 

the “in” branch, the remaining portion of the logic tree is used to define the hazard from this source. 

On the “out” branch the Charleston RLME source is not included in calculation of the total seismic 

hazard. 

H-7
Appendix H 

H.5.2.2 Localizing Feature 

The second node of the Charleston RLME source logic tree indicates whether future earthquakes in 

the Charleston seismic zone will be associated with a specific localizing tectonic feature. The 

approach used for this source is to model future ruptures to occur randomly with the source. 

H.5.2.3 Geometry and Style of Faulting 

The third node of the Charleston RLME source logic tree addresses the alternative geometries of the 

parameters Charleston RLME source. Three alternative source zone geometries are included in the 

model. These are shown on Figure H-5.2-2. The coordinates of the three source geometries are 

given in the file ―Charleston_RLME.xls.‖

The fourth node of the logic tree indicates the three values of seismogenic crustal thickness used for 

all source geometries. 

The geometries and style of faulting for the three source geometries are specified as follows. 

Charleston Local source configuration: Future ruptures are oriented northeast, parallel to the 

long axis of the zone. Ruptures are modeled as occurring on vertical strike-slip faults. All 

boundaries of the Charleston Local source are strict, such that ruptures are not allowed to 

extend beyond the zone boundaries. 

Charleston Narrow source configuration: Future ruptures are oriented north-northeast, 

parallel to the long axis of the zone. Ruptures are modeled as occurring on vertical strikeslip faults. The northeast and southwest boundaries of the Charleston Narrow source are 

leaky, whereas the northwest and southeast boundaries of the Charleston Narrow source are 

strict.

Charleston Regional source configuration: Future rupture orientations are represented by 

two alternatives: (1) future ruptures oriented parallel to the long axis of the source 

(northeast) with 0.80 weight, and (2) future ruptures oriented parallel to the short axis of the 

source (northwest) with 0.20 weight. In both cases, future ruptures are modeled as occurring 

on vertical strike-slip faults. All boundaries of the Charleston Regional source are strict. 

H.5.2.4 RLME Magnitude 

The sixth node of the Charleston RLME source logic tree defines the magnitude of future large 

earthquakes in the Charleston RLME source. The RLME magnitude distribution is given in 

Table H-5.2-1. Aleatory variability in the size of an individual Charleston RLME is modeled as a 

uniform distribution of ±0.25 M units centered on the expected RLME magnitude value. 

H.5.2.5 RLME Recurrence 

The remaining nodes of the Charleston RLME source logic tree address the uncertainty in modeling 

of the recurrence rare of Charleston RLMEs. 

Recurrence Method 

The recurrence data for the Charleston RLME source consists of ages of past RLMEs estimated 

from the paleoliquefaction record. Therefore, node seven of the logic tree indicates that recurrence 

H-8
Appendix H 

for the Charleston RLME source is based solely on the ―Earthquake Recurrence Intervals‖ 

approach. 

Time Period 

The eighth node of the Charleston RLME source logic tree assesses length and completeness of the 

paleoliquefaction record. Two alternatives are considered: the approximately 2,000-year record of 

Charleston earthquakes with 0.80 weight and the approximately 5,500-year record with 0.20 weight. 

Earthquake Count 

The ninth node of the Charleston logic tree addresses the uncertainty in the number of RLMEs that 

have occurred in the Charleston RLME source. For the 2,000-year record, a single model is used. 

For the 5.500-year, three alternatives are used as shown on Figure H-5.2-1. 

Earthquake Recurrence Model 

The tenth node of the Charleston RLME source logic tree defines the earthquake recurrence models 

used for the regional, local, and narrow source zones (Figure H-5.2-1). For the regional and local 

sources, only the Poisson model is used. For the more ―fault-like‖ narrow source zone, the Poisson 

model is assigned 0.90 weight, and the BPT renewal model is assigned 0.10 weight. Use of the BPT 

renewal model requires specification of the coefficient of variation of the repeat time for RLMEs, 

parameter α. The uncertainty distribution for α is shown on the eleventh node of the Charleston 

RLME source logic tree. 

RLME Annual Frequency 

The final (twelfth) node of the logic tree addresses the uncertainty distributions for the annual 

frequency of RLMEs. There are 20 uncertainty distributions corresponding to the various 

approaches and data sets defined in Levels 8, 9, 10, and 11 of the logic tree. These are given in 

Tables H-5.2 -2 through H-5.2-21. Tables H-5.2-2 through H-5.2-6 provide the recurrence rate 

distributions for the Poisson Occurrence model and Tables H-5.2-7 through H-5.2-21 provide the 

recurrence rate distributions for the BPT Renewal model. Figure H-5.2-1 shows the relationship 

between the branches of the logic tree and the recurrence rate distribution tables. 

H.5.3 Cheraw RLME Seismic Source Model 

The Cheraw RLME source is described in Section 6.1.3 of the main report. Figure H-5.3-1 shows 

the logic tree for the Cheraw RLME source. The parameters are located on the CEUS SSC Project 

web site in the file ―Cheraw_RLME.xls.‖

H.5.3.1 Temporal Clustering 

The first node of the logic tree (Figure H-5.3-1) addresses the issue of temporal clustering of 

earthquakes in the present tectonic stress regime. The within-cluster branch of the logic tree is 

assigned a weight of 0.9, and the out-of-cluster branch is assigned a weight of 0.1. These two 

branches lead to different recurrence rates 

H-9
Appendix H 

H.5.3.2 Localizing Feature 

The Cheraw RLME source is modeled as a single fault source. 

H.5.3.3 Geometry and Style of Faulting 

Two alternative lengths are used for the Cheraw RLME source. These are shown on Figure H-5.3-2. 

The mapped length is assigned a weight of 0.8 and the extended length is assigned a weight of 0.2. 

The coordinates for these two geometries are provided in the file ―Cheraw_RLME.xls.‖

The fourth node of the logic tree provides the uncertainty distribution for the thickness of 

seismogenic crust. The generic distribution of 13 km (weight of 0.4), 17 km (weight of 0.4), and 22 

km (weight of 0.2) is used. 

The fifth node of the logic tree addresses the uncertainty in the dip of the fault. The assigned 

uncertainty distribution is: 50°NW (0.6), 65°NW (0.4). 

The style of faulting is assessed to be normal. Future ruptures are to be confined to the modeled 

fault surface. 

H.5.3.4 RLME Magnitude 

The magnitude distribution for the Cheraw RLME source is given in Table H-5.3-1. Aleatory 

variability in the size of an individual Cheraw RLME is modeled as a uniform distribution of ±0.25 

M units centered on the expected RLME magnitude value. 

H.5.3.5 RLME Recurrence 

The remaining nodes of the Cheraw RLME logic tree address the uncertainties in modeling the 

recurrence rate of Cheraw RLMEs 

Recurrence Method 

Two types of data are used for assessing the recurrence frequency of Cheraw RLMEs. The first is 

the average slip rate of the fault and the second is the number and timing of previous RLMEs, 

allowing application of the ―Earthquake Recurrence Intervals‖ approach. These two approaches are 

assigned equal weights. 

Recurrence Data 

Two data sets are used for the assessment of the in-cluster recurrence rate of Cheraw RLMEs based 

on the ―Earthquake Recurrence Intervals‖ approach. The first is the occurrence of two earthquakes 

in 20-25 ka, with a weight of 0.4, and the second in the occurrence of three earthquakes in 20-25 ka, 

with a weight of 0.6. The total slip of the fault in the range of 3.2 to 4.1 m in 20-25 ka is used to 

assess the in-cluster slip rate. 

The out-of-cluster recurrence rates for the ―Earthquake Recurrence Intervals‖ approach are based on 

estimates of the time between in-cluster periods. Out-of-cluster slip rate is based on 7–8 m of offset 

in a time period ranging from 400 ka to 2 Ma. 

H-10
Appendix H 

Earthquake Recurrence Model 

The Poisson model is used as the earthquake recurrence model with weight 1.0 for the Cheraw 

RLME source. 

RLME Annual Frequency 

The assessed RLME recurrence frequencies for the various data sets are given in Tables H-5.3-2 

through H-5.3-6. Figure H-5.3-1 shows the relationship between the branches of the logic tree and 

the recurrence rate distribution tables. 

H.5.4 Meers RLME Seismic Source Model 

The Meers RLME source is described in Section 6.1.4 of the main report. The source logic tree is 

shown on Figure H-5.4-1. The data for the Meers RLME is located on the CEUS SSC Project web 

site contained in file ―Meers_RLME.xls.‖

H.5.4.1 Temporal Clustering 

The first node of the logic tree (Figure H-5.4-1) addresses the issue of temporal clustering. The incluster branch of the logic tree is given a weight of 0.8 and the out-of-cluster branch a weight of 0.2. 

These two alternatives affect both the recurrence rate of the RLMEs and their spatial distribution. 

H.5.4.2 Localizing Feature 

The second branch of the logic tree (Figure H-5.4-1) defined whether future earthquakes associated 

with the Meers RLME source are localized along the Meers fault scarp ( designated ―Fault‖ on the 

logic tree), or whether they may occur along other structures within the Oklahoma aulacogen 

(―Random in Zone‖ on the logic tree). For the in-cluster case, the ―Fault‖ model is used and RLMEs 

are constrained to occur on the Meers fault. For the out-of-cluster case, RLMEs the two alternatives 

are the ―Fault‖ model and the ―Random in Zone‖ model.

H.5.4.3 Geometry and Style of Faulting 

The third through fifth branches of the logic tree describe the source geometry and style of faulting 

(Figure H-5.4-1). 

The alternative geometries for the ―Fault‖ model consists of the mapped Quaternary trace of the 

Meers fault (weight 0.9) and an extended fault trace (weight 0.1). These two geometries are shown 

on Figure H-5.4-2. 

For the ―Random-in-Zone‖ model, the RLMEs are modeled as occurring uniformly distributed 

within the boundary of the OKA seismic source zone, also shown on Figure H-5.4-2. 

The seismogenic thickness for the Meers RLME source is modeled as either 15 km or 20 km with 

equal weights. 

For the ―Fault‖ model, future earthquake ruptures are to be modeled as either oblique earthquakes 

on a vertical fault (weight 0.5) or reverse-oblique earthquakes dipping 40 degrees southwest. 

Ruptures are confined to the model fault surface. 

H-11
Appendix H 

For the ―Random-in-Zone‖ model future ruptures are to be modeled as having a N60W strike and a 

random dip in the range of 90 to 40 degrees southwest. 

H.5.4.4 RLME Magnitude 

The sixth branch of the logic tree describes the earthquake magnitudes for the Meers RLME. The 

RLME magnitude distribution is given in Table H-5.4-1. Aleatory variability in the size of an 

individual Meers RLME is modeled as a uniform distribution of ±0.25 M units centered on the 

expected RLME magnitude value. 

H.5.4.5 RLME Recurrence 

The remaining branches of the logic tree define the uncertainty distributions for RLME recurrence 

rates. 

Recurrence Method 

The ―Earthquake Recurrence Intervals‖ approach is used with weight 1.0 (Figure H-5.4-1).

Recurrence Data 

The data used to assess the in-cluster recurrence rates consists of two earthquakes in 2.1 to 3 ka. 

The data used to assess the out-of-cluster case consist of the estimated time between clusters of 

activity on the fault. 

Earthquake Recurrence Model 

The Poisson model is used as the earthquake recurrence model with weight 1.0 for the Meers 

RLME source. 

RLME Annual Frequency 

The final node of the logic tree addresses the uncertainty distributions for the annual frequency of 

RLMEs (Figure H-5.4-1). These distributions are provided in Tables H-5.4-2 for the in-cluster case 

and Table H-5.4-3 for the out-of-cluster case. Note that the out-of-cluster model combined with the 

―Random-in-Zone‖ model for the spatial distribution is assigned the in-cluster recurrence rate 

distribution. 

H.5.5 New Madrid Fault System RLME Seismic Source Model 

The New Madrid Fault System (NMFS) RLME is discussed in Section 6.1.5 of the main report. 

Figure H-5.5-1 shows the logic tree for this source. The data for this source is on the CEUS SSC 

Project web site contained in file ―NMFS_RLME.xls.‖

H.5.5.1 Temporal Clustering 

The first node of the logic tree (Figure H-5.5-1) addresses the issue of temporal clustering. Three 

alternatives are modeled. 

With weight 0.9 the NMFS RLME is modeled as being in-cluster. 

H-12
Appendix H 

With weight 0.05 the RLME is modeled as being out-of-cluster with no earthquake activity 

occurring on the source. 

With weight 0.05, the RLME is modeled as being out-of-cluster with a long term rate 

assigned to only the Reelfoot Thrust (described below). 

H.5.5.2 Localizing Feature 

The RLMEs associated with the NMFS are modeled as occurring on three fault sources: (1) the 

New Madrid South (NMS) fault; (2) the New Madrid North (NMN) fault; and (3) the Reelfoot 

Thrust (RFT).

H.5.5.3 Geometry and Style of Faulting 

Each of the NMFS fault sources has two alternative geometries as shown on Figures H-5.5-2, H5.5-3, and H-5.5-4, respectively. Future NMFS RLMEs are confined to occur on these modeled 

faults. 

The seismogenic crustal thickness is modeled as being 13 km (weight of 0.3), 15 km (weight of 

0.5), or 17 km (weight of 0.2). 

The style of faulting for each of the fault sources is based on geologic and seismologic observations. 

The NMS fault is modeled as a vertical right-lateral strike-slip fault. The RFT fault is modeled as a 

reverse fault dipping an average of 40 degrees southwest. The NMN fault is modeled as a vertical 

right-lateral strike-slip fault. 

H.5.5.4 RLME Magnitude 

The magnitudes of RLMEs for the NMFS are assigned in terms of a joint distribution. 

Table H-5.5-1 lists the assigned distribution of rupture sets. Aleatory variability in the size of an 

individual RLME is modeled as a uniform distribution of ±0.25 M units centered on the expected 

RLME magnitude value for each fault source. 

H.5.5.5 RLME Recurrence 

The remaining nodes of the NMFS RLME source logic tree address the assessment of earthquake 

recurrence rates. 

Recurrence Method 

The ―Earthquake Recurrence Intervals‖ approach is used with weight 1.0 (Figure H-5.5-1). 

Recurrence Data 

In-cluster case recurrence rates are based on the 1811-1812, 1450 AD, and 900 AD sequences. Outof-cluster recurrence rates for the NMFS are based on timing between clusters. 

H-13
Appendix H 

Earthquake Recurrence Model 

The Poisson and renewal recurrence models are assigned weights of 0.75 and 0.25, respectively, for 

the in-cluster case. For the renewal model the BPT model is used with a distribution for the 

parameter α shown on the twelfth node of the source logic tree. 

RLME Annual Frequency 

The final node of the logic tree addresses the uncertainty distributions for the annual frequency of 

RLMEs (Figure H-5.5-1). These distributions are contained in Table H-5.5-2 for the in-cluster 

Poisson case, Tables H-5.5-3, H-5.5-4, and H-5.5-5 for the in-cluster renewal model cases, and in 

Table H-5.5-5 for the out-of-cluster Poisson case. 

For the in-cluster case, RLMEs are to be modeled as occurring on all three of the fault sources 

within a close period of time (e.g. similar to the 1811-1812 earthquake sequence). 

H.5.6 Eastern Rift Margin Fault RLME Seismic Source Model 

The Eastern Rift Margin (ERM) fault RLME sources are described in Section 6.1.6 in the main text. 

The source consists of southern and northern segments. Figure H-5.6-1 shows the logic tree for the 

southern segment, ERM-S and Figure H-5.6-2 shows the logic tree for the northern segment 

ERM-N. The data for these two sources are contained on the CEUS SSC Project web site in files 

―ERM-S_RLME.xls‖ and ―ERM-N_RLME.xls.‖

H.5.6.1 Temporal Clustering 

The first node of the logic trees addresses the issue of temporal clustering of earthquakes in the 

present tectonic stress regime. This node of the logic tree is not applicable to the ERM-S and 

ERM-N RLME sources.

H.5.6.2 Localizing Feature 

The ERM-S and ERM-N RLME sources are modeled as narrow zones. Figures H-5.6-3 and H-5.6-4 

show the geometries of the sources. Earthquakes are modeled as uniformly distributed in the source 

zones. 

H.5.6.3 Geometry and Style of Faulting 

There are two alternative geometries for the ERM-S RLME source: ERM-SCC (weight of 0.6) and 

the ERM-SRP (weight 0.4). These are shown on Figure H-5.6-3. A single geometry is specified for 

the ERM-N RLME source. 

The probability distribution used to model seismogenic thickness for the ERM-S and ERM-N 

RLME sources is: 13 km (weight of 0.3), 15 km (weight of 0.5), and 17 km (weight of 0.2). 

Future ruptures are to be modeled as vertical strike slip ruptures aligned parallel with the long axis 

to the RLME source zones. Both the northeastern and southwestern ends of the zones are modeled 

as leaky to allow for uncertainty in the extent of possible reactivated faults along the rift margin. 

H-14
Appendix H 

H.5.6.4 RLME Magnitude 

Tables H-5.6-1 and H-5.6-2 list the RLME magnitude distributions for the ERM-S and ERM-N 

RLMEs, respectively. Aleatory variability in the size of an RLME is modeled as a uniform 

distribution of ±0.25 M units centered on the expected RLME magnitude value given in the tables. 

H.5.6.5 RLME Recurrence 

The remaining nodes of the ERM-S and ERM-N logic trees address the estimation of recurrence 

rate of RLMEs. 

Recurrence Method 

The ―Earthquake Count in a Time Interval‖ approach is used to assess RLME recurrence frequency

for both the ERM-S and ERM-N sources. 

Recurrence Data 

For the ERM-S source, three alternative data sets are used to assess RLME recurrence rates: either 

two, three, or four earthquakes in a 17.7 to 21.7 ka period. The three alternatives have equal weight. 

For the ERM-N source, two alternative data sets are use: either one (weight 0.9) or two (weight 0.1) 

earthquakes in a 12–35 ka period. 

Earthquake Recurrence Model 

The Poisson model is used as the default earthquake recurrence model with weight 1.0 for both the 

ERM-S and ERM-N sources. 

RLME Annual Frequency 

Tables H-5.6-3, H-5.6-4, and H-5.6-5 list the distribution of RLME recurrence frequencies for the 

ERM-S source. Tables H-5.6-6 and H-5.6-7 list the distribution of RLME recurrence frequencies 

for the ERM-N source. 

H.5.7 Marianna Zone RLME Seismic Source Model 

The Marianna Zone RLME is described in Section 6.1.7 of the main report. The logic tree for this 

source is shown on Figure H-5.7-1. The data for this source is contained on the CEUS SSC Project 

web site in file ―Marianna_RLME.xls.‖

H.5.7.1 Temporal Clustering 

The first node of the logic tree for the RLME source (Figure H-5.7-1) addresses the issue of 

temporal clustering of earthquakes. The in-cluster model is assigned a weight of 0.5 and the out-ofcluster model is assigned a weight of 0.5. For the ―in‖ branch, the remaining portion of the logic 

tree is used to define the hazard from this source. On the ―out‖ branch the Marianna RLME source 

is not included in calculation of the total seismic hazard. 

H-15
Appendix H 

H.5.7.2 Localizing Feature 

RLMEs are modeled as occurring randomly with the boundary of the Marianna zone shown on 

Figure H-5.7-2. 

H.5.7.3 Geometry and Style of Faulting 

A single geometry for the Marianna RLME source is used. The geometry is shown on 

Figure H-5.7-2. 

The probability distribution used to model seismogenic thickness is 13 km (weight of 0.3), 15 km 

(weight of 0.5), or 17 km (weight of 0.2). 

Two equally weighted alternatives for future ruptures of RLMEs are modeled: either vertical strikeslip ruptures oriented northeast parallel to the sides of the Marianna zone or vertical strike-slip 

ruptures oriented northwest parallel to the sides of the Marianna zone. All boundaries to the MAR 

zone are leaky. 

H.5.7.4 RLME Magnitude 

The distribution for RLME magnitude for the Marianna RLME source is given in Table H-5.7-1. 

Aleatory variability in the size of an RLME is modeled as a uniform distribution of ±0.25 M units 

centered on the expected RLME magnitude value given in the table. 

H.5.7.5 RLME Recurrence 

The remaining branches of the logic tree describe the assessment of RLME recurrence rates. 

Recurrence Method 

The ―Earthquake Recurrence Intervals‖ approach is used with weight 1.0 (Figure H-5.7-1). 

Recurrence Data 

The two equally weighted data sets consist of either three or four earthquakes with the oldest 

occurring approximately 9.9 ka. 

Earthquake Recurrence Model 

The Poisson model is used as the default earthquake recurrence model with weight 1.0 for the 

Marianna RLME source. 

RLME Annual Frequency 

The final node of the logic tree addresses the uncertainty distributions for the annual frequency of 

RLMEs. These distributions are given in Tables H-5.7-2 and H-5.7-3. 

H.5.8 Commerce Fault RLME Seismic Source Model 

The Commerce RLME source is described in Section 6.1.8 of the main text. The source logic tree is 

shown on Figure H-5.8-1. The data for this source is contained on the CEUS SSC Project web site 

in file ―Commerce_RLME.xls.‖

H-16
Appendix H 

H.5.8.1 Temporal Clustering 

This node of the logic tree is not applicable to this source. 

H.5.8.2 Localizing Feature 

RLMEs are modeled as occurring randomly with the boundary of the Commerce zone shown on 

Figure H-5.8-2. 

H.5.8.2 Geometry and Style of Faulting 

A single geometry for the Commerce RLME source is modeled. 

The uncertainty distribution for seismogenic crustal thickness is: 13 km (weight of 0.3), 15 km 

(weight of 0.5), or 17 km (weight of 0.2). 

The Commerce RLME source is modeled as a zone of vertical strike-slip faulting. Ruptures are to 

be oriented N47°E, subparallel to the Commerce zone boundary. The northeast and southwest 

boundaries of the zone are considered leaky boundaries. 

H.5.8.4 RLME Magnitude 

Table H-5.8-1 lists the uncertainty distribution for the Commerce RLME magnitude. Aleatory 

variability in the size of an RLME is modeled as a uniform distribution of ±0.25 M units centered 

on the expected RLME magnitude value given in the table. 

H.5.8.5 RLME Recurrence 

The remaining branches of the logic tree describe the assessment of RLME recurrence rates. 

Recurrence Method 

The ―Earthquake Recurrence Intervals‖ approach is used with weight 1.0 (Figure H-5.8-1). 

Recurrence Data 

The preferred interpretation (weight 0.75) is that two earthquakes have occurred in the past 23 kyr 

with the possibility (weight 0.25) that the count is three earthquakes. 

Earthquake Recurrence Model 

The Poisson model is used as the earthquake recurrence model with weight 1.0 for the Commerce 

RLME source. 

RLME Annual Frequency 

Tables H-5.8-2 and H-5.8-3 list the alternative distributions for RLME frequency for the Commerce 

RLME source. 

H-17
Appendix H 

H.5.9 Wabash Valley RLME Seismic Source Model 

The Wabash Valley RLME source is described in Section 6.1.9 of the main text. The source logic 

tree is shown on Figure H-5.9-1. The data for this source is contained on the CEUS SSC Project 

web site in file ―Wabash_RLME.xls.‖

H.5.9.1 Temporal Clustering 

This node of the logic tree is not applicable to this source. 

H.5.9.2 Localizing Feature 

RLMEs are modeled as occurring randomly with the boundary of the Wabash Valley zone shown 

on Figure H-5.9-2. 

H.5.9.3 Geometry and Style of Faulting 

A single zone geometry is used to model the Wabash Valley RLME. This geometry is shown on 

Figure H-5.9-2. 

Two alternative estimates of the seismogenic thickness of the crust in the Wabash Valley RLME are 

used: 17 km (weight of 0.7) or 22 km (weight of 0.3). 

The boundaries of the Wabash Valley RLME source zone are modeled as leaky. Earthquakes are to 

be modeled with a random strike (uniform 0o to 360o azimuth). The earthquakes are a mixture of 2/3 

vertical strike-slip and 1/3 reverse (random dip in the range of 40o to 60o) 

H.5.9.4 RLME Magnitude 

Table H-5.9-1 lists the uncertainty distribution for the magnitude of Wabash Valley RLMEs. 

Aleatory variability in the size of an RLME is modeled as a uniform distribution of ±0.25 M units 

centered on the expected RLME magnitude value given in the table. 

H.5.9.5 RLME Recurrence 

The remaining branches of the logic tree describe the assessment of RLME recurrence rates. 

Recurrence Method 

The ―Earthquake Recurrence Intervals‖ approach is used with weight 1.0 (Figure H-5.9-1). 

Recurrence Data 

The available data for characterizing the recurrence rate of Wabash Valley RLMEs are the 

estimated ages for the Vincennes-Bridgeport and Skelton paleoearthquakes. 

Earthquake Recurrence Model 

The Poisson model is used as the earthquake recurrence model with weight 1.0 for the Wabash 

Valley RLME source. 

H-18
Appendix H 

RLME Annual Frequency 

The final node of the logic tree addresses the uncertainty distributions for the annual frequency of 

RLMEs. This distribution is listed in Table H-5.9-2.

H-19
Appendix H 

Table H-3-1 

Weighted Alternative Seismogenic Crustal Thickness Values for Mmax Zones 

Mmax Zone Crustal Thickness and [Weight]

Study Region 13 km [0.4], 17 km [0.4], 22 km [0.2]

MESE-W 13 km [0.4], 17 km [0.4], 22 km [0.2]

MESE-N 13 km [0.4], 17 km [0.4], 22 km [0.2]

NMESE-W 13 km [0.4], 17 km [0.4], 22 km [0.2]

NMESE-N 13 km [0.4], 17 km [0.4], 22 km [0.2]

Table H-3-2 

Aleatory Distributions for Characterization of Future Earthquake Ruptures for Mmax Zones 

Mmax Zone

Source 

Boundary 

Characteristics

Sense of Slip

(Relative 

Frequency)

Rupture Strike 

(Relative 

Frequency)

Rupture Dip 

(Relative 

Frequency)

Study Region, 

MESE-N, 

MESE-W, 

NMESE-N, 

NMESE-W

Leakya

Strike-slip (2/3)

N50W (0.2)

N00E (0.2)

N35E (0.4)

N60E (0.1)

N90E (0.1)

Uniformly 

distributed 60o to 

90o, equally likely 

dip direction

Reverse (1/3)

N50W (0.2)

N00E (0.2)

N35E (0.4)

N60E (0.1)

N90E (0.1)

Uniformly 

distributed 30o to 

60o, equally likely 

dip direction

a

 Leaky boundary denotes the case were earthquake ruptures are centered on the earthquake epicenter, the 

epicenters are contained within the source boundary, but the rupture is allowed to extend beyond the source 

boundary. 

Table H-3-3 

Maximum Magnitude Distributions for Mmax Distributed Seismicity Sources 

Weight Assigned 

to Mmax

Maximum Magnitude for:

Study 

Region MESE_N NMESE_N MESE_W NMESE_W

0.101 6.5 6.4 6.4 6.5 5.7

0.244 6.9 6.8 6.8 6.9 6.1

0.310 7.2 7.2 7.1 7.3 6.6

0.244 7.7 7.7 7.5 7.7 7.2

0.101 8.1 8.1 8.0 8.1 7.9

H-20
 

Appendix H 

Table H-4-1 

Seismotectonic Source Zones 

Zone Acronym Seismotectonic Source Zone

AHEX Atlantic Highly Extended Crust

ECC-AM Extended Continental Crust—Atlantic Margin

ECC-GC Extended Continental Crust—Gulf Coast

GMH Great Meteor Hotspot

IBEB Illinois Basin Extended Basement

GHEX Gulf Highly Extended Crust

MidC-A, MidC-B, 

MidC-C, MidC-D

Midcontinent-Craton alternatives 

OKA Oklahoma Aulacogen

PEZ-N and PEZ-W Paleozoic Extended Crust narrow and Paleozoic Extended Crust wide

RR and RR-RCG Reelfoot Rift and Reelfoot Rift including the Rough Creek Graben

SLR St. Lawrence Rift, including the Ottawa and Saguenay grabens

Table H-4-2 

Weighted Alternative Seismogenic Crustal Thickness Values for Seismotectonic Zones 

Mmax Zone Crustal Thickness and [Weight]

AHEX, GHEX 8 km [0.5], 15 km [0.5]

ECC-AM, ECC-GC, MidC-A, 

MidC-B, MidC-C, MidC-D, IBEB, 

NAP,PEZ-N, PEZ-W

13 km [0.4], 17 km [0.4], 22 km [0.2]

GMH, SLR 25 km [0.5], 30 km [0.5]

OKA 15 km [0.5] 20 km [0.5]

RR, RR-RCG 13 km [0.4], 15 km [0.4], 17 km [0.2]

H-21
Appendix H 

Table H-4-3 

Aleatory Distributions for Characterization of Future Earthquake Ruptures for Seismotectonic 

Zones 

Seismotectonic

Zone

Source 

Boundary 

Characteristics

Sense of Slip

(Relative 

Frequency)

Rupture Strike 

(Relative 

Frequency)

Rupture Dip 

(Relative 

Frequency)

AHEX, ECC-AM, 

MidC-A, MidC-B, 

MidC-C, MidC-D, 

PEZ-N, PEZ-W

Leakya

Strike-slip (2/3)

N50W (0.2)

N00E (0.2)

N35E (0.4)

N60E (0.1)

N90E (0.1)

Uniformly 

distributed 60o to 

90o, equally likely 

dip direction

Reverse (1/3)

N50W (0.2)

N00E (0.2)

N35E (0.4)

N60E (0.1)

N90E (0.1)

Uniformly 

distributed 30o to 

60o, equally likely 

dip direction

ECC-GC, GHEX Leakya

Strike-slip (2/3) Uniform 0o to 180o

Uniformly 

distributed 60o to 

90o, equally likely 

dip direction

Reverse (1/3) Uniform 0o to 180o

Uniformly 

distributed 30o to 

60o, equally likely 

dip direction

GMH Leakya

Strike-slip (0.2)

N40W (0.4)

N20E (0.4)

N90E (0.1)

Uniformly 

distributed 60o to 

90o, equally likely 

dip direction

Reverse (0.8)

N40W (0.4)

N20E (0.4)

N90E (0.1)

Uniformly 

distributed 30o to 

60o, equally likely 

dip direction

IBEB Leakya

Reverse Oblique 

(0.1) N20W (1.0) 75oE (0.5)75oW (0.5)

Reverse (0.3) N00E (1.0)

40oE (0.2)

40oW (0.2)

75oE (0.3)

75oW (0.3)

Strike-slip (0.6)

N50W (0.167)

N90E (0.333)

N40E (0.5)

90o (1.0)

NAP LeakyaStrike-slip (1/3)

N50W (0.2)

N00E (0.2)

N35E (0.4)

N60E (0.1)

N90E (0.1)

Uniformly 

distributed 60o to 

90o, equally likely 

dip direction

H-22
 

Appendix H 

Seismotectonic

Zone

Source 

Boundary 

Characteristics

Sense of Slip

(Relative 

Frequency)

Rupture Strike 

(Relative 

Frequency)

Rupture Dip 

(Relative 

Frequency)

Reverse (2/3)

N50W (0.2)

N00E (0.2)

N35E (0.4)

N60E (0.1)

N90E (0.1)

Uniformly 

distributed 30o to 

60o, equally likely 

dip direction

OKA Leakya Reverse Oblique

(1.0)

Parallel to Long 

Axis of Zone (1.0)

Uniform 45oN to 

75oN (0.5)

Uniform 45oS to 

75oS (0.5)

RR, RR-RCG Leakya

Reverse (0.35) N10W (1.0)

40oE (0.25)

40oW (0.25)

70oE (0.25)

70oE (0.25)

Strike-slip (0.65)

N50W (0.3)

N30E (0.3)

N55E (0.3)

N90E (0.1)

90o (1.0)

SLR Leakya

Strike-slip (1/3)

N25E (0.2)

N40E (0.2)

N70E (0.2)

N50W (0.15)

N70W (0.15)

NS (0.05)

EW (0.05)

Uniformly 

distributed 60o to 

90o, equally likely 

dip direction

Reverse (2/3)

N25E (0.2)

N40E (0.2)

N70E (0.2)

N50W (0.15)

N70W (0.15)

NS (0.05)

EW (0.05)

Uniformly 

distributed 30o to 

60o, equally likely 

dip direction

a

 Leaky boundary denotes the case were earthquake ruptures are centered on the earthquake epicenter, the 

epicenters are contained within the source boundary, but the rupture is allowed to extend beyond the source 

boundary. 

H-23
Appendix H 

Table H-4-4 

Maximum Magnitude Distributions for Seismotectonic Distributed Seismicity Sources 

Weight

Maximum Magnitude for:

AHEX ECC-AM ECC-GC GHEX GMH IBEB

MidC-A, 

MidC-B, 

MidC-C, 

and 

MidC-D NAP OKA

PEZ-N 

and 

PEZ-W RR RR-RCG SLR

0.101 6.0 6.0 6.0 6.0 6.0 6.5 5.6 6.1 5.8 5.9 6.2 6.1 6.2

0.244 6.7 6.7 6.7 6.7 6.7 6.9 6.1 6.7 6.4 6.4 6.7 6.6 6.8

0.310 7.2 7.2 7.2 7.2 7.2 7.4 6.6 7.2 6.9 6.8 7.2 7.1 7.3

0.244 7.7 7.7 7.7 7.7 7.7 7.8 7.2 7.7 7.4 7.2 7.7 7.6 7.7

0.101 8.1 8.1 8.1 8.1 8.1 8.1 8.0 8.1 8.0 7.9 8.1 8.1 8.1

H-24
 

Appendix H 

Table H-5.1-1 

Charlevoix RLME Magnitude Distribution 

Moment Magnitude Weight

6.75 0.2

7.0 0.5

7.25 0.2

7.5 0.1

Table H-5.1-2 

Annual Frequencies for Charlevoix RLME Events 

Data Set 1: 1870 and 1663 

RLME Frequency 

(Events/Year) Weight

9.3E-03 0.101

6.7E-03 0.244

4.2E-03 0.310

2.2E-03 0.244

7.7E-04 0.101

Table H-5.1-3 

Annual Frequencies for Charlevoix RLME Events 

Data Set 2: 3 Earthquakes in 6–7 kyr BP 

RLME Frequency 

(Events/Year) Weight

1.3E-03 0.101

8.4E-04 0.244

5.7E-04 0.310

3.7E-04 0.244

1.9E-04 0.101

H-25
Appendix H 

Table H-5.1-4 

Annual Frequencies for Charlevoix RLME Events 

Data Set 3: 4 Earthquakes in 9.5–10.2 kyr BP 

RLME Frequency 

(Events/Year) Weight

9.8E-04 0.101

6.7E-04 0.244

4.7E-04 0.310

3.2E-04 0.244

1.8E-04 0.101

Table H-5.2-1 

Charleston RLME Magnitude Distribution 

Moment Magnitude Weight

6.7 0.10

6.9 0.25

7.1 0.30

7.3 0.25

7.5 0.10

Table H-5.2-2 

Annual Frequencies for Charleston RLME Events 

Poisson Model, 2,000-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

4.7E-03 0.101

3.1E-03 0.244

2.1E-03 0.310

1.3E-03 0.244

6.8E-04 0.101

H-26
 

Appendix H 

Table H-5.2-3 

Annual Frequencies for Charleston RLME Events 

Poisson Model, 5,500-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

4.7E-03 0.101

3.1E-03 0.244

2.1E-03 0.310

1.3E-03 0.244

6.8E-04 0.101

Table H-5.2-4 

Annual Frequencies for Charleston RLME Events 

Poisson Model, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and D 

RLME Frequency 

(Events/Year) Weight

2.7E-03 0.101

1.9E-03 0.244

1.3E-03 0.310

8.8E-04 0.244

5.0E-04 0.101

Table H-5.2-5 

Annual Frequencies for Charleston RLME Events 

Poisson Model, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and E 

RLME Frequency 

(Events/Year) Weight

1.9E-03 0.101

1.3E-03 0.244

9.2E-04 0.310

6.4E-04 0.244

3.4E-04 0.101

H-27
Appendix H 

Table H-5.2-6 

Annual Frequencies for Charleston RLME Events 

Poisson Model, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, D, and E 

RLME Frequency 

(Events/Year) Weight

2.2E-03 0.101

1.5E-03 0.244

1.1E-03 0.310

7.8E-04 0.244

4.6E-04 0.101

Table H-5.2-7 

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.3, 2,000-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

6.4E-05 0.101

7.6E-06 0.244

9.5E-07 0.310

8.5E-08 0.244

2.3E-09 0.101

Table H-5.2-8 

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.5, 2,000-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

1.4E-03 0.101

3.8E-04 0.244

9.5E-05 0.310

1.7E-05 0.244

1.0E-06 0.101

H-28
 

Appendix H 

Table H-5.2-9 

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.7, 2,000-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

2.6E-03 0.101

9.8E-04 0.244

3.2E-04 0.310

7.1E-05 0.244

5.6E-06 0.101

Table H-5.2-10

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.3, 5,500-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

6.8E-05 0.101

8.0E-06 0.244

1.0E-06 0.310

9.2E-08 0.244

2.5E-09 0.101

Table H-5.2-11

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.5, 5,500-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

1.4E-03 0.101

3.9E-04 0.244

9.8E-05 0.310

1.7E-05 0.244

1.1E-06 0.101

H-29
Appendix H 

Table H-5.2-12

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.7, 5,500-Year Time Period 

Earthquakes 1886, A, B, and C 

RLME Frequency 

(Events/Year) Weight

2.7E-03 0.101

9.9E-04 0.244

3.3E-04 0.310

7.3E-05 0.244

5.8E-06 0.101

Table H-5.2-13

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.3, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and D 

RLME Frequency 

(Events/Year) Weight

3.5E-07 0.101

2.5E-08 0.244

2.2E-09 0.310

1.4E-10 0.244

2.7E-12 0.101

Table H-5.2-14

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.5, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and D 

RLME Frequency 

(Events/Year) Weight

2.2E-04 0.101

4.5E-05 0.244

9.3E-06 0.310

1.4E-06 0.244

7.6E-08 0.101

H-30
 

Appendix H 

Table H-5.2-15

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.7, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and D 

RLME Frequency 

(Events/Year) Weight

1.0E-03 0.101

3.3E-04 0.244

9.5E-05 0.310

2.0E-05 0.244

1.5E-06 0.101

Table H-5.2-16

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.3, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and E 

RLME Frequency 

(Events/Year) Weight

4.5E-09 0.101

2.0E-10 0.244

1.2E-11 0.310

5.4E-13 0.244

6.4E-15 0.101

Table H-5.2-17

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.5, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and E 

RLME Frequency 

(Events/Year) Weight

5.2E-05 0.101

8.2E-06 0.244

1.4E-06 0.310

1.7E-07 0.244

7.0E-09 0.101

H-31
Appendix H 

Table H-5.2-18

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.7, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, and E 

RLME Frequency 

(Events/Year) Weight

5.2E-04 0.101

1.4E-04 0.244

3.4E-05 0.310

6.1E-06 0.244

3.9E-07 0.101

Table H-5.2-19

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.3, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, D, and E 

RLME Frequency 

(Events/Year) Weight

1.5E-08 0.101

8.7E-10 0.244

7.0E-11 0.310

4.4E-12 0.244

8.2E-14 0.101

Table H-5.2-20

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.5, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, D, and E 

RLME Frequency 

(Events/Year) Weight

7.0E-05 0.101

1.3E-05 0.244

2.5E-06 0.310

3.7E-07 0.244

2.1E-08 0.101

H-32
 

Appendix H 

Table H-5.2-21

Annual Frequencies for Charleston RLME Events 

BPT Renewal Model, α = 0.7, 5,500-Year Time Period 

Earthquakes 1886, A, B, C, D, and E 

RLME Frequency 

(Events/Year) Weight

5.7E-04 0.101

1.6E-04 0.244

4.5E-05 0.310

9.2E-06 0.244

7.6E-07 0.101

Table H-5.3-1 

Cheraw RLME Magnitude Distribution 

Moment Magnitude Weight

6.8 0.3

7.0 0.3

7.2 0.3

7.4 0.1

Table H-5.3-2 

Annual Frequencies for Cheraw RLME Events 

In-Cluster Case, Data Set: 2 Earthquakes in 20–25 kyr 

RLME Frequency 

(Events/Year) Weight

2.4E-04 0.101

1.3E-04 0.244

7.6E-05 0.310

3.8E-05 0.244

1.4E-05 0.101

H-33
Appendix H 

Table H-5.3-3 

Annual Frequencies for Cheraw RLME Events 

In-Cluster Case, Data Set: 3 Earthquakes in 20–25 kyr 

RLME Frequency 

(Events/Year) Weight

3.1E-04 0.101

1.9E-04 0.244

1.2E-04 0.310

7.2E-05 0.244

3.2E-05 0.101

Table H-5.3-4 

Slip Rates for Cheraw Fault 

In-Cluster Case, Data Set: 3.2–4.1 m in 20–25 kyr 

RLME Fault Slip Rate

(mm/Year) Weight

0.14 0.185

0.16 0.630

0.19 0.185

Table H-5.3-5 

Annual Frequencies for Cheraw RLME Events 

Out-of-Cluster Case, Time Between Clusters 

RLME Frequency 

(Events/Year) Weight

5.0E-06 0.333

2.9E-06 0.334

2.0E-06 0.333

H-34
 

Appendix H 

Table H-5.3-6 

Slip Rates for Cheraw Fault 

Out-of-Cluster Case, Data Set: 7–8 m in 0.4–2.0 myr 

RLME Fault Slip Rate

(mm/Year) Weight

0.0038 0.101

0.0043 0.244

0.0054 0.310

0.0072 0.244

0.011 0.101

Table H-5.4-1 

Meers RLME Magnitude Distribution 

Moment Magnitude Weight

6.6 0.1

6.7 0.45

6.9 0.3

7.3 0.1

7.4 0.05

Table H-5.4-2 

Annual Frequencies for Meers RLME Events 

In-Cluster Case 

RLME Frequency 

(Events/Year) Weight

2.1E-03 0.101

1.2E-03 0.244

6.7E-04 0.310

3.4E-04 0.244

1.2E-04 0.101

H-35
Appendix H 

Table H-5.4-3 

Annual Frequencies for Meers RLME Events 

Out-of-Cluster Case 

RLME Frequency 

(Events/Year) Weight

5.0E-06 0.333

2.9E-06 0.334

2.0E-06 0.333

Table H-5.5-1 

NMFS RLME Magnitude Distribution 

Moment Magnitude for:

NMS RFT NMN Weight

7.9 7.8 7.6 0.167

7.8 7.7 7.5 0.167

7.6 7.8 7.5 0.250

7.2 7.4 7.2 0.083

6.9 7.3 7.0 0.250

6.7 7.1 6.8 0.083

Table H-5.5-2 

Annual Frequencies for NMFS RLME Events 

In-Cluster Case, Poisson Model 

RLME Frequency 

(Events/Year) Weight

6.0E-03 0.101

3.7E-03 0.244

2.4E-03 0.310

1.4E-03 0.244

6.2E-04 0.101

H-36
 

Appendix H 

Table H-5.5-3 

Annual Frequencies for NMFS RLME Events 

In-Cluster Case, BPT Model, α = 0.3

RLME Frequency 

(Events/Year) Weight

3.5E-03 0.101

1.1E-03 0.244

3.2E-04 0.310

6.4E-05 0.244

4.7E-06 0.101

Table H-5.5-4 

Annual Frequencies for NMFS RLME Events 

In-Cluster Case, BPT Model, α = 0.5

RLME Frequency 

(Events/Year) Weight

4.8E-03 0.101

2.2E-03 0.244

8.9E-04 0.310

2.6E-04 0.244

3.1E-05 0.101

Table H-5.5-5 

Annual Frequencies for NMFS RLME Events 

In-Cluster Case, BPT Model, α = 0.7

RLME Frequency 

(Events/Year) Weight

4.4E-03 0.101

2.2E-03 0.244

1.0E-03 0.310

3.4E-04 0.244

4.7E-05 0.101

H-37
Appendix H 

Table H-5.5-6 

Annual Frequencies for NMFS RLME Events 

Out-of-Cluster Case, Poisson Model 

RLME Frequency 

(Events/Year) Weight

1.3E-03 0.101

7.2E-04 0.244

4.2E-04 0.310

2.2E-04 0.244

8.0E-05 0.101

Table H-5.6-1 

ERM-S RLME Magnitude Distribution 

Moment Magnitude Weight

6.7 0.15

6.9 0.2

7.1 0.2

7.3 0.2

7.5 0.2

7.7 0.05

Table H-5.6-2 

ERM-N RLME Magnitude Distribution 

Moment Magnitude Weight

6.7 0.3

6.9 0.3

7.1 0.3

7.4 0.1

H-38
 

Appendix H 

Table H-5.6-3 

Annual Frequencies for ERM-S RLME Events 

Data Set: 2 Earthquakes in 17.7–21.7 kyr 

RLME Frequency 

(Events/Year) Weight

3.5E-04 0.101

2.1E-04 0.244

1.4E-04 0.310

8.0E-05 0.244

3.6E-05 0.101

Table H-5.6-4 

Annual Frequencies for ERM-S RLME Events 

Data Set: 3 Earthquakes in 17.7–21.7 kyr 

RLME Frequency 

(Events/Year) Weight

4.3E-04 0.101

2.8E-04 0.244

1.9E-04 0.310

1.2E-04 0.244

6.2E-05 0.101

Table H-5.6-5 

Annual Frequencies for ERM-S RLME Events 

Data Set: 4 Earthquakes in 17.7–21.7 kyr 

RLME Frequency 

(Events/Year) Weight

5.0E-04 0.101

3.4E-04 0.244

2.4E-04 0.310

1.6E-04 0.244

9.0E-05 0.101

H-39
Appendix H 

Table H-5.6-6 

Annual Frequencies for ERM-N RLME Events 

Data Set: 1 Earthquake in 12–35 kyr 

RLME Frequency 

(Events/Year) Weight

2.9E-04 0.101

1.5E-04 0.244

8.0E-05 0.310

4.0E-05 0.244

1.4E-05 0.101

Table H-5.6-7 

Annual Frequencies for ERM-N RLME Events 

Data Set: 2 Earthquakes in 12–35 kyr 

RLME Frequency 

(Events/Year) Weight

3.9E-04 0.101

2.2E-04 0.244

1.3E-04 0.310

7.2E-05 0.244

3.2E-05 0.101

Table H-5.7-1 

Marianna RLME Magnitude Distribution 

Moment Magnitude Weight

6.7 0.15

6.9 0.2

7.1 0.2

7.3 0.2

7.5 0.2

7.7 0.05

H-40
 

Appendix H 

Table H-5.7-2 

Annual Frequencies for Marianna RLME Events 

Data Set: 3 Earthquakes in 9.6–10.2 kyr 

RLME Frequency 

(Events/Year) Weight

6.9E-04 0.101

4.2E-04 0.244

2.7E-04 0.310

1.6E-04 0.244

7.2E-05 0.101

Table H-5.7-3 

Annual Frequencies for Marianna RLME Events 

Data Set: 4 Earthquakes in 9.6–10.2 kyr 

RLME Frequency 

(Events/Year) Weight

8.4E-04 0.101

5.5E-04 0.244

3.7E-04 0.310

2.4E-04 0.244

1.2E-04 0.101

Table H-5.8-1 

Commerce RLME Magnitude Distribution 

Moment Magnitude Weight

6.7 0.15

6.9 0.35

7.1 0.35

7.3 0.10

7.7 0.05

H-41
Appendix H 

Table H-5.8-2 

Annual Frequencies for Commerce RLME Events 

Data Set: 2 Earthquakes in 18.9–23.6 kyr 

RLME Frequency 

(Events/Year) Weight

2.5E-04 0.101

1.4E-04 0.244

8.0E-05 0.310

4.0E-05 0.244

1.4E-05 0.101

Table H-5.8-3 

Annual Frequencies for Commerce RLME Events 

Data Set: 3 Earthquakes in 18.9–23.6 kyr 

RLME Frequency

(events/Year) Weight

3.3E-04 0.101

2.0E-04 0.244

1.3E-04 0.310

7.6E-05 0.244

3.4E-05 0.101

Table H-5.9-1 

Wabash RLME Magnitude Distribution 

Moment Magnitude Weight

6.75 0.05

7.0 0.25

7.25 0.35

7.5 0.35

H-42
 

Appendix H 

Table H-5.9-2 

Annual Frequencies for Wabash RLME Events 

Data Set: 2 Earthquakes in 11–13 kyr 

RLME Frequency 

(Events/Year) Weight

4.4E-04 0.101

2.5E-04 0.244

1.4E-04 0.310

7.2E-05 0.244

2.4E-05 0.101

H-43
Appendix H 

Figure H-1-1 

Region covered by the CEUS SSC model 

H-44
 

Appendix H

Figure H-2-1 

Master logic tree for the CEUS SSC model

H-45
Appendix H 

Figure H-3-1 

Logic tree for the Mmax zones branch of the master logic tree

H-46
 

Appendix H

Figure H-3-2 

Mesozoic extended (MESE-W) and non-extended (NMESE-W) Mmax zones for the “wide” interpretation

H-47
Appendix H 

Figure H-3-3 

Mesozoic extended (MESE-N) and non-extended (NMESE-N) Mmax zones for the “narrow” interpretation

H-48
 

Appendix H

Figure H-4-1(a) 

Logic tree for the seismotectonic zones branch of the master logic tree

H-49
Appendix H 

Figure H-4-1(b) 

Logic tree for the seismotectonic zones branch of the master logic tree

H-50
 

Appendix H

Figure H-4-2 

Seismotectonic zones shown in the case where the Rough Creek Graben is not part of the Reelfoot Rift (RR) and the Paleozoic 

Extended zone is narrow (PEZ-N)

H-51
Appendix H 

Figure H-4-3 

Seismotectonic zones shown in the case where the Rough Creek Graben is part of the Reelfoot Rift (RR-RCG) and the Paleozoic 

Extended zone is narrow (PEZ-N)

H-52
 

Appendix H

Figure H-4-4 

Seismotectonic zones shown in the case where the Rough Creek Graben is not part of the Reelfoot Rift (RR) and the Paleozoic 

Extended zone is wide (PEZ-W) 

H-53
Appendix H 

Figure H-4-5 

Seismotectonic zones shown in the case where the Rough Creek Graben is part of the Reelfoot Rift (RR-RCG) and the Paleozoic 

Extended zone is wide (PEZ-W) 

H-54
 

Appendix H

Figure H-5-1 

Logic tree for the RLME source branch of the master logic tree

H-55
Appendix H 

Figure H-5-2 

Location of RLME sources in the CEUS SSC model 

H-56
 

Appendix H

Figure H-5.1-1 

Logic tree for Charlevoix RLME source 

H-57
Appendix H 

Figure H-5.1-2 

Charlevoix RLME source geometry 

H-58
 

Appendix H

Figure H-5.2-1(a) 

Logic tree for Charleston RLME source 

H-59
Appendix H 

Figure H-5.2-1(b) 

Logic tree for Charleston RLME source 

H-60
 

Appendix H

Figure H-5.2-2 

Charleston RLME alternative source geometries 

H-61
Appendix H 

Figure H-5.3-1 

Logic tree for Cheraw RLME source 

H-62
 

Appendix H

Figure H-5.3-2 

Cheraw RLME source geometry 

H-63
Appendix H 

Figure H-5.4-1 

Logic tree for Meers RLME source 

H-64
 

Appendix H

Figure H-5.4-2 

Meers RLME source geometries 

H-65
Appendix H 

Figure H-5.5-1 

Logic tree for NMFS RLME source 

H-66
 

Appendix H

Figure H-5.5-2 

New Madrid South (NMS) fault alternative RMLE source geometries: Blytheville Arch-Bootheel Lineament (BA-BL) and 

Blytheville Arch-Blytheville fault zone (BA-BFZ)

H-67
Appendix H 

Figure H-5.5-3 

New Madrid North (NMN) fault alternative RMLE source geometries: New Madrid North (NMN_S) and New Madrid North plus 

extension (NMN_L)

H-68
 

Appendix H

Figure H-5.5-4 

Reelfoot Thrust (RFT) fault alternative RMLE source geometries: Reelfoot thrust (RFT_S) and Reelfoot thrust plus extensions 

(RFT_L) 

H-69
Appendix H 

Figure H-5.6-1 

Logic tree for ERM-S RLME source 

H-70
 

Appendix H

Figure H-5.6-2 

Logic tree for ERM-N RLME source 

H-71
Appendix H 

Figure H-5.6-3 

ERM-S RLME source geometries 

H-72
 

Appendix H

Figure H-5.6-4 

ERM-N RLME source geometry 

H-73
Appendix H 

Figure H-5.7-1 

Logic tree for Marianna RLME source 

H-74
 

Appendix H

Figure H-5.7-2 

Marianna RLME source geometry 

H-75
Appendix H 

Figure H-5.8-1 

Logic tree for Commerce Fault Zone RLME source 

H-76
 

Appendix H

Figure H-5.8-2 

Commerce RLME source geometry 

H-77
Appendix H 

Figure H-5.9-1 

Logic tree for Wabash Valley RLME source 

H-78
 

Appendix H

Figure H-5.9-2 

Wabash Valley RLME source geometry 

H-79

NUREG-2115 DOE/NE-0140 EPRI 1021097

APPENDIX I 

PPRP Review Comments 

I

APPENDIX

PPRP REVIEW COMMENTS 

Appendix I 

CORRESPONDENCE—CONTENTS 

Participatory Peer Review Panel (PPRP) Letters 

1a) Letter dated May 22, 2008, to Mr. Salomone: Central and Eastern United States Seismic 

Source Characterization for Nuclear Facilities, Draft Project Plan, Rev 00, April 14, 2008: 

Participatory Peer Review Panel review meeting, May 8, 2008. 

1b) Attachment 1 (PPRP and Sponsor Representatives) dated May 22, 2008: CEUS SSC for 

Nuclear Facilities Participatory Peer Review Panel and Sponsor Representatives. 

1c) Attachment 2 (Consolidated Written Comments on Draft Project Plan) dated May 22, 2008:

Consolidated PPRP Comments on Draft Project Plan: Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities, Rev 00 04/14/08. 

2a) Letter dated August 15, 2008, to Mr. Salomone: Central and Eastern United States Seismic 

Source Characterization for Nuclear Facilities: Participatory Peer Review Report on Workshop 

No. 1. 

2b) Attachment A (PPRP Key Issues for CEUS SSC Relevant to Workshop #1 via e-mail dated 

June 3, 2008, including elaborated inputs from William J. Hinze, Jeffrey K. Kimball, and Jon P. 

Ake).

3) Letter dated March 10, 2009, to Mr. Salomone: Central and Eastern United States Seismic 

Source Characterization for Nuclear Facilities: Participatory Peer Review Report on Workshop 

No. 2. 

4) Letter dated September 18, 2009, to Mr. Salomone: Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities: Participatory Peer Review Report on 

Workshop No. 3. 

5) Letter dated April 7, 2010, to Mr. Salomone: Central and Eastern United States Seismic 

Source Characterization for Nuclear Facilities: Feedback on CEUS SSC Preliminary Model. 

6) Email dated October 4, 2010 to Mr. Salomone: Central and Eastern United States Seismic 

Source Characterization for Nuclear Facilities—PPRP Review Comments on CEUS SSC Draft 

Report of July 31, 2010

7) Email dated October 13, 2010, to Mr. Salomone: Key Issues for TI Team to be Attentive to as 

They Revisit the CEUS SSC Model and Revise the Project Report (PPRP Informal 

Communication) 

8) Email dated February 23, 2011, to Mr. Salomone: PPRP Feedback on CEUS SSC Working 

Meeting #9 (PPRP Informal Communication)
Appendix I 

9) Email dated September 26, 2011, to Mr. Salomone: Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities—Mandatory PPRP Review Comments on 

the CEUS SSC Final Report

10) Email dated September 26, 2011, to Mr. Salomone: Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities—PPRP Non-Mandatory Review 

Comments on Installments 1 and 2 of Final Report

11) PPRP Comment Response Table 

Technical Integration (TI) Team and Project Manager (PM) Response to PPRP 

Letters 

1) Letter dated September 16, 2008, to Drs. Arabasz and Stepp: Response to Central and Eastern 

United States Seismic Source Characterization for Nuclear Facilities: Participatory Peer Review 

Report on Workshop No. 1, dated August 15, 2008. 

2) Letter dated March 20, 2009, to Drs. Arabasz and Stepp: Response to Central and Eastern 

United States Seismic Source Characterization for Nuclear Facilities: Participatory Peer Review 

Report on Workshop No. 2, dated March 10, 2009. 

3) Letter dated September 25, 2009, to Drs. Arabasz and Stepp: Response to Central and Eastern 

United States Seismic Source Characterization for Nuclear Facilities: Participatory Peer Review 

Report on Workshop No. 3, dated September 18, 2009.

4) Letter dated April 19, 2010, to Drs. Arabasz and Stepp: Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities: Feedback on CEUS SSC Preliminary 

Model dated April 7, 2010.
CEUS SSC_PPRP #1_r2

May 22, 2008 

Lawrence A. Salomone 

Washington Savannah River Company 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for

 Nuclear Facilities, Draft Project Plan, Rev 00, April 14, 2008: 

 Participatory Peer Review Panel review meeting, May 8, 2008 

This letter states the observations and recommendations of the designated Participatory 

Peer Review Panel (PPRP) for the referenced project relating to the draft project plan and 

the plan review meeting held in Palo Alto on May 8, 2008. The PPRP was able to review 

the draft project plan and provided its written comments prior to the meeting. Members 

of the Panel are listed in Attachment 1; the Panel’s written comments on the draft project 

plan together with additional comments provided by sponsor agencies are in Attachment 

2. We want to express our appreciation for the opportunity to meet with the Project 

Team and project sponsor representatives and for the responsive and thorough 

discussions of our written comments during the meeting. We believe the discussions and 

follow-on actions that grew out of them satisfactorily resolve our written comments. 

The paramount goal of the project is to develop a seismic source characterization (SSC) 

model for the central and eastern United States (CEUS) that can be adopted by the 

sponsoring organizations as an accepted starting basis model for performing a sitespecific probabilistic seismic hazard analysis (PSHA) at any geographic location within 

the region. In order to achieve this overarching goal the SSC model must have the 

stability of being broadly accepted by the informed scientific and technical community 

and must remain valid for a period into the future. The CEUS SSC assessment will 

implement current practice and guidance on the use of experts and assessment of 

uncertainty described in Budnitz, et al., 19971

 (the SSHAC process). The planned 

approach is to use a SSHAC Level 3 process for assessing key SSC issues and a Level 2 

process for assessing issues that have lesser hazard significance.

Our written comments on the draft project plan were satisfactorily resolved by 

discussions during the meeting and with planned revision of the plan. We have the 

following additional observations and recommendations following the meeting. 

1

 Budnitz, R. J., G. Apostolakis, D. M. Boore, L. S. Cluff, K. J. Coppersmith, C. A. 

Cornell, and P. A. Morris, 1997. Recommendations for Probabilistic Seismic Hazard 

Analysis: Guidance on Uncertainty and Use of Experts. NUREG/CR-6372, Washington, 

DC, U.S. Nuclear Regulatory Commission.

1a
Lawrence A. Salomone 2 5/22/08 

1. We endorse the planned use of a SSHAC Level 3 process for key issues of the 

CEUS SSC model. However, the planned use of Level 2 processes for “those 

issues having lesser hazard significance or are not subject to large uncertainty” is 

potentially problematic vis-à-vis desired stability. At a minimum, decisions to 

use Level 2 processes in developing aspects of the CEUS SSC model should be 

carefully scrutinized both by the Technical Integrator (TI) team and the PPRP. 

We recommend that consideration be given to using the Level 3 process for 

assessment of all SSC issues regardless of the level of uncertainty about the issue 

or its hazard significance. The planned early identification of the most hazardsignificant issues should serve to more efficiently focus the workshops and 

assessments. However, a uniformly implemented Level 3 assessment will assure 

uniform thoroughness and completeness of the assessments and will raise 

scientific and public confidence in the result. Implemented this way, we are 

confident that the Level 3 assessment will result in a SSC model that properly 

reflects the uncertainty of the informed scientific community and that will serve 

as a stable starting basis for performing site-specific PSHA’s. 

2. The TI Team should make every effort to comprehensively address proponent 

positions on the various SSC issues and to thoroughly evaluate the issues in 

workshops. The workshop proceedings and the assessments of the issues should 

be thoroughly documented and summarized within the main body of the report, 

with more detail provided in the appendix of the report. It is clear that scientific 

investigations will continue to expand the available database and to improve 

scientific understanding of earthquake processes into the future. Organizations 

that adopt the SSC model should develop and implement procedures for 

evaluating the significance of such advances in scientific knowledge in order to 

fully achieve the desired longevity goal for use of the study results into the future.

We consider the development of such procedures to be a user function beyond the 

scope of this project since the appropriate procedures and evaluations would be 

specific to each organization as required to meet its seismic regulations. 

3. The TI Team is constituted of individuals who are among the most experienced 

available for implementation of the SSHAC process. However, considering that 

the paramount goal of the study is to develop a broadly accepted CEUS SSC 

model that will remain stable into the future, we strongly recommend expanding 

the TI Team. Specifically, we urge the inclusion of experts—either as full 

members of the Team or as heavily involved resource experts—who have expert 

knowledge about CEUS tectonic and earthquake processes and experience with 

other seismic source assessments for seismic hazard mapping programs that may 

elect to adopt the study results. We consider achievement of this level of 

participation across programs to be essential. 

4. We understand that the project is limited by available resources and must be 

optimized to the extent achievable. Nevertheless, we consider six test sites for 

development of hazard results feedback to be minimum. We strongly endorse the 

plan to select locations for the test sites so as to optimally capture the sensitivity 

of hazard to elements and parameters of the CEUS SSC model. In order to 

optimize the benefit of the feedback workshop, arrangements should be made to 
Lawrence A. Salomone 3 5/22/08 

provide real-time analysis of the sensitivity of hazard to elements and parameters 

of the SSC model.

5. The project database is clearly fundamental for performing the assessments for 

development of the SSC model. A complete and well-qualified database should 

be the essential objective in order to reduce data uncertainty to the extent 

achievable. We recommend efficient open electronic access to the database by 

the project participants, to the extent achievable. 

6. We endorse the planned briefings for the project sponsors on the SSC model and 

how to use the model to perform a site-specific PSHA. We recommend that the 

project prepare a document describing lessons learned at the end of the project 

and include this as part of the briefings and as an appendix to the final report. 

7. In order to promote broad user community participation in, and subsequent use of, 

the CEUS SSC results, the PPRP was intentionally constituted to include qualified 

individuals from sponsoring organizations that expect to adopt the results and 

from other hazard mapping programs. Accordingly, the PPRP believes it is 

important to state the following. The PPRP intends to appropriately perform its 

function to provide critical review of procedural and technical aspects of the 

project. The Panel participants will focus their comments primarily on technical 

validity, technical completeness, and conformity to the SSHAC process. We 

expect the sponsoring organizations to communicate explicit statements of their 

views to the Project Team independently of the PPRP.

These observations and recommendations are our primary ones at this time. The Panel 

intends to provide, in a timely way, further comments regarding specific issues for 

consideration by the Project Team in planning Workshop 1. 

Do not hesitate to contact us to discuss any of our observations and recommendations. 

 Sincerely, 

J. Carl Stepp Walter J. Arabasz 

871 Chimney Valley Road 2460 Emerson Avenue 

Blanco, TX 78606-4643 Salt Lake City, UT 84108 

Tel: 830 833 5446 801 581 7410 

cstepp@moment.net arabasz@seis.utah.edu

 

 

Attachments 

• PPRP Members and Sponsor Representatives 

• Consolidated Written Comments on Draft Project Plan 
Larence A. Salomone 5/22/08 Attachment 1 

CEUS SSC for Nuclear Facilities 

Participatory Peer Review Panel and Sponsor 

Representatives

J. Carl Stepp Co-chairman 

871 Chimney Valley Road 

Blanco, TX 78606-4643 

Tel: 830 833 5446 

Fax: 830 833 5724 

cstepp@moment.net

Walter J. Arabasz Co-chairman 

2460 Emerson Avenue 

Salt Lake City, UT 84108 

Tel: 801 581 7410 

Fax: 801 585 5585 

arabasz@seis.utah.edu

Jon P. Ake 

USNRC 

Washington, DC 20555-0001 

Tel: 301 415 0716 

Jon.ake@nrc.gov

William J. Hinze 

Purdue University 

30 Brook Hollow Lane 

West Lafayette, IN 47906 

Tel: 765 583 2530 

Wjh730@comcast.net

Jeffrey K. Kimball 

17636 Wheat Fall Drive 

Derwood, MD 20855 

Tel: 202 694 7181 

jeffreyk@dnfsb.gov

Donald P. Moore 

Consulting Engineer 

Southern Nuclear Operating Company, Inc. 

42 Inverness Center Parkway 

Birmingham, AL 35242 

Office: 205-992-6672 

Fax: 205-992-5145 

dpmoore@southernco.com

Mark D. Petterson 

USGS 

Box 25046, MS 966 DFC 

Denver, CO 80225 

Tel: 303 273 8546 

Fax: 303 273 8600 

mpetterson@usgs.gov

Annie Kammerer 

USNRC 

Washington, DC 20555-0001 

Tel: 301 415 7964 

Annie.kammerer@nrc.gov

Clifford Munson 

USNRC 

Washington, DC 20555-0001 

Tel: 301 415 6947 

Clifford.munson@nrc.gov

Brent J. Gutierrez 

NPH Engineering Manager 

USDOE – SR 

Tel: 803 208 2969 

Fax: 803 208 0343 

Brent.gutierrez@srs.gov

1b
Larence A. Salomone 5/22/08 Attachment 2 

1

Consolidated PPRP Comments on 

DRAFT PROJECT PLAN: CENTRAL AND EASTERN UNITED STATES 

SEISMIC SOURCE CHARACTERIZATION FOR NUCLEAR FACILITIES, REV 

00 04/14/08 

For discussion and resolution at Project Planning Meeting #2, May 8, 2008 

For discussions at the May 8, 2008 EPRI CEUS SSC Project meeting to address the 

PPRP review of the draft Project Plan, non-editorial PPRP review comments that require 

discussion are consolidated in this document. No effort has been made to integrate the 

comments; some address overlapping issues and can be grouped under a single agenda 

item. In addition, some comments go to details of implementation and may more 

appropriately be addressed in the detailed task implementation planning. 

Jon P. Ake, Annie Kammerer, Clifford Munson

NRC staff generally has a positive response to the DPP. However, we do have a few 

specific comments, which are summarized below according to section of the DPP. Some 

high-level concerns we have identified include: 

The ability to fulfill the project objectives with only three workshops, 

The timeline, which seems fairly aggressive, 

The specific roles and responsibilities of the participatory peer review panel 

(PPRP) and the sponsor representatives. In particular the relationship between the 

PPRP, sponsors, and TI team needs to be clarified. 

In general the Project Plan needs more detail if the aggressive timeline laid out is 

to be met. 

The project documentation is to be captured as an EPRI Technical Report, it 

needs to be explicitly stated that this information will be readily available to the 

general public at nominal cost (i.e. for reproduction) or through download at the 

NRC or DOE website.

The makeup of the TI team is entirely industry representatives, some thought 

should be given to the potential addition of an NRC or DOE person to the team. 

Given that the objective of this project is to produce a new seismic source 

characterization model, the role of the ESPs in this project is not clear. The ESPs 

focused on updating or modifying the EPRI-SOG model. 

Executive Summary 

On a philosophical note, the purpose of the project is to produce an up-to-date, 

comprehensive, robust and defensible characterization of seismic sources in the CEUS.

As a result of following a disciplined, structured process (such as that in the SSHAC 

guidelines) we will achieve stability and longevity. However, stability and longevity is 

not the purpose in itself. 

Given that the first meeting of project personnel, the peer review team and project 

sponsors will not occur until May 8th, it seems that scheduling the first workshop in July 

1c
Larence A. Salomone 5/22/08 Attachment 2 

2

is somewhat optimistic. Perhaps more detailed discussion of exactly what needs to be 

done by the time of the meeting would make the basis for this timeline clearer. 

After the review of the draft report by the PPRP it would be appropriate to have a final 

meeting (not necessarily a workshop) to close out any remaining comments from PPRP 

and project staff prior to production of the final report. 

Introduction and Context of Study 

The specification of six sites to be used in the seismic hazard calculations may be 

premature. To fully capture and understand the effects of certain source model 

assumptions or choices it may necessary to evaluate more than six sites. To assess the 

impact of seismicity boundaries and smoothing assumptions it may useful to look at a 

larger number of sites in a small area. 

The discussion in this section (second paragraph on page 3) regarding Mmax leads to 

some questions regarding the conduct of a Level 3 versus Level 4 study. In a Level 4 

study the experts/teams would each develop a distribution for Mmax and by integrating 

across the teams we have a measure of the range of technical interpretations of the 

broader informed community. Achieving that goal in a Level 3 study is somewhat more 

challenging. It appears that achieving the goal of broad community input will be a shared 

responsibility of the participatory peer review panel and TI team. This will lead to 

additional interactions between the PPRP and TI team. It would be beneficial to 

specifically schedule time before each of the workshops for the PPRP to meet and “get on 

the same page” and then to meet and debrief with the TI team immediately after each of 

the workshops. This additional meeting time would be an opportunity to effectively 

maximize the usefulness of participatory peer review. If this work is not performed in a 

thoughtful and thorough way, we will probably not achieve the goal of representing the 

full spectrum of community opinion. 

Objectives 

Please see the comment above regarding the philosophy of study objectives.

The specification of six sites to be chosen from next generation power plants and/or sites 

within the DOE complex for the sensitivity calculations needs to be carefully considered 

and justified.

Selection of SSHAC Study Level 

In the first paragraph, there is discussion of the possibility of specification of lower levels 

of evaluation (SHAC Level 2) for some issues that are not as important. When will the 

importance of issues be defined? It seems like that will be done in Task 4 which should 

be done prior to Task 5 (Workshop #1), which is scheduled for July of 2008. Any 

decision making in this regard should be conducted with input from the PPRP. 

Work Plan 

Task 2: Database Development 
Larence A. Salomone 5/22/08 Attachment 2 

3

Any literature compiled for use by the TI team should also be made available to the 

PPRP, and should ultimately be compiled into a publically available database. 

Task 3: Seismicity Catalog Development 

There is lots of good detailed discussion in this section. In the last bullet it seems an 

assessment of hazard sensitivity to catalog completeness estimates is needed (perhaps this 

will be done in Task 9?). 

Task 4: Assessment of Hazard-Significant Issues 

It is noted that three hypothetical site conditions will be assumed for each demonstration 

site to be evaluated (hard rock, shallow soil, and deep soil). Will these be the same 

conditions and amplification functions used in EPRI-6395 or will new functions be 

developed? If so, when will the PPRP be able to evaluate the choice of properties for the 

profiles?

Task 5: Workshop #1-Significant Issues and Databases 

Please note the comment above regarding the timing of this workshop. It also not clear 

exactly who the resource experts will be and if it is possible to make arrangements (i.e. 

contract or travel or USGS support) to have them participate in a meeting in July. 

Task 6: Workshop #2-Alternative Interpretations 

This is the key task in the project. The objectives for this workshop described in the DPP 

are broad in scope and will be complex. The challenge of evaluating and incorporating 

alternative viewpoints into a hazard model that is flexible and broad enough to 

incorporate the evaluation of alternative conceptual models that might arise at a later date 

will be challenging. It seems that specifying a workshop duration of two days a priori is 

somewhat optimistic. This workshop should be of whatever duration is required to 

explore the reasonable alternative interpretations. 

Task 7: Construct Preliminary SSC Model 

Alternative methods for the assessment of maximum magnitude, such as those used in the 

PEGASOS Project, should also be evaluated. A current project for the evaluation of 

Mmax in the CEUS is being conducted by the USGS with support from the NRC. The 

results of that study should be considered or incorporated in Task #7.

Task 9: Perform Preliminary Hazard Calculations and Sensitivity Analyses 

The DPP suggests that the sensitivity studies will show changes with respect to 

alternative source parameters, smoothing assumptions and relative to the EPRI-SOG 

sources. Since the objective of the project is to develop a SSC model that replaces the 

EPRI-SOG model, we assume this comparison is only of use to illustrate the change in 

hazard due to the evolution in our (the earthquake community) perceptions of hazard. Is 

this correct or is there another reason for this comparison? 

Task 12: Document CEUS SSC Project in Draft Report 

The discussion of the approach for documentation seems sound. Based on our reading of 

this section of the DPP it is not clear how many documents will be prepared. Will there 
Larence A. Salomone 5/22/08 Attachment 2 

4

be a document that summarizes the technical bases for the assessments used in the hazard 

model and a separate Hazard Input Document or a single document? This is important 

from the standpoint of assessing how realistic the schedule and budget is. The 

development of complete and transparent documentation is essential for the longevity of 

the results by allowing for new information to be appropriately assessed. 

Task 13: Review of Draft Report by PPRP 

We assume the meeting described in this section will be between the TI team, PPRP, and 

Sponsor reviewers. What is not defined is when this meeting will take place (we find it 

hard to see from the spreadsheet) and exactly how the incorporation of comments will be 

done. There is a need to define the relationship between the various entities (TI team, 

PPRP, and Sponsor reviewers) and to consider how PPRP and Sponsor reviewer 

comments will be incoroporated. Some thought needs to be given to this beyond the box 

charts shown in Figures 1 and 2. We believe that the Sponsor reviewers should be treated 

as de facto members of the PPRP, in addition to the special responsibilities of 

representing the sponsor agencies.

Task 15: Brief NRC and DNFSB on CEUS SSC Study 

DOE should be explicitly identified in the list of groups to be briefed. 

Task 16: Participatory Peer Review Panel 

Given the significant amount of material that will need to be reviewed and evaluated by 

the PPRP, and the responsibility that the PPRP has to assure that the breadth of the 

informed technical community is represented, it seems meetings of the PPRP beyond 

what is outlined in this section will be needed. This may or may not need to be physical 

meetings in all cases; teleconferences may work for some issues. 

Walter J. Arabasz

1. The Draft Project Plan is well organized and structured—reflecting considerable 

thought and effort. Key information I lack as a reviewer is some indication of the 

qualifications of the individuals or teams or contractors who will perform some of the 

tasks (perhaps outside the scope of desired comment at this point). As an example, will 

some expert(s) in statistics be involved in Task 3 (Seismicity Catalog Development) or 

only seismologists? My confidence in the expected products and their stability and 

longevity depends not only on knowing task breakdowns but also on having some idea of 

who will be doing the work. 

2. Will there be a Web-based resource (possibly managed by the database contractor) 

to facilitate controlled access to basic project information and data—e.g., project 

documents, bibliographic literature, data and/or information products associated with 

relevant data, PowerPoint presentations made at workshops, etc.? Given the complexity 

and duration of the project, participants (including the PPRP) will be able to function far 

more efficiently and incisively if they don’t have to be their own information managers. 

(We’ve all been there!)
Larence A. Salomone 5/22/08 Attachment 2 

5

3. Figure 1: Given the long intervals between the activity points (stars) for the PPRP, I 

suggest there be at least one teleconference, or some other form of communication, for 

the PPRP between each milestone to keep them informed and reasonably engaged. 

Access to a well-designed project Web site would motivate them to stay engaged (even 

on unpaid time).

4. Task 2 (Database Development), page 6: Regarding “available data in the academic 

sector,” expect the usual problem of quality control for data and peer-reviewed status for 

information that may be introduced. Guidelines will likely have to be established by the 

TI team for using unpublished data and information from the academic sector (a 

common source of “red herrings”). 

5. Task 3 (Seismicity Catalog Development), page 8: The task breakdown includes 

tasks that, in my judgment, need to be performed or overseen by one or more experts in 

statistics. The plan importantly states that alternative approaches will be examined for 

the identification of dependent events within the catalog. Various stochastic approaches 

have been developed by statisticians since the work of Veneziano and Van Dyck as part 

of the EPRI-SOG project, so stability and longevity are issues here. Similarly, other 

approaches have subsequently been developed for assessing catalog completeness, 

and alternative approaches should be considered in order to give confidence to other 

practitioners about the stability of results. 

6. Task 7 (Construct Preliminary SSC Model), page 10: Many practitioners in seismic 

source characterization tend not to use terms identical to those defined in Appendix A of 

NRC Regulatory Guide 1.165 (e.g., capable tectonic source, seismogenic source). The 

project may want to consider adopting—or at least incorporating—terms consistent with 

NRC terminology to avoid having to translate later. 

7. Task 7 (Construct Preliminary SSC Model), Earthquake Recurrence, page 11: 

Mention is made of “Where data are available, paleoseismic recurrence will be 

incorporated...” If fault sources are identified, moment balancing may need to be 

considered for fault rupture models.

8. Task 11 (Finalize SSC Model), page 13, paragraph 1: What does it mean that, 

“Alternative models considered will be discussed”? Draft documentation part of this 

task? 

9. Task 12 (Document CEUS SSC Project in Draft Report), page 13: Apart from 

“documentation” of software, are there project requirements for validation or other forms 

of quality control? 

10. Project Organization, page 15: Other than the Database Manager, it’s not clear how 

other Specialty Contractors (mentioned in the Executive Summary) fit into the Project 

Organization.

Brent J. Guetierrez (DOE) 

1. Executive Summary, 2nd paragraph; clarify the overall purpose of the CEUS SSC 

project is in achieving stability and longevity; e.g., in what? Isn’t the real purpose of the 

project to develop a new and updated CEUS SSC model with the benefits of wide 
Larence A. Salomone 5/22/08 Attachment 2 

6

acceptance in the technical community and with sufficient technical robustness that 

affords longevity of the SSC model? 

2. Executive Summary, 2nd paragraph; the sentences defining stability and longevity at 

present appear somewhat incongruous as written. How can you achieve the longevity as 

defined and expect the technical underpinnings to remain valid when new scientific 

findings becomes generally accepted by the technical community? 

3. Page 7, 2nd paragraph; make the copies of the key papers available to the project 

sponsors and agency technical representatives. 

4. Page 7, last paragraph before Task 3 and Page 16, Quality Assurance: This paragraph 

describes the management and documentation of data in accordance with a data 

management procedure, data assessment, and data storage, yet the quality assurance 

“tone” for this project is described as that meeting or exceeding the quality assurance 

associated with publication in a peer reviewed technical journal without being under the 

auspices of a project quality assurance program. Given the apparent vast nature of the 

data to be complied across several existent databases and sources, a more defined quality 

assurance/quality control program should be implemented for this project. 

5. Page 3 and Page 9; on both of these pages reference is made to the NGA East project. 

For completeness, suggest you add additional text describing how the results of the NGA 

East project will be incorporated into this project (as they are available) and what 

potential impacts the results may have on this project. 

William J. Hinze

1. Executive Summary: The two sentences – “Stability means that the study enjoys public 

and regulatory confidence that it is generally accepted by the technical community.

Longevity means that the technical underpinnings will remain valid in the future, despite 

the development of new scientific findings.” - are the lynchpin of the Project Plan. I 

understand the stability issue and this is well documented in the SSHAC report. 

However, I do have concerns about the “longevity” issue. Longevity is an ambiguous 

term. Its meaning will change depending on the user. I find no reference to longevity in 

the SSHAC report. The “experience” that shows longevity is “ ... best achieved...” needs 

to be documented to make this a credible statement. I am concerned that longevity will 

mean to some users of the results of the proposed study that we can anticipate no 

improvements in seismic source characterization in the central and eastern U.S in the 

foreseeable future. This is potentially dangerous because science and databases continue 

to improve. Examples are the perceived need for this study and DOE’s Probabilistic 

Volcanic Hazard Analysis – Update of Yucca Mountain. I suggest that some constraints 

be placed on the longevity issue to clarify its meaning in this context. Furthermore the 

results of Earth Scope studies in the central and eastern US are likely to impact seismic 

source characterization. 

2. Selection of SSHAC Study Level: “Balancing the need for stability and longevity with 

the need to expedite the study, the CEUS SSC project will be conducted using a Study 
Larence A. Salomone 5/22/08 Attachment 2 

7

Level 3 process for the key SSC issues. Lesser emphasis and Level 2 processes will be 

given to those issues having lesser hazard significance or are not subject to large 

uncertainty.” Is it possible that these two criteria may work contrary to each other, i. e., 

some regions of lesser hazard may have a larger uncertainty? Which will take 

precedence? 

Jeffery W. Kimball

1. CEUS SSC Objective: The DPP states that the overall objective of this work is to 

achieve stability and longevity. It is suggested that stability and longevity should be 

desired attributes for the work being performed, but not the objective. The objective of 

the CEUS SSC Project should be to develop an up-to-date assessment of probabilistic 

seismic hazard analysis (PSHA) seismic source characterization for the CEUS that (1) 

includes full assessment and incorporation of uncertainties, (2) appropriately includes the 

range of diverse technical interpretations from the informed scientific community, (3) 

includes consideration of an up-to-date data base, (4) that is properly documented, and 

(5) peer reviewed. If these objectives are achieved then the product (CEUS SSC input) 

should have stability and longevity. 

2. Focus on replacing 1986 EPRI-SOG: In a number of places the DPP speaks to 

replacing the 1986 EPRI-SOG PSHA work. It is not clear why this emphasis is 

necessary. The introduction properly notes that the project will take full advantage of 

data from several seismic hazard studies. If all participants agree that we should work 

towards developing a community based CEUS PSHA, then this effort becomes a key part 

of that goal. If that goal is achieved all users, including critical facility owners, would be 

comfortable with using the results.

3. Role of the United States Geological Survey (USGS): The DPP appropriately includes 

a representative from the USGS on the participatory peer review panel. To work towards 

a community based CEUS PSHA it may be good to add an appropriate USGS person to 

both the TI Team and TI Staff. That would work if the USGS would agree to support the 

time and travel of these people. This would have the added benefit of increasing USGS 

confidence that the CEUS SSC products should become the national map products 

(supporting a community based PSHA). While it is understood that USGS personnel are 

not “officially” representing their agency (neither am I, for example), getting the right 

people throughout the organizational framework of this effort will provide long term 

benefits.

4. SSHAC Level: The DPP states that the higher the Study Level, the higher the 

assurance that the views of the community have been captured and represented. While 

this tends to be true, the intent of the SSHAC guidance report would be to have adequate 

confidence with any Study Level, otherwise how could you support anything less than 

SSHAC Study Level 4? Following SSHAC guidelines, the responsibility for assuring 

that the views of the community have been captured and represented rests with the 

Technical Integrator (TI) or Technical Facilitator/Integrator (TFI). The DPP is based on 

the assumption that an overall SSHAC Study Level 3 is appropriate for this effort, thus 

the overall approach is based on using a TI. As a starting basis this approach is workable, 
Larence A. Salomone 5/22/08 Attachment 2 

8

but this should be confirmed at the end of Task 5, once it is determined which CEUS SSC 

issues are most significant. While all PSHA’s assign an overall SSHAC Study Level to 

the project, the SSHAC guidance can be read as intending that SSHAC Study Levels 

apply to issues, not projects. The DPP recognizes that some issues may be addressed at 

Study Level 2. It may be that certain issues require some aspects of a Study Level 4. 

They key is to manage this appropriately given the available resource and time 

constraints.

5. Task 4 – Assessment of Hazard-Significant Issues: While in concept the completion of 

sensitivity studies on PSHA parameters is an important aspect of assessing the 

significance of PSHA SSC issues, care must be taken to ensure that no bias is introduced 

into this assessment. It is assumed that the purpose of the sensitivity studies will be to 

prioritize PSHA issues, and that the CEUS SSC input will be a “complete” update; not 

relying on existing SSC input from the 1986 EPRI-SOG study. It may be appropriate for 

the TI Team to request that the participatory peer review panel provide their PSHA 

experience in listing those PSHA SSC issues that could be significant. For example, 

experience with CEUS PSHAs would suggest that the following issues may be 

potentially significant. Many of these issues represent state-of-practice advances since 

the EPRI-SOG work.

Potentially Significant CEUS PSHA SSC Issues: 

Relationship between moment magnitude and source dimension such as source 

area or fault length. 

Treating seismic sources as point sources versus extended sources, for both 

specific seismic source zones (such as New Madrid, Charleston), and within 

broader areas of lower seismicity. 

Magnitude distribution approach, such as characteristic magnitude distribution 

versus truncated magnitude distribution. When to use which relationship. 

Magnitudes assigned to earthquakes found via paleoliquefaction evidence. In 

particular, the proper assessment of site response impacts on assignment of 

magnitudes. 

Approach to establishing maximum magnitude for regions of low seismicity. 

The seismic source approach to areas of low seismicity, specifically defined 

source zones versus use of smoothed seismicity. 

Approach to modeling faults for well defined source zones such as New Madrid 

and Charleston. Should faults be oriented randomly, or with specific 

orientations?

6. Project Documentation: The DPP could be improved in terms of listing expected 

documentation for each of the tasks and/or expected from project participants. In terms 

of the participatory peer review panel, will it operate as a unit, with written comments 

provided from the panel as a whole? 

Donald P. Moore
Larence A. Salomone 5/22/08 Attachment 2 

9

I have reviewed the draft project plan and find it to be an excellent document that 

provides sufficient detail of the tasks required. As a SSHAC Level 3 effort and issues 

related to QA I think it is very important to retain complete documentation of all tasks 

and interactions that will form the basis for the new seismic source characterization. Also 

this documentation should be stored in a controlled fashion to allow easy recover of 

information. Possiblely a procedure could be developed for this purpose. 

Mark D. Petterson

The U.S. Geological Survey recently completed a national seismic hazard model 

considering many of the Central and Eastern U.S. hazard issues that will be discussed by 

the TI team. There has been some discussion about whether or not the USGS should 

participate on the TI team. After internal discussions, we feel that we should not be 

involved as technical integrators because of a perceived conflict of interest. The plan 

needs to make it clear that my participation on the review panel does not imply an 

endorsement by the USGS. I plan to contribute as an advisor to the NRC in reviewing 

this new source characterization. 

The success of this project will depend on new databases of input data (e.g., moment 

magnitude catalogs, magnitude uncertainty and round-off estimates, liquefaction data, 

etc.); as well as objective and reproducible assessments of earthquake sources, rates, and 

magnitudes. We expect that all of this will be open to the public. 

Section Objectives page 4 states: “the use of an appropriate ground motion model, which 

will be held constant” to isolate the relative importance of SSC issues will be required. 

Recent ground models vary by a factor of two between median ground motions for most 

magnitudes and distances. It seems like you may want to apply two equations that span 

the epistemic uncertainty within the relations. 

Task 2: Database Development 

The list of datasets should also include : 

(1) the liquefaction dates from published literature. This is the basis for the recurrence 

models of the Wabash zone, New Madrid zone, and Charleston zones. 

(2) Reflection data in localized or regional areas such as Charleston SC where the data 

indicated folded Miocene strata in the offshore region, Helena Banks fault zone. 

(3) Bob Hermann’s catalog of regional earthquakes and the CMT catalogs that include 

moment calculations (to make the conversion between mblg and Mw – Task 3). 

Task 7: Construct Preliminary SSC Model 

Spatial distribution: I was confused by the meaning of item 2) identification of alternative 
Larence A. Salomone 5/22/08 Attachment 2 

10

conceptual models regarding spatial distribution and assignment of weights to the 

alternatives. How will zones be delineated? 

Maximum magnitude Assessment: I am confused by the Baysian estimation procedure 

(i.e., how the prior distribution is obtained and how the short catalog gives information 

that can update the maximum magnitude prior distribution. Are other models going to be 

considered? 

Earthquake Recurrence: I was confused by the statement that these codes will be updated 

to produce a- and b-values on a finer grid and in low historical activity rates. What 

methods will be used to determine rates? 
CEUS SSC_PPRP #2_final 

August 15, 2008 Via e-mail 

Lawrence A. Salomone 

Washington Savannah River Company 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities: Participatory Peer Review Report on Workshop No. 1. 

Acronyms

CEUS Central and Eastern United States 

COLA Combined Operating License Application 

EPRI Electric Power Research Institute 

PPRP Participatory Peer Review Panel 

PSHA Probabilistic Seismic Hazard Analysis 

SOG Seismicity Owners Group 

SSC Seismic Source Characterization 

SSHAC Senior Seismic Hazard Analysis Committee 

TI Technical Integrator 

USGS U.S. Geological Survey 

This letter constitutes the report of the Participatory Peer Review Panel on Workshop 

No. 1 (WS-1), “Significant Issues and Databases,” for the referenced project. The 

workshop was held July 22–23, 2008, at EPRI headquarters in Palo Alto, California.

Following guidance described in the implementation plan for the PPRP1

, and consistent 

with the expectations of the SSHAC process2, the PPRP participated in WS-1 in order to 

be informed and to review both procedural and technical aspects of the workshop. 

Five members of the PPRP (J. Ake , W. Arabasz, W. Hinze, A. Kammerer, and D. Moore) 

and one of the Sponsor Representatives (C. Munson) attended WS-1 and were able to fully 

observe all aspects of the workshop. The other three PPRP members (J. Kimball, 

M. Petersen, and C. Stepp) and the other Sponsor Representative (B. Gutierrez) were 

subsequently provided with electronic copies of all presentations made at WS-1. 

1 Implementation of the PPRP’s Participation in the CEUS SSC Project: Written statement 

communicated by J. Carl Stepp to L. Salomone and the TI Team on June 16, 2008. 

2

 Budnitz, R. J., G. Apostolakis, D. M. Boore, L. S. Cluff, K. J. Coppersmith, C. A. 

Cornell, and P. A. Morris, 1997. Recommendations for Probabilistic Seismic Hazard 

Analysis: Guidance on Uncertainty and Use of Experts. NUREG/CR-6372, Washington, 

DC, U.S. Nuclear Regulatory Commission.

2a
Lawrence A. Salomone 2 August 15, 2008 

Based on our observations we offer the following comments and recommendations: 

1. Basic goals of workshop — Under the pressure of an aggressive schedule, the 

Management and TI teams (hereafter “Project Team”) organized a successful 

workshop that achieved many of the basic goals of WS-1. The TI Team effectively 

framed the CEUS SSC project and gave useful, informative introductory overviews 

to the project participants. Results of detailed sensitivity analyses were presented 

that provide a sound basis for initiating the identification and evaluation of issues 

that will be of primary significance to the SSC project. The resource experts that 

were convened described and discussed diverse databases pertinent to the 

assessments required for development of a CEUS SSC model, and they generated 

productive discussions. 

We concur in general with the important seismic hazard issues identified in the 

presentation on sensitivity results. However, evaluating these requires some 

fundamental considerations such as those elaborated in Item #3, below. These 

include a state-of-knowledge understanding of the mechanisms involved in 

earthquake occurrence in the CEUS, the definition of earthquake sources, the 

assessment of maximum earthquake magnitude, and the characterization of the 

New Madrid and Charleston seismic zones.3

While the resource experts did a high-quality job of describing data sets, the 

uncertainty in the data sets was not generally described. Uncertainty involving 

both quality and quantity of data—including non-uniqueness of interpretation—is 

fundamentally important for assessing a SSC model, both for evaluating 

alternatives and for considering the longevity of the results of the study. Future 

improvements in the quantity and quality of the data being used in the analysis may 

have an important effect on uncertainty and thus the stability of seismic hazard 

assessment. Evaluation and understanding of the present uncertainty in the data 

sets should be a key element of the assessment. In order to fully address this 

important need, we recommend that the TI Team continue to interact with the data 

resource experts to evaluate the uncertainty in their data. In this connection, we 

emphasize the importance of obtaining germane reference lists from the resource 

experts.

2. How will data sets be used? — As the workshop unfolded, the tight schedule 

resulted in decoupling two aspects that were intended to be more integrated. The 

stated goal of WS-1 was “to identify the issues of highest significance to a SSC 

model for the CEUS and to identify the data and information that will be required 

3

 The considerations referred to in this paragraph were originally described in a 

memorandum from the PPRP to the Project Manager and the TI Team on June 3, 2008 to 

aid in planning WS-1. The memorandum was accompanied by elaborations on key issues 

for the CEUS SSC written by three individual PPRP members. We include a copy of these 

materials here as Attachment A, which serves simply as an information item and for useful 

documentation. 
Lawrence A. Salomone 3 August 15, 2008 

to address those issues.”4

 The parts were presented, but the whole was not 

developed to the extent that it was clear how the data sets described and discussed, 

other than the earthquake catalog, will be used by the TI Team in assessing the SSC 

model. We recognize that evaluation and use of diverse databases will be the focus 

of efforts by the TI Team before Workshop #2, but we are concerned whether the 

schedule for data compilation will fully support these efforts. 

We note the following potential scheduling conflicts and issues: 

The schedule for the project specifies that a preliminary SSC model be 

completed over the period December 2008 to August 2009. However, the 

data sets, including the earthquake catalog, that will be used to evaluate and 

assess sources are not scheduled to be completed until June 2009. We 

recommend prioritizing this work element to ensure that the critical data 

sets are completed early so that the assessment is not left until the final two 

months of the assessment effort.

Use of the data sets would be very much enhanced if the quality and 

quantity of the data over the CEUS could be identified in the data maps and 

within the data sets and if the information is clearly documented. This 

concern arises because of the highly variable nature of data quality and 

quantity over the CEUS. Further, documentation of the quality of any data 

incorporated into the SSC will ultimately be a requisite for this and future 

PSHAs.

A comprehensive data set of seismic reflection profiling over the CEUS was 

not presented at the Workshop, and it is not clear that procedures are in 

place to identify relevant seismic reflection profiles and to make them 

available to the project. A number of important reflection profiles, either 

acquired from industry or conducted by academic institutions, have been 

interpreted in terms of crustal structure and tectonic elements relevant to the 

CEUS SSC. Interpretations of these data that are in the public domain are 

spread throughout the geoscience literature. In view of the potential 

significance of the information from the seismic reflection profiles, not only 

for identifying seismic source zones and their properties but also for 

evaluating competing tectonic models, we recommend that interpretations 

of relevant seismic reflection profiles over the CEUS that are in the public 

domain be compiled for use in the project.

Experience from past projects shows that unless the scientific utility of diverse data 

sets is thought through at an early stage, the default will be heavy reliance on 

historical and instrumental seismicity. The issue of stationarity must be 

addressed—while keeping in mind that an implicit goal of the project is to achieve 

a good predictor of seismicity for the next 50 years. 

4

 Task 5: Workshop #1 Significant Issues and Databases, Project Plan: Central and 

Eastern United States Seismic Source Characterization for Nuclear Facilities, EPRI, June 

2008, p. 4-4. 
Lawrence A. Salomone 4 August 15, 2008 

3. Identifying key SSC issues and alternative viewpoints — The PPRP recognizes the 

difficulty of identifying the SSC issues and relevant alternative interpretations that 

will be central to achieving the goals of Workshop #2 (WS-2). We recommend that 

the TI Team initiate identification and evaluation of these issues and interpretations

as early as possible—to allow time for their full consideration prior to WS-2 and to 

ensure completeness vis-à-vis the diversity of views within the informed technical 

community. To this end, the PPRP has identified some key issues that should be 

considered when preparing for WS-2; these are listed below. 

Seismotectonic Model — A fundamental requirement for the CEUS SSC is 

a state-of-knowledge understanding of the tectonic mechanisms (i.e., 

processes that explain the occurrence of earthquakes in time and space) 

involved in the occurrence of earthquakes within the study region.

Important issues related to elements of the model would include: (1) the 

origin, direction, and strength of ambient stress; (2) the potential influence 

of variations in tectonic structure and crustal material properties on 

variations in the stress field; (3) the time-frame over which the stress field 

can be considered stationary; (4) the current knowledge base for age of 

tectonic faulting and for the correlation of age of tectonic faulting with 

tectonic domains and tectonic history; and (5) properties of the intermediate 

crust at depths where most earthquakes nucleate and the spatial correlation 

of these properties with historic and instrumental seismicity. 

Definition of Earthquake Sources — A systematic approach and 

procedure for defining earthquake sources would contribute to the 

consistency and transparency of the assessment. A transparent approach 

would be to develop a matrix of criteria that would be used to perform a 

weighted integrated assessment of the state of knowledge. This would 

apply to observed tectonic structures and tectonic structure domains, 

knowledge about the age of tectonic faulting, knowledge about the material 

properties of the crust, and knowledge about seismicity rates. All of this 

would be in the context of the seismotectonic model used for defining and 

characterizing tectonic structure-specific sources, area tectonic domain 

sources, and tectonic-based background sources.

Approach to Establishing Earthquake Rates Using Smoothed 

Seismicity — For a trial area source zone it may be useful to compare 

results using the USGS approach to smoothing seismicity (for the U.S. 

National Seismic Hazard Maps) versus the smoothing options used in the 

EPRI-SOG project5

. Such a comparison could help in understanding 

5 Seismic Hazard Methodology for the Central and Eastern United States, 10 Volumes, 

EPRI NP-4726, July 1986. 
Lawrence A. Salomone 5 August 15, 2008 

differences between the two approaches and in establishing a suitable basis 

for assessing use of the two approaches in the current study.

Assessment of Maximum Earthquake Magnitude — An approach is 

needed for assessing maximum magnitudes for earthquake sources that 

takes into account current knowledge and uses systematic procedures for 

assessing maximum magnitude based on the tectonic characteristics of an 

earthquake source—whether a structure-specific source, an area source, or a 

background source. 

Characterization of New Madrid and Charleston Seismic Zones —

A fundamental issue relates to the interpreted repeat occurrence within the 

past few thousand years of large earthquakes in the CEUS (specifically, 

earthquakes associated with the New Madrid and Charleston seismic 

zones)—without evidence of substantial deformation in the near-surface 

rocks during post-Cretaceous time. The body of observed data and 

information (paleo-liquefaction mapping and interpretations) that form the 

basis for these interpreted repeat earthquakes should be critically evaluated.

Also, the uncertainties in both the observations and interpretations need to 

be thoroughly understood. Further, interpretations of these data that 

postulate localized high rates of seismic strain release within the recent 

past—without observed significant surface deformation—require 

explanation in the context of a viable tectonic model. 

We consider a comprehensive implementation of this step of the SSC assessment to 

be central and essential in order to achieve the shared goals of the Project Team and 

the Project Sponsors for (a) the stability of the SSC assessment and (b) its desired 

broad use into the future. Because of the key importance of WS-2, we recommend 

that the Project Team actively engage the PPRP in reviewing and commenting on 

the planning of WS-2 and in the development of the workshop agenda. 

4. Longevity of the SSC and ability to update it in the future — In the Project Plan, 

longevity was defined to mean “that the technical underpinnings will remain valid 

in the future, despite the development of new scientific findings.” Anticipating 

industry and regulatory needs, the PPRP urges careful attention to two aspects of 

the SSC process: (1) that there be transparency in the SSC model, the technical 

bases of the SSC model, the related uncertainties, and the SSC process—so that the 

resulting product can readily be updated in the future and (2) that front-end 

decisions not compromise the usefulness of the SSC product in the future.

To explain what we mean by the second statement, consider the working criterion 

suggested at WS-1 to define a threshold of significance in the sensitivity analyses 

(namely, a specific percentage change in hazard). While such an approach is useful 

in focusing attention on what is important, we want to ensure that such a cutoff 

does not curtail analysis or documentation that may be important later. An 

example might be the elimination of logic-tree branches with an assigned low 

weighting (at this time). When users in the future ask how the SSC team would 
Lawrence A. Salomone 6 August 15, 2008 

have treated a particular new development, the question should be answerable from 

the documentation of the CEUS SSC project. 

5. Six test sites for hazard calculations — The PPRP believes that the six (or more) 

test sites to be selected for hazard calculations as part of the CEUS SSC project 

(Project Tasks 4 and 9) will be fundamentally important to the success of the 

project, both scientifically and vis-à-vis stakeholder interests. Accordingly, the 

PPRP has an ongoing interest in learning more about how the test sites will be 

selected and how hazard calculations at the selected sites will guide future stages of 

the project. The selection of sites can usefully be used “to challenge the process” 

of the SSC modeling, and it can test the influence of major seismic sources outside 

the study area. 

We note that the Project Plan called for the selection of six test sites (under Task 4) 

prior to WS-1 for sensitivity studies to assess key SSC issues, but this was not 

accomplished. Instead, sensitivity calculations were presented for a group of sites 

(“Group A sites”) extending along a line roughly transverse to a major line source 

and for another group of sites (“Group B sites”) at differing distances from a major 

areal source. 

 Insofar as the planned test sites (a) have not yet been selected and (b) apparently 

will play an important role later in the SSC process, the criteria for site selection 

will be of great interest to the PPRP beyond the example given in the Project Plan. 

We note that in the discussion of the test site selection in the Project Plan (see

p. 4-4) the provision is made that the sites should be “as generic as possible.”

We recommend that the sites should be representative of the range of 

seismogenesis over the region of applicability of the CEUS SSC model.

6. Applicable study region — The CEUS SSC model assessed in this study will be 

used for developing site-specific PSHAs for sites within the United States eastward 

of the Rocky Mountains. Regarding database coverage, the Project Plan issued in 

June 2008 (p. 4-1) states: 

“The database will be designed to include the following regional data 

layers to provide coverage of the entire CEUS and extend a minimum of 

200 miles beyond the coastline (or the edge of the continental slope if it 

is less) and 200 miles from the US borders with Canada and Mexico.

The western boundary of the study region will be the foothills of the 

Rocky Mountains (about longitude 105 W), except that it will include 

the Rio Grande Rift system . . .” 

We observe that various discussions during WS-1 touched on the potential 

importance of large magnitude sources distant from a site, which might include, for 

example, seismic sources in the Caribbean or Canada beyond the planned 200-mile 

limit. Thus, in considering scoping issues for database and SSC coverage, the 

Project Team needs to be mindful of limitations that may result in the applicability 

of the project’s products for future siting in some parts of the CEUS. Recent 

COLA applications regarding geographic areas of potential interest for future siting 
Lawrence A. Salomone 7 August 15, 2008 

(e.g., Texas, Florida) and appropriate interactions with industry sponsors can help 

inform the decision-making about geographic scoping.

These observations and recommendations are our primary ones at this time. We thank you 

for facilitating our participation in WS-1 and for the opportunities to pursue discussions 

with you and other members of the Project Team. 

 Do not hesitate to contact us if you wish to discuss any of our observations and comments. 

 Sincerely, 

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801 581 7410 830 833 5446 

arabasz@seis.utah.edu cstepp@moment.net 

Attachment: Copy of memo (with three enclosures) from PPRP to L Salomone, 

K. Coppersmith, and TI Team, communicated by e-mail on June 3, 2008 

Copy:

PPRP Members 

Sponsor Representatives 
ATTACHMENT A 

To: Lawrence Salomone [Via e-mail on June 3, 2008] 

 Kevin Coppersmith 

 CEUS SSC Project TI Team 

From: CEUS SSC Project PPRP

Subject: Key Issues for CEUS SSC Relevant to Workshop #1 

By this memorandum we are transmitting the PPRP’s identification of some key tectonic 

and data evaluation issues for assessment of a seismic source model for the Central and 

Eastern United States. The intent is to aid the Project TI Team in planning Workshop #1. 

PPRP members in their informed resource expert role identified the key tectonic and data 

evaluation issues summarized in this memorandum. Thus, at this point the items herein 

represent thoughtful views rather than prescriptive recommendations by the PPRP. Some 

elaborations of individual PPRP members’ inputs are enclosed. 

Seismotectonic Model – A state-of-knowledge understanding of the mechanisms 

[processes that explain the occurrence of earthquakes in time and space] involved in the 

occurrence of earthquakes within the study region is a fundamental requirement for the 

assessment and characterization of seismic sources. Important issues related to elements 

of the model include: 

• The origin, direction, and strength of ambient stress, 

• The potential influence of variations in tectonic structure and crustal material 

 properties on variations in the stress field, 

• The time-frame over which the stress field can be considered stationary,

• Current knowledge base for age of tectonic faulting and the correlation of age of 

 tectonic faulting with tectonic domains and tectonic history, and

• Properties of the intermediate crust at depths where most earthquakes nucleate 

 and the spatial correlation with historic and instrumental seismicity. 

Definition of Earthquake Sources – A systematic approach and procedure for defining 

earthquake sources would contribute to the consistency and transparency of the 

assessment. An optimum approach would be to develop a matrix of criteria that would be 

used to perform a weighted integrated assessment of the state of knowledge regarding 

observed tectonic structures, tectonic structure domains, knowledge about the age of 

tectonic faulting, knowledge about the material properties of the crust, and knowledge 

about seismicity rates in the context of the seismotectonic model for defining and 

characterizing tectonic structure-specific sources, area tectonic domain sources, and 

tectonic based background sources.

For both the development of a state of knowledge seismotectonic model for the study 

region and for the assessment of earthquake sources, the vertical and horizontal 

resolution of gravity and magnetic anomaly data for the CEUS is an important issue. 

These data are particularly important for evaluating the material properties of the crust 

and for determining the depth extent of tectonic features. 

2b
Salomone, et al. 2 6/3/08 

Assessment of Maximum Earthquake Magnitude – The approach to assessing 

maximum magnitudes for earthquake sources is perceived to be a significant issue. 

Development of current knowledge together with systematic procedures for assessing 

maximum magnitude based on tectonic characteristics of an earthquake source [structurespecific source, area source, or background source] are needed. 

Characterization of New Madrid and Charleston Seismic Zones – A fundamental 

issue relates to the interpreted repeat occurrence of large earthquakes in the CEUS 

[specifically, associated with the New Madrid and Charleston seismic zones] within the 

past few thousand years without evidence of substantial deformation in post-Cretaceous 

time in the near-surface rocks. The body of observed data and interpretations 

[paleoliquefaction mapping and interpretations] that form the basis for these 

interpretations should be critically evaluated. A thorough understanding of the 

uncertainty in both the observations and interpretations is perceived to be a fundamental 

requirement. Equally importantly, interpretations of these data that postulate localized 

high rates of seismic strain release within the recent past in the absence of observed 

significant deformation require explanation in the context of a viable tectonic model. 

Enclosures

1. William J. Hinze elaborated inputs 

2. Jeffrey K. Kimball elaborated input 

3. Jon P. Ake elaborated input
Salomone, et al. 6/3/08 Enclosure 1 

1

To: Carl Stepp, Walter Arbasz; PPRP 

From: William J. Hinze 

Subject: Hazard-Significant Seismic Site Characterization Issues 

Date: May 29, 2008 

The following outlines some thoughts on the hazard-significant seismic site 

characterization issues that may be considered during Workshop #1 of the CEUS SSC. 

The list is exclusive of consideration of the study’s seismicity catalog and ground motion 

considerations.

The list includes issues of varying importance and level of detail. No attempt has been 

made to establish a priority ranking. Some are described as statements while others are 

more definitively considered as questions.

There are a variety of ways to subdivide the issues. I have chosen a four-fold division of 

Earthquake Mechanisms, Earthquake Stresses, Earthquake Sources, and Earthquake

Parameters. Mechanism concerns potential processes leading to the origin of 

earthquakes, stresses involves the nature and origin of stresses that cause the structural 

development of the crust leading to earthquakes, sources considers the identification and 

bounding of local and regional seismic sources, and parameters relates to characteristics 

of the earthquakes in the identified seismic sources. 

Earthquake Mechanisms – As in other intraplate terranes the mechanisms involved in 

the origin of earthquakes in the CEUS are not well known. Nonetheless numerous 

mechanisms have been suggested and considered in seismic hazard analysis (20 were 

identified in the EPRI/SOG study). They are generally based on spatial or temporal 

variations in prevailing stress field or spatial changes in the strength of the brittle crust. It 

is not necessary to establish the mechanism for earthquakes of the CEUS to perform a 

seismic hazard analysis, but the results of the analysis are much more credible and thus 

more stable when mechanisms for the activity can be identified. 

Numerous mechanisms have been identified for the origin of earthquakes in 

the CEUS including zones of weakness (e.g., tectonic faults, ancient plate 

boundaries, meteorite impact sites); inhomogeneities in crustal lithology; stress 

concentrations due to storage of strain energy associated with fault offsets or 

curvature, localized intrusions of the crust, and variations in crustal 

composition, thickness, and temperature; and elastic rebound of the 

lithosphere. The credibility of proposed earthquake mechanisms for intraplate 

earthquakes in the CEUS needs study and analysis. 

A fundamental issue relates to the occurrence of major earthquakes in the 

CEUS within the past few thousand years without evidence for substantial 

deformation in post-Cretaceous time in the topography and near-surface rocks 

of the region. This paradox should be evaluated considering for example that 

the major earthquake activity is very young, is episodic with recurrence times 

measured in tens or hundreds of million years, migrates over broad regions of 

the CEUS, or is mechanically decoupled from the observed surface 

sedimentary rocks. 
Salomone, et al. 6/3/08 Enclosure 1 

2

Another issue relating to earthquake mechanisms is the manner in which the 

mechanisms vary with spatial scales, magnitude, foci depth, etc. 

Earthquake Stresses – Understanding the origin, direction, and strength of ambient 

stresses that cause strain leading to earthquake activity is important to the credibility and 

stability of seismic hazard analysis. Issues that relate to earthquake stresses in the CEUS 

include:

The origin of stresses observed in the CEUS was largely related to ridge-push 

tectonic forces in the 1980’s seismic hazard analysis. The importance of 

these forces is now open to question. Thus it is important to consider the 

origin of these forces and the resulting implications to seismic hazard 

analysis of the CEUS. 

Measurements of the azimuth of the observed stress field vary somewhat 

over the CEUS. The source of these variations should be considered. They 

may vary simply due to errors in measurement, but they may also have other 

origins including stress deflections as a result of local geologic structure and 

lithology and depth and stresses of local origin. 

Temporal changes in stress may take place at a range of time scales. Changes 

may occur in periods of thousands to hundreds of thousands of years due to 

elastic rebound of the earth due to Pleistocene glaciations and deglaciation 

especially in the northern part of the CEUS and loading of the crust by 

sediment concentrations in deltas at the shoreline of the continent or at time 

scales of minutes or hours due to the passage of seismic waves. The latter 

“far-field” triggering of earthquake activity with major earthquakes has been 

noted in recent years and should be evaluated in the CEUS. 

If major seismicity migrates over the CEUS the current seismic activity in 

some regions may simply be due to aftershocks. Thus it should be of interest 

to determine whether earthquakes in these regions, e.g., the New Madrid 

seismic zone, are Poissonian in nature or follow the aftershock law. 

Earthquake Sources – A significant amount of effort has been put into identifying and 

bounding the seismic zones of the CEUS by mapping historical and pre-historical 

earthquake epicenters. These zones can be classified as either local or regional.

Local seismic zones (special seismic zones of the USGS) are restricted to a limited 

geographic region that has been the subject of relatively intense seismic activity in 

historic time. They are not related to the magnitude of the observed earthquakes. 

Generally they are marked by occurrence of relatively low magnitude earthquakes (< 5), 

but others such as the New Madrid seismic zone and the Charleston (SC) zone are noted 

for infrequent (order of hundreds to thousands of years) high magnitude earthquake(s) of 

the order of 7 and frequent smaller magnitude quakes. Analyses of the geology, 

geophysics, and Seismicity of these zones attempt to identify a source structure 

controlling the extent of the zone and its characteristic earthquakes. 

Regional earthquake zones (seismotectonic zones or uniform background zones of the 

USGS) are broad expanses of the CEUS that are subject to infrequent, widely dispersed 
Salomone, et al. 6/3/08 Enclosure 1 

3

earthquake activity that have magnitudes commonly less than 5. They are not identified 

with any particular local structure but may be related to a specific crustal terrane based on 

age, tectonic history, and structure and composition. Identification of local and regional 

seismic zones leads to the following issue questions: 

What criteria identify local and regional seismic zones and their geographic 

limits? 

Seismic source zones are volumes rather than an area as depicted in surface maps. 

Accordingly surface geology, seismic activity, and geophysical data are used to 

define the character of source zones at depth. Geophysics is the primary 

investigative tool because of the paucity of earthquake data and the limited 

information derived from surface geology. As a result a significant issue is the 

resolution, both vertical and horizontal of geophysical methods, particularly of the 

extensively used regional gravity and magnetic anomaly data of the CEUS. This 

is particularly important in evaluating the ability to obtain information on the 

depth extent and surface area of fault faces. 

What is the significance of deep crustal expression in identifying seismic zones 

and their characteristics? 

Is the continental/oceanic transition (boundary) zone in both the Atlantic Ocean 

and the Gulf of Mexico a seismic zone? 

Smoothing of seismic source zones can be used to recognize that the specific 

boundaries of zones are seldom known to a high degree of accuracy because of 

insufficient information or inadequate resolution of the methodologies used to 

define them. Should smoothing be used and if so what criteria should be used to 

define the smoothing method? 

Although more is known about the New Madrid seismic source zone than any 

other seismic zone in the CEUS, several issues remain concerning its potential 

seismic hazard. For example, what is the origin of the zone of diffuse epicenters 

that is separated from but parallels the Reelfoot rift to the northwest? Why is there 

no such similar zone to the southeast? What is the origin and seismic hazard 

significance of linear trends of epicenters that parallel the Reelfoot rift north of 

the main seismic flux? Why does the axis of the rift have more seismic activity 

than the bounding fault margins? 

Should crustal structures that are potential zones of weakness oriented favorably 

for reactivation in the current regional stress field be identified as seismic source 

zones even if they have little or no record of historical or pre-historical earthquake 

activity? This should include basement structures that have been reactivated in 

Phanerozoic time as evidenced in sedimentary structures. 

Identified continental rifts that show evidence of tectonic activity in Mesozoic era 

to recent times are the source of roughly one-half the historical earthquake 

activity in the CEUS. What differentiates these rifts from older rifts as local 

seismic source zones? 

Are cross-structures to rifts capable of mechanically decoupling rifts so that local 

seismic zones can be restricted to only a portion of the rift bounded by the cross 

structure? Related to this is the question of the extension of the New Madrid 

seismic zone into the Wabash River Valley seismic zone. 
Salomone, et al. 6/3/08 Enclosure 1 

4

What establishes the potential seismicity of ancient (Precambrian faults) that are 

oriented favorably for reactivation in the current stress field? 

Should similar crustal geological features that are recognized in geophysical and 

geological data and that are roughly oriented in the same azimuth be considered a 

similar seismic hazard regardless of the historical seismic record? Are differences 

in the historical seismic record of these features simply a result of low Seismicity 

and long recurrence periods? 

Earthquake Parameters of Local and Regional Seismic Zones –

The more active seismic zones of the CEUS provide useful information on the earthquake 

characteristics of the region. However, the low seismic flux limits this information 

leading to several important issues regarding the credibility of predicted earthquake 

parameters. These issues include the following: 

Aftershock sequences are observed following some of the more major 

earthquakes in the CEUS, the nature of these sequences can provide important 

information on the nature of the sources and the seismic strain. 

The temporal pattern of earthquakes of varying magnitude in a seismic zone 

are important to defining recurrence intervals and can be useful in defining 

maximum magnitudes anticipated in the zone. These patterns require definition 

and are particularly important in identifying the maximum magnitudes of 

earthquakes in zones. The problem of maximum magnitude is especially 

problematic in regional seismic zones. 

Pre-historical earthquakes identified by paleoseismology techniques have an 

important role in assessing the seismic hazard of the CEUS. However, there 

are numerous problems associated with the use of paleoliquefaction features 

including their recognition as associated with a particular earthquake event and 

calibrating them to the magnitude of the event. 

Earthquake wave attenuation is generally assumed to be constant over the 

CEUS. However, there are significant variations in crustal thickness, 

composition, and structure over this region and seismic anisotropy exists. As a 

result attenuation of seismic energy may vary across the area. 

“Slow” earthquakes are now identified in some regions. Do these occur in 

intraplate regions such as the CEUS and if so what are their impact on seismic 

hazards and what are their relation to ordinary earthquakes? 

Earthquake foci over the CEUS are at depths not exceeding a few tens of 

kilometers. Is the depth of foci an important parameter in identifying the origin 

of earthquakes and identifying seismic zones and their potential hazard? 
Salomone, et al. 6/3/08 Enclosure 1 

5

Excerpts from Memo by Bill Hinze to PPRP Dated May 12, 2008 

Relevant to Planning of CEUS SSC Workshop #1 

Upon reflecting on issues and discussions at the CEUS SSC meeting on May 8, 2008 I 

have had some thoughts that I wish to share with Panel. Most of them are a result of 

asking myself how the credibility of the results of the study can be increased. . . 

Data needs and related resource experts. 

The 300 km rind of data surrounding the study area should include the 

area to the west and south of 105o W. This includes a seismically active 

region of for example the Rio Grande rift, the Rocky Mountain front, and 

northwestern Mexico. These will become more important in the future to 

central US nuclear facilities. 

The resource experts that will be invited to Workshop #1should be 

encouraged to discuss the metadata for the germane data sets, but they 

should also be encouraged to identify where appropriate the types of 

geologic sources that are portrayed in the data sets with examples, the 

horizontal and vertical resolution of the data, precision and accuracy, and 

the limitations of the data set. If possible they should also discuss 

competing data sets and their relative merits. 

There are several other data sets that should be made available to the TI 

team in addition to those listed in the draft plan. These should include 

derived data sets which emphasize particular attributes of the data. A map 

should be furnished with the location of crustal refraction and reflection 

profiles including those in the 320 km rind in Canada. The deep seismic 

reflection profiles will be more of a problem than the refraction profiles 

but review of COCORP, GLIMPCE, USGS, etc. data sets should capture 

the vast majority of the available profiles. These profiles that were 

generally not available at the time of the EPRI SOG study should be most 

useful in defining and characterizing seismic source zones. Note that 

current gas exploration renaissance in the Appalachian Mountains includes 

new reflection profiling that could be valuable to the SSC if they were 

available for the public sector. 

I learned . . . at the May 8th meeting that GPS data are not to be included in 

the data available to the TI team. . . . Neglecting [GPS] data at least to the 

point of evaluating their precision is a potentially serious error that will 

decrease the credibility of the findings of the SSC. 

It is likely in the analysis of data that there may be the need for additional 

data sets that will assist in interpretation and analysis beyond those 

identified prior to the study. Minimal resources should be made for adding 

a few additional data sets during the progress of the study. 

Mapping of prehistoric earthquakes by paleoliquefaction data is an 

important component of the SSC study. However, mapping of 
Salomone, et al. 6/3/08 Enclosure 1 

6

paleoliquefaction features should also include maps which show stream 

valleys, etc. that have been mapped and show no liquefaction features 

although the surface materials are amenable to paleoliquefaction. Negative 

evidence is important as well as positive evidence in this situation. 

We were told at the May 8th meeting that no data would be assembled for 

higher resolution studies within the 40 km range around the sites selected 

for intensive analysis. Yet the reflection data within these regions would 

be used where available. Experience suggests that interpretation of seismic 

reflection profiles are enhanced, often significantly, by being integrated 

with potential field and other geophysical data. I suggest that the decision 

regarding the omission of higher resolution data in the specific study areas 

be reconsidered. Use of these data where available will decrease 

uncertainties. 

Unless stratigraphic studies of the sedimentary formations of the CEUS 

can be shown to be important to seismic properties (e.g., attenuation) there 

is no apparent compelling reason for exerting a good deal of effort on 

these studies. 
Salomone, et al. 6/3/08 Enclosure 2 

1

Key Issues That Require Evaluation for Assessment of the CEUS

Seismic Source Model as Input for Planning Workshop #1 

Jeff Kimball, May 29, 2008 

The issues are listed followed by a table which could be used to cross link the issues to the database.

While I have not attempted to comprehensively fill out the table, review of the issues indicates that 

database focus may need to be adjusted to include more focus on paleoliquefaction data and seismic 

source dimension data {source inversions, stress drop}. 

High Priority Seismic Source Issues: 

1. Relationship between moment magnitude and source dimension such as source area or fault 

length.

2. Treating seismic sources as point sources versus extended sources. Needs consistency with 

ground motion modeling; larger {M>6} events should be treated as extended sources. 

3. Seismic source approach to areas of low seismicity. Should large “open” sources be considered 

{extended margin, craton}? 

4. Magnitude distribution approach, such as characteristic magnitude distribution versus truncated 

exponential magnitude distribution; when to use which approach. 

5. Magnitudes assigned to earthquakes found via paleoliquefaction evidence. 

6. Approach to establishing maximum magnitude for regions of low seismicity. 

Other Seismic Source Issues: 

1. New Madrid – source boundaries, approach to modeling faults, fault orientation. 

2. New Madrid – assessing uncertainty in timing of paleoearthquakes. 

3. Charleston – source boundaries, approach to modeling faults, fault orientation. 

4. Charleston – assessing uncertainty in timing of paleoearthquakes. 

5. Wabash Valley – source boundaries, approach to modeling faults, fault orientation. 

6. Wabash – assessing uncertainty in timing of paleoearthquakes. 

7. Identification of tectonic features and impact of seismicity; when features are identified but 

seismicity is not smoothed does this default to “smoothed seismicity”? 

8. USGS smoothed seismicity versus EPRI approach to smoothing – which to use and why. 

9. Areas of low seismicity – lower limit on maximum magnitude given implied source dimensions? 

Seismic Source Related Issues 

 Key Issue Database 

General

Issues

1. Relationship between moment magnitude and source 

dimension such as source area or fault length. 

Earthquake source 

inversions, stress drop. 

2. Treating seismic sources as point sources versus 

extended sources. Needs consistency with ground 

motion modeling; larger {M>6} events should be 

treated as extended sources. 

Workshop #2? 

1. New Madrid – source boundaries, approach to 

modeling faults, fault orientation. 

GSG, paleoliquefaction 

data
Salomone, et al. 6/3/08 Enclosure 2 

2

Fault

Source

Issues

2. Charleston – source boundaries, approach to 

modeling faults, fault orientation. 

GSG, paleoliquefaction 

data

3. Wabash Valley – source boundaries, approach to 

modeling faults, fault orientation. 

GSG, paleoliquefaction 

data

Area

Source

Issues

1. Seismic source approach to areas of low seismicity. 

Should large “open” sources be considered 

{extended margin, craton}? 

Workshop #2? 

2. Identification of tectonic features and impact of 

seismicity; when features are identified but 

seismicity is not smoothed does this default to 

“USGS smoothed seismicity”? 

GSG; Should we request 

sensitivity studies to 

address this issue {USGS 

vs. EPRI}? 

Earthquake Occurrence – Magnitude Distribution Issues 

 Key Issue Database 

General

Issues

1. Magnitude distribution approach, such as 

characteristic magnitude distribution versus 

truncated exponential magnitude distribution; when 

to use which approach. 

Workshop #2? 

2. Magnitudes assigned to earthquakes found via 

paleoliquefaction evidence. 

Critical review of 

published data, but this 

data should be compiled. 

3. Approach to establishing maximum magnitude for 

regions of low seismicity. 

Seismicity catalog. 

Workshop #2? 

4. USGS smoothed seismicity versus EPRI approach to 

smoothing – which to use and why. 

Should we request 

sensitivity studies to 

address this issue {USGS 

vs. EPRI}? 

Specific

Issues

1. Areas of low seismicity – lower limit on maximum 

magnitude given implied source dimensions? 

Workshop #2? 

2. New Madrid – assessing uncertainty in timing of 

paleoearthquakes.

New Madrid 

Paleoliquefaction data 

3. Charleston – assessing uncertainty in timing of 

paleoearthquakes.

Charleston

Paleoliquefaction data 

4. Wabash – assessing uncertainty in timing of 

paleoearthquakes.

Wabash

Paleoliquefaction data 

GSG = geologic, seismologic, geophysical data.
Salomone, et al. 6/3/08 Enclosure 3

 1 

Key Issues for CEUS SSC Project 

Jon Ake 

6/1/2008

1. Source characterization for regions other than New Madrid, Wabash Valley and 

Charleston. Two end member scenarios are the very large zones (extended margin vs 

craton etc.) defined in the USGS approach and numerous very small zones defined in the 

EPRI-SOG study. If very large zones are used it implies little understanding of the 

seismotectonic differences across large areas. Conversely, the smaller zones often lack a 

sufficient number of earthquakes to allow for a stable estimate of rate. 

2. The approach to use for computing rates using “gridded seismicity”. There at least two 

alternative approaches being used currently, the penalized likelihood EPRI model and the 

kernel smoothing approach used by the USGS. These probably need to be viewed as two 

proponent models and we need to evaluate the impact of the differences. There are also 

questions that need to be addressed with respect to the degree of smoothing applied 

(correlation distance in the kernel approach and Wa and Wb in the EPRI formulation). 

3. The approach to be used for definition of maximum magnitude in source zones (i.e. not 

New Madrid, Charleston, Wabash Valley). Again there are several models available that 

should be considered. This is an area where the data set for estimating magnitude from 

paleo-liquefaction evidence probably needs to be reviewed to ensure there is not a 

systematic bias in the resultant magnitudes. 

4. To ensure that appropriate source dimensions are assigned we need to re-examine the 

source scaling in the CEUS. This needs to be done for the revised ground motion models 

as well. Assigning source dimensions based on a WUS model is clearly inappropriate. 

5. A detailed examination of hypocentral depths (and associated uncertainties) in the 

CEUS. This will need to be used with heat flow and potential field data to evaluate limits 

on seismogenic thickness. 

6. Source boundaries for Wabash, Charleston, New Madrid etc. Will the boundaries be 

“hard” and no ruptures be allowed to extend outside, or will they be “soft” where the 

ends of fault ruptures may extend outside the source zone? 

7. The uncertainty in the timing of paleoearthquakes needs to be evaluated more fully as this 

issue is “co-mingled” with any assessment that might be made relative to cluster models 

for sources like New Madrid. 

8. Seismicity catalog updates. The need to compile the best possible catalog is a very high 

priority. The discussion in the Draft Project Plan (DPP) on this issue is very good. The 

need to convert the available data to moment magnitudes is discussed in the DPP, the 

techniques that will be applied to the historical data as well as the instrumental data is 

something that needs to be carefully considered.
CEUS SSC_PPRP #3_final 

March 10, 2009 Via e-mail 

Lawrence A. Salomone 

Washington Savannah River Company 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities: Participatory Peer Review Report on Workshop No. 2. 

Acronyms

CEUS Central and Eastern United States 

EPRI Electric Power Research Institute 

GPS Global Positioning System 

PPRP Participatory Peer Review Panel 

PSHA Probabilistic Seismic Hazard Analysis 

SSC Seismic Source Characterization 

SSHAC Senior Seismic Hazard Analysis Committee 

TI Technical Integrator 

This letter constitutes the report of the Participatory Peer Review Panel (PPRP) on 

Workshop No. 2 (WS-2), “Alternative Interpretations,” for the referenced project. The 

workshop was held February 18–20, 2009, at EPRI headquarters in Palo Alto, California.

Following guidance described in the Project Implementation Plan for the PPRP1

, and 

consistent with the expectations of the SSHAC process2

, the PPRP participated in WS-2 in 

order to be informed and to review both procedural and technical aspects of the workshop. 

All eight members of the PPRP (J. P. Ake, W. J. Arabasz, W. J. Hinze, A. M. Kammerer, 

J. K. Kimball, D. P. Moore, M. D. Petersen, and J. C. Stepp) attended WS-2 and were able 

to fully observe all aspects of the workshop.

1 Implementation of the PPRP’s Participation in the CEUS SSC Project: Written statement 

communicated by J. Carl Stepp to L. Salomone and the TI Team on June 16, 2008. 

2

 Budnitz, R. J., G. Apostolakis, D. M. Boore, L. S. Cluff, K. J. Coppersmith, C. A. 

Cornell, and P. A. Morris, 1997. Recommendations for Probabilistic Seismic Hazard 

Analysis: Guidance on Uncertainty and Use of Experts. NUREG/CR-6372, Washington, 

DC, U.S. Nuclear Regulatory Commission.

3
Lawrence A. Salomone 2 March 10, 2009 

General Observations 

We observed that the workshop generally achieved the goal of compiling the range of basic 

data and proponent experts’ interpretations that together constitute the current state of 

knowledge of the technical community, which the TI Team must evaluate for assessing the 

seismic source model for the CEUS region. We noted that potential field data remain to be 

compiled and incorporated into the TI Team’s evaluation. We understand from the 

discussion of actions remaining to be taken prior to WS-3 that this important compilation 

and evaluation will be accomplished as part of planned working meetings of the TI Team 

prior to WS-3. 

We observed that the skillful organization of the workshop stimulated lively inquiry and 

debate among proponent experts and members of the TI Team. The results will be useful 

for the TI Team in subsequent evaluations and assessments of uncertainties both in 

elements and parameters of the CEUS seismic source model. The questions provided by 

the TI Team to the proponent experts in advance of the workshop proved to be useful and 

effective. The questions focused the presentations by the invited experts and they 

stimulated interactions not only between the TI Team and proponents of specific 

hypotheses and interpretations of data but also among proponent experts. 

Specific Comments and Recommendations 

Provided below are comments and recommendations for follow-up actions by the TI Team 

for completing its evaluations and the CEUS seismic source model assessment. We note 

that many of these comments were touched on by Kevin Coppersmith in the final 

presentation of the workshop in which he described the actions that the TI Team already 

plans to take to complete its evaluations and the model assessment. If the TI Team 

successfully implements those actions, then most of the items described below would be 

adequately addressed. 

1. Need for a Tectonic Framework: The range and complexity of alternative hypotheses 

and interpretations presented at WS-2 reinforce our previous recommendations concerning 

the need, first, to evaluate an overall tectonic framework for the study region and, second,

to properly incorporate this evaluation into the CEUS seismic source model assessment.

We consider a transparent evaluation of uncertainty to be a necessary element of the 

tectonic framework evaluation. The tectonic framework should have a universal role in the 

seismic source model assessment. This would establish the approach and scale for the 

seismic source model assessment, and it would provide a transparent, consistent 

assessment (weighting) of the complex alternative interpretations and hypotheses that 

constitute the current state of knowledge of the technical community.

We observed that some proponent interpretations regarding seismic sources and the origin 

of the seismicity in the CEUS pointed to the significance of evaluating the geological and 

seismological characteristics of the entire lithosphere—including the upper brittle crust, the 

ductile lower crust, and the upper mantle. Geological and geophysical evidence indicates 

that these various zones of the lithosphere are laterally heterogeneous, which could have 
Lawrence A. Salomone 3 March 10, 2009 

profound impact on the seismicity of the brittle upper crust. As a result, we recommend 

that the TI Team should include the attributes of the entire lithosphere in their evaluation 

of the tectonic framework and their seismic source model assessment.

2. Approach to Seismic Source Assessment and Scale:

a) “Granularity” of Seismic Source Model (i.e., the scale of uniform scrutiny): During 

the workshop, geological structures ranging in scale from very local to continental-scale 

were described and discussed. We recommend that the TI Team provide early assurance,

through assessment criteria that are explained and justified, that a systematic approach and 

procedure are being used for defining and assessing seismic sources in terms of scale.

These assessment criteria will facilitate subsequent use of the model for a site-specific 

PSHA at any site in the study region. The assessment criteria should be at a level of detail 

that appropriately incorporates the state of knowledge of the sources and the current 

understanding of their inherent complexity. Using the criteria, one should be able to 

distinguish specific sources that have significant, identifiable, and relatively consistent 

seismic hazard potential. This systematic approach should be applied consistently across 

the study region. 

b) Approach to Smoothing: We observed that there was little discussion or consideration 

of uncertainty involved in smoothing recorded seismicity versus deductive seismic source 

assessment, and there was no evaluation of alternative smoothing parameters. We consider 

this to be an important part of the assessment for the CEUS seismic source model and we 

recommend greater attention to the issue of smoothing and corresponding documentation.

3. Integrated Evaluation of Paleoliquefaction and Interpretations of Paleo-Fault 

Displacements:

a) Uncertainties in age dating: Multiple proponent experts discussed their interpretations 

of evidence for recent fault movement or the dating of geologic surfaces related to the 

formation of paleoliquefaction features. The proponents did not sufficiently describe the 

uncertainties in the age dating within their respective studies, and as such, the overall 

quality and reliability of this information is in question. The TI Team should strive to 

better understand the overall quality of these studies and develop a cohesive understanding 

of how the results can and cannot be used to establish recurrence information for various 

seismic sources. We recommend that the TI Team perform an integrated analysis of the 

body of paleoseismic investigation results in the vicinity of the New Madrid Seismic Zone 

using appropriate statistical methods. The study should incorporate uncertainty in the 

interpretations, to the extent that the uncertainty is described in or can be reasonably 

interpreted from the study results, in order to better correlate event times and rates of 

activity. 

b) Size of paleoearthquakes: Paleoliquefaction is widely accepted to be a useful basis for 

assessing a seismic source model for the CEUS region; it is likely to gain even more 

importance in the future. The new approaches presented at WS-2 for assessing uncertainty 

in the observed data and interpretations and for using the interpretations for estimating the 
Lawrence A. Salomone 4 March 10, 2009 

size of causal earthquakes have great promise and should be pursued in the future. At 

present, the uncertainties resulting from both the current and the newly presented methods 

are poorly constrained. We recommend that particular care be taken in estimating 

magnitude and in assigning corresponding uncertainties. We further recommend that the 

lack of evidence of paleoliquefaction not be used to determine maximum magnitude.

c) Time-dependent models: Given the importance of paleoliquefaction studies for 

evaluating the New Madrid and Charleston seismic zones, the TI Team should make a 

fundamental decision whether the incorporation and use of time-dependent recurrence 

models should be pursued. While this topic came up during the workshop, there was no 

discussion focused on what weight should be given to time-dependent recurrence models. 

It was not clear how the TI Team would assess the views of the technical community on 

this issue. 

4. Documentation of how alternative views are used: At WS-2 a wide range of 

proponent views within the scientific community were presented about a number of 

important seismic source related issues. It is clear that, when assessed in detail, most 

CEUS locations are complex, with heterogeneities playing an important role in creating the 

data observed in the field. The TI Team needs to document how alternative views are 

accounted for in the assessment of the seismic source model to be presented in May 2009.

5. The hypothesis of late aftershocks: During the workshop, a proponent, using chiefly 

qualitative evidence, offered the view that much of the contemporary seismicity observed 

in the CEUS represents late aftershock activity of prior moderate to large earthquakes. If 

this view is used by the TI Team as a working hypothesis, it should first be critically 

examined. Standard seismological and statistical tools exist for verifying whether 

observed contemporary seismicity can plausibly be related to prior earthquakes, consistent 

with aftershock decay models such as the modified Omori model or Ogata’s epidemic-type 

aftershock sequence (ETAS) model. Modern aftershock sequences in the CEUS, for 

example, can provide Omori parameters that can be used to test the hypothesis of longlived aftershock sequences in the region.

6. Temporal Clustering: One uncertainty that was briefly discussed is whether the New 

Madrid seismic source zone is coming out of a cluster in terms of short repeat times for 

larger earthquakes. Some proponents cited GPS data that indicate little if any measurable 

strain in the New Madrid seismic zone region over the past 20 years, and one proponent 

presented geologic evidence that could be interpreted to indicate a history of clustering 

with very long geologic time intervals between clusters. The available data and overall 

lack of understanding of the mechanisms that may drive a clustering model for the New 

Madrid seismic source zone warrant caution about the supposition that a clustered 

sequence of higher recurrence behavior is ending.

7. SSHAC process issues: Under SSHAC guidelines, the makeup of the TI team has 

implications for ownership issues relating to the seismic source model and subsequent 

hazard results. As evident during the workshop, there are blurred boundaries between the 

TI Team specified in the CEUS SSC organization chart and the TI Staff. The working “TI 
Lawrence A. Salomone 5 March 10, 2009 

Team” appears to consider itself a larger group than listed in the Project Plan. The makeup 

of the “TI Team” in terms of individuals who will be responsible for ownership of the SSC 

inputs should be clarified.

We also note that in the SSHAC framework there conventionally is a distinction between 

the TI (or TI Team) and the hazard analyst. In the CEUS SSC project this distinction is 

blurred with Robin McGuire having a dual role as a member of the TI Team and as one of 

the key analysts responsible for computing hazard at seven demonstration sites. This is not 

a conflicting role and indeed adds strength to the project. We suggest, however, that this 

circumstance be explained in the final project report.

Do not hesitate to contact us if you wish to discuss any of our observations, comments, or 

recommendations. 

Sincerely,

J. Carl Stepp Walter J. Arabasz 

871 Chimney Valley Road 2460 Emerson Avenue 

Blanco, TX 78606-4643 Salt Lake City, UT 84108 

Tel: 830-833-5446 Tel: 801-581-7410 

cstepp@moment.net arabasz@seis.utah.edu 

 

Copy:

PPRP Members 

Sponsor Representatives 
CEUS SSC_PPRP #4_final 

September 18, 2009 Via e-mail 

Lawrence A. Salomone 

Savannah River Nuclear Solutions, LLC 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities: Participatory Peer Review Report on Workshop No. 3. 

This letter constitutes the report of the PPRP1

 on Workshop No. 3 (“WS-3”) for the 

referenced project. The Feedback workshop was held August 25–26, 2009, at EPRI 

headquarters in Palo Alto, California. Following guidance described in the Project 

Implementation Plan for the PPRP2

, and consistent with the expectations of the SSHAC 

process3

, the PPRP participated in WS-3 in order to be informed and to review both 

procedural and technical aspects of the workshop. 

Seven members of the PPRP (J. P. Ake, W. J. Arabasz, W. J. Hinze, A. M. Kammerer, 

D. P. Moore, M. D. Petersen, and J. C. Stepp) attended WS-3 and were able to fully 

observe all aspects of the workshop. The Panel’s eighth member (J. K. Kimball) was 

unable to attend the workshop because of an unavoidable conflict but was provided with 

electronic copies of all presentations made at WS-3 together with other workshop materials 

to enable his participation in this review. 

General Observations 

The Project Manager and TI Team Leader worked together very effectively, executing 

their respective roles, and the TI team members were well prepared and effective in their 

respective contributions, all of which resulted in a successful workshop. The Panel 

commends the continuing effective leadership of the Project Manager and TI Team Leader 

and the professional preparation of the TI team members that were displayed in this 

workshop. We observed that the workshop accomplished the stated goals established for 

this important milestone of the CEUS SSC assessment. 

1

 Acronyms are explained in the Appendix. 

2 Implementation of the PPRP’s Participation in the CEUS SSC Project: Written statement communicated by 

J. Carl Stepp to L. Salomone and the TI Team on June 16, 2008. 

3

 Budnitz, R. J., G. Apostolakis, D. M. Boore, L. S. Cluff, K. J. Coppersmith, C. A. Cornell, and P. A. 

Morris, 1997. Recommendations for Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and 

Use of Experts. NUREG/CR-6372, Washington, DC, U.S. Nuclear Regulatory Commission. 

4
Lawrence A. Salomone September 18, 2009 

2

WS-3 imposed a deadline for completing work tasks such as compilation of the seismicity 

catalog, the completion of a first-stage seismic source model for the CEUS termed “the 

SSC sensitivity model,” and hazard sensitivity analyses based on the SSC sensitivity 

model. As such, WS-3 in effect was the TI Team’s first opportunity to review and discuss 

its initial integrated evaluations of the range of the larger technical community’s 

interpretations, although considering still incomplete data. The Panel recognizes that all of 

the evaluations reviewed in WS-3 constitute just a starting point for the TI Team to 

progressively build a seismic source model for the CEUS. 

We observed that the informative presentations made by the TI Team Leader at the 

beginning and end of Day 2 effectively focused the Team’s discussion on important 

evaluations remaining to be done going forward to support the SSC assessment. At the 

beginning of Day 2, Dr. Coppersmith summarized key conclusions he had extracted from 

the diverse feedback discussions during Day 1, and at the end of Day 2 he facilitated a 

lively discussion that actively engaged the TI Team in identifying additional feedback they 

required from the hazard analysts to effectively complete their SSC assessment. We found 

these discussions to be very informative and we consider them to have significant value for 

tracking how the TI Team is progressing with its implementation of the SSHAC 

guidelines.

Specific Comments and Recommendations

Provided below are comments and recommendations for consideration and follow-up 

action by the TI Team. The comments are not ranked in order of priority. Because the 

PPRP will not have another scheduled opportunity to comment on the CEUS SSC Project 

for a number of months, some of our comments extend beyond the content of WS-3. 

1. The Principal SSHAC Goal for a PSHA: We appreciate Dr. Coppersmith’s 

informative presentation of the background and context of the principal SSHAC goal 

for a PSHA: “to represent the center, the body, and the range of technical 

interpretations that the larger technical community would have if they were to 

conduct the study.” His description of the historical context of the treatment of 

uncertainties in seismic regulation practice illustrates the critical importance to safety 

decision making of proper treatment of uncertainty, which formed the basis for the 

SSHAC’s evolution of this important goal as well as the process that the SSHAC 

defined for achieving it. The SSHAC assessment process defines roles for participants 

as well as process activities that when properly implemented provide reasonable 

assurance that the goal for a PSHA established by the SSHAC is achieved. Based on 

Dr. Coppersmith’s presentation and the follow-on discussions during the workshop, 

we concur that the assessment process activities being implemented for the CEUS 

SSC Project satisfy the SSHAC guidance. We recommend that this important 

presentation be developed in the form of a white paper suitable for inclusion as a 

section in the project final report and that the white paper be distributed among the 

project participants, including the PPRP and sponsor technical representatives, for 

early review.
Lawrence A. Salomone September 18, 2009 

3

2. USGS Open-File Report on Maximum Magnitude: Although briefly mentioned during 

the workshop, it was not clear to us how the soon-to-be issued USGS Open-File 

Report on estimation of maximum magnitude for seismic sources in the CEUS will be 

considered by the TI Team. We recommend that the report be considered as part of 

the information base for assessment of the CEUS SSC model.

3. CEUS Earthquake Catalog: The development and attendant analyses of the updated 

CEUS Earthquake Catalog are important contributions of the CEUS SSC Project that 

could potentially have high value for use in future PSHAs. The work summarized by 

Dr. Youngs on the catalog reflects a tremendous amount of work and represents a 

significant advancement in this important hazard data base. In order to be assured of 

the catalog’s continuing high value, arrangements should be made to continually 

maintain this consensus catalog, and the analyses should be periodically updated as 

warranted by the addition of new data. Because multiple agencies and organizations 

will use the SSC Model, we recommend that the Project suggest a plan for keeping the 

CEUS Earthquake Catalog current into the future as a companion product for use of 

the SSC Model.

4. Comments on Smoothing:

We recognize that the concept of smoothing of seismicity is attractive from the 

standpoint of honoring the general location of past seismicity as well as allowing 

the TI Team a method to incorporate the uncertainty in the location of historical 

events. However, there needs to be careful consideration given to smoothing 

applied on a very small scale, especially in the “b-value”. There are certainly 

implicit tectonic and/or structural assumptions associated with having the b-value 

changing over small distances. We believe a physical rationale should be supplied 

to support the Team’s implementation of this approach. The examples shown at 

WS-3 utilized several different smoothing approaches but all were applied across 

very large regions or the entire CEUS. The use of a constant approach across the 

entire region may not be appropriate. It is not clear to us at this time whether that is 

the approach being planned by the TI team. 

The smoothing methodologies discussed in the workshop are not described in any 

detail in the HID. It is not clear to us where the full documentation of the 

alternative smoothing procedures will appear. However, enough detail must be 

included in the HID to allow an experienced analyst to reasonably perform the 

hazard calculations for any point in the CEUS. 

We consider the alternative procedures for smoothing seismicity that were 

presented and discussed during the workshop to be valuable tools for the TI Team 

to use to express uncertainty in its tectonic-based assessments of the spatial 

variation of seismicity. Accordingly, we recommend that the use of these tools 

(i.e., the choice of smoothing method, the use of anisotropic kernels, priors on 

parameters, and so on) be justified in terms of the Team’s evaluations of tectonic 

processes governing earthquake occurrence.
Lawrence A. Salomone September 18, 2009 

4

5. Independent Check. The PPRP encourages the Project and the TI Team to perform the 

necessary independent checks of the analyses completed as part of developing the 

CEUS Earthquake Catalog and the Alternative Smoothing Procedures to ensure that 

this computational work is of the highest quality. It would be sufficient for the PPRP 

that this checking be performed using the TI Team participants so long as the "checker" 

is independent of the original work performed. 

6. Data Summary Table and Data Evaluation Table: The Data Summary Table appears

to be a highly valuable means of documenting the current range of the larger technical 

community’s technical interpretations. We believe that the Data Evaluation Table

also is an important part of the documentation of the CEUS SSC assessment that can 

serve the important need for transparent documentation of the TI Team’s evaluations 

supporting its assessments of the center and body of uncertainty in the larger technical 

community’s technical interpretations. The Data Evaluation Table also is potentially 

useful as a record of lessons learned and as such will be valuable in considering the 

need for and planning future investigations of the CEUS. This includes not only the 

utility of the various data most important in the SSC assessment, but also the nature 

and quality of data which imposed limitations on their use in identification and 

characterization of the seismic source zones. A summary of the various documents, 

their contents, and relationships would likely prove helpful and increase clarity for 

future implementation of the SSC Model. We recommend that the Project and TI 

Teams give careful consideration to these important potential uses of the Data

Evaluation Table as the assessment goes forward.

7. Sensitivity studies: We consider the sensitivity studies to be highly valuable for 

providing insights and gaining understanding of the sensitivity of PSHA at a specific 

site to various elements of the SSC model. Additional sensitivity studies at a range of 

distances from the sources of frequent large earthquakes could add value for future use 

of the SSC model. However, we recommend that the sensitivity studies not be used to 

justify devoting a reduced effort to assessing any fundamental element of the SSC 

model. (See also Comment 11.)

8. Lack of Consideration of Focal Depths: There was a lack of discussion of earthquake 

focal depths in the workshop presentation on the updated CEUS seismicity catalog. 

This omission should be rectified. Because focal depth is a potentially important 

contributor to our knowledge of seismic hazards, useful in characterizing and defining 

the limits of seismic source zones, and helpful in assessing potential ground motion, 

we recommend that greater consideration be made of this parameter in the CEUS SSC.

9. Plan for use of gravity and magnetic data. Gravity and magnetic anomaly data and a 

variety of maps processed from these data are important in mapping largely hidden 

geological structures of the CEUS that may be useful in identifying seismic source 

zones and their geographic boundaries. We note that the contract for preparing the 

gravity anomaly data and associated maps has been let to the University of Oklahoma, 

but the contract has not been executed for preparing and processing the magnetic 

anomaly data. Furthermore, the Expanded Schedule for the CEUS project (7/14/09) 

set the completion date for both of these contracts as October 30, 2009, which we 
Lawrence A. Salomone September 18, 2009 

5

learned at WS-3 has now been delayed until December 31, 2009. Despite the lack of 

the products from these contracts, the work of the TI team including the identification 

and delimiting of source zones must continue. As a result, we recommend that after 

December 31, 2009, once the new data sets and maps are available, a thorough review 

be conducted of decisions on identification and bounding of source zones that were 

reached prior to the availability of the gravity and magnetic anomaly data and related 

maps. This review may lead to modification of previous decisions.

.

10. Preliminary Seismic Source Zones: The seismic source zones used for the sensitivity 

evaluations and discussions during WS-3 are still tentative, but a cursory review of 

these zones raises several concerns: 

Where the evidence for the identified seismic source zones and their geographic 

limits are not described in referenced publications, we recommend that a 

comprehensive description be provided for the basis underlying the assessments of 

the source zones and their boundaries.

It is unclear why certain regions were selected as “zones of elevated seismicity.” 

What is their role? Why was the Clarendon-Linden region identified but not 

southeastern New York, the Niagara Peninsula, and other CEUS regions of abovenormal seismicity in the historical record? We recommend that definitive criteria 

be cited for the selection of elevated seismicity zones.

Earlier at Workshop No. 2, a scheduled presentation by Nano Seeber on seismicity 

and faulting in Ohio, Pennsylvania, New York State, and New York City was 

canceled and no similar presentation on this topic was made. Has anything been 

done to fill this void in the consideration and treatment of alternative 

interpretations? For example, a 2008 paper by Sykes and others4

 suggests an 

alternative view of seismicity in the New York City area that has not been cited in 

the Data Summary Table. We recommend that the list of alternative 

interpretations be updated to include those pertaining to the region that was to be 

discussed by Dr. Seeber at WS-2.

There may be an inconsistency in the way that “extended zones” are used in the 

identification of seismic source zones. The area of the extended zone with normal 

faulting associated with the Iapetan Rift Margin is moved hundreds of kilometers 

west into the stable craton from the mapped rift margin. However, the limits of the 

seismic source zone associated with Iapetan (Cambrian) rifting in the 

midcontinent, including the New Madrid Rift Zone and its extensions, appear to be 

limited to mapped grabens without consideration of a bordering extended zone. Of 

particular note is the lack of an extended zone associated with the Grayville graben 

in southern Indiana. The “wide” interpretation of the seismic source zones is a 

step in the correct direction, but without further documentation on the factors 

defining the boundaries of this interpretation, it is difficult to determine if the 

broader extended zone is being captured in this interpretation. We recommend 

4

 Sykes, L. R., Armbruster, J. G., Kim, W.-K., and Seeber, L., 2008, Observations and tectonic setting of 

historic and instrumentally located earthquakes in the greater New York City-Philadelphia area: Bulletin of 

the Seismological Society of America, v. 98, no. 4, pp. 1696–1719. 
Lawrence A. Salomone September 18, 2009 

6

that the TI Team consider the possibility of an “extended zone” marginal to 

midcontinent seismic source zones.

11. Pruning the Logic Tree and Need for Complete, Clear Documentation. The use of an 

initial sensitivity model to inform evaluations to support the final model assessments 

is a sound and efficient approach. However, care must be taken to fully and clearly 

document the results of the sensitivity study, particularly as it impacts development of 

the final model and particularly in cases where alternative branches are removed. In a 

SSHAC level-3 study, the degree of credibility that the technical community grants the 

final model may be based heavily on the clarity and completeness of documentation 

and the ability of the technical community to understand the basis of assessments 

made by the TI team. In addition, robust documentation can more easily allow for the 

incorporation of new data and site-specific information into the model. In fact, 

specific guidance on how new or site-specific data should be evaluated could prove 

very valuable to the practitioner. 

The final model must represent the range of legitimate interpretations of the informed 

technical community in a scientifically defensible way. While some pruning of the 

tree based on the sensitivity study is desirable, we recommend that the sensitivity 

study not be used to trim branches that represented significant concepts or alternate 

hypotheses, even if the inclusion of alternate branches does not impact hazard. Some 

computational efficiencies could possibly be gained for the future hazard analyst if the 

study provides specific guidance as to the distance from the more significant sources 

at which the source no longer impacts hazard, and can be trimmed from the model.

12. Evaluation and Assessment of Time-Dependent and In-vs.-Out-of-Cluster Models.

The approach to evaluating and assessing the time-dependent and in-vs.-out-of-cluster 

models need to be better explained. The time-dependent models require an 

aperiodicity parameter for use in the Brownian-Passage-Time calculations. Previous 

working groups in California determined a range of potential aperiodicity (or COV) 

parameters based on examining recurrence data with the associated uncertainties. It 

appears that the CEUS-SSC model may adopt this same range of parameters that was 

used in California. Since this is such an important parameter in determining the 

hazard, there should be some justification in the documentation regarding this choice 

considering the very different tectonic process that appears to be operative. The 

cluster models also need some further clarification. Sometimes the cluster models 

allow for activity in other nearby regions (migration of activity) when the primary 

source turns off and sometime they don’t. In addition, different cluster-model weights 

for the Cheraw and Meers faults have been applied. It would be important to 

understand the basis for these weights and all other weights associated with these 

temporal models. 

13. Sanity Check for Seismic Sources Defined by Paleoliquefaction: We recommend that

the TI Team make a sanity check for those seismic sources defined by

paleoliquefaction—that is, whether the source boundaries make sense, given the 

assumed magnitude versus area (or length) using relationships between magnitude and 

the maximum distance to liquefaction. For example, the magnitude-versus-area 
Lawrence A. Salomone September 18, 2009 

7

relationship for the CEUS results in an assumed rupture length of ~21 km for M = 6.7. 

For the currently defined Charleston source options, can ruptures at the far ends of the 

source (e.g., the southeastern or northwestern corners of the large zone shown on 

Figure 15 in the HID) explain the observed paleoliquefaction at the opposite end of the 

source? The TI Team may need to factor in how they are modeling the recurrence of 

the source relative to the paleoliquefaction—but they need to make sure that the 

sources for the paleoliquefaction regions do not become too large when considering 

how rupture length is being modeled relative to paleoliquefaction. 

14. Integration with Ground-Motion Prediction Equations. During the workshop there 

was discussion of the impact of the choice of ground-motion prediction equations on 

hazard results, particularly for sites in areas such as the Gulf region where the 

initiating seismic sources may be in other types of seismic-wave attenuation domains. 

It may be beneficial to consider recommendations to the practitioner with regard to the 

ground-motion prediction equations when different seismic-wave-propagation 

domains are involved in the PSHA. 

15. Need for Uniform Rigor in Assessing Rate-Information Inputs. Examination of the 

SSC Sensitivity Model shows an apparent unevenness in rigor applied to assessing 

rate-information inputs in terms of significant figures and assessed distributions. This 

stands in contrast to the systematic rigor applied, say, to recurrence modeling. 

Because of the fundamental importance of rate information to hazard, we recommend 

careful uniform attention to the assessment of rate inputs. Such assessments should 

meet the basic expectations of a normative expert in a PSHA if one were overseeing 

the assessments. 

16. PPRP Observers in Remaining Working Meetings. Under the CEUS SSC Project 

Expanded Schedule (dated July 14, 2009), the next face-to-face meeting of the PPRP 

with the TI Team will be in March 2010. Because this will be at a relatively late stage 

of shaping a near-final (albeit still “preliminary”) SSC model, we recommend that the 

Project Manager facilitate participation of at least two PPRP members as observers in 

the TI Team’s Working Meeting #6 (October 20–21, 2009) and Working Meeting #7 

(January 12–13, 2010).

Do not hesitate to contact us if you wish to discuss any of our observations, comments, or 

recommendations. 

Sincerely,

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801-581-7410 Tel: 830-833-5446 

arabasz@seis.utah.edu cstepp@moment.net 

Copy: PPRP Members 

Sponsor Representatives 
Lawrence A. Salomone September 18, 2009 

8

APPENDIX 

Acronyms

CEUS Central and Eastern United States 

COV Coefficient of Variation 

EPRI Electric Power Research Institute 

HID Hazard Input Document 

PPRP Participatory Peer Review Panel 

PSHA Probabilistic Seismic Hazard Analysis 

SSC Seismic Source Characterization 

SSHAC Senior Seismic Hazard Analysis Committee 

TI Technical Integrator 

USGS U.S. Geological Survey 
CEUS SSC_PPRP #5_final 

April 7, 2010 Via e-mail 

Lawrence A. Salomone 

Savannah River Nuclear Solutions, LLC 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities: Feedback on CEUS SSC Preliminary Model. 

This letter constitutes the report of the PPRP1

 (“the Panel”) providing feedback on the 

CEUS SSC Preliminary Model. Our feedback is based on a one-day PPRP and USGS 

Briefing Meeting (“the Briefing Meeting”) held on March 24, 2010, at EPRI headquarters 

in Palo Alto, California, and on materials provided to us beforehand. These materials 

included Draft Data Summary and Data Evaluation Tables, a Hazard Input Document for 

the CEUS SSC Preliminary Model, and a Draft CEUS SSC Report Outline. 

All eight members of the PPRP (J. P. Ake, W. J. Arabasz, W. J. Hinze, A. M. Kammerer, 

J. K. Kimball, D. P. Moore, M. D. Petersen, and J. C. Stepp) attended the Briefing 

Meeting. On the following day (March 25), all eight members of the PPRP met privately 

for a half day to discuss observations and plan this feedback report.

General Observations 

The Briefing Meeting was well organized, the TI team members were well prepared, and 

the Team members’ respective presentations effectively stimulated discussion, all of which 

resulted in a successful meeting. The atmosphere of open discussion that prevailed 

throughout the briefing significantly enhanced the Panel’s participation. We observed, 

however, that several elements of the model had not reached the stage of completeness of 

analysis and assessment that we had expected. These will be addressed more completely 

by Specific Comments.2

We commend the Project Manager and TI Team leader for their continuing effective 

leadership of the Project. This leadership continues to stimulate and maintain productive 

interactions among TI Team members and between the Project Team and the Panel. 

Actions required to complete the Project identified in “Path Forward” discussed at the end 

of the meeting appear to be well formed and achievable. The Panel noted, however, that 

the actions do not include a feedback interaction following completion of the Panel’s 

review of the Draft Project Report to be delivered on September 1, 2010. We recommend 

1

 Acronyms are explained in the Appendix. 

2

 As in earlier PPRP reports, recommendations are underlined for emphasis and ease of recognition. 

5
Lawrence A. Salomone April 7, 2010 

2

that a process for resolving the Panel’s comments and recommendations aimed at

completing the Final Project Report be identified and scheduled. 

Specific Comments and Recommendations

Provided below are comments and recommendations for consideration and follow-up 

action by the TI Team. The comments are not ranked in order of priority. We realize that 

this report is intended to represent the Panel’s last formal opportunity to comment on the 

CEUS SSC Model before it moves ahead from “Preliminary” to “Final.” However, 

because parts of the Model are still incomplete, some additional interactions between the 

TI Team and the Panel are desirable in the coming weeks to ensure the Panel’s “buy-in” to 

the Final Model. 

Among the diverse comments and recommendations contributed by the Panel members, 

two common themes will become apparent: 

Part of the Panel’s responsibility in reviewing the Draft Technical Report in 

August will be to address the clarity and completeness of documentation of the 

SSC. So in this document we have included early advisories about potentially 

confusing terminology, missing pieces, and some expectations of what needs to be 

documented. 

The Master Logic Tree has progressively been contracted to characterize seismic 

sources in the CEUS in a way that eliminates elements that, in the judgment of the 

TI Team, do not contribute significantly to the resulting hazard—thus providing a 

simpler conceptual framework and allowing efficient computation of hazard. 

Where credible views of the Informed Technical Community (“ITC”) do not 

appear to be included in the Master Logic Tree, there is a clear burden on the TI 

Team to address and document how those views have been considered and duly 

accounted for in the Model. 

Because the Master Logic Tree includes major changes in characterizing earthquake 

potential in the CEUS, compared to past PSHAs, the Panel believes that the TI Team will 

need to be aggressive and pre-emptive in explaining these changes.

1. Availability and completeness of work products for review: The review period for the 

final report documentation is very short. It is critical that the PPRP be provided a 

complete final draft on August 2 so that Panel members can submit a set of complete 

and meaningful review comments. (Because of schedule constraints, some PPRP 

members need to begin their review immediately upon receipt of the Draft Technical 

Report on August 2.) In addition, the PPRP would find it beneficial to evaluate certain 

products that are finalized (after April 30) and at an early stage prior to the submittal of 

the Draft Final Project Report on August 2. Of particular interest would be the Mmax 

distribution and summary information used to develop the distribution for each seismic 

source zone (largest observed event, N, prior). Summary rate maps for individual 

source zones would also be useful for PPRP assessment prior to August 2. 
Lawrence A. Salomone April 7, 2010 

3

2. Differences Between Seismic Source Zones: The TI Team stated that the conceptual 

approach used to define distributed seismic sources, specifically those defined on a 

seismotectonic basis, focused on four key factors: (1) earthquake recurrence rates; (2) 

maximum magnitude; (3) expected earthquake characteristics; and (4) tectonics. The 

Data Evaluation Tables provide information on some of these factors indicating some 

differences between seismic source zones. However, because the TI Team had not 

completed development of the final earthquake catalog, implementation of the 

approach to defining maximum magnitude and spatial smoothing of earthquake 

recurrence rates for each of the distributed seismic sources had not been finalized. As a 

result it is difficult for the PPRP to have high confidence that the preliminary seismic 

source characterization model captures the center, body, and range of the ITC. While 

some significant differences between distributed seismic sources may be anticipated 

(e.g., Mmax differences between Non-Extended crust relative to differences between 

the Illinois Basin Extended Basement (IBEB) and Mid-continent Crust seismic 

sources), it is not intuitive that such differences will fully support the seismotectonic 

zones that subdivide the Mesozoic Extended crust, and as a result the conceptual 

approach used to define distributed seismic sources. The PPRP had expected that the 

Hazard Input Document would have included information to justify the approach being 

used. The PPRP recommends that the TI Team provide this information for PPRP 

review concurrent with providing hazard input to the project’s hazard analyst.

We recommend the following with respect to maximum magnitude: (1) The TI Team 

should describe how paleoliquefaction evidence was used to define seismic source 

likelihood functions. (2) The TI Team should provide specific likelihood functions and 

posterior distributions for each of the Hybrid and Seismotectonic source zones, for 

each of the prior assumption cases considered. 

With respect to the application of the smoothed seismicity approach, we recommend 

that the PPRP be provided with sufficient activity rate maps for each hybrid and 

seismotectonic source zone (such as for M = 5) to appreciate the significance of 

recurrence rate differences between seismic sources.

3. Organization of the Logic Trees: We note that there are significant changes in the 

organization of the logic trees of the current CEUS SSC from previous PSHAs of the 

region. The Panel is generally supportive of these changes, but we recommend that the 

documentation of the design of the logic trees include a clear and detailed explanation 

of the reasoning involved in making the changes from previous studies. For example, 

the magnitude of the largest observed events (both historical and inferred from 

paleoliquefaction) is a major factor in isolating source zones for detailed 

characterization (the RLMEs), while regions of moderate to intense earthquake activity 

without moment magnitudes that exceed mid-5 values such as eastern Tennessee, 

northeastern Ohio, the Humboldt fault zone (Nemaha Ridge), and the Ramapo fault 

that have been included in earlier studies are not called out as specific seismic zones. 

Furthermore, we have the sense that some lines of evidence used by the ITC in 

identifying and characterizing the seismic source zones of the CEUS have not received 
Lawrence A. Salomone April 7, 2010 

4

the attention in the current study that they have been given by some members of the 

ITC and in former PSHAs of the region. For example, contrary to the present study, 

some investigators place considerable emphasis on recent strain (GPS) measurements 

and others give considerable weight to tectonic features of the CEUS that have been 

mapped directly or indirectly in the identification and characterization of seismic 

source zones. The project would be well served by documented justification of the 

reasoning supporting minimization of these elements by the TI team in their 

decisions—and we recommend that the Draft Technical Report include such 

documentation.

Lastly, it would be helpful if the TI Team paid particular attention to, and provided an 

appropriate level of discussion about, areas toward which the technical community is 

moving. For example, the use of strain rates is an area that will likely expand in the 

future. So, although these data may not have had a significant impact at this time, it is 

important for the study documentation to fully discuss the data available and how it 

was treated now.

4. Clarity of terms in the Master Logic Tree: In labeling and discussing branches of the 

Master Logic Tree, clarity can be improved. The TI Team may want to consider 

another term for “hybrid” at the very front end of the tree. The term is a vestige from 

labeling a former three-branch node (now collapsed to two), and many readers would 

expect a hybrid branch to be a combination of two other branches. Referring to 

“zoneless” seismicity sources is confusing insofar as these sources lie within 

demarcated areas of differently affected Mesozoic crust. In general, we recommend 

that the TI Team examine jargon that has evolved in their internal discussions and 

evaluate whether terms used in their working discussions now help or hinder clear

communication to others. Labeling of Iapetan Extended/Non-extended as a different 

case from Mesozoic Extended/Non-extended may be confusing to those unfamiliar 

with the arcane term “Iapetan.” Labeling of “Inter-event Times” as a Recurrence 

Method for the RLME logic tree branches is confusing because the method used in fact 

involves the use of both inter-event and event-interval paleoearthquake data. In source 

geometry branches for RLME sources (e.g., Figures 15 and 17 in the HID), “extended 

trace” should be used instead of just “extended” to avoid confusion with crustal 

extension.

5. Assigning Weights to the Logic Trees: As mentioned during the Briefing Meeting, we 

recommend that TI Team describe the overall approach to assigning weights to the 

logic trees, and that this written description be included in the Draft Technical Report.

In some cases these weights represent an explicit statistical assumption or distribution 

while in other cases these weights are the TI’s evaluated judgment of the informed 

technical community views. In these cases it would be useful to have an understanding 

of how the TI assigned weights from a generic perspective.

6. Spatial Smoothing: Conceptually, the PPRP endorses the direction the TI team is 

taking with respect to spatial smoothing approach and implementation. However, thus 

far there has been no written documentation provided to us that: (1) describes the 
Lawrence A. Salomone April 7, 2010 

5

method in detail as it is being applied in this project, (2) describes the bases for choices 

of parameters of the model, or (3) justifies reliance entirely on the penalized likelihood 

method. We recommend that the eventual documentation not only describe the 

adopted technique in detail but also document any perceived advantages of this 

technique relative to simpler kernel techniques. Some discussion of “floor” values in 

regions of very low rates should also be included. It would benefit our review to 

receive this section for review as soon as is practicable. 

7. ALM Area Characterization: The TI Team presented its independent evaluation of 

published field data, including original field copies of trench logs and field 

photographs of features that Randy Cox had described in WS #2 and interpreted as 

liquefaction features. “Project-specific Criteria for Identifying Earthquake-Induced 

Liquefaction Features Used in Development of Paleoearthquake Chronologies” were 

used to perform the evaluation. Discussions during the TI Team’s presentation 

identified that these criteria are current state of practice for determining whether 

observed features are earthquake-induced liquefaction features or properly explained as 

depositional or due to another geologic process. First, given that the criteria are 

identified as representing the state of practice of the informed technical community, the 

“project-specific” qualification is confusing and misleading. We recommend that these 

criteria be clarified or removed.

Second, the Team’s evaluation appears to reasonably support their conclusion that the 

features do not satisfy the informed community’s criteria for reasonably assessing that 

the features are earthquake-induced. However, this evaluation appears inconsistent 

with the highly qualified ALM area model assessment conclusion: “the 

paleoliquefaction data from the ALM region are immature and highly uncertain and, at 

the present time, do not provide strong evidence for a source of RLME in the ALM 

area.” This highly qualified conclusion clearly conveys a level of uncertainty that 

would support giving some assessed weight to an interpretation that the ALM should 

be modeled as a RLME. Perhaps what is meant is that the information in the current 

dataset, when assessed using the criteria for determining whether features are indeed 

liquefaction features consistent with current state of practice, does not support the 

interpretation that these are paleoliquefaction features. We strongly support the TI

Team’s decision, as stated during the discussion, to revisit and clarify this 

assessment—and we recommend that the TI Team do so.

To support this last point, it would be helpful if the discussion of the criteria include 

not only what the specific criteria are but the scientific and technical basis of each 

criterion. This would support not only this assessment, but would provide a valuable 

tool for projects in the future when datasets are not clear, or even as new information 

becomes available in the ALM area. 

8. Data Summary and Evaluation Tables: The Panel finds the Data Summary and Data 

Evaluation tables to be highly important in supporting and annotating the decisions 

regarding identification and characterization of the seismic source zones of the CEUS. 

Every effort should be made to include in these tables documentation for the current, 
Lawrence A. Salomone April 7, 2010 

6

complete center, body, and range of the ITC by seeking feedback from appropriate 

current investigators prior to finalizing the tables. A full description is warranted of the 

procedures used in selecting material for the Data Summary table. Additionally, both 

tables are essential in reviewing the basis for, and the assessments regarding, seismic 

source zones—but there remains the need for a full narrative that will allow the user of 

the CEUS SSC Model to completely understand the data evaluations that support the 

assessments made by the TI Team. We recommend that the Draft Technical Report 

include such a full narrative for the Data Summary and Data Evaluation tables.

9. Earthquake Model for RLME Sources: In the Master Logic Tree, full weight is given 

to the maximum-moment model as the “Earthquake Model” applicable to RLME 

seismic sources. In the western U.S., where detailed data are available to assess 

earthquake behavior on major active faults, increasing attention is being given to a 

variable-slip model—which allows the slip, rupture location, and length to change with 

each earthquake (see, for example, K. Scharer, “Changing views of the San Andreas 

fault”: Science, vol. 327, 26 February 2010, p. 1089–1090). To defend a weight of 1.0 

for the maximum-moment model vis-à-vis the ITC, the TI Team clearly has to 

demonstrate (if correct) that the choice is one of simplified methodology, which 

considers and accounts for other credible models of earthquake behavior.

10. “Other” Reviews of the CEUS SSC Model: At the Briefing Meeting, the Project 

Manager showed tracking milestones including “Review of Draft [Technical] Report 

by PPRP, USGS, and Sponsor Reviewers—August 2, 2010 to September 1, 2010.” It 

seems appropriate to call attention to the following statement in Implementation of the 

SSHAC Guidelines for Level 3 and 4 PSHAs—Experience Gained from Actual 

Applications (USGS Open-File Report 2009-1093, p. 35: 

The PPRP is the only legitimate review panel recognized by the SSHAC 

Guidelines; there is only one PPRP for a SSHAC Level 3 or 4 study, and its 

sole and unique obligation is to provide on-going commentary to TI/TFI as 

the project develops. All other “review panels” should be considered as 

observers, unless the project leadership agrees in advance to a different 

role/format for them. 

The Panel recognizes the prerogative of the Project Sponsors to request 

comments on the Draft Technical Report from other parties of its choosing for 

its own purposes. However, we recommend—and believe it is essential—that 

any comments on the CEUS SSC Model provided to the TI Team that result 

from a TI Team request be made available to the PPRP for its awareness and 

consideration.

11. Comments on Draft Report Outline: We recognize that the Draft Report Outline dated 

March 9, 2010, is preliminary (in its present form, the outline is a mix of topical 

phrases and explanations of what specific subsections will contain). As such, a 

detailed review is premature, and we only offer some general comments (not 

exhaustive). We recommend that the PPRP have another opportunity to review the 
Lawrence A. Salomone April 7, 2010 

7

Draft Report Outline after the TI Team finalizes it. This could avoid some late-stage 

criticisms of the content of the Draft Technical Report during our August review. 

Because the Project Report will become a legal document with the authority of a 

regulatory guide, clarity is essential. As examples: do not use “seismicity catalog” 

for “earthquake catalog”; “event” for “earthquake”; “paleoseismicity” for 

“paleoearthquake”; “process” for “assessment.” 

In providing guidance for future applications of the CEUS SSC Model, adhere to 

specific terminology of “refinement” for site-specific applications and “revision” 

for future updates of the Model. 

In section 2.1, consider a discussion of (1) the fundamental goal of safety 

regulation, i.e., “reasonable assurance based on current knowledge” and (2) the role 

of technical regulatory guidance for reasonably assuring the goal of safety 

regulations has been met. 

List of Acronyms needed. 

Need Glossary of key terms (e.g., seismic source, Conceptual SSC Framework, 

SSC Model, etc.) It will be essential to define “Conceptual SSC Framework” and 

its role in the assessment process. How does it support or frame the assessment? 

What weight is it given? 

Labeling section 2, which deals chiefly with process, as an apparent primary 

“Methodology” section is misleading. Either organize explanations of technical 

methodology into one section or guide the reader (as in the label for section 3.3) by 

prominently labeling, “Methodology for __________.” 

Make the outline of sections/subsections reader-friendly. For example, the number 

of subsections in section 4 is too large. Subsections 4.5 and 4.6 appear to be distinct 

from earlier parts of section 4 (general characterization of seismic sources) and can 

be broken out into a separate section containing descriptions of specific sources in 

the logic tree. 

Missing discussion of GIS database, both under section 3.2 and in the Appendices. 

Missing discussion of metadata. 

In section 6, a subsection is needed relating to consideration of new data and/or 

information and determining when the SSC Model requires revision (updating). 

Declustering of the earthquake catalog was undertaken using methods described in 

the original EPRI study documentation. Because that study is not broadly 

accessible, it is important that a full discussion be included in the documentation. 

It should be complete enough to allow for members of the technical community to 

understand and repeat the work. 

Section 1.2.2 is currently titled “Conducted using SSHAC Level 3 approach.” This 

section should discuss not only how the project met the standards for a level 3, but 

also WHY a level 3 was conducted instead of a level 4. It may also be useful to 
Lawrence A. Salomone April 7, 2010 

8

discuss how this decision was made and what have been the benefits and 

drawbacks. 

Perhaps the PPRP review documents should be included as an Appendix. The form 

of the final report has not been clarified; but it could be a summary letter report that 

has the previous comment sets as attachments. 

Closing Comment 

The Panel is aware that, at the request of the Project, the USGS is preparing to deliver to 

the TI team independent feedback on the Project Earthquake Catalog and on the draft HID 

focusing on completeness of datasets, models, and tools being used in the CEUS SSC 

assessment. Based on telephone discussions between the PPRP and the Project Team on 

April 5, 2010, we understand that the TI Team will evaluate the USGS comments and will 

consider them in its final assessment and in its development of the final HID for the 

Project. We further understand that the TI Team’s evaluation of the USGS comments will 

be finalized as part of its final working meeting scheduled to be held on April 12-13, 2010, 

in which one or more PPRP members will participate as observers. 

Note: We may choose to provide additional PPRP feedback following the April 12-13 

working meeting and receipt of information relating to completion of the TI Team’s 

evaluation of the USGS comments and any modifications the Team may make to its 

datasets, models, or tools as a consequence.

Please contact us if you wish to discuss any of our observations, comments, or 

recommendations. 

Sincerely,

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801-581-7410 Tel: 830-833-5446 

arabasz@seis.utah.edu cstepp@moment.net 

Copy: PPRP Members 

Sponsor Representatives 
Lawrence A. Salomone April 7, 2010 

9

APPENDIX 

Acronyms

ALM Arkansas-Louisiana-Mississippi 

CEUS Central and Eastern United States 

EPRI Electric Power Research Institute 

GIS Geographic Information System 

GPS Global Positioning System 

HID Hazard Input Document 

IBEB Illinois Basin Extended Basement 

ITC Informed Technical Community 

Mmax Maximum Magnitude 

PPRP Participatory Peer Review Panel 

PSHA Probabilistic Seismic Hazard Analysis 

RLME Repeated Large Magnitude Earthquake 

SSC Seismic Source Characterization 

SSHAC Senior Seismic Hazard Analysis Committee 

TI Technical Integrator 

USGS U.S. Geological Survey 
CEUS SSC_PPRP #6_final 

October 4, 2010 Via e-mail 

Lawrence A. Salomone 

Savannah River Nuclear Solutions, LLC 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities: PPRP Review Comments on CEUS SSC Draft Report of 

July 31, 2010

This letter constitutes the report of the PPRP1

 (“the Panel”) providing review comments on 

the Central and Eastern United States Seismic Source Characterization for Nuclear 

Facilities, Draft Report, July 31, 2010.

All eight members of the PPRP (J. P. Ake, W. J. Arabasz, W. J. Hinze, A. M. Kammerer, 

J. K. Kimball, D. P. Moore, M. D. Petersen, and J. C. Stepp) participated in this peer 

review through written input, e-mail exchanges, and teleconference discussions. The 

General Comments and the Specific Comments (explained below) represent the consensus 

views of the Panel, arrived at through a process deliberately independent of any other 

review.2

Peer Review Responsibility of the PPRP 

The Draft Report delivered to the PPRP was accompanied by a transmittal letter (dated 

July 31, 2010) signed by K. J. Coppersmith and L. A. Salomone, indicating that the Panel’s 

review should focus on: 

1) Identifying any data, models, methods that exist within the technical community 

that the TI Team may not have considered and that could substantively impact the 

result of the assessment 

2) Reviewing the evaluation process in workshops and working meetings and 

offering advice regarding hypotheses and views put forward by members of the 

technical community 

3) Reviewing the technical bases provided by the TI Team in the report, thereby 

substantiating their integration process of capturing the center, body, and range of 

the informed technical community 

1

 Participatory Peer Review Panel. For other acronyms, see the list of acronyms contained in the 

CEUS SSC Draft Report.

2

A submission of review comments by the USGS, transmitted on August 30, 2010, was copied to 

W. J. Arabasz, co-chair of the PPRP. However, the review comments were not shared with the 

PPRP and were not considered by Dr. Arabasz in his contributions to the PPRP review. Input from 

Dr. J. Ake (NRC), Dr. A. M. Kammerer (NRC), and Dr. M. D. Petersen (USGS), represented their 

independent views as members of the PPRP. 

1

6
Lawrence A. Salomone October 4, 2010 

Further, the PPRP was instructed that it should: 

Validate that there is reasonable assurance, based on a preponderance of evidence, 

that the views of the informed technical community have been properly captured in 

the final seismic source characterization model 

Provide assurance that uncertainties have been properly considered and 

incorporated 

Consider whether the guidelines for a SSHAC Level 3 assessment have been 

properly considered and incorporated 

Additionally, the SSHAC guidelines require the PPRP to provide assurance that “the 

documentation of the study is clear and complete” (SSHAC, 1997, p. 48). 

Format of Review Comments 

For each chapter of the CEUS SSC Draft Report, we have organized our review comments 

into three categories: General Comments (numbered for tracking), Specific Comments

(also numbered for tracking), and Comments by Section. The third category generally 

includes comments aimed at clarity and completeness of documentation; typographical 

errors are also noted. For the front matter and appendices, the categories may differ 

slightly but typically include General Comments and Comments for Clarity and 

Completeness.

Herein, we do not use the convention, adopted in earlier PPRP reports, of underlining 

specific recommendations for attention and response by the TI Team. Our review 

comments, particularly the Specific Comments (and some of the General Comments) for

the main body of the report, inherently involve recommendations and suggestions that we 

believe are important to arrive at a final report that the PPRP can endorse. In many of our 

review comments, replacement text is liberally suggested. These should be viewed as 

suggested alternative wording for improved clarity—not a dictation of how the TI Team 

should word its report. 

Please contact us if you have questions or need more information regarding the PPRP’s 

review comments. 

For the PPRP,

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801-581-7410 Tel: 830-833-5446 

arabasz@seis.utah.edu cstepp@moment.net 

Copy: PPRP Members 

Sponsor Representatives 

2
PPRP REVIEW COMMENTS 

Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities 

Draft Report, July 31, 2010 

Format for Numbered Comments: X Y-N

X Type of Comment: G (General) or S (Specific)

Y Part of Report: 1, 2, . . . , 11 (Chapter 1, 2, . . . , 11)

A, B, . . . , K (Appendix A, B, . . . , K)

Acr = Acronyms

ES = Executive Summary

FM = Front Matter

N Sequence Number: 1, 2, . . . , n

Key to Characterization of Numbered Comments

CBR Center, body, range (appropriate representation of the community distribution) 

CC Clarity and completeness of documentation 

DMM Data, models, and methods

NAR No action required

SSHAC SSHAC guidance

U Uncertainties (proper consideration)

3
PPRPReviewComments,pageFM1

FRONT MATTER

EXECUTIVE SUMMARY 

General Comments 

G ES-1. (CC) The Executive Summary seems generally complete (see Specific Comment 

below). However, the PPRP’s extensive comments on the body of the CEUS SSC Project report 

may lead to significant changes in the report. The Project Team will likely need to revise the 

Executive Summary to properly describe any such changes. 

Specific Comments 

S ES-1. (CC) Emphasis on the Importance of Results Described in Chapters 8 and 9

The critically important results described in Chapters 8 and 9 offer potentially valuable insights 

that could serve as guidance for future users of the CEUS SSC Model. Consequently, the 

significance of these results should be properly described in the Executive Summary. 

Specifically with regard to the results presented in Chapter 8, the differences in the CEUS SSC 

model, the USGS model, and COLA models that primarily cause the differences in computed 

hazard results at the seven test sites should be described in the Executive Summary. Similarly, 

the important results presented in Chapter 9 likely will have far reaching impact on resolution of 

seismic safety issues as well as on the formulation of criteria for updating the CEUS SSC model 

in the future as new data are acquired and scientific knowledge evolves. A perspective summary 

of this result and its potential value for regulatory decision-making should be included in the 

Executive Summary. 

Comments for Clarity and Completeness 

p. v, par. 1, line 9.: Awkward word string — “Office of the Chief of the [sic] Nuclear 

Safety and the Office of Nuclear Regulatory Research of the Nuclear Regulatory 

Commission (NRC)” 

[Reviewer’s note: The affiliations listed do not exactly match those in the 

Acknowledgements (e.g., in the Acknowledgements, the Office of the Chief of 

Nuclear Safety is part of DOE).] 

p. v, par. 2, line 8: Poor syntax and long awkward sentence — 

The methodology for a SSHAC Level 3 Study as applied for the CEUS SSC Project is 

explained in the SSHAC report (Budnitz et al., 1997), which was written to discuss the 

evolution of expert assessment methodologies conducted during the previous three 

decades for purposed of probabilistic risk analyses. 

4
PPRPReviewComments,pageFM2

Suggestion: 

The methodology for a SSHAC Level 3 Study, an important framework for the CEUS 

SSC Project, is explained in the SSHAC report (Budnitz et al., 1997). The SSHAC report 

was written to discuss the evolution of expert assessment methodologies conducted 

during the previous three decades for purposes of probabilistic risk and hazard analyses. 

[Reviewer’s note: Prior analyses not only of risk but also hazard (e.g., EPRI-SOG 

and LLNL) were clearly considered by SSHAC.] 

p. v, par. 2, last sentence: As the only citation appearing in the Executive Summary, 

“(Coppersmith et al., 2010)” is unnecessary and can be deleted. 

p. v, par. 3, first sentence: The sentence structure including “then” and “finally” in 

this topical sentence misleadingly suggests a first-order summary of what the CEUS 

SSC report contains. Suggestion: “The CEUS SSC report presented here includes a 

review of the significant studies and case histories that led to the development of the 

SSHAC guidelines as well as projects conducted up to the present that have 

subsequently implemented those guidelines.” [Original wording referring to “the 

SSHAC development process” is unclear and easily deleted.] 

p. v, last sentence (continuing onto p. vi): The important claim, beginning with 

“Based on the evidence presented in this report,” warrants careful attention. 

Rewording should be consistent with any adopted changes in the second paragraph of 

Chapter 2 on p. 2-1 and the “Conclusion” paragraph of section 2.1.2.3 on p. 2-23 (see 

review comments for Chapter 2). 

p. vii, last paragraph, first sentence: Large-magnitude earthquakes are defined as (M

6). In the text (e.g., p. 4-14, 6-1), large-magnitude is defined as (M 6.5). 

ACKNOWLEDGEMENTS 

It is our understanding that the Acknowledgements were carefully vetted by the Project Manager 

in consultation with the named agencies and individuals. So we refrain from offering any 

comments on wording. 

The Project Team may wish to consider using the more conventional spelling of 

“Acknowledgments” (preferred in American English) vs. “Acknowledgements” 

(preferred in British English). 

SPONSORS’ PERSPECTIVES 

On p. xiii, par. 1, first sentence: We suggest changing “Probabilistic seismic hazard 

assessment (PSHA)” to Probabilistic seismic hazard analysis” to conform to the list of 

Acronyms and to usage of PSHA elsewhere in the report. 

5
PPRPReviewComments,pageFM3

ACRONYMS

General Comments 

G Acr-1. (CC) The inclusion of a list of acronyms is good practice, both for complete 

documentation and to help the reader. A decision needs to be made whether all acronyms, 

except for conventional abbreviations such BC or the designation of units, should be explained 

when first presented in the text (desirable). This is inconsistently done in the draft report. Note 

that many acronyms included in the appendices do not appear in the list. 

Specific Comments for Clarity and Completeness 

Identified corrections and additions to the list of acronyms are presented below. Not all missing 

acronyms may have been identified. We leave that to the technical editing of the final report. 

Corrections

EPRI-SOG Electric Power Research Institute- Seismic Seismicity Owners Group 

SHmax maximum horizontal shortening principal stress 

Missing Acronyms and Terms (not exhaustive) 

AFE annual frequency of exceedance (p. 1-4) 

ANSS U.S. Advanced National Seismic System (p. 3-3) 

BPT Brownian passage time (p. 4-20) 

CERI University of Memphis Center for Earthquake Research and Information (p. 3-4) 

ISC International Seismological Centre (p. 3-3) 

NEDP _____ (p. 3-5) 

NEIC USGS National Earthquake Information Center (p. 3-1, 3-4) 

NSHMP USGS National Seismic Hazard Mapping Project (p. 1-3) 

Pa Probability of Activity 

PDE Preliminary Determination of Epicenters (p. 3-1) 

SUSN Southeastern United States Seismic Network (p. 3-1) 

6
PPRPReviewComments,page11

CHAPTER 1 — INTRODUCTION 

General Comments 

G 1-1. (NAR) This chapter is well structured and introduces the reviewer to all elements of 

this complex project report. The chapter usefully discusses the need for community-based 

studies and comparisons with other approaches. Here and throughout this Draft Report, we 

recognize the great effort that has gone into the writing and documentation, and we commend 

the TI Team for its diligent efforts to distill and report a massive amount of detail. Mindful of 

the criteria we have been given to guide our critical review (see cover letter), we proceed to 

specific comments. 

Specific Comments 

S 1-1. (SSHAC) Justification for Using the SSHAC Level 3 Assessment Process 

A key issue related to the selection of the SSHAC assessment level, specifically a Level 4 

assessment versus Level 3, relates to the ability of the selected experts to act as impartial 

evaluatorsthe perceived higher level of assurance provided by Level 4 comes with significant 

additional costs, some of which are associated with making sure the use of experts or expert 

teams as impartial evaluators is being done properly. The Hanks (2009) Open File reports 

notes, appropriately, that most geosciences experts are quite inexpert in one or more of several 

matters important to higher level SSHAC assessments. But generally, they are not experienced 

evaluators of uncertainty, given competing hypotheses and interpretations that require 

evaluation using diverse sets of geological, geophysical, and seismological data. This particular 

point needs to be brought out more in the draft report, both here and in Chapter 2. 

Experience has shown, even for some projects that have claimed SSHAC Level 4 assessment, 

that the actual success of experts or expert teams as evaluators has been limited. At the present 

time for the CEUS it may be that the technical community is best able to implement a SSHAC 

Level 3 assessment (high confidence that a TI Team can be selected to act as impartial 

evaluator) versus a Level 4 assessment. While some could view this point as less important, it 

is a key point that those outside the project (other agencies, ACRS, others) must appreciate and 

understand. 

Based on cumulative experience using the SSHAC Methodology, particularly given the time 

constraints, we have confidence that this project can be successfully implemented using a 

SSHAC Level 3 assessment versus Level 4. 

S 1-2. (CC, SSHAC) Clear Communication is Essential: Chapter 1 and Entire Report 

Keeping in mind that words are the stuff of thought and that clear communication of thought is 

essential, especially for regulatory guidance documents intended for long term use, usages of 

words and terms must clearly and accurately convey the concepts that are being described. It is 

also essential that the words and terms be used in their proper meaning consistently throughout 

the report. 

The practice of using nuanced words as synonyms contributes to a lack of essential clarity. For 

example, throughout Chapter 1 the word “study” is used interchangeably in multiple meanings. 

7
PPRPReviewComments,page12

In most instances “study” is used to mean either “project” or “assessment”; it is used in its 

proper meaning in only a few instances, for example in subsection 1.4.4.4. Serious 

miscommunication will result from incorrectly using the word “study” to convey the activities 

that constitute a SSHAC assessment process—or that constitute a “SSHAC Study Level 3 

Approach” or a “SSHAC Study Level 3 Methodology,” which are alternatively used when 

referring to the SSHAC assessment process. 

The word “study” does not properly communicate the complex activities and processes that 

constitute the SSHAC Methodology or SSHAC assessment process. These activities together 

constitute a structured assessment process that involves compilation of the state of scientific 

and technical knowledge, compilation of datasets, evaluations of state of practice, and finally, 

assessments that represent the integrated knowledge of the scientific community and the 

community’s knowledge uncertainty as represented in the logic tree of the SSC model. 

It should be kept in mind that the SSHAC assessment process is accepted by the Nuclear 

Regulatory Commission (NRC) as the current state of practice for a technical process whereby 

seismic hazard models are assessed. Thus, it has the same standing as a consensus standard 

(ASCE Standard 43-05, for example). It is incorporated into the Agency’s accepted seismic 

regulatory procedures (Regulatory Guide 1.208) for demonstrating compliance with the seismic 

regulation 10 CFR Part 100.23; it also is accepted by the Department of Energy (DOE) as part 

of the Agency’s seismic safety policies and regulatory procedures. 

We emphasize that it is essential to clearly establish in Chapter 1 that the SSHAC Methodology 

is an assessment procedure that is accepted by the NRC and the DOE for developing seismic 

hazard models that are, in turn, accepted as providing reasonable assurance, consistent with 

these Agency’s seismic safety decision-making practice, of compliance with their seismic 

safety regulations and policies. Reasonable assurance is expressed in the outcome of using the 

SSHAC Methodology as the representation of the center, body and range of scientific 

community knowledge. In order to clearly convey the fact that the assessment of the CEUS 

SSC model has been accomplished through implementation of an accepted structured 

assessment process, we believe that the terminology “SSHAC Level 3 assessment process” 

should be adopted and used consistently throughout the CEUS SSC Report, notwithstanding 

use of alternative terminology in other documents. This would require extensive technical 

editing. 

Similarly, a careful edit should be performed, replacing the words “study/studies,” which do 

not properly apply when describing the activities performed in the CEUS SSC Project, with 

“project” or “assessment,” as appropriate. As examples, “LLNL study” and “EPRI-SOG 

study” are properly “LLNL Project” and EPRI-SOG Project.” Although the term “SSHAC 

Study Level” has been used in past documents, we recommend use of the term “SSHAC 

assessment process” in order to clearly convey the complex activities performed in the CEUS 

SSC Project. 

The word “event” is used confusingly to mean “earthquake” throughout this chapter and the 

report. While it can be argued that the usage is understood in context, regulatory documents, 

which are intended to be used for an extended time by many people having differing 

backgrounds, require clarity. Consider making a blanket change of the word “event” to 

“earthquake” where appropriate. 

8
PPRPReviewComments,page13

Comments by Section 

Section 1.1 

1st paragraph: Consider replacing the 2nd sentence with: 

“As such, the CEUS SSC model replaces regional seismic source models for this region 

that are currently accepted by the Nuclear Regulatory Commission (NRC) for satisfying 

the requirements of the seismic regulation, 10 CFR Part 100.23, for assessing 

uncertainty in seismic design bases. These include the Electric Power Research 

Institute–Seismicity Owners Group (EPRI-SOG) model (EPRI, 1988) and the Lawrence 

Livermore National Laboratory (LLNL) model (Bernreuter et al., 1989).” 

This change would require some additional editing of the paragraph. 

Note that the proper reference to the EPRI-SOG Project is EPRI (1988). The date should be 

corrected in the References. Note also, that EPRI (1989) contains hazard computations at the 

SOG utility’s NPP sites. This report was not submitted to NRC for review. (See also 

Comments by Section for Chapter 3, under References.) 

2nd paragraph: Consider replacing the 2nd sentence with: 

 “The project used a SSHAC Level 3 assessment process in order to assure compliance 

with the requirements of seismic regulations that uncertainties in the model have been 

properly quantified, evaluating the range of views and interpretations of the technical 

community.” 

And add to the end of the paragraph: “These models are expected to be adopted as part of the 

seismic safety regulatory guidance, replacing the EPRI (2004, 2006) models.” 

Section 1.1.1

“Studies” should be replaced with “Projects” here and throughout the report when referring to 

the EPRI-SOG and LLNL projects. 

Section 1.1.2 

 “Studies” should be replaced with “Expert Elicitation Projects.” In the 1st paragraph, consider 

replacing sentences 4 through 6 with: 

 “These included the EPRI-SOG and LLNL projects.1

 Although both of these large 

projects relied on assessments by multiple experts, there were significant technical and 

procedural differences between the two, and there were large differences in the hazard 

results obtained at many common sites compared by the two projects. The formation of 

SSHAC was motivated by the need to understand these differences and to develop 

guidance acceptable for meeting the requirements for seismic safety regulation of 

nuclear facilities for assessing uncertainty in seismic hazard models”. 

 

1

 See Section 2.1 for a discussion of the history of the SSHAC process. 

9
PPRPReviewComments,page14

 This change would require editing of the subsection as needed to be consistent. 

Typo: In the first sentence of paragraph 2, change “time if their issuance” to “time of their 

issuance” 

Section 1.1.3 

Suggested wording change in the first sentence: “just as important as the basis of the technical 

assessments.” In the subsection heading: “SSHAC Methodology” or “SSHAC Guidance.” 

At the top of p 1-3, the sentence, “As will be discussed in Section 2.2, the roles and 

responsibilities that a SSHAC process defines for all project participants must be scrupulously 

adhered to throughout the process to ensure its success” is overstated. Section 2.2 makes no 

mention that “scrupulous adherence” is a condition for success. Suggestion: 

“The roles and responsibilities of participants in the CEUS SSC project were explicitly 

defined, consistent with SSHAC guidelines for a successful Level 3 assessment project 

(see Section 2.2), and were diligently followed.” 

Section 1.1.4 

“Study” should be replaced with “Project” or “CEUS SSC Model”; edit the subsection as 

needed for consistency. 

Suggested word change in paragraph 2, line 2: “The CEUS SSC model is based on a 

comprehensive, transparent, and traceable process, . . .” 

In the last sentence of paragraph 1, given the purpose of the CEUS SSC project (as described in 

the following paragraph), it seems strange to mention the DNFSB explicitly but not the NRC in 

this first general statement. Suggestion: 

“Standardization at a regional level will provide a consistent basis for computing 

seismic hazard, which will assist regulators such as the NRC [acronym defined earlier 

in section 1.1] and the Defense Nuclear Facilities Safety Board (DNFSB) in their 

oversight of nuclear facilities.” 

Section 1.1.5 

In the last line of paragraph 1 on p. 1-3, change “participated or observed the CEUS SSC 

Project” to “participated in or observed the CEUS SSC Project.” 

Differences from USGS National Seismic Hazard Mapping Project: In the 1st paragraph on p. 

1-4, the quoted AFEs should be verified. The national seismic hazard maps and USGS PSHA 

work is for AFEs in the range of 10-2 to 10-4 (building code maps are developed for an AFE of 

4.04 x 10-4), and the CEUS SSC results will provide results for AFEs in the range of 10-3 to 10-6

for design purposes. 

10
PPRPReviewComments,page15

In the same paragraph, lines 6 and 7, suggested wording change: “critical safety requirements 

of these facilities” rather than “the robustness of these facilities.” [Delete comma preceding 

period at the end of this sentence.] 

In the same paragraph, line 11, suggested wording change: “hypotheses and parameter values 

are included where appropriate” 

In the same paragraph, line 12, consider changing “witnessed in the paleoseismic record” to 

“observed in the paleoseismic record” 

Section 1.2.1 

Consider replacing the section heading with “Regional Seismic Source Model that Represents 

Current Knowledge and Data Uncertainties of the Technical Community” (see Comment 

S 1-1). 

In paragraph 2, line 1, consider changing “proper” to “appropriate.” The last sentence of this 

section discusses the possibility that local sources can be used to refine the CEUS SSC model 

for site-specific application. We suggest that this sentence be deleted. Any change to the 

CEUS SSC model will need to be evaluated in terms of the PSHA distance influence for that 

change. Thus, what constitutes a local SSC model change versus a regional SSC model change 

is somewhat vague. The SSC report should recognize that site-specific studies are required but 

be silent on what happens if these studies indicate an SSC model change. NRC and others will 

have to decide what to do with any recommended SSC change (the distance extent to which 

that change must apply) and whether updates to calculations for “regions” are necessary. 

Section 1.2.2 

The section heading should be changed to “Conducted Using the SSHAC Level 3 Assessment 

Process,” and edit the section to be consistent with the change (see Comment S 1-1). 

In paragraph 1, consider replacing the 3rd sentence with: “For regional seismic hazard 

models intended for use at many sites, the higher assessment levels provide the level of 

assurance required by the regulators for future use in seismic safety decision-making.” 

In paragraph 2, line 9, suggested wording change: “the success of these assessment 

levels is the implemented process followed, which . . .” 

Third paragraph: Time and costs are issues that the regulatory agencies are committed 

to take into account, but reasonable assurance of safety as required by the seismic safety 

regulations and regulatory safety practice are primary. This section should be edited to 

reflect this understanding. Consider replacing the first sentence of this paragraph with: 

“Selection of a SSHAC assessment level depends on the scope and complexity of the 

required evaluations and the intended use of the assessed seismic hazard model.” 

At the end of the paragraph consider adding the sentence: “Moreover, after several 

years experience using the SSHAC Methodology, a Level 3 assessment is now accepted 

for developing regionally-applicable seismic hazard models intended for use over an 

extended time as the starting basis for computing PSHAs at multiple sites.” 

11
PPRPReviewComments,page16

Section 1.2.3 

In paragraph 1, line 3, suggested wording change: “a SSHAC process should not be subject to 

significant change without new hazard-critical scientific findings.” 

Suggested wording change in paragraph 2, line 2: “Although these findings may lead to” 

Suggested wording change in paragraph 2, line 3: “. . . it is likely that the assessment will 

remain viable, avoiding the need for an extensive revision.” 

In paragraph 2, third sentence: The text states, “Longevity means that the model will last for 

several years before requiring a significant revision or update.” The last sentence in the 

paragraph states, “It is expected that the longevity for studies such as the CEUS SSC Project 

will be at least 10 years before there will be the need for a significant revision.” To avoid 

confusion, the wording defining longevity should be sharpened. 

Section 1.2.4 

The section heading should be changed to “Interface with Ground Motion Models” 

Use of the words “debate” and “interaction” in the 2nd paragraph, do not properly 

convey the role of the workshops for implementing the assessment process. Consider 

replacing the last two sentences of the paragraph with: 

 “The TI Team brought together a panel of ground motion experts constituted of 

proponents of the range of available models in a series of three workshops, 

structured to gain a common understanding of the uncertainties in the modeling 

approaches and to structure the evaluation and assessment process for 

representing the uncertainty distribution of the technical community.” 

The subsection should make clear that the Expert Panel represented the range of 

community ground motion modeling knowledge for the CEUS. 

Suggested wording change in paragraph 2, line 8: “The TI Team interacted with the 

Expert Panel to . . .” 

Section 1.3 

As discussed in Comment S 1-1, the word “study” does not convey the activities and processes 

that constitute the SSHAC Methodology. The section heading should be changed to “CEUS 

SSC Model Region.”

Regarding the 4th sentence of paragraph 1: Are there any contributing sources that are in 

oceanic crust? 

In this same paragraph, the text incorrectly (or at least misleadingly) states that “On the north 

and southwest, the study region extends a minimum of 322 km (200 mi.) from the U.S. borders 

with Canada and Mexico.” Examination of Figure 1.3.1 shows that the SSC model region 

extends 200 mi. into Mexico only along the Gulf Coast. It does not generally extend 200 miles 

into Mexico “on the southwest.” 

12
PPRPReviewComments,page17

Section 1.4 

“Study” should be changed to “Project” in the section heading (see Comment S 1-1). 

Section 1.4.1 

In the section heading, use of the word “Complete” is not clear, and the word “Study” is 

misleading. Section heading should be changed to “Seismic Source Model Region.” 

Need to introduce the three stages of the SSC Model assessment: In section 1.4.1, the reader 

should be informed that the SSC Model was developed in three stages—the sensitivity SSC 

Model, the preliminary SSC Model, and the final SSC Model. This can be done effectively at 

the end of this section—prior to Chapter 2 where the terms appear for the first time on p. 2-19 

unexplained. 

In paragraph 1 (see line 10), the text states, “sources of repeated large-magnitude earthquakes 

(M 6.5) earthquakes (RLMEs) are identified . . .” The rationale for selecting the threshold of 

M 6.5 for RLMEs should be explained. 

In this same paragraph, next-to-last line, change “and the forecast future occurrences” to “and 

the forecast of future occurrences” 

Kijko Methodology as “State-of-the-Art”: On p. 1-9 in the first paragraph, the text describes 

“two methods for assessing Mmax: a Bayesian methodology . . . and the Kijko methodology 

that is state-of-the-art within the technical community.” The latter assertion raises questions 

about the Kijko methodology vis-à-vis the project. If state-of-the-art, then why was the 

methodology only considered at a late stage of the project (see p. 2-44) and why was it not 

identified at the USGS Mmax workshop as state-of-the-art? Suggestion for a broad-brush 

statement needed here: “. . . and a well-founded mathematical procedure that estimates Mmax 

based on seismic data (where sufficient) only for the source being considered.” 

Section 1.4.2 

In the 3rd line, consider changing “third party” to “future user” 

In this same paragraph, lines 10–11, consider changing “for a project” to “for seismic hazard 

analysis at a specific site.” 

Section 1.4.4.2 

 In the 4th sentence, suggested word change: “Where applicable, GIS data layers were 

developed, and this included new geophysical data compilations developed specifically for the 

project.” 

Section 1.4.4.3 

In line 4, change “all events up through 2009” to “all earthquakes through 2008.” The project 

catalog (Chapter 3) extends through the end of 2008. 

In line 7, suggested word change: “a number of historical earthquakes were reviewed in order 

to develop reliable moment magnitudes for these shocks.” 

13
PPRPReviewComments,page18

Section 1.4.4.4 

In the title of this section elsewhere in the report, paleoseismicity data tends to be used loosely

as synonymous with paleoliquefaction data. Paleoliquefaction data are a subset of 

paleoseismicity data, which notably include results of geological trenching of active faults, 

such as for the Meers and Cheraw faults. The report includes varied types of paleoseismic data, 

and correct terminology is important for clarity. 

Consider replacing the first sentence of this section with: 

“Because of the emerging use and significance of paleoliquefaction data in the CEUS, 

part of the scope of the project was a compilation of these data and development of 

written guidance for representing uncertainty in evaluations and interpretations of the 

data to estimate the locations, occurrence times, and magnitudes of causative 

earthquakes.” 

Section 1.4.4.5 

The first sentence of the second paragraph is awkwardly worded. Suggestion: “This report 

contains an evaluation . . .” 

 

 

14
PPRPReviewComments,page21

CHAPTER 2 — SSHAC LEVEL 3 PROCESS AND IMPLEMENTATION 

General Comments 

G 2-1. (CBR, CC) This chapter contains generally informative and valuable background 

information, but it does not adequately achieve the goal of explaining the chapter heading for a 

number of reasons: (1) the chapter is not organized effectively, with too much discussion of 

history that, in its present form, distracts from a necessary focus on this project1

; (2) there is not 

enough discussion of what the TI Team did to ensure that they were objective evaluators to 

“represent the center, body, and range of the technical interpretations that the larger informed 

technical community (ITC) would have if they were to conduct the study”; and (3) the 

discussion of the workshops needs to be enhanced to describe what the TI Team did to ensure 

that (a) the workshops focused on the right issues (completeness), (b) the workshop goals were 

met, and (c) the experts who attended the workshops were appropriate and sufficient for the 

purpose of defining the community knowledge and associated uncertainties.

G 2-2. (CC) The discussion regarding a “SSHAC Level 3 process” and the concept of the 

“informed technical community” (ITC) is of great importance for substantiating key claims 

about the implementation and results of the CEUS SSC project. But, it is marred by imprecise 

wording that may contribute to confusion or invite argument. Our Comment S 1-2 (clear 

communication) applies equally to Chapter 2, and we offer additional specific comments to 

help strengthen the logic underpinning key claims in this chapter. 

Specific Comments 

S 2-1. (CC, SSHAC) Explaining the Goals of the Chapter 

Writing always involves individual choice, and there are different ways to explain the goals of 

the Chapter at the outset. In the following example text2

 an attempt is made to give the reader a 

road map—intentionally with a regulatory framework in mind: 

The goals of this chapter are, first, to describe the SSHAC Level 3 assessment process 

and how it was implemented to assess the CEUS seismic source characterization (SSC) 

model and, second, to demonstrate that the implementation was accomplished in 

compliance with the SSHAC guidance. The SSHAC developed guidance for four levels 



1

 There are 16 pages of narrative before the reader finds out what this project did to ensure it was 

executed properly. The described history led to the SSHAC and Hanks reports, which this project uses. 

Understanding the history does not guarantee success. The text needs to focus on what this project 

specifically did to ensure success—Section 2.1.2.2 gets lost as organized. 

2

 As stated in our cover letter, suggested text “should be viewed as suggested alternative wording for 

improved clarity—not a dictation of how the TI Team should word its report.” 

15
PPRPReviewComments,page22

of implementing an assessment, depending on the degree of uncertainty and contention 

involved and the intended use of the seismic hazard model.3

The SSHC guidance emphasizes that, independent of the implementation level, the goal 

of a SSHAC assessment is “to represent the center, the body, and the range of the 

technical interpretations that the larger informed technical community would have if 

they were to conduct the study” (SSHAC, 1997, p. 21). The “center, the body, and the 

range” is taken to mean a representation of the uncertainty in the technical community’s 

knowledge, referred to by the SSHAC as “the community distribution.” The latter, as a 

representation of the uncertainty in the technical community’s knowledge, can be 

termed “the community uncertainty distribution.” A proper representation of the 

community uncertainty distribution appropriately meets the requirements of the NRC’s 

seismic regulation, 10 CFR 100.23 

The SSHAC recommended that a Level 3 or a Level 4 assessment process be used for 

complex assessments, the products of which have high public importance and attract 

public scrutiny, such as regional seismic hazard models intended to be used over a 

sustained time period as base-case models for site-specific PSHAs. Such models 

require the highest level of assurance that the community uncertainty distribution has 

been properly represented. For this project, the decision was made to use a SSHAC 

Level 3 assessment process.4

 The CEUS SSC Project arrived at this decision based on 

experience gained with implementations of the SSHAC guidance, which has shown that 

a properly executed Level 3 assessment process can provide a level of assurance of 

meeting the SSHAC goals comparable to that of Level 4, which is much more costly to 

implement. 

This chapter begins with a discussion of the fundamental SSHAC goal of representing 

the center, body, and range of the technical community’s knowledge, including why this 

goal was developed. This is followed by a discussion of how the SSHAC Level 3 

assessment process has been implemented by the CEUS SSC Project, including the 

roles of key participants, project organization, key activities, and participation of the 

Participatory Peer Review Panel (PPRP). 

S 2-2. (CC, SSHAC) “Capture” and the Informed Technical Community 

We caution the TI Team that repeated use of the word “capture”—a highly nuanced term as it 

relates to the center, body, and range (CBR) of the technical interpretations of the ITC—may 

confound clear thinking.



3

 Seismic hazard model is used here and elsewhere in these comments to mean either an SSC model or a 

Ground Motion model. 

4

 See Section 3 of the CEUS SSC Project Plan (June 2008). 

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PPRPReviewComments,page23

In its 1997 report, the SSHAC most often uses the words “represent” or “a representation of” 

for actions relating to “the center, the body, and the range of technical interpretations that the 

larger informed technical community would have if they were to conduct the study” (SSHAC, 

p. 21).5

 In Chapter 2, the dominant action word used for the CBR is “capture,” emphasized, for 

example, by the headings for sections 2.1.2 and 2.1.2.2. Coppersmith et al. (2010)6

 use 

“capture” (at least 17 times) in the context not only of the CBR but variously in terms of 

capturing uncertainty, capturing insights, capturing the community distribution, capturing rate 

of occurrence and randomness, and so on.

The problem with capturing the CBR of technical interpretations of the ITC, as opposed to 

representing them, is that it invites critical scrutiny of what may have been left out, not fully 

preparing the reader for the need to understand important concepts dispersed elsewhere in the 

report—notably, identification and due consideration of alternative views, allowance not to 

include views judged to have an insignificant effect on the hazard, and the integration function 

performed by the TI Team in its role of assessing and representing the CBR of the ITC.

S 2-3. (CC) Claim that CEUS SSC Robustly Implemented SSHAC Guidance 

On p. 2-1, par. 2, the text states: 

“These sources, as well as projects conducted prior to the development of SSHAC 

guidance, offer confirmation that the CEUS SSC process was a robust implementation 

of both the “spirit” and the “letter” of the law, namely SSHAC.” 

It is illogical to say that prior sources “confirm” a later “robust implementation.” And it 

is misleading to refer to SSHAC guidelines as “the law.” The astute reader will 

compare the claim made in this introductory part of Chapter 2, with the conclusion 

eventually reached in section 2.1.2.3 (p. 2-23), where one finds wording such as 

“addressed adequately,” “preponderance of evidence,” and “reasonable assurance.”



5

 The PPRP anticipates discussion with the TI Team regarding terminology. The term “community 

distribution,” used by the SSHAC (SSHAC, p. 22), may offer a useful compact term to avoid having 

repeatedly to refer to the center, body, and range of the informed technical community (ITC). It may 

also help avoid fixation on the ITC (see Comment S 2-4) by appropriately focusing on the distribution

of the technical community’s knowledge (and lack thereof), which the TI Team has the responsibility to 

represent through its evaluation and integration functions. 

6 Disclosure: Two members of the PPRP (J. Ake and A. M. Kammerer) are coauthors of Coppersmith et 

al. (2010), which is one of three sources cited and used in Chapter 2 as a basis for correctly interpreting 

SSHAC guidance.

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PPRPReviewComments,page24

Suggestion:

 “These sources, as well as projects conducted prior to the development of SSHAC 

guidance, provide a basis for concluding that the CEUS SSC assessment process 

followed in a robust way both the “spirit” and the “letter” of SSHAC guidance. The 

end result is reasonable assurance that the CEUS SSC final model achieves the primary 

goal intended by the SSHAC guidelines.” 

S 2-4. (SSHAC, CC) Importance of “Site-Specific” Knowledge and Being “Informed” 

In section 2.1, p. 2-2, par. 2, the text emphasizes that, “what constitutes an ‘informed’ member 

of the technical community” is “knowledge of site-specific and other relevant data.” The 

CEUS SSC model is described to be a regional seismic source model, to be modified by 

including local seismic sources, if needed, for site-specific application as required by the 

seismic regulatory guidance—Regulatory Guide 1.208. So the need for site-specific 

knowledge in the case of the CEUS SSC may confuse the reader. Overall the argument seems 

weak. Moreover, the notion itself of an informed community causes confusion and debate 

because it implies reliance on a subgroup with “specialized knowledge.” The confusion and 

debate comes about because this notion conflicts with regulatory safety decision-making 

principles and practice and is distasteful to the larger scientific community. 

The PPRP believes that defining the qualifications a person must have to be accepted as an 

“informed member” of the scientific/technical community is disruptive. While it is not possible 

to recover the thinking process of the SSHAC, it is possible and essential to consider the 

“informed technical/scientific community” within regulatory safety decision-making practice. 

In all regulatory practice, all experts with equal subject-matter training are accepted as being 

equally informed for purposes of regulatory decision-making. Regulatory practice does not 

accept a special subset of the members of the scientific community as being more expert; it is 

counter-productive to promote such a designation. That is why standards of practice form the 

foundation for making regulatory safety decisions and why seismic safety decisions for nuclear 

facilities are made by means of a structured regulatory process. Implementation of such a 

process is accepted by the NRC for performing evaluations, analysis, and assessments to 

demonstrate compliance with the seismic safety regulations—and reasonable assurance of 

safety.

The SSHAC Methodology is one of the standards of practice that together constitute the NRC’s 

seismic regulatory guidance. What will provide reasonable assurance that the CEUS SSC 

model represents the center, body, and range of the current scientific and technical knowledge 

is proper implementation of the SSHAC assessment process—not that the TI Team, whether 

large or small, was made up of special “informed” experts.

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PPRPReviewComments,page25

We recommend that the entire argument in Section 2.1, at least through Subsection 2.1.1.1, be 

changed and framed in the context of (a) the seismic safety decision-making process and 

practice and (b) the role of the SSHAC Guidance within the NRC’s decision-making process 

for nuclear facilities. The terminology “informed technical/scientific community,” coined by 

the SSHAC, has to be understood in this context.

S 2-5. (CC) Historical Context and Evolution of Use of Expert Assessment (Section 2.1.1) 

The length of this subsection detracts from this chapter. While this section is informative, 

Sections 2.1.1 through 2.1.2.2 and Table 2-1 could be moved to an appendix, with a short 

summary provided here. Also, the text (specifically in Section 2.1.2) and Table 2-1 would be 

improved if the authors provided their thoughts on how well the experts or expert teams did as 

evaluators for those projects that were completed at a SSHAC Study Level 4. It is our 

impression that results are mixed in this regard. If the authors agree, this should be discussed 

and noted.

 In order to completely chronicle the origins of the NRC’s probabilistic seismic hazards 

program, it should be stated that during the mid to late 1970s, the Advisory Committee 

on Reactor Safeguards (ACRS) persistently urged the NRC to undertake research aimed 

at quantifying the uncertainty embodied in SSEs derived following the requirements of 

the seismic regulation 10 CFR Part 100, Appendix A, which had been adopted in 1973.

The ACRS also urged the NRC to undertake a parallel program with the aim of 

quantifying the margin embodied in the NRC’s seismic design criteria and procedures. 

In response, the NRC developed and funded a seismic margins research program and, a 

short time later, a seismic hazard research program, both conducted by the Lawrence 

Livermore National Laboratory (LLNL). The seismic hazard research program adopted 

from the decision analysis community the structure and formalism of classic expert 

elicitation processes. 

S 2-6. (CC, SSHAC) “Capturing” the Center, Body, and Range (Section 2.1.2) 

Consider changing “Capturing” to “Representing” in the section title. 

As a lead-in to Section 2.1.2, consider this example text (see also Comment S 2-4):

Reasonable assurance is the standard for reaching administrative decisions about public 

safety across the spectrum of hazards to which the public is exposed. Regulations, 

regulatory guidance, regulatory review, and administrative hearings all invoke the 

standard of reasonable assurance. Regulations state the safety requirements, regulatory 

guides provide guidance for technical methods and procedures that are accepted for 

demonstrating compliance with applicable regulations, regulatory review provides 

reasonable assurance that regulatory guidance has been properly implemented, and an 

administrative hearing determines whether the safety conclusions are supported by 

preponderance of the evidence developed by the regulatory review process.

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PPRPReviewComments,page26

In this safety decision-making process the SSHAC assessment process is a technical 

process accepted in the NRC’s seismic regulatory guidance for reasonably assuring that 

uncertainties in data and scientific knowledge (stated by the SSHAC as the center, 

body, and range of views of the informed scientific community) have been properly 

represented in seismic design ground motions consistent with the requirements of the 

seismic regulation 10 CFR Part 100.23. 

S 2-7. (CC) “Standard of Proof” (Section 2.1.2.1) 

Better wording for the title of section 2.1.2.1 would be “The Reasonable Assurance 

Standard,” which is the primary focus of this subsection. The claim made in the fourth 

sentence of this subsection that, “there is no need for such proof” is out of place (the 

claim is explained later in the second paragraph).

Based on arguments made in our Comment S 2-5, we recommend deletion of the entire 

first paragraph of this subsection and revision of the remainder. The standard of proof 

is reasonable assurance, and reasonable assurance is demonstrated by proper 

implementation of the NRC’s regulatory decision-making procedures. In the instance 

of the CEUS Project reasonable assurance that the CEUS SSC Model represents the 

center, body, and range of the views (prefer knowledge) of the scientific community is 

demonstrated by proper implementation of the SSHAC Level 3 assessment process. 

S 2-8. (CBR, SSHAC) Evidence That CEUS SSC Project Has Captured the Informed 

Technical Community (Section 2.1.2.2) 

 Adherence to the SSHAC guidelines is necessary evidence, but it is not sufficient to show that 

the CBR of the technical community has been represented in the assessment. How can 

sufficient evidence be obtained? Certainly that is not easy, but sufficiency can be approached 

by peer review of the report. That is what the review of the draft report by the PPRP, the 

USGS, and supporting parties is doing. These parties are judging the completeness of the 

process carried out by the TI Team. The question is, do these reviews achieve the goal of 

evaluating the results of the process? This will be a subjective appraisal. It would be well for 

the report to discuss the subjectivity of the evaluation and the role of reviews in the evaluation.

 This subjectivity is acknowledged in Section 2.1.2.1 [Standard of Proof] in the description of 

the technical community as a “hypothetical community” and the regulatory use of reasonable 

assurance. The idea that the technical community is hypothetical is contrary to seismic 

regulatory principles and practice (see our Comment S 2-5). There is a very real technical 

community that has developed the evidence and views regarding specific topics that are 

important to seismic source characterization and assessment in the CEUS. This community 

does not consider themselves to be hypothetical.

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PPRPReviewComments,page27

S 2-9. (CC) PPRP Attendance at the Eight Working Meetings of the TI Team: 

The report contains differing statements about the attendance of PPRP observers at the TI Team 

Working Meetings: 

“All of the working meetings were observed by one or more members of the PPRP.” (p. 

2-20)

“[The PPRP] participated in many TI Team working meetings to plan and review the 

process and progress of the project.” (p. 2-36) 

“One to three representatives from the PPRP attended the working meetings in order to 

observe the deliberation and technical assessment processes.” (p. 2-42) 

For the record, PPRP attendance was as follows: 

WM # 1 

WM # 2 Hinze, Kammerer, Kimball 

WM # 3 Ake, Petersen 

WM # 4 

WM # 5 

WM # 6 Ake, Stepp 

WM # 7 Ake, Arabasz, Kimball 

WM # 8 Kammerer 

Comments by Section

Chapter 2 (Title) 

In order to emphasize that the CEUS SSC Project implemented an assessment process, we 

recommend the Chapter title be changed to: SSHAC LEVEL 3 ASSESSMENT PROCESS 

AND IMPLEMENTATION (see Comments S 1-1 and S 1-2).

Chapter 2 (Introductory Text) 

Spell out PPRP when it is first used in report. 

Section 2.1 

p. 2-2, par. 3, line 3: “the data that applies” (inconsistency: data used as singular here; 

plural elsewhere in report)

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Section 2.1.1 

par. 1: The text states, “The SSHAC report was written in response to an evolution of 

expert risk assessment methodologies that had been conducted for purposes of 

probabilistic risk analyses during the previous three decades.” According to the 

footnote on p. 34, the only identified studies predating the SSHAC report that dealt with 

risk were the WASH-1400 study and the NUREG-1150 study; all the other studies 

dealt with hazard.

Section 2.1.1.1 

p. 2-5, par. 3, line 1: Change “The EPRI-SOG study” to “In the EPRI-SOG Project” 

p. 2-7, next-to-last par.: “and offered a prophecy for future guidance:” What exactly is 

prophesied in the subsequent quoted text? Suggestion: “and future guidance was 

envisioned”

Section 2.1.1.2 

p. 2-10, par. 2, line 7: Suggest replacing “third party” with “future user” 

p. 2-11, par. 2, line 3: Suggest replacing “gone up” with “increased” 

p. 2-11, par. 2, second sentence: There is unclear phrasing in the second half of this 

critical sentence. The difference between the PEGASOS results and the older results 

were shown to be due to “an appropriate treatment of the ground motion aleatory 

variability and an error in the calculations in the previous hazard studies (NAGRA, 

2004, Section 8.4.2).” Was the treatment appropriate in the older studies or in 

PEGASOS? 

p. 2-11, par. 2, line7: “to discredit the study” — Clarify which study is being referred 

to.

p. 2-11, par. 3, line 11: Change “TI” to “TI Team” 

p. 2-11, par. 3, line 2: Because ESP and COL appear in the list of Acronyms, consider 

writing, here at their first mention in the text, “Early Site Permits (ESPs) and Combined 

Construction and Operating License (COL) applications”

p. 2-11, par. 3: The narrative of what happened in the EPRI (2004) Level 3 process is 

confusing. The text describes that “A small TI Team was responsible for the 

assessments and a panel of resource experts/proponents provided their views of the 

existing ground motion models and their applicability to the CEUS.” Subsequent text 

describes the problem of the experts not taking ownership of the resulting composite 

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PPRPReviewComments,page29

model. As written, why would “resource experts/proponents” be expected to take 

ownership? In the EPRI (2004) Project, the TI Team requested that the Resource 

Expert Panel endorse the assessed model. The Panel did not challenge the 

implementation of the assessment process, but persisted in the role of proponent 

experts, insisting that their proponent model should have more weight. 

Suggestion:

“A lesson learned in the project was that if broad expertise is needed to perform the TI 

role of representing complex technical views of the informed technical community, then 

a small TI Team may not suffice. In the case of the EPRI (2004) assessment, the panel 

of ground-motion experts was not charged with the TI role, but they were asked to 

review and endorse the assessed ground motion model; individual members of the panel 

persisted in acting as proponents, advocating higher weighting of their individual 

proponent models. Subsequent Level 3 . . .” 

p. 2-11, par. 3, last line: Suggest replacing “claim” with “accept: 

p. 2-11, last paragraph, line 6: Suggest deleting “developing” 

p. 2-12, line 1: Typo. Change “significance advances” to “significant advances” 

Section 2.1.2 

par. 1, third sentence: What is meant by “many of the technical issues that drive 

seismic hazard . . . are rare?” Suggestion: Delete “rare and” 

Section 2.1.2.1 

par. 1: See Comment S 2-3 regarding the notion of “capturing the informed technical 

community.” If the authors insist on using “capture,” for clarity at least describe 

capturing the views or technical interpretations of the informed technical community—

not the jargon of “capturing the informed technical community.” 

p. 2-17, par. 1, last line: Typo. “have the like highest likelihood” 

p. 2-17, par. 3: It will be helpful to clarify for the reader that what is “not yet available” 

is not the article written by Coppersmith et al. (2010) but rather the NUREG document 

discussed in Coppersmith et al. (2010). Suggestion: “to develop a NUREG-series 

document (see Coppersmith et al., 2010).” 

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PPRPReviewComments,page210

Section 2.1.2.2 

In the discussion of Item 3 (Provide a uniform data base to all experts), mention should 

be made of the development of the seismicity catalog. 

p. 2-19, par. 2, last sentence: What “will provide a valuable methodology step for 

future Study Level 3 projects” isn’t “these tables” but rather something like “the 

structure of these tables.”

On p. 2-19 near the end of the next-to-last paragraph, the reader encounters, for the first 

time, “the development of the sensitivity SSC model, the preliminary SSC model, and 

the final SSC model”—terms which aren’t explained until the bottom of p. 2-20. These 

are fundamentally important for the reader to understand. A good place to introduce the 

reader to these terms would be at the end of Section 1.4.1, explaining that the SSC 

model was developed in three stages. 

On p. 2-10, Item 5, 7th bullet: Typo. “Renewal vs. Poison Poisson recurrence models.” 

p. 2-19, last par.: For complete documentation (useful for future readers) give the dates 

of the maximum magnitude workshop in Golden, Colorado, and the CEUS workshop in 

Memphis, Tennessee. 

p. 2-20, Item 5. Elicit SSC judgments from experts: The text describes eight working 

meetings of the TI Team and goes on to state that “Each working meeting was 

structured around a particular aspect of the project, as follows:”—but ten bullets follow, 

not eight. To compound the problem, a different list of eight bullets later appears on 

p.2-41 to describe the focus of the eight meetings. On p. 2-37 under the header TI 

Team, mention is made of nine working meetings. 

Section 2.1.2.3 

Where are the conclusions regarding the selection of the study level—an important part 

of the process? 

Section 2.3 

par. 3: Change “TI Lead” to “TI Team Lead” consistent with the organizational chart in 

Figure 2.3-1. 

p. 2-37, par. 2: To soften jargon, consider replacing “Technical Integrator (TI) Team” 

with “Technical Integration (TI) Team” 

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PPRPReviewComments,page211

Section 2.4.2 

par. 1, line 9: Text states, “annual frequencies of interest (e.g., 10–4 to 10–7/yr) for 

nuclear facilities.” Executive Summary states 10–4 to 10–6/yr. 

Section 2.4.3

The text should describe what was done to identify resource experts for Workshop #1 

and the approach used to ensure that the experts who participated in the workshop were 

appropriate and sufficient. 

Sections 2.4.3 and 2.4.4 

It would be helpful to have more references to the workshop information in the 

appendices, particularly the workshop summaries and the presentations. 

Section 2.4.4

The text should describe what was done to identify proponent experts for Workshop #2 

and the approach used to ensure that the experts who participated in the workshop were 

appropriate and sufficient. 

Section 2.4.8

A short summary of the purpose of the Data Summary and Data Evaluation tables and the use 

that was made of them would be informative here. 

Section 2.4.9.1 

The HID is a valuable document. It would be useful here to expand on its purpose and to note 

specifically that this document is meant for the analyst—providing clarity about the model to 

be implemented and obviating the need to distill the model from the full report. This document 

helps assure that implementation of the model (which is sometime challenging) is as intended. 

Section 2.4.9.2 

First sentence: This sentence appears to be the objective of the report. Suggest that it be 

moved forward or reappear in an appropriate place in Chapter 1. 

Table 2-2 

Under “Other Technical Experts . . .” there are duplicate entries for Al-Shukri and Mueller 

To avoid confusion about the listing of names in this table, delete “Other” in “Other Technical 

Experts” because some of the experts are also listed in the first two categories of the table.

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PPRPReviewComments,page31

CHAPTER 3 — EARTHQUAKE CATALOG 

General Comments 

G 3-1. (NAR) This chapter summarizes the project approach to developing the earthquake 

catalog for use in the CEUS seismic source model. The process followed in this project is 

similar to many others in that it consists of three basic elements: (1) assembly of available, 

relevant sources of earthquake data into a single, magnitude-consistent earthquake catalog; (2) 

identification of dependent events; and (3) evaluation of catalog completeness. 

G 3-2. (NAR) Chapter 3 is arranged logically as it describes the goals for earthquake catalog 

development (Section 3.1), the compilation of available data from continental and regionalscale catalogs as well as special studies (Section 3.2), development of various relationships to 

convert all earthquake size estimates to moment magnitude (Section 3.3), catalog declustering 

(Section 3.4), and catalog completeness (Section 3.5). 

G 3-3. (NAR) It is appropriate to emphasize that, the comments below notwithstanding, the 

catalog that has been developed for this project represents a major achievement and is a real 

step forward for the entire seismic hazard community. It is a major improvement over previous 

catalogs in that it incorporates more regional catalogs and has developed moment magnitude 

estimates for all the earthquakes. The efforts of the TI Team, together those of collaborators 

from the USGS and the Geological Survey of Canada (GSC), are to be commended. The 

detailed and thorough approach followed has led to a product that will be widely used. The TI 

Team, USGS, and GSC staff should consider producing something in the open literature that 

documents this work. The development of a specific catalog for non-tectonic events in this 

region may not seem like an interesting product, but for practitioners in this field it will be very 

useful (especially if it is maintained over time). 

Having said the above, in order to achieve a clear and complete description of the efforts that 

went into developing the catalog and of the results, Chapter 3 needs to be improved, as we 

proceed to explain. 

G 3-4. (CC) The text and explanation of figures in Section 3.3 are too terse. The 

knowledgeable practitioner may be able to “read between the lines” or infer the meaning of 

unexplained dashed and dotted lines on many of the figures, but the documentation for this 

project report must be clear and complete for all readers. 

G 3-5. (CC) This chapter would be enhanced by a description of the problems associated 

with obtaining useful focal depths in the region, limitations on focal-depth resolution, and 

general observations or conclusions regarding the depth of earthquake foci in the CEUS. 

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PPRPReviewComments,page32

Specific Comments 

S 3-1. (CC) Non-PPRP Review Comments

Section 3.1 documents the emphasis placed on the earthquake catalog as it provides the basic 

earthquake rate information that “drives” the seismic hazard model for most of the CEUS. This 

section describes the process of compiling the relevant catalogs and data sources and 

summarizes the rationale for returning to the basic data sources for magnitude or intensity data. 

A brief synopsis on review of the catalog by other interested and experienced seismologists is 

contained in Section 3.1.3. However, no mention is made of any results, comments, or changes 

due to those reviews (hence uncertainty whether suggested changes were implemented in the 

final catalog). Will those review comments (particularly those of the USGS) be part of the 

project documentation in any form? They do not appear as an Appendix. Will they be 

documented in project files in a form that could be retrieved by interested individuals? 

S 3-2. (CC) Clarity and Completeness in Figures

The meaning of different line symbols is incompletely explained on several of the magnitudeconversion figures. On Figures 3.3.1-1 and 3.3.1-2, the addition of an added point to extend the 

regression to lower values needs more explanation and justification. On Figure 3.3.4-1, the 

labeling in the Explanation of “CEUS dependent catalog” makes the content on the figure 

ambiguous. The text on p. 3-11 states that “the catalog of earthquakes” is shown on the 

figure—but two sentences later, the text states, “Therefore, dependent earthquakes (foreshocks 

and aftershocks) must be identified . . . .” So “dependent catalog” can be read as the catalog of 

dependent events. 

S 3-3. (CC) Corrected Moment Magnitudes from Atkinson

Section 3.3 provides the summary of the development of the various conversions of earthquake 

size measures (instrumental magnitude or macro-seismic observations) to moment magnitude. 

This step is essential to ensure consistent earthquake counts and compatibility with modern 

ground motion prediction equations. Section 3.3.1.1 describes the first of the specific 

instrumentally determined moment magnitude studies utilized (Atkinson, 2004). To make it 

clear to the reader how the conversion was carried out, additional detail should be added to 

3.3.1.1. This additional discussion will ensure that the other 3.3.1.x sections are clear. For 

instance, for events that are used from Atkinson’s study, our understanding is that her estimated 

M values are “corrected” to moment magnitudes consistent with the results of waveform 

inversion studies for those events. If this is not what was done, considerably more detail must 

be supplied as the correction process is not clear to the PPRP. 

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S 3-4. (CC) Approximate vs. Instrumentally Determined Moment Magnitudes

In Section 3.3.1, second paragraph, the text notes that some “moment magnitude estimates 

were obtained from three studies that determined M by approximate methods . . . .” As part of 

the project documentation, it would be helpful to identify these earthquakes in a table 

(presumably, the number involved is manageable). Also, to aid future users of the catalog, and 

for transparency, instrumentally determined moment magnitudes in the Earthquake Catalog 

should be flagged—ideally in Appendix B, or in files available to interested parties. 

S 3-5. (DMM, U, CBR, CC) Sensitivity of Recurrence or Hazard to Choice of Declustering 

Method

Section 3.4 provides a discussion of the approach used to perform declustering of the 

magnitude-corrected earthquake catalog. Because the PSHA formulation used for area source 

zones relies on the assumption of earthquake occurrences following a Poisson process, it is 

necessary to identify any dependent events in the catalog and remove them prior to performing 

any rate calculations. A number of different approaches have been used in the past to perform 

declustering analyses in major seismic hazard studies. The work of Gardner and Knopoff 

(1974), Reasenberg (1984), and Reasenberg and Jones (1989) have been widely used. The 

Gardner and Knopoff technique, as well as similar region-specific methods (Urhammer, 1986; 

Gruenthal, 1985), rely on removing events within fixed magnitude-dependent time and distance 

windows about a “main” earthquake. The method developed by Reasenberg defines variable 

space-time windows for individual event clusters using statistical tests and related to a 

particular model of aftershock occurrence. 

In contrast, the approach that has been used in the CEUS-SSC study is a stochastic approach 

developed in the mid-1980s as part of the EPRI-SOG Project. Section 4.3 cites EPRI (1988) as 

the source document for this approach to declustering, this reference is missing from the 

reference list (see note on EPRI references below). The EPRI approach begins by treating each 

earthquake as a main event and then evaluates the rate of earthquake occurrences within a 

“local window” about the main event and compares that rate to that within an “extended 

window,” i.e., one larger in space-time dimension. If the rate of earthquakes within the local 

window is significantly higher (based on an un-specified statistical test) than within the 

extended window, then smaller events are removed within the local window until the rate 

approaches the extended window (“background”) rate. However, in regions of low seismic 

activity, stable estimates of rate in the larger window can be problematic and hence lead to bias 

due to the unwarranted removal of events. 

The PPRP has several specific concerns related to the approach taken to declustering of the 

catalog used in the CEUS SSC Project: 

1. The lack of clear documentation. The discussion of declustering in Section 3.4 is less than 

one page long. The discussion and development of the EPRI declustering algorithm 

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contained in EPRI (1986, Vol. 1, Pt. 2, Sections 3 and 4) runs to more than 20 pages and is 

not trivial to follow. EPRI (1988) contains a thorough discussion of the various 

declustering approaches and the assumptions associated with each. The EPRI declustering 

method was designed to minimize the number of assumptions required about the clustering 

process. The description of the adopted declustering methodology in Chapter 3 needs to be 

significantly expanded. 

2. Given that the declustering fundamentally alters the number of earthquakes in the catalog 

for calculations of recurrence—and thus hazard, more discussion is warranted about 

associated uncertainty. What are the implications if a different method were used (e.g., the 

Gardner and Knopoff method, which reportedly produces 15 percent fewer dependent 

events and thus more main events)? In the case of the EPRI-vs.-Gardner and Knopoff 

comparison, were smaller magnitude bins systematically more affected? This issue of 

uncertainty associated with declustering methodology could be addressed in one of two 

ways: (1) sensitivity studies displaying the impact that this assumption has on recurrence 

relationships or hazard results, or (2) explicit consideration of alternative declustering 

models each with an appropriate weight. If sensitivity calculations aren’t explicitly made, 

can experience from other PSHAs be used to amplify on uncertainties associated with the 

choice of the declustering method? Also, because any declustering algorithm is sensitive to 

the choice of declustering parameters used, some discussion is warranted about the efforts 

made in the earlier EPRI Project to determine suitable parameters for the CEUS. 

3. EPRI (1988) is in the open literature. However, it is difficult to obtain, not widely used 

outside a small number of individuals, and in the view of the PPRP, not uniquely 

representative of the CBR of the ITC. If it is the position of the TI Team that in fact the 

EPRI declustering approach is superior to all other approaches and the only approach that 

should be considered, then that needs to be more clearly articulated and documented. In 

point of fact, the EPRI approach has been used only by a few of the teams in the Yucca 

Mountain PSHA and in updates to the EPRI-SOG seismic source model used for recent 

COL/ESP applications. The seismic source characterization teams in the PEGASOS 

project used either the Gardner and Knopoff approach or variants thereof, or a modified 

version of the Reasenberg approach. Most other seismic hazard studies for critical facilities 

in the US have used similar approaches to those in PEGASOS. Alternative approaches to 

declustering should be examined, documented, and if warranted considered for inclusion in 

the present study to satisfy the goal of capturing the CBR of the ITC. 

4. Figure 3.4-1 displays the results using the EPRI (1988) procedure, showing dependent 

event time and distance windows for events down to about M*

 = 2.5. Are these considered 

large events? Note: definition of main, large, and independent earthquakes needs to be 

clearly articulated in this section. If the PPRP is interpreting these figures properly the 

estimated time windows for many individual small (M* < 4) events are significantly longer 

than time windows for many individual larger (M* from 5.5 to 6) events. For M*

 just below 

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5, the time window ranges from 4 days to about 6.5 years. The PPRP questions if that range 

would be endorsed by the broader community of observational seismologists. Based on the 

information provided, it is not clear whether these outcomes are unique to the model 

selected, and whether the model properly models the uncertainty associated with identifying 

dependent events. 

S 3-6. (DMM, CC, U) Catalog Completeness

Section 3.5 describes the approach used to assure catalog completeness in the CEUS SSC 

Project. The methodology used for catalog completeness is that developed in the EPRI-SOG 

Project and works with the uniform magnitude, M*. The EPRI approach defines spatially 

discrete zones that have uniform levels of magnitude completeness and defines magnitude 

specific probabilities of detection (PD) in each. For the CEUS SSC Project, the TI Team 

augmented the completeness regions used in the earlier EPRI study slightly to address 

additional catalog information and to properly cover the current study region. 

Many of the same comments made regarding Section 3.4 can be made regarding Section 3.5. 

The lack of detail and clarity make a proper evaluation of this section virtually impossible. The 

sole reliance on reference to the EPRI documents as the technical basis fails to meet the 

standard of documentation required in a study of this scope. It is not discussed in this section, 

but the probability of detection thresholds defined and shown in Table 3.5-1 were derived by 

simultaneously maximizing the log likelihood functions for PD as well as the “a” and “b” values 

in the earlier EPRI approach. Based on our reading of Section 5 it is not clear if the same 

approach was used in the current study. As with the discussion of declustering, there are 

alternative methods for performing completeness assessments in the literature and those should 

at least be discussed and evaluated. The PD and equivalent time period of completeness 

methodology used is quite powerful as it maximizes the number of events used from the 

declustered catalog. However, it needs to be more completely described and evaluated against 

alternative methodologies if it is to be the sole approach used. 

Comments by Section 

Entire Chapter 

The word “study” should be replaced with “project” throughout the chapter where used in as 

part of the designation of an integrated assessment project; e.g., “EPRI-SOG Project”, “this 

project”, and so on. 

Section 3.1 

Suggestion: The reader would find a summary preceding this to be helpful. 

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Sections 3.1.1 through 3.2.2 

Numerous acronyms are unexplained and do not appear in the list of acronyms. These include: 

SUSN, NEIC, PDE (p. 3-1), ISC, ANSS (p. 3-3), CERI (p. 3-4), NEDB (p. 3-5) 

Section 3.1.1 

 p. 3-1, par. 2, line 1: Change “CGS” to “GSC” 

Section 3.1.3 

line 3: Typo. “Therefore, and an important part of the catalog development process was 

review by seismologist seismologists with extensive knowledge . . .” 

line 7: Affiliation for Martin Chapman as “Virginia Technological University” is incorrect. 

The school is called either Virginia Tech or Virginia Polytechnic Institute and State University 

(see http://www.vt.edu/). 

Section 3.2 

p. 3-3, 1st paragraph: It would be helpful to give an example of the numbering scheme as it is 

not entirely obvious how the scheme will appear in the summary catalog. 

Section 3.2.1 

p. 3-3, 1st paragraph, line 3: Typo. Change “and primary earthquake listing” to “and the

primary earthquake listing”) 

p. 3-3, 2nd paragraph: EPRI (1988) reference is missing. (Please see comment on EPRI 

references below.) 

Section 3.2.3 

p. 3-4, 1st paragraph: Typo in line 3? (“locations and/or depths”?); in line 6, change 

“Boatwrigth” to “Boatwright” 

p. 3-4, 2nd paragraph: Typos. Change “catalog” to “catalogs”; “are area” to “an area”); “The 

second is” to “the second was” (for consistency with tense in preceding sentence). 

Section 3.2.4 

p. 3-4, 3rd line: Reference to Section 3.2.4 should be to 3.2.3 

Section 3.2.5 

The scheme for assigning order of preference to events located south of the US-Canada border 

is not clear. We assume that all the regional networks have equal weight and events located 

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near New Madrid would default to CERI or St Louis University, and if in New Jersey would 

default to Lamont Doherty. If not, this needs to be made clearer. 

Section 3.3.1.1 

line 5: Typo. Change “over estimates” to “overestimates” 

Section 3.3.1.3 

Typos. In line 2, change “an coda wave technique” to “a coda wave technique”); in line 4, 

change “abet” to “albeit” 

Section 3.3.2.1 

Define fN, and FN

Section 3.3.2.2 

5th line and equation 3.3.2-3: Missing word and typo. “The Johnston (1996) relationship is 

reasonably consistent with the project data. Also, is Equation 3.3.2-3 the Johnston (1996) 

relationship, and is that what was actually used? Not clear as written. 

Sections 3.3.3.1 and 3.3.3.2 

Unclear whether the locally-weighted least-squares fit or a constant offset model was used in 

the conversions between MN and mbLg to moment magnitude M, as shown on Figures 3.3.3-1 

and 3.3.3-2. 

Section 3.3.3.2 

Add a sentence after the equation indicating the variables ZCAN and Z1995 are as defined in 

Section 3.3.3.1. 

Section 3.3.3.3 

Suggestion: “The A third mb body-wave magnitude scale (mb) is also more commonly used in 

the US than in Canada . . . .” Also note that mbLg is used in this section when it should be mb. 

Perhaps add a reference for robust regression. 

Section 3.3.3.5 

Typo in first sentence. Should be surface-wave magnitude (MS) not “local magnitude ML”; the 

same error is in equation 3.3.3-5. 

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Section 3.3.3.8 

The discussion of unknown magnitude (MU) is not clear. For any given earthquake, how was 

the decision made as to which conversion should be used? 

Section 3.3.4 

p. 3-10, line 3: Typo. Change “Section s” to “Sections” 

p. 3-10: Following equation 3.3.4-1, the reference to E[M|X] should perhaps indicate this is 

illustrated by the confidence interval for the mean shown on Figures 3.3.1-1, 2, 3 etc. for 

example. We suggest that equations 3.3.4-2 and 3.3..4-3 be double checked as comparison 

with equations 3-8 and 3-9 in Vol.1. Pt.2 of the EPRI-SOG report indicates some discrepancies. 

Since the corrected magnitudes are ultimately used to derive the “b-value” one may wish to 

comment on the sensitivity (or hopefully lack thereof) to the “b-value” used in equation 3.3.4-

3. In equation 3.3.4-4 the 2

M|M instrumental is not clear. Is it the 0.1 value assigned to the 

instrumentally determined values referenced in the paragraph above equation 3.3.4-1? 

p. 3-10, last paragraph: The text states, “As discussed in EPRI (1988) uncertainty in the 

magnitude estimates and its propagation through the magnitude conversion process introduces 

a bias in the estimated earthquake recurrence rates.” It would be helpful to the general reader 

to add some explanatory detail, rather than placing the burden on the reader seek another 

publication to understand the purpose or basis of the information that follows. 

Section 3.4 

 p. 3-11, par.1,line 6: The text states, “The standard method of creating a catalog of 

independent earthquakes developed by Gardner and Knopoff . . . .” It is misleading to describe 

the Gardner and Knopoff procedure as “the standard method.” Researchers in earthquake 

statistics outside the U.S. would likely use Ogata’s well-established epidemic-type aftershock 

sequence (ETAS) model as the basis for declustering. 

p. 3-11, par. 1, next-to-last sentence: In the report, “large” earthquakes are defined as M 6.5, 

so it is confusing to write “and distance interval about a large earthquake.” Suggestion: “and 

distance interval about a relatively large earthquake.” 

p. 3-11, par. 1, last sentence: The text states, “If the rate of earthquakes is significantly higher 

than the background rate . . . , then earthquakes are removed until the rate becomes consistent 

with the background rate.” Does this mean that a few earthquakes that would clearly be 

declared as aftershocks, say by Gardner and Knopoff, remain in the final catalog in order to 

match the background rate? In other words, is the declustered catalog not strictly a catalog of 

main shocks? 

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p. 3-11, par. 2, second sentence: For clarity (because Figure 3.4-1 contains two plots), consider 

writing, “The data points in the two plots represent the length in days of individual clusters and 

the maximum distance between earthquakes assigned to a cluster, respectively.” 

p. 3-11, par. 3, first sentence: Typo. Change “European earthquake” to “European 

earthquakes” 

p. 3-11, par. 3, last sentence: The narrative describing that the EPRI procedure identifies about 

15 percent more dependent events may confuse readers examining Figure 3.4-1. For clarity, 

consider cautioning the reader not to confuse numbers of dependent events with the number of 

data points for dependent-event parameters associated with individual clusters on Figure 3.4-1. 

Section 3.5

First sentence: Typo. Change “EPRI SOG” to “EPRI-SOG” 

p. 3-12, par. 2, line 6: Could not find Figure 8-1 in Report; what is the basis for the boundaries 

of the completeness regions? For example, how were the boundaries of Region 15 defined, 

which is one of the new regions? Is there a rationale for including both the Gulf of Mexico and 

Florida offshore in the same completeness region? 

p. 3-12, 4th paragraph: The terms PENB, PENA and WEDT are not defined. 

p. 3-12; 6th par., line 2: The text states, “in the time period 1995 to 2008” but in Table 3.5-1 

the limiting year is 2009. 

Figures

Labeling of page numbers on pp. 3-31, 3-32, and 3-33 needs to be corrected. 

Figures 3.3.1-1 through 3.3.1-3

Add more detail to the figure captions, and indicate the 1:1 line and the 90% confidence 

interval for the mean. Typo in Figure 3.3.1-2: (1994) not (19944). 

Figure 3.3.2-1 

Lots of lines on the figure with no explanation in the figure caption. What exactly is 

approximate M in this figure? 

Figure 3.3.4-1 

Is the map of epicenters south of Florida complete to the shown boundary of the study region? 

If not, explain justification for neglecting these. Was the Caribbean seismicity catalog accessed 

to determine earthquakes in the study region? 

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Figure 3.4-1 

The text should comment on the very large disparity in cluster duration and spatial dimension 

for similar magnitudes. Virtually all readers will be left with distrust of the methodology based 

on these results, absent any additional discussion. 

References 

EPRI (1988) is missing from reference list. 

EPRI reports need to be properly referenced (see next page). 

This is how the EPRI reports are referenced in the CEUS/SSC report:

Electric Power Research Institute (EPRI), 1986, Seismic Hazard Methodology for the Central 

and Eastern United States: Volume 1, Part 2, Methodology (Revision 1): Final Report, 

EPRI-NP-4726-A-1(1). 

Electric Power Research Institute (EPRI), 1989, Probabilistic Seismic Hazard Evaluations at 

Nuclear Power Plant Sites in the Central and Eastern United States: Resolution of the 

Charleston Earthquake Issue: EPRI Technical Report EPRI NP-6935-D. 

The references below are how the EPRI Project documents are referenced in the 

PEGASOS report. 

EPRI-SOG 1986: Seismic Hazard Methodology for the Central and Eastern United States, 

Electric Power Research Institute NP-4726A, Volumes 1-11. 

EPRI 1989: Probabilistic Seismic Hazard Evaluations at Nuclear Power Plant Sites in the 

Central and Eastern United States, Electric Power Research Institute NP-4726, 9 v. 

The PPRP suggests the proper reference is the following: 

EPRI-SOG 1988: Seismic Hazard Methodology for the Central and Eastern United States, 

Electric Power Research Institute NP-4726A, Revision 1, Volumes 1-11. 

The EPRI-SOG Project was completed and submitted as “EPRI NP-4726” in 10 volumes to the 

NRC for review as a topical report. The review was completed in 1988. The report number 

designation “4726-A, Revision 1” identifies that the report has been revised in response to 

NRC’s review and that it is accepted by NRC for future use for licensing submittals and 

contains the NRC’s Review Report and Acceptance Letter. Volume 11 is the NRC’s requests 

for additional information and EPRI’s responses. 

The above noted inconsistency is indicative of the problem with just broadly referencing the 

EPRI documents within this chapter of the report and the attendant issues with transparency 

and availability. The PPRP has two systemic recommendations regarding utilization of methods 

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from the EPRI-SOG Project and citations. First, be much more specific when referencing the 

EPRI studies (i.e. volume, section etc.). Second, the TI Team should strongly consider 

reproducing and expanding the discussions and developments in the EPRI-SOG report in the 

CEUS-SSC report. This will enhance clarity and transparency and facilitate utilization of some 

of the methods by the broader community. 

Other references either missing from Chapter 3 and/or that probably should have been cited 

Gardener, J.K. & Knopoff, L. 1974: Is the sequence of earthquakes in Southern California, with 

aftershocks removed, Poissonian? Bull. Seism. Soc. Am. 64, 1363-1367.

Grünthal, G. 1985: The up-dated earthquake catalogue for the German Democratic Republic 

and adjacent areas – statistical data characteristics and conclusions for hazard 

assessment. In: Proceedings 3rd International Symposium on the Analysis of Seismicity 

and Seismic Risk, Czech. Ac. Sc., Prague, 19-25. 

Reasenberg, P.A. 1985: Second-order moment of central California seismicity. J. Geophys. 

Res. 90, 5479-5495. 

Reasenberg, P., and L. M. Jones (1989), Earthquake hazard after a mainshock in California, 

Science 243, 1173–1176. 

Stepp, J.C. 1972: Analysis of completeness of the earthquake sample in the Puget Sound area 

and its effect on statistical estimates of earthquake hazard. Proceedings of the 

International Conference on Microzonation 2, 897-910. 

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CHAPTER 4 — CONCEPTUAL SSC FRAMEWORK 

General Comments 

G 4-1. (CBR, CC) Chapter 4 describes the Conceptual SSC framework. This chapter is 

generally well-written, organized in a logical format, and responsive to early PPRP 

recommendations for creating a structured systematic approach to SSC, including the 

establishment of criteria for defining seismic sources. However, it is incumbent on the TI 

Team to document how these criteria were used to define seismic source zones. While the 

PPRP appreciates the role that informed judgment has on assessing weights for various 

branches of the logic tree, these weights must have a documented basis. In response to the 

PPRP April 7, 2010 letter, the TI agreed that project documentation must provide a detailed

(emphasis added) discussion of the criteria that were used to identify seismic sources and a 

justification for all logic tree branches and weights.

G 4-2. (NAR) The development of Data Evaluation and Data Summary Tables has been 

extremely important with respect to making the seismic source characterization process more 

transparent and complete (see detailed comments on these tables). These types of tables 

represent a foundation upon which future SSC seismic hazard evaluations can be efficiently 

built. This is particularly true for seismic source characterization projects that have a broad 

regional extend. The TI Team is to be commended for taking the time to create these tables. 

The tables include an unprecedented level of information that external reviewers can use to 

understand the assessments that have been made and represented in the logic trees. An 

important point that was developed in Section 4.2.2 was that the Data Summary and Evaluation 

Tables are not intended to replace the documentation of the SSC effort but to supplement it.

Specific Comments 

S 4-1. (CC) Terminology

The nuanced words “study,” “capture,” and “event” are used throughout Chapter 4, 

contributing to a lack of clarity. We recommend replacing with words that convey the specific 

contextual meaning: that is, replacing “study” with “project” or “assessment” as appropriate; 

“capture” with “represent” as appropriate; and “event” with “earthquake” as appropriate.

S 4-2. (CBR) Master Logic Tree and Representing the Community Distribution

The assessment of a conceptual tectonic framework is ultimately represented in the master 

logic tree as the weights applied to branches of this logic tree (major alternatives related to the 

overall tectonic framework). Interactions with the broad scientific community in Workshops 

#1 and #2, and the scientific knowledge base developed through these interactions, informed: 

(a) the TI Team’s assessments for the conceptual tectonic framework, (b) the TI Team’s 

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evaluations of the hazard significance of various seismic source characterization issues (Section 

4.3.2), and (c) development of criteria for defining seismic sources (Section 4.3.3). 

For assessment of SSC models of this regional extent, it is now clear to the PPRP that it could 

have been useful to have additional feedback of the conclusions discussed in Section 4.3.2 and 

the criteria discussed in Section 4.3.3 to enhance confidence that this information can be used 

(i.e., appropriately represents the CBR of the ITC) to create a detailed SSC logic tree. From a 

generic perspective, this should be considered a lesson learned, recommended for Level 3 

assessment projects of broad regional extent, to directly link the overall development of the 

seismic source assessment logic tree with a broader segment of the ITC. The TI Team is 

strongly encouraged to consider whether additional feedback with a targeted group of subject 

experts is warranted. 

S 4-3. (SSHAC) Level 3 Assessment Process

In the first paragraph of Chapter 4, the text states that the justification for the use of a SSHAC 

Level 3 assessment process is given in the CEUS SSC Project Plan. While the project plan did 

discuss the selection of the assessment level, this project report must demonstrate that 

execution of this assessment level is appropriate, resulting in a high quality product consistent 

with the requirements for seismic regulatory decision-making. We suggest that this sentence be 

deleted.

S 4-4. (CBR, CC) “Generic” Data Evaluation (Section 4.2.1)

The development of Table 4-3 and the discussion of this table are beneficial to this 

report. The text would be strengthened if at the end of this section the TI Team 

discussed how they developed the numbers in the table. Specifically past PSHA 

experience, results from Workshop #2, and discussions with a wide range of people 

who are part of the ITC were all used to make these assessments (See Comment S 4-2).

Finally, there should be discussion of how the numbers were or were not used to guide 

the weights ultimately assigned on the logic tress. 

S 4-5. (CC) Logic-Tree Branches and “Credible” Alternatives (Section 4.1.1.1)

In Comment S 1-2, caution was raised about the use of particular wording that may lead to 

confusion or invite argument. We offer a similar caution here about declaring that only 

“credible” alternatives are included in the logic tree. Having to defend the assertion of zero

credibility in the case of excluded alternatives can become a red herring. The nature of the TI 

Team’s assessment of a representation of the views of the ITC is explained at great length in 

Chapter 2. Allowance is made for excluding an alternative view or parameter based on the 

judgment that its relative weighting would lead to an insignificant effect on the hazard. When 

discrete probability distributions are used to represent the center, body, and range of a 

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continuous distribution, it is recognized that the distributions have tails of low-to-zero 

probability. Instead of having to assess exactly where the zero bounds are, acceptable practice 

allows representing the significant mass of the distribution. We recommend removing 

“credible” from the section title. 

S 4-6. (CC) Methodology for Identifying Seismic Sources (Section 4.3)

This section would be improved if there were a discussion how Workshop #2 was used 

to guide the TI Team in terms of developing a methodology for identifying seismic 

sources.

S 4-7. (CC, SSHAC) Hazard-Informed Approach: Section 4.3.1

In the last paragraph on page 4-10, the following statement is very confusing, seemingly in 

conflict with SSHAC guidance, and likely to create controversy:

“Rather, it reminds us that the purpose of the CEUS SSC Project is to develop a seismic 

source model to be used in a seismic hazard analysis, and not to attempt to answer or 

even capture the larger technical community’s questions about SCR earthquake 

causative mechanisms. The exceptions are those cases where a hypothesis might have 

profound implications on the geometry, Mmax, or recurrence for a seismic source such 

that it would affect the hazard results.” 

Perhaps the intent is to convey the fact that the CEUS SSC Project is an assessment based on 

existing knowledge rather than an attempt of advance knowledge or resolve competing 

arguments. The two sentences could be removed without loss of continuity. In any case, some 

clarification is essential. 

S 4-8. (CC) Criteria for Defining Seismic Sources (Section 4.3.3)

It would be appropriate and helpful here to note that geological and geophysical studies of the 

crust since the 1980s have provided little significant new information about tectonic features 

and the geological history of the region that may have a bearing on evaluation of seismic 

hazards. The only possible exception is the improved understanding of the Illinois basin 

extended zone and its features. However, paleoliquefaction studies have been useful in 

defining and characterizing seismic source zones. 

S 4-9. (CBR) Weights on the Two Conceptual Models (Section 4.4.1)

One of the critical logic tree assessments is the weights on the two conceptual models used to 

represent classes of seismic sources. Section 4.3.3 establishes criteria for assessing seismic 

sources while Section 4.4.1 provides a description of the logic tree elements. This section does 

not develop a strong argument for the weights assigned, particularly the strong preference 

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assigned to the seismotectonic zone branch. Additionally, it is not clear where the TI Team 

demonstrates that the development of seismotectonic zones leads to hazard significant changes 

in the model. 

The text states that the development of seismotectonic zones allows for more relevant 

information on the characteristics of future earthquakes (the third criteria in the sequence 

defined in section 4.3.3)—but this seems to be a TI Team judgment, as opposed to a 

documented evaluation and assessment. Section 4.1 (Item #3) makes the point that a 

methodology for identifying seismic sources that takes into account defensible criteria is a 

critical attribute of this project, but the project must demonstrate that the TI Team has properly 

executed these criteria. Perhaps some type of summary table can be prepared to synthesize 

how the criteria distinguish between seismic sources. 

The weight assessed for the seismotectonic branch has increased from 0.33 (August 2009, 

when three branches were considered) to 0.60 (March 2010) to 0.8 (July 2010 and the draft 

report). The PPRP notes that these weights could be viewed as somewhat counter to the overall 

ITC trend that has been documented in the USGS National Seismic Hazard Maps (three cycles 

including regional workshops) and not necessarily a logical outcome from Workshop #2 of this 

project. At a minimum, the TI Team needs to bolster their arguments for the weights assigned.

The PPRP encourages careful consideration of this issue and the potential need for adjusting 

the weights toward more parity between the two overall SSC models.

S 4-10. (CBR, CC) Mmax Zones Logic Tree (Section 4.4.1.2)

The discussion of the magnitude weighting provides no explanation or basis for the 

weights. The same holds true for the approach to spatial distribution of seismicity rates 

(smoothing). PPRP comments on these weights are provided in Chapter 5. Once these 

comments are addressed these discussions should, at a minimum, refer to specific 

sections in Chapter 5, and be enhanced to summarize the basis as appropriate.

S 4-11. (DMM) Table 4-3 (p. 4-41)

Does “(4) Rift Basins” overlap with “(2) Extended Margins”? Does this include basins 

formed as a result of regional extension in a Highly Extended Terrain such as the 

Triassic grabens of the EUS? A comprehensive description of continental rift structures 

is presented by Olsen and Morgan (Continental Rifts: Evolution, Structure, Tectonics, 

Elsevier, 1995; Chapter 1). Does “(4) Rift Basins” also overlap with “(5) Failed Rift 

(Paleozoic and younger)” as in the Oklahoma aulacogen? A failed arm of a rift is a 

branch of a triple junction that did not develop into an ocean basin. A paleorift that has 

been reactivated by compressional deformation is an aulacogen, e.g., Oklahoma 

aulacogen. Does (4) include Precambrian continental rifts that were reactivated in later 

Precambrian time? Why is “(5) Failed Rift” rated lower than (4) if the Failed Rifts are 

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limited to the Phanerozoic? The Oklahoma failed rift (aulacogen) has the Meers fault, 

while Recent faulting is not observed on Triassic graben faults, to the best of our 

knowledge.

Comments on Sections 

Chapter 4 (title and introductory text) 

Consider spelling out SSC in the title of chapter. 

In the first sentence of par. 1, suggested wording change: “for use in future PSHAs.”

In next-to-last line of par. 1: Typo. “how that the framework” 

On p. 4-1, last sentence: Consider changing “the master logic tree that is the backbone of the 

SSC model” to “the master logic tree of the SSC model” 

Section 4.1 

In Item #3, line 1: Consider replacing “that takes into account” with “that is based on”; in 

line 2, consider replacing “takes advantage of” with “incorporates”; in line 3, “identifies” 

instead of “captures.” 

Section 4.1.1 

To more clearly represent the activities described in this section and in the report as a whole, 

we recommend changing the title of Section 4.1.1 to “Logic Tree Approach to Representing 

Alternatives and Assessing Uncertainties,” conveying that the alternatives represent the center, 

body, and range of scientific community’s knowledge and that the assessed uncertainties 

represent the community uncertainty distribution. 

On page 4-2, last paragraph, line 3: Consider replacing “identifying” with “representing; also 

in line 10 of the same paragraph. 

On page 4-3, 1st paragraph, last line: Consider changing “that express the relative credibility 

of the alternatives” with “that represent an assessment of the relative credibility of the 

alternatives” 

On page 4-3, last paragraph, line 7: Consider replacing “those assessments that are judged” 

with “those assessed alternatives”; see also Comment S 4-5).

On page 4-4, first full paragraph, line 1: Consider replacing “considered” with “assessed to 

be”; in line 2, consider replacing “degree of belief” with “assessment”; in line 7, consider 

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replacing “and not worthy of” with “so did not warrant”; in the last line, consider replacing 

“assigned” with “assessed.”

On page 4-4, 2nd full paragraph, line 2: Consider replacing “assigned to” with “assessed for”; 

in line 6, consider replacing “the TI Team considered the available data” with “the TI Team 

evaluated the alternatives using available data”; in line 13, consider replacing “the weights 

assigned to” with “the weights assessed for.” 

On page 4-4, 2nd full paragraph, line 5: When writing that “there is rarely a quantitative basis 

for assigning these weights,” it should be made clear that this refers to the assessment of 

subjective probabilities. The CEUS SSC methodology uses five-point distributions to represent 

quantified continuous distributions of selected parameters. 

Section 4.2 

On page 4-5, 2nd paragraph, line 1: Consider changing “an attempt was made to provide more 

structure and transparency” with “more structure and transparency has been provided”; in the 

next-to-last line, replace “study” with “evaluations and assessments of the TI Team” 

Section 4.2.1 

First paragraph, line 3: Consider replacing “as the technical community evolves its thinking 

regarding” to “as the knowledge of the technical community evolves regarding”

On page 4-5, first bullet, line 7-8: Consider replacing “which is an SCR” with “which 

geologically is constituted of SCR crust”

Section 4.2.2

On page 4-7, last paragraph, 2nd paragraph: The text states that “errors in the data generally 

exceed the signal” (data referring to geodetic data). It is suggested that this be changed to 

“errors in the data may exceed the signal.” 

Section 4.3 

First paragraph, line 2: Consider replacing “three decades in SSC” with “three decades in 

assessing SSCs”; in line 3: consider changing “community” to “scientific community”; in line 

4, consider replacing “a regional PSHA that can be applied” with “a regional SSC assessment 

that can be applied; in line 5: consider replacing “requires that a methodology include” with 

“requires that the assessment include”; in the last line, consider replacing “across the study 

region” with “throughout the regional SSC model.” 

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In the last paragraph on p. 4-8, Regulatory Guide 1.208 is mentioned with respect to guidance 

for commercial reactors. ANS Standards 2.27 and 2.29 provide similar guidance for other 

nuclear facilities, and this should be recognized.

In the first paragraph on p. 4-9, the message conveyed by the first sentence is not clear. 

Consider replacing the word “intuitive” with “subjective” or “common practice.” 

Section 4.3.1 

The meaning of the first sentence is not clear and it seems to be inconsistent with the content of 

the paragraph. It could be deleted, as the following sentence seems to properly introduce the 

content of the paragraph.

Add Pa to List of Acronyms. 

Section 4.3.3 

On page 4-14, next-to-last paragraph, line 3: Consider replacing “captured by” with “obtained 

from”; in the last paragraph, line 7, replace “reasonable assessment” with “reasonable 

interpretation” 

On page 4-15, 3rd full paragraph, line 4: Replace “PSHAs” with “seismic hazard models” 

On page 4-16, first partial paragraph, lines 4-5: Consider replacing “Because the CEUS SSC 

Project is a regional study and not a site-specific study,” with “Because the CEUS SSC Project 

developed a regional SSC model rather than site-specific one,” 

Section 4.4.1

It would be useful to start this discussion with recognition that RLME sources are 

identified based on well defined evidence for Late Quaternary or Holocene direct 

evidence of repeated large magnitude earthquakes. Also when discussing the 8th node 

of the logic tree, the discussion needs to be enhanced, consistent with the information 

shown on the logic tree figure.

Section 4.4.1.1 

On page 4-18, the text refers to Table 4.4.1.1-3, which is not included in the report. Rather it 

appears to be labeled Table 4-6, which is included in the body of the text of the chapter. We 

suggest that this numbering be corrected, that the tables be numbered in a consistent manner, 

and that a List of Tables be included in the report. 

On page 4-19, 1st paragraph: In the first sentence, make it clear that the issue is “the temporal 

clustering of large magnitude earthquakes.”

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Section 4.4.1.2 

Page 4-20, last paragraph: In the second sentence beginning, “For the CEUS SSC Project . . .” 

need a connector (“and” or a semi-colon) at the start of the last clause (e.g., “and the prior 

distributions from that study were reassessed.”). 

On page 4-21, second paragraph, suggest moving up the last sentence “As discussed in Section 

6.2...” prior to the sentence that lists the weights assigned to the logic tree branches.

Four additional review comments relate to the discussion in the second paragraph on p. 4-21: 

1. Two alternative locations of the Mesozoic and younger separation branch are identified: 

the wide and the narrow. Unfortunately, no map is provided for the location of the 

narrow zone. Reference is made to Figure 4.4.1.2-3 in line 6, which is presumably this 

map, but it is missing from the report as well as the List of Figures. 

2. Figure 4.4.1.2-2 is labeled as showing the narrow Mesozoic alternative, but instead it 

shows the wide alternative. 

3. Note that the caption of Figure 4.4.1.2-2 is not complete in the List of Figures. All 

captions in the List of Figures should be checked against those given on the figures. 

4. The boundary of the project area shown on Figure 4.4.1.2-2 and subsequent figures of 

this chapter are not the same as shown in the defining figure of the boundary, Figure

1.3-1, and in Figure 4.4.1.1-2. Apparently the boundary in these figures has been 

modified to incorporate identified seismic source zones in Canada, which is the 

northeastern segment of the project area. Inconsistent project area boundaries should be 

avoided to prevent confusion. 

Section 4.4.1.3 

In the first paragraph, change “shown on Figures 4.4.1.3-2 through 4.4.1.3-7” to “shown on 

Figures 4.4.1.3-2 through 4.4.1.3-5”

Tables and Figures 

The order of presentation of text, tables, and figures needs to be standardized in all chapters. In 

this chapter, the order is different than in preceding chapters.

Table 4-3 

Page 4-39, last row: Assumed the intended wording is small r recent, not capital R Recent. 

Perhaps a more definitive and less confusing word could be used—perhaps Phanerozoic? 

Page 4-42, first row: Suggest replacing “Orientation” with “Fault orientation” 

Page 4-42, third row: Suggest adding “High-resolution seismic reflection” in third column. 

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CHAPTER 5 — SSC MODEL: OVERVIEW AND METHODOLOGY 

General Comments 

G 5-1. (CC) Chapter 5 provides an overview of the SSC model and some of the 

methodologies used within that model. This section is generally well written and provides a 

good description and summary of a number of the technical elements of the SSC model. The 

work that the TI Team completed to update the SCR database, performing new statistical 

analyses, and updating prior distributions is an important contribution to improving assessment 

of maximum magnitudes. However, some specific elements of the model and/or 

documentation thereof are problematic in the PPRP’S view. Significant changes or additional 

justifications may be warranted. 

G 5-2. (CC ) In addition to the PPRP review, to ensure thorough review of the many 

equations contained in the report, the PPRP recommends that all knowledgeable members of 

the TI Team carefully examine all equations, especially equations in sections that they were not 

tasked to write. 

Specific Comments 

S 5-1. (DMM, CC) Implications of Kafka’s Studies for Spatial Smoothing

Section 5.1 provides a well-written overview of the approach to spatial and temporal models of 

earthquake occurrence in the current CEUS-SSC model. Section 5.1.1 describes the TI team 

interpretation that the spatial pattern of observed seismicity provides predictive information 

about the spatial distribution of future moderate-to-large magnitude earthquakes. The PPRP 

notes that the studies by Kafka (2007, 2009, and Workshop #2) indicate this is generally

(emphasis added) the case. Various versions of the cellular seismology results presented by 

Kafka suggest that much (55–85%), but not all, seismicity is predicted by the spatial occurrence 

of past earthquakes. This suggests that the report should at least discuss the possibility of 

specifying a very high level of smoothing within source zones. This is utilization of subjective 

rather than objectively defined smoothing parameters that would specifically define a 

seismicity floor in some regions. 

S 5-2. (SSHAC, CC) Inconsistency With Principles of Seismic Hazard Model Assessment 

In Section 5.1.2, par. 3, second sentence, the statement: “The TI Team has taken a very 

cautious approach, however.” conveys a clear violation of the SSHAC guidance principals for 

seismic hazard model assessment; namely the goal to represent the center, body, and range of 

the community scientific knowledge. An explanation is required. It would be made clearer if 

“assumed” were replaced with “used” in the last line of this paragraph (and if the awkward 

sentence were inverted). 

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S 5-3. (DMM, CC) Inadequate Description of the Assessment Process 

In Section 5.1.2, the last paragraph on p. 5-3 (continuing on p. 5-4) is critically important, as it 

introduces the reviewer to the TI Team’s assessment of temporal clustering, arguably the most 

uncertain assessment for the CEUS SSC model. For example, the topic is introduced with the 

weak statement, “consideration was given to” instead of wording such as “assessed,” which 

links directly to the SSHAC guidance. With similar effect, “considered” is used in line 4, 

where the word “assessed” would more accurately convey the appropriate action and at the 

same time connect with the SSHAC guidance. In line 5 continuing on line 6, the physical 

process would be explained more clearly if the words “based on the concept of” were deleted, 

leaving the sentence to read: “The physical underpinning of a renewal model is a quasi steady 

state . . . .” In line 10, it would be clearer to change “concept” to “physical process.” We 

recommend that this paragraph be rewritten, expanding the discussion to convey the state of 

scientific knowledge about an earthquake cycle in which strain is released as clustered large 

earthquakes. The most relevant data appear to be the absence of measurable levels of strain 

accumulation in the Charleston and New Madrid seismic zones, where the short-term geodetic 

strain rates are in apparent conflict with interpretations of “in-cluster” rates of occurrence of 

large earthquakes. 

S 5-4. (CC) Weak Support for Conclusion

In the first paragraph of Section 5.1.3, the last two sentences, beginning with “The TI Team 

reviewed . . .” convey an evaluation and conclusion of the TI Team that is greatly important 

for the CEUS SSC model assessment. Yet support for the strong conclusion seems general and 

weak. Consider elaborating on the basis for the conclusion. For example, the last sentence 

begins with “With a few exceptions . . . .” Describe the data that permitted the exceptions and 

describe how the data were used in the assessments. 

S 5-5. (DMM, CBR, CC) Maximum Earthquake Magnitude Assessment

Section 5.2 describes the methodology for assessing maximum magnitude (Mmax) that was 

used in the CEUS-SSC Project. The text notes that the maximum magnitude earthquake for 

any given source zone in regions of low-to-moderate seismicity (such as the CEUS) happens 

rarely, relative to the period of observation. As a result, the record of historical seismicity 

provides information, but rarely hard constraints, on the source-specific Mmax value. This fact 

has led to the investigation of global tectonic analogues to address this issue. The scheme for 

assessment of Mmax in the CEUS-SSC Project incorporated the uncertainties in both 

conceptual models and the parameters within models. The approach utilized in the CEUS-SSC 

Project provides a quantitative and repeatable process for estimating Mmax that is easily 

updatable if new information becomes available.

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The discussion of the development of the Bayesian Mmax approach in Section 5.2.1.1 is 

generally clear and guides the reader through the development of the approach. The PPRP 

believes that the significant effort invested by the Project in the update and re-investigation of 

the global SCR database was worthwhile. This refinement represents a significant advancement 

for the community. However, the PPRP notes there are points that require further clarification 

and assessments that require additional justification as noted in the following two comments. 

S 5-6. (DMM, CBR, CC) USGS Mmax Workshop and Mmax Approaches Considered

In Section 5.2.1, the discussion of the evaluation of alternative approaches to Mmax in the 

CEUS, lacks any meaningful discussion of the USGS workshop on this topic (Wheeler, 2009), 

and does not strongly support the TI Team’s selection of Mmax approaches beyond the 

Bayesian approach. The approach developed by Kijko is not the only viable alternative 

discussed as part of the USGS workshop. Additionally, the approach developed by Kijko was 

not given much support in the USGS workshop, needing additional study before it becomes 

commonly used in PSHAs. This section should provide more discussion of the USGS Mmax 

workshop and the Mmax approaches considered by the TI Team, and why they are, or are not, 

selected for assessment. 

S 5-7. (DMM, CC) “Kijko Approach” — Terminology and Description

Defining how this approach or procedure will be referred to in the report and appropriate 

attribution for its origin need to be established upon first mention. In section 5.2.1 (pg. 5-6, 

paragraph 3), two alternative approaches are described for estimating Mmax: the Bayesian 

procedure and “the Kijko (2004) procedure.” Later in section 5.2.1-2 (pg. 5-15), the first 

sentence states: “The Kijko approach (Kijko and Graham, 1998; Kijko, 2004) . . .” 

In referring to the “Kijko approach,” misleading statements are made. On pg. 5-7 (paragraph 1, 

last sentence), the text states, “However, the approach relies on the assumption that the 

distribution of earthquake magnitudes follows a doubly truncated exponential distribution.” 

Later on pg. 5-15 (section 5.2.1.2, paragraph 1, first sentence), the text repeats that the 

approach is based on the simple assumption that “the distribution of earthquakes in a region 

follows a doubly truncated exponential distribution.” In Kijko (2004, pg. 1) the reader plainly 

finds: 

“This paper provides a generic equation for the evaluation of the maximum earthquake 

magnitude mmax for a given seismogenic zone or entire region. The equation is capable 

of generating solutions in different forms . . . . It includes the cases (i) when earthquake 

magnitudes are distributed according to the doubly-truncated Gutenberg-Richter 

relation, (ii) when the empirical magnitude distribution deviates moderately from the 

Gutenberg-Richter relation, and (iii) when no specific type of magnitude distribution is 

assumed.” 

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S 5-8. (DMM, CBR) “Kijko Approach” — Justification of Weighting

Adding to Comment S 5-7 on the TI Team’s use of the “Kijko approach” (Section 5.2.1.1), this 

is an approach that was not identified in the any of the CEUS-SSC workshops as a potential 

approach. Further, the approach was not discussed in detail at the 2009 USGS Mmax 

workshop. The Kijko approach is one that is represented by the form: Mmax = Mmaxobs +. At 

the USGS Mmax workshop this class of methods was given little credence. However, the 

discussion was mostly focused on models that specified a fixed magnitude increment for  (0.5 

magnitude unit, for example). Kijko’s approach is different in that it utilizes a statistical 

assessment of seismicity in the region of interest to obtain estimates of  (and uncertainties). 

The approach(es) developed by Kijko have not seen wide usage. The PPRP endorses the 

utilization of an alternative approach that uses zone-specific data for estimation of this 

important parameter, but notes that the assignment of equal weights to the Kijko KSB approach 

and the Bayesian global tectonic analog approach may be inconsistent with the CBR of the 

ITC. Inspection of the results suggests the Kijko method is only used when it agrees with the 

Bayesian results. (See also earlier Comment S 5-5 and Comment S 5-10 below regarding the 

justification of the relative weighting of approaches.) 

The P(mu

>8.25) threshold of 0.5 does not seem unreasonable, but it does lead to the question of 

sensitivity of the final distribution to that choice. If P(mu>8.25) were set to 0.25 or 0.75 what 

effect would that have on the number of zones for which the Kijko result would be used? 

The choice of M 4.8 for the lower bound of the Kijko approach needs additional discussion. 

This leads in some cases (see Section 7) to non-zero probability assigned to Mmax branches of 

M < 5.25 in large source areas. The PPRP is not convinced this result is consistent with the 

ITC. It will certainly provoke discussion and hence should be justified to the maximum extent 

practicable. 

S 5-9. (DMM, CBR, CC) Bayesian Mmax Approach

The discussion of the updated domain dataset analyses in Section 5.2.1.1 (and subsections) is 

confusing and lacks sufficient information to fully understand what was done. The text states 

that Table 5.2.1-1 list Mesozoic and younger extended superdomains, yet the table appears to 

list all ages of extended superdomains (and Table 5.2.1-2 is for all ages of non-extended 

superdomains). Without listing the actual p-values of the statistical tests it is difficult to 

appreciate the improvements that are being discussed as you assess subsets of the data. Given 

that Appendix K only provides tables of the SCR Mmax databases, more specifics should be 

provided in this section (see also Comments on Appendix K – more detail needs to be provided 

there also). It is suggested that there be a displayed, on one or more figures, the Mmax-obs 

distributions for the various classes being compared. Was an assessment made of the impact 

for using an alternative choice for the lower cutoff of magnitude for each of the domains (such 

as M 5 or M 5.5)? 

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Statistical analyses are good, but not necessarily the only basis for assigning weights to the 

prior distributions. It seems clear that the Mean Mmax between the two-priors is likely to be 

important from a PHSA perspective (7.1 versus 6.35). The text states that a stronger weight 

(0.6) is not assigned to the two priors because the statistical significance of the separation is not 

strong. Assignment of relative weights should consider the seismologic views of the ITC in 

addition to any statistical significance—based on the text, the TI Team seems to be making the 

statistics the primary consideration. Discussion at the USGS Mmax workshop and the public 

workshops held to support the National Seismic Hazard Maps could suggest that the ITC would 

put more emphasis on the “two-priors” model (the TI Team’s intuitive judgment). The OpenFile Report from the USGS Mmax workshop should be reviewed in this context, along with 

pertinent discussion from Workshop #2. A stronger basis for assigning relative weights is 

needed. 

The description of the methodology to assess Mmax for all seismic sources contains a 

discussion of the role of the RLME sources in the assessment. The report suggests that a 

potential problem is that the global SCR database includes events from RLME sources (e.g., 

New Madrid) and that the Bayesian approach is being applied to non-RLME sources (p. 5-7). It 

seems that this methodology assumes that all RLME’s have been identified in the current 

model. Otherwise, the model does not consider RLME’s that may be found in the future. The 

report should explicitly describe how the model accounts for non-identified RLME’s that may 

have maximum magnitudes the size of New Madrid or Charleston. 

S 5-10. (CBR) Weights for the Alternative Mmax Approaches (Section 5.3.1.3)

Given the TI Team’s noted high regard for the Bayesian approach, it is difficult to understand 

why the Kijko approach was assigned equal weight under any circumstances (large number of 

larger earthquakes). Discussion at the USGS Mmax workshop and the discussion at the 

regional workshops to support the National Seismic Hazard Maps would suggest that the ITC 

gives considerably more weight to the global tectonic analog/Bayesian approach. Beyond the 

Bayesian approach, there were several potential approaches considered at the USGS workshop, 

thus it is not clear why the TI Team selected the Kijko approach as the only alternative. The 

Mmax distributions shown in the report appear to be bi-modal in some cases. The TI Team has 

not properly discussed and justified the weights assigned to the alternative Mmax approaches. 

S 5-11. (DMM, U, CC) Approach to Earthquake Recurrence Assessment 

Section 5.3 describes the approach to earthquake recurrence assessment used in the Project. 

This section is generally well-written (given the complexity of the topic) but could certainly 

benefit from the inclusion of additional steps in the derivations and from additional discussion 

in some places (we elaborate in following comments). 

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A fundamental assumption of the methodology used in the CEUS-SSC Project (and most others 

as well) is that the magnitudes of earthquakes in the corrected catalog can be represented as 

exponential variables with a density function f(m) =*exp(-(m-m0)). Lombardi (BSSA, 2003, 

vol. 93, no. 5, pp. 2082–2088) argues that main shocks (i.e., those in the “corrected” catalog) 

do not satisfy this assumption. Lombardi suggests a different density function for the use with 

these main events that depends not only on  but on N (the number of events) as well. In fact, 

her comparisons utilizing Southern California data suggest much lower b-values for main 

shocks than for all the events in the catalog. The PPRP suggests that some discussion of these 

alternative assumptions be included in the report—and that the methodology used by the TI 

Team be checked, vis-à-vis implications of the Lombardi paper, to ensure that there is no 

systematic bias in the maximum-likelihood estimates of b-values. 

S 5-12. (DMM, CBR, CC) Smoothing to Represent Spatial Stationarity (Section 5.3.1) 

The argument is presented in this section that the penalized likelihood approach to spatial 

smoothing of seismicity is superior to other approaches and the only method to be considered 

in the CEUS-SSC Project. The PPRP does not find this argument to be adequately supported 

by the report as written in its present form. Keeping in mind that the objective of the SSHAC 

Level 3 process is to represent the CBR of the ITC, we note that, other than one or two 

members of the TI team, no other members of the technical community are utilizing the 

penalized likelihood approach to perform smoothing of observed seismicity. The 

overwhelming majority of the community is utilizing either a fixed-kernel or adaptive-kernel 

approach to smoothing. The kernel approaches are conceptually much simpler and easier to 

implement and, as a result, yield enhanced transparency. 

The PPRP notes that in Section 5.2.1 (p. 5-7, 2nd paragraph) the report states, “[I]t was decided 

that for representing the center, body, and range of views of the informed technical community, 

the assessment would need to include alternative conceptual models for Mmax.” The PPRP 

wonders if one were to replace “Mmax” with “smoothing technique” in this statement, why the 

argument presented in Section 5.2 would not apply in Section 5.3. 

The penalized likelihood method, as developed in the EPRI-SOG Project and in the present 

report, possesses some very positive attributes. Some are briefly discussed in Section 5.3.1 but 

developed more fully in Section 5.3.2.4. It would enhance clarity to refer the reader to Section 

5.3.2.4 in Section 5.3.1. 

While the TI Team recognizes that the selection of the smoothing option requires expert 

judgment, the text goes on to note that “The smoothing operation within the distributed 

seismicity zones results in variations of a- and b-values over scales that were judged by the TI 

Team to be reasonable . . . .” The report has not provided an adequate basis for making this 

statement. The text does not compare the computed smoothing results to other studies, and 

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does not point to any explicit data that indicates that the seismicity parameters fall within a 

reasonable range. 

S 5-13. (DMM, CC) Penalized Likelihood Function — Differences with EPRI-SOG?

In Section 5.3.2.1 the model for the penalized likelihood function for recurrence parameters is 

formally developed. Many aspects of the approach appear to be similar to those of the EPRISOG Project. It would be useful to specify the differences in the present approach relative to 

the EPRI-SOG Project. The PPRP identifies the following differences (or at least this section 

of the current report is not clear enough to be sure if these are in fact differences relative to the 

EPRI-SOG Project): 

1. One of the attributes of the EPRI-SOG model was the simultaneous solution of 

recurrence parameters and incompleteness. On pg. 5-23 the text states the probability 

of detection (PD) values are calculated in Section 3.3.3 (typo-this should be Section 3.5). 

This statement plus the remainder of Section 5.3.2.1 give the appearance that PD is 

calculated independently and no longer simultaneously solved for. 

2. The smoothing functions are now analytically determined (objective estimates) as 

opposed to the general, judgment-based smoothing specified by the expert teams in the 

EPRI-SOG study. 

3. The use of the Monte Carlo-Markov Chain simulation approach to develop alternative 

maps in the present study as opposed to the parametric bootstrapping used in the EPRISOG study. 

4. The use of quarter-degree cells instead of one-degree cells and only using the cells that 

share sides (4 nearest neighbors instead of 8). 

S 5-14. (DMM, CBR, CC) Model for the Penalized Likelihood Function — Need for Scrutiny 

The development of the statistical approaches used in this Section 5.3.2.1.1 should undergo 

independent review either using an appropriately qualified member of the TI Team or an 

outside expert. It is not sufficient to simply provide a description of the approach used. To 

facilitate a thorough and transparent review, the software developed should be made available 

for use in the review process. 

The text implies that selecting a small cell dimension, more cells, is an improvement relative to 

larger cell dimensions. It is not clear, from a seismologic perspective, considering the short 

historic record, why this would be the case. Review of the alternative recurrence maps 

(Appendix J) suggests that there are broad areas where the rates of M > 5 are effectively zero, 

there is wide variation (several orders of magnitude) in rates and b-values between alternatives, 

with generally lower b-values (< 0.8). It is not clear how the choice of cell dimension may 

have impacted these observations. 

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This section has not adequately demonstrated how the method chosen quantitatively compares 

to other methods such as the kernel approach. While section 5.3.2.4 provides some discussion, 

it is not sufficient by itself to support the sole use of the method chosen. It appears that the TI 

Team is using the argument that b-values are not constant within a “larger” seismic source. 

The variation (or lack of variation) of b-values is subject to considerable discussion within the 

ITC. What is the basis for supporting the position that the variation of b-values is consistent 

with the views of the ITC? 

The weights on the reduced-weight option for the magnitude intervals listed on Table 5.3.2-1 

are not properly discussed and justified. Presenting only two figures as a demonstration that 

the approach is not sensitive to these weights is not compelling. What was the basis for 

assigning these weights to each of the magnitude intervals? 

A few additional aspects in Section 5.3.2.1 could certainly be clarified further to enhance 

readability and understanding: 

The reader is challenged to derive 5.3.2-11 from 5.3.2-9. 

What is the basis for eight alternative maps as opposed to four or ten? 

Section 5.3.2.3 is not clear enough to understand the generation of the alternative maps 

from the eigenvalues and eigenvectors of the covariance matrix Sx. 

S 5-15. (CBR, CC) Application of the Smoothing Model (Section 5.3.2.2)

In Section 5.3.2.2, no basis is given for weights on b-value priors. The alternatives are shown 

to be unimportant later, indicate that fact in this section to avoid confusion over the lack of 

basis for weights. 

S 5-16. (DMM,CBR, CC) Constant b-value Kernel Approaches

Section 5.3.2.4 discusses the constant b-value kernel approaches to smoothing of seismicity. 

The PPRP believes that significantly more discussion and comparisons are needed to justify the 

use of a sole unity-weighted branch in the logic tree for this important choice of model. We 

note that one of the strengths of the penalized likelihood approach, relative to the fixed b-value 

approaches, is the ability to allow for coupled rate and b-value behavior within sources. 

However, the results shown in Figures 5.3.2-3 and 5.3.2-5 suggest the penalized likelihood 

approach with the CEUS data yields very high smoothing levels on the b-value. In other 

words, the data may be insufficient to make a strong case between variable and fixed b-value 

approaches at the seismic source level—thus significantly reducing one of the strengths and 

justifications for the penalized likelihood approach. Additional comparisons with the fixed bvalue kernel smoothing approaches are warranted. 

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S 5-17. (DMM, CC) Seismogenic Crustal Thickness 

In the title and text of Section 5.4.1.4, the term should be “seismogenic thickness” not 

“seismogenic crustal thickness.” The statement that the focal depth distributions of wellstudied earthquakes established the basis for the assessment of seismogenic thickness is overly 

generalized. This section goes on to note that the base of the seismogenic zone is identified as 

lying near the base of observed focal depths at about the 95th-percentile depth; review of the 

depths listed in the updated earthquake catalog would suggest that a depth of 13 km may not be 

consistent with recorded data. If there are specific “well-studied” earthquakes used to establish 

the TI Team’s assessment, these should be listed and summarized. Later in Chapter 6 when 

discussing the assignment of crustal thickness to specific seismic source zones, the report 

appears to ignore the stated intent that observed focal depths at about the 95th-percentile depth 

is an important consideration. 

S 5-18. (CC) Relationship of Rupture to Source Zone Boundaries 

In Section 5.4.1.7, the discussion of strict versus leaky source boundaries is not clear. While it 

is recognized that TI Team judgment is important here, it seems that some type of systematic 

approach would be appropriate. It may be important to note that the assumed rupture 

dimension relationships establish limits that must be explicitly considered in assigning strict 

versus leaky, and that this constraint is considered on a case-by-case basis. Otherwise it is not 

clear why some RLME sources move from strict to leaky, given the defined boundary. The 

same is true for difference between seismotectonic source zones—why are some leaky and 

some strict? 

S 5-19. (CC) Assessment of Future Earthquake Characteristic 

In Section 5.4, the introduction of Table 5.4-2 invites discussion before the reader has a chance 

to read the specifics related to each seismic source in Chapters 6 and 7. It is suggested that this 

table be split into two tables that can be provided as useful summaries at the end of Chapters 6 

and 7, respectively, for the sources zones discussed in those chapters. In this way, the reader 

will have had the benefit of understanding the TI Team’s basis for the source-specific weights 

that are assigned. 

Comments by Section 

Entire Chapter 5 

Throughout Chapter 5, we recommend that “event” not be used as a synonym for “earthquake.” 

In order to achieve the needed clarity for a regulatory document, we recommend making a 

blanket search to replace “event” with “earthquake” where that meaning is the case. Other 

instances of confusing uses of synonyms are identified elsewhere in the following comments. 

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Section 5.1.1 

First sentence: Replacing “led to the belief” with “led to acceptance” would be clearer (note 

that in line 4 the word “conclusion” is used). 

On p. 5-2, par. 2, line 9: Suggest replacing “secondary effects” with “liquefaction phenomena 

associated with them” 

In the same paragraph, line 10: Suggest replacing “paleoseismic events” with 

“paleoearthquakes interpreted using the distribution of liquefaction phenomena” 

In the same paragraph, last line: Replace “studies” with “SSC model assessments” 

On p. 5-2, par. 3, line 3: Change “EPRI-SOG study” to “EPRI-SOG Project” 

In the same paragraph, line 8: Suggest replacing “capturing” with “representing” 

In the same paragraph, line 10: Change “in EPRI-SOG” to “in the EPRI-SOG Project” 

Sections 5.1.2

In the first paragraph, line: Change “PSHA” to “SSC model assessments” 

In the same paragraph, last line: Change “PSHAs” to “SSC model assessments” 

On p. 5-3, par. 2, line 9: Change “CEUS SSC study” to “CEUS SSC Project” 

Section 5.1.3 

In the second paragraph, suggest rewording the first sentence to read: “Another area of 

ongoing research with potential implications for recurrence behavior relates to geodetic strainrate measurements.” 

Section 5.2 

In the first line of the second paragraph: Consider deleting “issue” and change “EPRI-SOG 

study” to “EPRI-SOG Project” 

Section 5.2.1 

In the first sentence of the first paragraph: Suggest replacing “calls for” with “incorporates” 

Section 5.2.1.1 

On p. 5-11, sequential paragraphs describe the results of performing Student’s t-test as yielding 

“a very high probability (p-value),” then “a lower p-value,” and then “a further reduction in the 

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p-value.” But the p-values are not given! Finally, the fourth paragraph reports the results of an 

additional step that “yielded a p-value of 0.14.” The other p-values also need to be reported 

and documented for the reader to evaluate whether the extended and non-extended 

superdomain classifications are statistically significant. 

Section 5.2.1.1.1 

In the first paragraph, line 4: Consider replacing “known stress” with “known characteristics of 

tectonic stress” 

In the next paragraph, first sentence: Change “study area” to “model region” 

Section 5.2.1.1.2 

In the first sentence: Consider replacing “applicable” with “appropriate”; change “study 

region” to “model region” 

Section 5.2.1.1.3 

In the first sentence: Replace “assigned” with “assessed” 

In the same paragraph, line 3: Consider replacing “an intuitive” with “our subjective” 

Section 5.2.1.1.4 

In the second sentence, line 2, delete “likely”; in line 3, change “For this study” to “For this 

project” 

Section 5.2.1.2 

In the last line of the first paragraph: Consider deleting “possible” (or explain) 

On p. 5-16, in the second full paragraph, line 4: Consider deleting “relatively” (or explain) 

On p. 5-16, in the last full paragraph, line 6: Replace “decided” with “assessed”; in the last 

sentence of this same paragraph, consider replacing “the following key assumptions are made 

in the application of” with “the following constraints are placed on the application of” 

On p. 5-17, first bullet: Replace “accounted for” with “assessed” 

On p. 5-17, third bullet: Consider replacing “regard for” with “reliance on” 

Section 5.2.1.3 

In the first paragraph, line 3: Consider replacing “assigning weights to” with “weighting” 

In the same paragraph, lines 4 and 6: Consider replacing “assigned” with “assessed” 

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Section 5.2.1.4 

In the first paragraph, line 5: Consider replacing “assigned” with “assessed” 

On p.5-18, in the partial paragraph at the top of the page: Consider replacing “assigned” with 

“assessed” 

On p. 5-18, first full paragraph, lines 3 and 7: Consider replacing “assigned” with “assessed” 

On p. 5-18, second full paragraph, line 3: Consider replacing “assigned to” with “assessed for” 

Section 5.3.1 

In the last paragraph on p. 5-19, line 9: Replace “study region” with “CEUS SSC model 

region” 

On p. 5-20, first full paragraph, last sentence: Consider replacing: “were judged by the TI 

Team to be reasonable, given the technical community’s views” to “were judged by the TI 

Team to represent the technical community’s views” 

Section 5.3.2.1.1

Regarding m0 and the definition of : Is in fact calculated for m > m0 or m m0 (e.g., 

McGuire, 2004; Weichert, 1980)? If calculated as the latter, then corrections should be made to 

equation 5.3.2-1 (and associated text on pg. 5-20), on pg. 5-29 (paragraph 2, line 2), and 

perhaps elsewhere. 

On p. 5-21, third line from the top of the page: Change “This study” to “This project” 

On p. 5-22, par. 4, line 2: Consider replacing “one may wish to assign lower weights to lower 

magnitudes” with “the assessment may result in a lower weight on lower magnitudes” 

In this same paragraph, second sentence: Consider replacing this sentence with “For instance, 

the magnitude-recurrence law may deviate from exponential, or the magnitude-conversion 

models or completeness model may be less reliable for lower magnitudes.” 

On p. 5-22, last paragraph, line 1: Consider replacing “considered” with “incorporated” 

On p.5-23, par. 1, line 5: Change reference to “Section 3.3.3” to “Section 3.5” 

On p. 5-25, last full paragraph: Consider replacing “are specified by the expert teams on the 

basis of judgment” to “are assessed by the expert teams on the basis of their evaluations” 

On p. 5-26, first text line at the top of the page: Change “study” to “project” 

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On p. 5-26, first full paragraph, line 4: Consider replacing “refer to” with “formulate” 

On p. 5-26, par. 3: In line 1, change “Equation 13” to “Equation 5.3.2-13”; in line 2, consider 

changing “a characterization” to “an assessment”; in lines 7–8, consider replacing “An 

additional, practical requirement is that one must represent the epistemic uncertainty by means 

of a small number of ” with “An additional practical requirement is that epistemic uncertainty 

must be represented. This can be accomplished by means of a small number of “ 

On p. 5-27, par. 3, line 4: Change “Equation 15” to “Equation 5.3.2-15” 

On p. 5-27, par. 4, lines 7–8: Typo. “maps of to represent” 

Section 5.3.2.2.1 

 On p. 5-29, second bullet: Change “in EPRI-SOG” to “in the EPRI-SOG Project” and change 

“study region” with “SSC model region” 

Section 5.3.2.2.2 

On p. 5-31, first full paragraph, line 6: Replace “assigned” with “assessed”; in line 7, consider 

deleting “reflected” 

Section 5.3.2.3 

Last line: Consider replacing “small-scale” with “local” 

The first example used to examine model results in parameter space needs to be more explicit 

in describing how the expected earthquake counts in the polygons are derived. It would also be 

helpful to discuss the data error bars for the magnitude bins with no events. The figure captions 

for these figures need additional information. 

Section 5.3.2.3.1 

On p.5-32, par. 2, line 1: It is an overstatement to claim that Figures 5.3.2-20 and 5.3.2-21 

show a “very close” agreement between model and data. In the following paragraph, “good 

agreement” is claimed between model and data for results shown on Figures 5.3.2-22 and 

5.3.2-23. Admittedly, such statements are qualitative, but don’t stretch the reader’s credulity. 

Section 5.3.2.4 

In the first paragraph, first sentence, change “this study considered” to “this project evaluated”; 

in line 3, change “considered” to “evaluated”; in line 4, change “study” to “project” 

In the second paragraph, line 2, change “has been specified subjectively” to “has been assessed 

subjectively” 

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On p. 5-34, next-to-last paragraph, line 6: Consider changing “idea” to “understanding” 

Section 5.3.3.1

Equation 5.3.3-2 should be checked. The N! in the denominator appears to be an error. 

Because the normalization procedure used to generate the probability density function for  

isn’t explained, it’s not evident why the y-axis values are so low (0.00, 0.02, 0.04). Rescaling 

the x-axes of both plots would be helpful to avoid the awkward labeling of 5e-05, etc., making 

it easier to read the plots. Checking the five discrete levels on the CDF points to an error in 

Table 5.3.3-1: The value of cumulative probability in column 1, row 1 can’t be 0.304893 

(other values in the table suggest it should be 0.034893). 

Section 5.3.3.1.3 

First paragraph: In the first sentence, consider replacing “is generally used to represent 

uncertainty in the inputs” to “is used to represent uncertainty in the SSC model “inputs”; in the 

last sentence, change “CEUS project” to “CEUS SSC Project” 

Section 5.3.3.1.3 

In the section title, consider changing “Estimation” to “Assessment” 

Section 5.3.3.1.3 

On p. 5-39, par. 3, line 1: Note that a 50-year life is stated elsewhere 

On p. 5-39, last line: Missing word. Insert “on the time before present” 

Section 5.3.4 

In the section title, consider “Assessment of RLME Magnitude Distribution” 

First paragraph: In the first sentence, consider deleting “are intended to”; in line 6, change 

“study” to “project; in line 7, consider deleting “set to be”; in the last sentence, consider 

substituting “is” for “was chosen as” 

Section 5.4 (and Tables 5.4-1 and 5.4-2 

Some additional discussion is required to explain the bases for the development of weights for 

the characteristics (or improved cross-referencing). 

On p. 5-41, par. 1, line 5: Consider deleting “a consideration of” 

On p. 5-41, par 2, line 7: Consider replacing “considering” with “evaluating” 

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Section 5.4.1 

First paragraph: In line 3, consider replacing “considered” with “evaluated”; in lines 7–8, 

consider rewording the last clause to read: “the assessed values in column 2 of the table are 

based on assessments by the TI Team of the default characteristics that represent the current 

state of scientific knowledge” 

Section 5.4.1.3 

In the first sentence: Consider rewording to read: “information about the characteristics of 

earthquake sources, modeled as finite faults in much the same manner as earthquake sources 

are modeled in the WUS.” 

In line 6, consider replacing “in light of” with “using” 

In the last line: Consider deleting “largely” (or explain) and replacing “consideration” by 

“evaluations” 

Section 5.4.1.4 

In line 2: Consider deleting “upper” (or explain) 

In line 4: Replace “study” with CEUS SSC Model” 

On p. 5-43, first partial paragraph at top of page: In line 1, consider replacing “some” with “a 

high”; in line 2, replace “study” with “CEUS SSC Model” 

Section 5.4.1.5 

In line 5: Replace “capture” with “represent”; in line 6, consider rewording to read: “The 

relationship used (Somerville et al., 2001)” 

In the last line: Replace “study” with “assessment” 

Section 5.4.1.6 

In line 2: Consider replacing “a consideration” with “an evaluation” 

In line 4: Replace “assumed to be equidimensional” to “assessed to be equidimensional” and 

change “For progressively larger areas” to “For progressively larger rupture areas” 

In line 6: Consider deleting “it was assumed that” 

In line 10: Consider deleting “assumed to be” 

In line 11: The NAGRA approach should be explained, as reviewers are unlikely to have this 

report. 

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In the last line: Consider replacing “associated with” with “of” 

Section 5.4.1.7 

In line 1: Consider replacing “Assuming” with “For”, and “assumed to have” by “defined by” 

In line 2: Replace “defined” with “represented” 

In line 5: Replace “assigned to” with “assessed for” 

Table 5.2.1.1 

Does the last row contain numbers of earthquakes “Greater than M 4.5” or M 4.5? 

Figures 5.2.1-7 and 5.2.1-8 

Typo in legend. Change “Disribution” to “Distribution” 

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CHAPTER 6 — SSC MODEL: Mmax ZONES BRANCH 

General Comments 

G 6-1. (NAR) The core of the TI Team’s assessment of the Mmax zones approach within the 

CEUS SSC model is described in this chapter. As such it is a critical chapter understanding of 

the assessment by future users. The TI Team has described an immense amount of data 

together with its evaluations of these data in characterizing and assessing this branch of the 

CEUS SSC model; in doing so the TI Team generally has described the assessment in sufficient 

scope and detail to inform future users of the model. 

G 6-2. (CBR, U) Chapter 6 is generally well written. The discussion of each of the RLME 

sources is laid out logically providing a general description of the source, localizing feature(s), 

geometry, recurrence, and maximum magnitude. However, the basis for some of the 

assessments is not clearly articulated. Some specific examples are mentioned below, but the 

PPRP recommends the TI Team review all the subsections with an eye to improving the clarity 

and strength of the bases for assessments. For example, it is not always clear why one source is 

using the generic seismogenic crustal thickness assumptions while others are not. The same 

holds true for differences in assessed weights for clustered behavior. Another example is the 

empirical relationships used to derive magnitudes given assumed dimensions for seismic 

sources. To the extent possible, the TI Team needs to clearly establish their overall approach to 

assessing these weights; in some instances additions to Chapter 5 should be considered to 

establish the basic approach to how the TI Team decided to modify generic weights, or what 

generic data (discussed in Workshop #2?) influence the assignment of weights to individual 

seismic sources. 

G 6-3. (CC) In the 3rd paragraph of Section 6.1 the report states: “By identifying the RLME 

sources and including them in the model, there is no implication that the set of RLME sources 

included is, in fact, the total set of RLME sources that might exist throughout the study region.” 

This sentence and the remainder of the paragraph make a very important point about a 

fundamental assumption included in this model. This point needs to be articulated, specifically 

in Section 4 of the report as well. 

Specific Comments 

S 6-1. (CC, SSHAC) Achieving Clarity Necessary for Future User

The importance of Chapter 6 for informing future users of the CEUS SSC model places a heavy 

demand on the TI Team to clearly document its assessment. As a framework for achieving 

necessary clarity of documentation, it may be useful for the TI Team to keep in mind the steps 

involved in implementing the SSHAC assessment process: (1) compiling the community 

knowledge; (2) compiling the relevant data; (3) evaluating the community’s knowledge, 

understanding the community’s uncertainty, and characterizing alternatives for assessment; and 

(4) assessing weights for the alternatives representing the community uncertainty. Generally 

the TI Team has provided very thorough documentation of steps 1 and 2 in this chapter. 

Documentation of steps 3 and 4 is often less clear. Much of the lack of clear presentation can 

be attributed to misuse of terms. This is particularly evident in descriptions of the TI Team’s 

assessments where many different words (define, characterize, modeled, given, constrain, 

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allowed, chosen, assign, assumed ...) are used for assessment. In addition to conflicting 

meanings, the impact of using words with such diverse meanings for the core SSHAC 

methodology requirement, namely “assessment,” is that they undermine the essential discipline 

that a SSHAC assessment requires. Other instances of misuse of terms coupled with lack of 

completeness in descriptions detract from the reviewers’ understanding of the evaluations 

performed and weaken the usefulness of the document for future users. Consider as an 

example the following edited first paragraph of Section 6.1 compared to the original. 

By definition, RLME sources are the locations of repeated (more than one) largemagnitude (M 6.5) earthquakes in the historic and (or) paleoearthquake record. 

Because of the rarity of repeated large-magnitude earthquakes relative to the period of 

historical observation, evidence for these earthquakes comes largely from the 

paleoearthquake record. For example, paleoearthquakes identified by interpretations of 

paleoliquefaction features and fault displacement (paleoseismic) studies combined with 

those in the historical record result in the catalog of large-magnitude earthquakes in the 

central New Madrid region and at Charleston. At Charlevoix, RLMEs are observed in 

the historical record and are supplemented by the paleoearthquake record. For the 

Meers and Cheraw faults as well as the Wabash Valley source, there are no largemagnitude earthquakes in the historical record. The RLMEs for these sources are 

characterized by evaluating repeated surface-faulting displacements identified in 

trenches across the faults and, for the Wabash Valley source, by interpretations of the 

geographic distribution of paleoliquefaction features. 

S 6-2. (CC) Improving the link to the Data Summary and Data Evaluation Tables 

Prior to discussing specific seismic sources, the reader should be reminded that the information 

in the Data Summary and Data Evaluation tables provides a comprehensive assessment of the 

current information related to each seismic source. It is the PPRP’s view that external readers 

and reviewers of the CEUS report need to be at least familiar with those tables prior to 

objectively commenting on the TI Team’s assessment. This section would also benefit from a 

brief discussion of how the earthquake recurrence for RLME sources was modeled, specifically 

how the lower-bound magnitude for integration for these sources was established by the TI 

Team. 

S 6-3. (DMM, CC, U) Earthquakes of M  6.5 in the Charlevoix RLME

The first paragraph in Section 6.1.1 describes two historical earthquakes of M 6.5 (one of M

7 in 1663 and one of M 6.5 in 1870). The reader is then pointed to the Charlevoix RLME logic 

tree (Figure 6.1.1-2) which has branches for the “Events/Data” node that do not appear to 

include the two historical earthquakes in the stated event count for M 6.5 (e.g., “3 eqs in 9.5–

11.2 kyr”). Section 6.1.1.2 goes on to describe paleoearthquakes, including one “historic” 

paleoearthquake with “a bracketed age of at least 540 yr BP.” These descriptions need to be 

clarified for the reader to understand the basis of rate information. 

To appearances, the RLME rate information and calculated uncertainties for Charlevoix in the 

HID (Appendix H, Section 5.2) do not account for the two historical earthquakes in 1663 and 

1870—only the paleoearthquakes. (For an example of better clarity, see the logic tree and HID 

tables for the Charleston RLME, where the reader is explicitly informed with labeling such as 

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“1886, A, B, C” that the count includes one historical earthquake and three paleoearthquakes.) 

Adding to the problem of event counts, the text in Section 6.1.1.2 (first sentence of par. 2) 

states that “Tuttle and Atkinson (2010) provide evidence for at least three Holocene 

paleoearthquakes in Charlevoix with M 6.2 . . . .” If 6.2 is not a typo, then an assessment 

has to be made for how many of those events were of M 6.5 (or explain assumptions). 

S 6-4. (U, DMM, CBR, CC) Unclear Interpretation Impacting Uncertainty

In Section 6.1.1.2, par. 3, the third sentence states, “Focal mechanisms for earthquakes of 

magnitude 3 show reverse faulting, whereas smaller-magnitude earthquakes indicate some 

strike-slip and normal faulting, suggesting that local stress conditions affect rupture style 

(Lamontagne and Ranalli, 1997).” This indicates that there is a local source of tectonic stress. 

If this is the intent, the interpretation would be in conflict with the community’s knowledge and 

would require additional evaluation of uncertainty. 

S 6-5. (CC, DMM) Charlevoix—Geometry and Style of Faulting

In the fourth paragraph of Section 6.1.1.2, while discussing the geometry and style of faulting 

for the Charlevoix RLME, the report indicates that future ruptures for this source are modeled 

as randomly-oriented thrust faults with dips between 45 and 60 degrees in either direction. 

Later on p. 6-6 the report indicates the RLME boundaries should be treated as leaky with 

ruptures permitted to extend beyond the source boundaries. There are a number of questions 

that arise in interpreting these statements that apply to several other RLME sources as well. 

The preceding paragraphs of the section describe fault orientations derived from small 

magnitude earthquakes. Keeping in mind the fact that a RLME source is for large (M 6.5) 

earthquakes and hence requires large rupture areas, the applicability of these results for smallmagnitude earthquakes needs to be carefully explained. 

For the RLME sources it is not clearly explained what assumptions are being made regarding 

the recurrence model, i.e. is it Mmax ± 0.25 magnitude unit about each of the four identified 

Mmax values (noted briefly in Section 5)? This would be a “perfectly characteristic” or 

maximum-moment type model. This represents the epistemic uncertainty in Mmax plus the 

aleatory variability in the future occurrence of each of the characteristic events. The 

“interaction” between the lower ranges of magnitudes for the characteristic RLME source that 

will overlap with the upper end of the truncated exponential distribution being applied for the 

Mesozoic Extended Mmax source zone needs to be explained. This point is true for all the 

RLME sources. Since Charlevoix is the first of the RLME sources described, the TI Team 

should clearly explain these issues in this section. 

S 6-6. (CC) Charlevoix—Maximum Magnitude 

In the last paragraph of Section 6.1.1.3, the discussion of boundary dimensions leading to the 

TI Team’s conclusion that the boundary is leaky requires more discussion. Given the assigned 

Mmax values, are the boundary dimensions too small to fit these magnitudes fully within the 

boundaries? To the extent possible quantitative discussion should be provided. 

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S 6-7. (DMM, CC) Unclear Logic for Performing Assessment

In the first paragraph of Section 6.1.2.1, the meaning of “time periods of interest” as used is not 

clear. Is it the projected life of an NPP, the projected life of the CEUS SSC model, a geologic 

time period? In any case it is not clear how “time periods of interest” influences an assessment 

of whether tectonic strain release in the Charleston area is in or out of a cluster. Moreover, the 

TI Team must explain its evaluation, characterization, and assessment of the community’s 

knowledge about tectonic driving forces and the physics of tectonic strain release in a clustered 

sequence of large earthquakes at about 500-year intervals in the absence of any measurable 

strain deformation. Otherwise, the reviewer and potential future user of this report will not be 

able to understand the basis for the assessment. 

S 6-8. (CBR, U) Charleston—Evidence for Clustered Behavior

In Section 6.1.2.1, the TI Team’s assessment of “in” or “out” of a cluster requires more 

justification. While the TI Team appropriately discusses the evidence of long-term 

versus short-term behavior, the fact remains that there is direct evidence of repeated 

large earthquakes in the Holocene and little if any direct evidence that we are at the end 

of a cluster. Perhaps there needs to be some type of generic discussion of this issue in 

Chapter 5, with Workshop #2 providing the ITC background to characterize and assess 

this issue. Otherwise the assessment that we are at the end of a cluster seems to come 

across as somewhat arbitrary versus informed assessment. What is different between 

Charleston and other RLME sources such as Cheraw? 

S 6-9. (CC) Charleston—Geometry and Style of Faulting

In Section 6.1.2.3, the discussion of boundary dimensions leading to the TI Team’s conclusion 

that the boundary for the three source geometries is either strict or leaky requires more 

discussion. Given the assessed Mmax values, are the boundary dimensions too small to fit 

these magnitudes fully within the narrow source boundary relative to the other two source 

definitions? To the extent possible, quantitative discussion should be provided. The TI 

Team’s assessment of using the default values for seismogenic crustal thickness requires 

additional justification. While all of the references cited for seismogenic crustal thickness are 

within the range for the default values, several suggest more preference (higher weight?) for 

values between about 15 and 20 km. Given this, the basis for assessing a weight of 0.4 to a 

seismogenic crustal thickness of 13 km is not clear. 

S 6-10. (CC) Charleston—Weights for Charleston Narrow and Regional Sources

In Section 6.1.2.3.1, the discussion of the basis for the weight assessed for the Charleston Local 

Source seems well developed. However, the discussion for the relative weighting of the 

Charleston Narrow and Regional sources is not clear. 

S 6-11. (U, DMM, CBR, CC) Contextual use of the term “microseismicity” 

In Section 6.1.2.3.1, first paragraph, the use of the term “microseismicity” potentially leads to 

confusion about tectonic processes. “Seismicity” is defined in terms of the spatial and temporal 

occurrence of earthquakes, a generally accepted measure of space-time tectonic strain release in 

earthquakes. The term “microearthquake” is now generally accepted to mean an earthquake of 

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M  3. But the PPRP is not aware of a community definition of the term “microseismicity.” 

Consequently, the TI Team needs to explain its use of the term in the context of this evaluation. 

For example, is “microseismicity” used to mean “seismicity of microearthquakes,” possibly 

implying a strain cycle process that is different from that implied by “seismicity”? The 

discussion should clearly convey how the TI Team evaluates “microseismicity” as one of the 

four observations cited as the basis for assessing the “Charleston Local source zone”? 

S 6-12. (CC, DMM) Charleston—Recurrence 

Given the uncertainty in length and completeness of the paleoliquefaction record and 

interpreted number of separate episodes, and the very general description of the process used to 

develop recurrence values contained in Section 5.3.3, the PPRP strongly encourages the TI 

Team to include a step-by-step example of the application of the procedure used for at least one 

of the RLME sources. This should include additional figures and text. This will significantly 

improve clarity and transparency. Consider the following criticisms, some of which apply to 

recurrence calculations and corresponding HID tables for other RLMEs: 

In Section 6.1.2.5, the recurrence method is noted to be “based solely on inter-event times 

estimated from the paleoliquefaction record.” What this section fails to communicate clearly to 

the reader—especially amid the elaborate analysis and description of those inter-event times—

is that the methodology used to calculate the annual frequency of earthquakes of M 6.5 

(Section 5.3.3.1.2) ultimately uses only the elapsed time since the oldest event in the sequence

and the number of events counted. The Charleston RLME logic tree (12th node), for example, 

points the reader to the HID tables. Referring to those tables, it will not be readily evident to 

the reader that the key pieces of information are N and the elapsed time since the oldest 

earthquake in the sequence of N events. Also, given that the oldest earthquakes (Table 6.1.2-1) 

have an age specified by a range, an explanation is needed whether (or how) that uncertainty 

was addressed. 

The unalert reader (or analyst) examining the HID tables for computed annual frequencies for 

the Charleston RLMEs may potentially be confused by: (1) the inverted order for the 5-point 

distributions compared to Table 5.3.3.-1, which was used to define the 5-point distribution; and 

(2) the need to refer to Tables 6.1.2-1 and 6.1.2-2 to discern the elapsed time since the oldest 

earthquake counted in the sequence. For example, examining “Table Charleston_HID-3,” it 

may escape the reader’s attention that the 5-point distribution is not for four events in 5500 

years, but rather four events in 1,524–1,867 years (or possibly in 1,569–1,867 years). To 

reproduce the results in the table (and for virtually all the Poisson-model tables in the HID), 

there is no explicit information about the exact elapsed time that was used. To add to the 

confusion, the text does not explain what the age ranges listed in Tables 6.1.2-1 and 6.1.2-2 

represent. Do they represent the mean ± 2 sigma from the probability distributions in Figure 

5.3.3-2? 

As the reader progresses to the BPT renewal model there are terse descriptions of the weighting 

(without justification of the weights) and cross reference to Section 5.3.3 for methodology—but 

the text does not provide any discussion of the results. How do the BPT results compare to 

those for a Poisson model? Do they make sense? 

 

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S 6-13. (CC) Charleston—Time Period for Recurrence

In Section 6.1.2.5.2 the discussion of the completeness period of the paleoliquefaction record 

(at least the last three sentences) seems equivocal. However, the weight assessed for the 

shorter completeness period, 0.8, indicates a strong preference; additional discussion seems 

required to justify the strong weighting. 

S 6-14. (U, CC) Clear Representation of the Community’s Knowledge for Characterizing 

Alternatives and Uncertainties 

The discussion in Section 6.1.2.5.3 calls attention to the need for clear representation of the 

community’s knowledge and uncertainty as the basis for characterizing alternatives in the logic 

tree and for assessing the community uncertainty. We offer the following edited paragraph as 

an example for comparison with the original paragraph: 

The ninth branch of the Charleston logic tree represents alternative characterizations of 

the community’s knowledge and the TI Team’s assessment of the community 

uncertainty for recurrence of large earthquakes in the Charleston Seismic Zone, 

developed as part of the CEUS SSC Project (Figure 6.1.2-1). Alternative interpretations 

of the distribution of liquefaction features include a total of four large earthquakes in the 

past approximately 2,000 years and between four and six large earthquakes in the past 

approximately 5,500 years. The alternative characterizations represented in the logic 

tree are based on (1) interpreted length of the paleoliquefaction record; (2) interpreted 

types of constraining ages; and (3) evaluations of the area distribution and 

interpretations of which prehistoric liquefaction features were caused by largemagnitude earthquakes centered in the Charleston area and which were caused by 

moderate-magnitude local earthquakes. 

The clarity of this section could be greatly improved by technical editing to better link the 

descriptions of the current knowledge with characterizations of alternatives in the logic tree and 

with the assessment of the community uncertainty. 

S 6-15. (CC) Cheraw Fault—Evidence for Temporal Clustering

In Section 6.1.3.1, the discussion of weights assigned to in or out of a cluster requires 

additional discussion given the statements that there is no evidence to indicate that this source 

is out of a cluster. It is not clear what the differences are for this source relative to other 

sources, such as Charleston as an example. 

S 6-16. (CC, U) Cheraw Fault—Magnitude

In Section 6.1.3.3, p. 6-19, the discussion of relationships used to estimate magnitude from 

fault area includes “Somerville et al. (2001).” At various places in the Project report the 

citations for this relationship include Somerville et al. (2001), Somerville et al. (2005), and 

Somerville and Saika (2000). This needs to be double-checked and a validated reference cited 

(the Somerville references are in the gray literature and difficult to find, and the basis of the 

citation was not evident). A verifiable citation and reference need to be included in the Project 

database. 

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On page 6-20, in the discussion of maximum and average displacement for the Cheraw fault the 

report notes: “There is insufficient information to establish whether the displacement per event 

measured at the sole trench site (emphasis added) along the Cheraw fault represents average or 

maximum values.” In the last sentence of this paragraph, the report concludes the values are 

maximum values. The conclusion does not seem to follow from the discussion in the paragraph 

as written. 

S 6-17. (CC) Meers Fault—Clustered Behavior

In Section 6.1.4.1, the explanation of weights assessed for in or out of a cluster requires 

additional discussion, given the statements that there is no evidence to indicate that this source 

is out of a cluster. It is not clear what the differences are for this source relative to other 

sources such as Charleston as an example. 

S 6-18. (DMM) Meers Fault—Discussion of Potentially Relevant Data 

In Section 6.1.4.2, potentially relevant data for the assessment are not discussed. Specifically, 

the Meers fault is located on the sector of the boundary of the Wichita uplift that has greatest 

structural relief by a wide margin. The magnitude of the structural relief between the Wichita 

Mountains and the Anadarko Basin is the source of a very large gravity gradient indicating 

significant induced stress across the northern Wichita Mountains frontal fault system along this 

sector. A discussion of these potentially important data should be included for perspective. 

Also, is “Arbuckle-Wichita-Amarillo uplift” a proper usage? A reference to the source of this 

usage is needed. 

S 6-19. (CC, U) Meers Fault—Localizing Feature

In Section 6.1.4.2, it is not made clear in the discussion of the potential for the occurrence of 

Meers-like ruptures in the Oklahoma Aulacogen why “only one Meers-like structure is active 

within the aulocogen at a time.” 

S 6-20. (DMM, CC, U) Meers Fault—Geometry and Style of Faulting 

In Section 6.1.4.3, on page 6-24: When Meers-like earthquakes are allowed to migrate off the 

fault they are limited to occurring within the OKA. How are the earthquakes within the OKA 

to be modeled? The next paragraph suggests the strike to be N60W (parallel to the AmarilloWichita-Arbuckle uplift) with a dip between 40 and 90 degrees. However (and this comment 

holds for several of the other RLME sources), it is not clear how the analyst should model this 

situation. As a series of fictitious parallel faults distributed throughout the appropriate portion 

of the OKA? If so, how many are appropriate? This answer will clearly be determined by the 

location of the site of interest relative to the source. What was assumed by the hazard analysts 

for the demonstration and sensitivity calculations? 

On pages 6-24 and 6-25: The discussion indicates there is a significant amount of uncertainty 

in the appropriate H/V values to assign to the displacement observations. It does not seem as if 

this uncertainty is represented in the final recurrence values for the Meers RLME. Additional 

clarification seems necessary. 

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On p. 6-24, third paragraph: The assignment of seismogenic thickness for the Meers fault 

source based on one reference seems to be inconsistent with how this parameter has been 

assessed for other seismic sources including Charleston. Consistency in assessment of each of 

the branches of the logic tree is an important consideration. If outside reviewers see 

inconsistencies in the assessment of weights for the logic tree branches, then their confidence in 

the overall assessment may be weakened. 

S 6-21. (CC, U) Meers Fault—RLME Magnitude 

In Section 6.1.4.4, the use of four seismic source dimension relationships to characterize and 

assess magnitude for this seismic source contrasts with the approach to other seismic sources. 

It is not clear why the Meers source is any different than other seismic sources to justify these 

differences. A consistent approach to characterizing and assessing magnitude based on source 

dimensions seems to be appropriate. There does not appear to be any unique property of the 

Meers fault that would justify using rupture area relationships for the Meers fault but not other 

RLME sources such as Charlevoix, Charleston, or Cheraw. 

S 6-22. (CBR, CC) New Madrid—RLME Magnitude

In Section 6.1.5.3, the use of unpublished information (Hough and Page) needs careful 

consideration. Has the paper been accepted for publication? Additionally, the text discusses 

the use of the characteristic earthquake recurrence model. Other sections of the text indicate 

that the characteristic earthquake recurrence model is not being used. 

S 6-23. (CBR, CC) New Madrid—Recurrence

Section 6.1.5.4 presents an insufficient basis for the assessed weights for the two alternative 

recurrence models characterized. The text should refer to Workshop #2 for discussion of this 

topic and present more information to justify the weight assessed for the renewal recurrence 

model. 

S 6-24. (CBR, CC) Reelfoot Rift—Eastern Rift Margin Fault, Evidence for Temporal 

Clustering: Section 6.1.6.2

In Section 6.1.6.1, for this seismic source, the TI Team has assessed non-clustered behavior 

with a weight of 1.0. The evidence for this assessment is stated to be insufficient information 

on the number or timing of earthquakes. This contrast with other RLME sources where the 

main issue pertained to evidence of short-term versus long-term behavior and the logic that 

short-term rates cannot extend through extended time frames. That logic also appears to apply 

to the ERMF. The TI Team needs to develop a consistent approach to assessing clustered 

versus non clustered behavior. 

S 6-25. (CBR, CC) Reelfoot Rift—Marianna Zone, Evidence for Temporal Clustering 

In Section 6.1.7.1, the text states, “It also is unclear whether some of the paleoliquefaction 

features are due to earthquakes on the Eastern Rift Margin (ERM, RLME) source . . . .” Given 

this statement, it is not clear why this seismic source has a probability of activity of 1.0. The 

discussion and justification of the weight for temporal clustering need to be strengthened. 

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Similarly, the basis for characterizing the seismic source boundary is “leaky” needs to be 

improved. 

S 6-26. (CC) Reelfoot Rift—Marianna Zone, Geometry and Style of Faulting

In Section 6.1.7.2, last paragraph, the probability distribution on seismogenic thickness is 

different than the default distribution. Given this, the text should provide more details on the 

number of well-located earthquakes in this source and how they are used to establish a 

distribution on seismogenic thickness that is different than the default values. 

S 6-27. (CBR, CC) Reelfoot Rift—Commerce Fault, Evidence for Temporal Clustering

In Section 6.1.8.1, the text notes that the liquefaction and secondary faulting used to document 

Holocene events may be related to strong ground motion from earthquakes occurring elsewhere 

in the Reelfoot Rift. Given this statement, it is not clear why this seismic source has a 

probability of activity of 1.0. The basis for assessing a weight of 1.0 to nonclustered behavior 

is not clear. 

S 6-28. (CC) Reelfoot Rift—Commerce Fault, Geometry and Style of Faulting

In Section 6.1.8.2, last paragraph, the basis for characterizing the northwest and southeast 

boundaries of the seismic source as fixed and the northeast and southwest boundaries as 

“leaky” is not clear. 

S 6-29. (CC) Wabash Valley—Temporal Clustering: Section 6.1.9.1

In Section 6.1.9.1, the basis for the weight of 1.0 on “in a cluster” needs to be improved and to 

be consistent with the bases for this assessment for all RLME seismic sources. 

S 6-30. (DMM, CC) Wabash Valley—Future Ruptures

On pages 6-59 and 6-60 there is no specific discussion of how the future ruptures are to be 

modeled. The text refers to Table 5.4-1 (should be Table 5.4-1 and 5.4-2). But as noted 

previously, additional guidance for the hazard analyst would be useful. 

S 6-31. (CC) Wabash Valley—Alternative Mmax Zones

In Section 6.2, the discussion of alternative Mmax zones only discusses the Bayesian approach 

to Mmax estimation and its relevance to source zone characterization. The consistency of the 

results using the Kijko method should be discussed as well. 

S 6-32. (CC) Criteria for Definition of Boundary—Mesozoic Extended Narrow Zone

In the last sentence of Section 6.2.1.1 on p. 6-64, the text states: “These observations support 

the weight of 0.8 that this geometry represents crust extended in the Mesozoic.” The PPRP 

does not feel the section make the case well. A series of well written observations are 

presented, but the relevance of the observations to source characterization and specifically to a 

weight of 0.8 is not clearly articulated. This same comment applies to the other sections on 

Mmax zones. 

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S 6-33. (CBR, U) Comparison of Recurrence Parameters to Catalog

As discussed in Section 6.4.2, Figures 6.3-7 through 6.3-16 (should be corrected to read 6.4-7 

through 6.4.16) show that the recurrence model for the large seismic source zones tends to 

overestimate the rates for magnitudes 5 or higher. What does this mean to the TI Team? A 

systematic trend such as the one discussed, should be questioned in detail by the TI Team in 

terms of evaluating whether all assumptions of the analysis are appropriate. The consistent 

overestimates of the rates suggest that assumptions related to smoothed seismicity may need to 

be adjusted to provide a better match between the recurrence model and observed seismicity. 

The PPRP strongly believes additional discussion and investigation is warranted regarding 

these results. 

S 6-34. (CR, DMM, U) Need for TI Team Assessment of Spatial Variation of Rate and bvalues 

The results of the recurrence-rate analysis presented in Section 6.4 clearly show that TI Team 

assessments of priors on rate and b-values are required. The derived b-values in particular 

appear to be almost entirely below the range of values supported by studies world-wide over 

many years. We recommend that the Project arrange to further evaluate this analysis. 

Comments by Section 

Chapter 6 (Title) 

Given that 60 of the 70 pages in this chapter deal with RLME sources, the chapter title should 

be changed to something like, SSC MODEL: MMAX ZONES BRANCH AND RLME 

SOURCES. 

Chapter 6 (Introductory text) 

In the introductory paragraph at the top of p. 6-1, after the second sentence, it would be helpful 

to most readers to repeat a very helpful description that appeared on p. 4-16f in Section 4.4.1: 

The “Mmax zones” model involves the direct use of observed seismicity by spatial smoothing 

of distributed seismicity and the inclusion of RLMEs that are defined primarily by paleoseismic 

evidence. The “seismotectonic zones” model involves the use of additional tectonic data to 

define the spatial distribution of future events. 

Section 6.1.1 

p. 6-2, 2nd paragraph: Regarding “(source IRM in the R model)”: we assume this refers to the 

Canadian study; clarification is needed. 

p. 6-2, 3rd paragraph: The phrase “investigations undertaken for the . . .” probably should be 

“investigations evaluated . . . ” The PPRP believes only evaluations were performed. 

Section 6.1.1.2

Note: There are two sections labeled 6.1.1.2—one on p. 6.4 and one on p. 6-6. 

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On p. 6.4, in paragraphs 3 and 4, “thrust” and “reverse” are used inconsistently vis-à-vis the 

definition provided in the Glossary for “Fault, Thrust” (< 45) and “Fault, Reverse” (> 45). 

On p. 6-6, 2nd paragraph, next-to-last sentence: “. . . favors three events to four based on field 

observations.” A citation would be helpful. 

Section 6.1.2.1 

In last sentence of the first paragraph, the reader is referred to a non-existent Section 5.3.3.6. In 

scanning Chapter 5, it’s not clear that there is a “definition” of the temporally clustered 

earthquake model. 

On p. 6-8, 2nd full paragraph: No justification is given for weights on whether the Charleston 

RLME is “in” or “out” of a cluster. 

Section 6.1.2.5.3 

p. 6-14, last paragraph, line 10: Typo. (see See Appendix E . . .). 

Section 6.1.2.5.4 

The use of “occurrence model” in the section title and text is at odds with “recurrence model” 

used predominantly throughout the text (easily verified by a global search for “recurrence 

model,” which shows repeated instances of “Renewal vs. Poisson recurrence models”) and in 

the Glossary. There is at least one other appearance of “occurrence model” in the text (Section 

4-19, p. 4-20, beginning of second full paragraph). “Occurrence” rates/probability also appears 

in Section 5.3.3.2 and should be corrected globally. 

Section 6.1.3.2 

p. 6-19, 3rd paragraph: The weights assigned to the two dip cases sum to more than 1.0. 

Section 6.1.3.4 

p. 6-21, second full paragraph, line 3: The term “interval-based approach” is ambiguous and 

potentially misleading. The data used are the number of earthquakes in a specified time 

interval (e.g., Figure 6.1.1-2, 7th node), not the interval between earthquakes, as some readers 

might assume. 

p. 6-21, fourth full paragraph, line 1: Consider replacing “occurrence rates” with “recurrence 

rates” 

p. 6-21, 4th full paragraph: Typo in cited recurrence values: 200, 350, and 500 years, should 

be k-years. 

Section 6.1.4.2 

par. 1, lines 6–7: Suggested rewording. The text currently says “...have observed Quaternary 

faulting (e.g., Crone and Wheeler, 2001 . . . .” Suggest being specific and indicating observed 

Quaternary surface faulting. 

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Section 6.1.2.4.3 

p. 6-13, 2nd paragraph: “The UCSS magnitudes and weights . . . .” UCSS not defined. 

Section 6.1.4.5 

2nd par., line 4: Typo. Change “500,00 years” to “500,000 years” 

Section 6.1.5 

In the Table on the top of p. 6-33: The note for the 1811-1812 earthquakes indicates 138 yr BP 

± 100 yr. As written, suggests the uncertainty is 100 years; this needs to be clarified. 

Section 6.1.5.3 

p. 6-39, last paragraph: The text references Table 6.1.5-3 which appears to be missing. 

Section 6.1.5.4 

p. 6-41, first full paragraph, last sentence: Replace “only includes of all three” with “only 

includes the alternative of all three components” 

p. 6-41: The paragraph containing equation 6.1.5-1 is not clear. The use of the equation needs 

to be explained within the source characterization scheme. 

Section 6.2.1.2 

p. 6-66, 2nd full paragraph line 9: Typo. (** mi) 

Section 6.3 

line 4: Typo. “source( described...” 

Section 6.3.1 

p. 6-69, first full paragraph, line 9: Reference is made to “the 1882 earthquake”; this event is 

not in the table on the previous page and there is no context. Adding a short descriptive 

sentence for clarity would help the reader. 

Section 6.4.1 

In the first line, change “Figures 6.3-1 through 6.3-6” to “Figures 6.4-1 through 6.4-6” 

Section 6.4.2 

In the first line, change “Figures 6.3-7 through 6.3-16” to “Figures 6.4-7 through 6.4-17” 

Figure 6.1.1-1 

Two of the large earthquakes are incorrectly labeled: 1663/2/5 is labeled M=3.71 (text in 

Section 6.1.1 says “M 7”; 1791/12/6 is labeled M 5.5 (text in Section 6.1.1 says “M 5.8). The 

labeled magnitude for only one of the other three large earthquakes corresponds exactly to the 

text in Section 6.1.1. 

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Figure 6.1.1-2 

In the Charlevoix RLME logic tree, the header for the 10th node should be changed from 

“Earthquake Occurrence Model” to “Earthquake Recurrence Model” (see comment on Section 

6.1.2.5.4). 

Figure 6.1.2-1 

In the Charleston RLME logic tree, the header for the 10th node should be changed from 

“Earthquake Occurrence Model” to “Earthquake Recurrence Model” (see comment on Section 

6.1.2.5.4). 

Figure 6.1.2.4 

Figure 6.1.2-4 shows the three zones along with the magnitude and gravity anomalies. It is not 

clear how these zones were delineated based on these geophysical data. 

Figure 6.1.3-1 

In the Cheraw RLME logic tree, under Recurrence Method, the uppermost branch should more 

correctly be labeled “Earthquake Count in Time Interval” (as for the Charlevoix RLME logic 

tree instead of “Inter-event Times.” 

Figure 6.1.3-1 

In the Meers RLME logic tree, under Recurrence Method, the upper and lower branches should 

more correctly be labeled “Earthquake Count in Time Interval” (as for the Charlevoix RLME 

logic tree) instead of “Inter-event Times.” In the corresponding HID tables (Table 

MEERS_HID-2 and HID-3), information on the data set (N events, T time) should usefully be 

provided, as in Table Marianna_HID-2. 

Figure 6.1.5-1 

In the logic tree for the NMFS RLME source, under Equivalent Annual Frequency, references 

to the HID tables should be labeled NMFS instead of NMF. Under Events/Data, the labeling of 

“1811–1812, 1450 AD, and 900 AD” is difficult to relate to the dates in the table presented at 

the top of p. 6-33 (for example, 900 AD corresponds to 1110 yr BP—but in the table one finds 

“1,050 yr BP ± 150 yr). Exactly which elapsed time was used in Table NMFS_HID-2? (In that 

table, information on the data set (N events, T time) should usefully be provided, as in Table 

Marianna_HID-2. 

Figure 6.1.6.2 

What are the yellow stars on the figure? No explanation in legend or caption. 

Figures 6.4-1 through 6.4-6 

Consider adding a note to the caption explaining what the mean maps are. 

 

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Tables 6.1.5.1, 6.1.5.2, and 6.1.5.3 missing 

Table 6.1.5-1 discussed on page 6-32 is missing. Table 6.1.5-2 discussed on page 6-37 is 

missing. Table 6.1.5-3 discussed on page 6-39 is missing. 

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CHAPTER 7 — SSC MODEL: SEISMOTECTONIC ZONES BRANCH 

General Comments 

G 7-1. (NAR) In this chapter, as in Chapter 6, the TI Team has described and evaluated an 

immense amount of data and information and deserves praise for its efforts. The chapter 

addresses the “seismotectonic zones” branch of the master logic tree, as developed in Chapter 4 

and portrayed in Figure 4.4.1-11

 (and companion figures referenced therein). The TI Team’s 

assessment is supported by Data Evaluation and Data Summary tables in Appendices C and D. 

This conceptual branch of the logic tree splits into two source groups—seismotectonic zones 

and the independent RLME sources, described in Chapter 6. Chapter 7 deals only with the 

twelve seismotectonic zones and their seismic characteristics. 

G 7-2. (CBR, CC) A significantly higher weight is assessed for the seismotectonic zones 

branch relative to the “Mmax zones” branch. As stated in Section 4.4.1 on p. 4-17: “A higher 

weight (0.8) is assigned to the seismotectonic zones branch than the Mmax zones branch (0.2) 

because the seismotectonic zones branch allows for more relevant information on the 

characteristics of future earthquakes to be included in the model.” This information is the 

subject of the majority of Chapter 7. However, no full explanation or validation is presented in 

the introduction to this chapter to support the decision on the specific weights assessed for the 

two conceptual approaches at the front end of the master logic tree. A description of the 

justification of the weights would be an important and useful addition to the chapter. 

G 7-3. (CC, DMM, U) Although the chapter provides an abundance of geological detail, it 

fails to make a compelling case for identifying many of the seismotectonic zones as separate 

sources distinct from the larger Mmax zones described in Chapter 6. Considering the weight 

that is given to this branch (0.8), it is especially important that the definition of each of the 

seismotectonic zones be very clear and well supported with convincing evidence. 

Unfortunately, a persuasive case is not developed for the identification of several of the zones 

described in this chapter. 

G 7-4. (CC, DMM) The identification of the zones appears to be made largely on the basis 

of isolating regions of differing geological and tectonic histories that may have little direct 

relevance to the SSC characterization criteria that are specified in Section 4.3.3 (p. 4-14). These 

criteria are : (1) earthquake recurrence rate, (2) maximum earthquake magnitude, (3) expected 

future earthquake characteristics (e.g., style of faulting, rupture orientation, depth distribution), 

and (4) probability of activity of tectonic feature(s). The latter criterion was not used in 

developing the CEUS SSC model (Section 7.1, pg. 7-1), but no justification is given for not 

addressing this criterion. Furthermore, there is no uniform or systematic description of the 

application of the first three criteria which allow ready identification of the merits of the zones 

and which permit comparison among zones. Additional information pertaining to how the 

sources meet the defining criteria and more systematic organization of the content of the 

description of the zones would increase the rigor of the decisions reached in the report and their 

presentation. A summary table specifying the critical information that identifies each source 

zone based on criteria described in Chapter 4 would be helpful in organizing the information 

and comparing source zones. 

 1

 There are two figures labeled Figure 4.1.1-1; we refer to the one on p. 4-27. 

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G 7-5. (CC) Chapter 7 includes an impressive compilation of information and interpretations 

representing the range of relevant current knowledge of the scientific community. The scope 

and detail of this information are important in identifying and characterizing the seismotectonic 

zones and will be of great value to future users of the CEUS SSC Model. This information is 

well supported by comprehensive and timely references to the scientific literature. The level of 

detail is generally consistent throughout the description of the zones, but unfortunately the 

organization of the descriptions is not consistent. For example, some source zones have initial 

sections dealing with Background, others with Geologic Evidence, and still others with Basis 

for Defining Seismotectonic Zone. This lack of consistency in the description of the identified 

zones is an impediment to the review and comparison of the zones and needs to be corrected. 

The uneven descriptions appear to be due, in part, to multiple authorship, and some subsections 

apparently have not been updated since the application of the Kijko Mmax procedure in the 

Project. Some updating and rewriting appears warranted to alleviate these problems. 

G 7-6. (CC) The level of detail in this chapter is high, which will be useful in future 

seismotectonic studies within the CEUS. However, this level of detail will make it difficult for 

those readers of the report not well versed in the geology and geography of the region or the 

geologic time scale to comprehend the significance of the detail. Thus, to support the detail it 

would be advisable to (1) add maps that identify the location of geologic features, (2) provide 

more geologic terms in the glossary, and (3) accompany the glossary with a geologic time 

scale. Additionally, the descriptions of the seismotectonic zones should be reviewed to 

determine if some of the more specialized terminology, e.g., essexite, T-axes, Neoproterozoic, 

can be eliminated or simplified so that they can be meaningful to the spectrum of users of the 

report. 

G 7-7. (CC, SSHAC) As with previous chapters, this chapter could be greatly improved by a 

thorough technical edit. There are numerous editorial modifications required to achieve 

consistency in presentation, remove editorial errors, and improve clarity. Special attention 

should be given to clearly describing the bases for characterizing alternatives represented in 

alternative branches of the logic tree. Also, consideration should be given to describing the 

basis for the assessed weights for alternative characterizations representing the community 

uncertainty. Finally, care must be exercised to use words in their correct meaning, avoid 

casual terminology, and use terms that properly convey the essential activities of 

characterization of alternatives and assessment of the community uncertainty. 

G 7-8. (DMM) The Data Summary Tables of Appendix D are an important supplement to 

the descriptions of the seismotectonic zones. Unfortunately there appear to be omissions in 

Appendix D so that supporting information is not consistently available for this draft chapter. 

This will need to be remedied in revision of the report. Additional comments on Appendix D 

are given in a review of that segment of the report. 

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Specific Comments 

S 7-1. (CC) Suggestion for Rewrite of Introductory Paragraph 

The introduction to Chapter 7 could be improved with significant editing. Consider the 

following as an example. 

As discussed in Section 4.3, the Conceptual Framework for assessing the CEUS SSC 

model is characterized by two alternative branches of the master logic tree: the Mmax 

zones branch and the seismotectonic zones branch. The seismotectonic zones branch, 

which is assessed a higher weight of 0.8 versus 0.2 for the Mmax zones branch, 

subdivides the CEUS SSC region according to differences in the seismic source 

assessment criteria described in Section 4.3.3. A common element of both the Mmax 

zones and the seismotectonic zones branches is the RLME sources. Because the 

paleoearthquake data that indicate the presence, location, and size of the RLMEs are 

essentially independent from data used to assess seismotectonic sources, the RLME 

branch is present in both models. An overview of the approaches for characterization 

and assessment of the zones is in Section 7.3. 

S 7-2. (DMM) Need for Specifics Regarding Geologic Conditions that Affect Mmax

The first paragraph of Section 7.1 (p. 7-1) describes how the seismotectonic zones branch 

relates to Mmax. The basic premise is that regional differences in characteristics related to 

Mmax and/or future earthquake characteristics are best dealt with by identifying source 

zones of uniform properties. A region may possess characteristics that would lead to a 

different Mmax than adjacent regions, including a different prior distribution or different 

maximum observed earthquake. Mmax was described in Chapter 5, but it would be helpful 

to the users of the report for the authors to present examples of specific physical properties 

of the zones (e.g., thinner crust, lithospheric strength characteristics, aulacogens) and 

describe why these different conditions might result in different Mmax distributions. This 

information would help to sharpen the need for, and the significance of, the detailed 

information in the subsequent text which define Mmax and future earthquake 

characteristics. 

S 7-3. (CC) Description of Charlevoix RLME Source; Section 7.3.1.1.3, pg. 7-6. 

In Section 7.3.1.1.3 (p. 7-6), the description of the Charlevoix RLME seismic source (which is 

assumed to exist as a distinct seismic source) as part of justifying the St. Lawrence Rift (SLR), 

confuses the understanding of whether the SLR is a distinct seismotectonic zone. Part of the 

confusion relates to how the project is using historic earthquakes as part of the development of 

recurrence and maximum magnitudes. Are the historic earthquakes assigned to the SLR, even 

though they may be located within the boundaries of the Charlevoix RLME source? 

S 7-4. (DMM) Significance of Vp/Vs Ratio

On p. 7-14 of Section 7.3.2, under Geophysical Evidence, what is the significance of results 

from teleseismic receiver functions described in last sentence of this section? 

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S 7-5. (DMM) Evidence for Separating the Northern Appalachian Seismic Zone from the 

Paleozoic Extended Zone 

In Section 7.3.3.2 (p. 7-20), under Basis for Zone Geometry: The separation of the Northern 

Appalachian seismic zone (NAP) from the similar Paleozoic Extended zone (PEZ) to the south 

appears to be largely based on the location of the Triassic Hartford basin. However, a linear 

connection of the eastern boundaries of these zones would include only a small segment of the 

northern extent of the basin as shown in Figure 7.3.7-1 similar to the situation observed farther 

south along the boundary of the PEZ. Is the termination of the NAP being driven by the studies 

of Adams et al. in defining the seismic source zones of Canada? 

S 7-6. (DMM) Future Earthquake Characteristics;

In Section 7.3.3.4 (p. 7-21), under Future Earthquake Characteristics for the Northern 

Appalachian seismotectonc zone, the text notes that all earthquakes with known depths are 

relatively shallow, but goes on to use the default depth distribution for the seismic source. The 

basis for assigning the depth distribution for distinct seismic sources, including the NAP, 

should be based on a common approach to using earthquakes with known depths. Otherwise, 

assignment of the default depth distribution lacks rigor. Also note that a search of Chapter 5 

shows no “default depth” term. 

S 7-7. (DMM) Background of the Paleozoic Extended Zone 

In Section 7.3.4.1, the text needs to make clear that the Giles County Seismic Zone, the Eastern 

Tennessee Seismic Zone, and the Clarendon-Linden Fault System, are not unique from a 

seismotectonic perspective. Otherwise it is not clear why these features are not considered 

distinct seismic source zones. 

S 7-8. (DMM) Basis for Western Margin of the Paleozoic Extended Zone

In Section 7.3.4.2 (p. 7-29), under Basis for Zone Geometry: A reentrant of the Paleozoic 

Extended seismic zone extends into the craton in the vicinity of Kentucky, moving the western 

margin of the zone farther west. There is no support for this feature in the text of the report. 

The reference in the report that is used most extensively in defining the western margin is 

Wheeler (1995), but his studies did not indicate this reentrant; rather his margin to this zone in 

essentially a straight line through this region. A strongly supported description of the cause of 

this feature is needed or it should be eliminated. No references are cited to provide an 

indication that this feature is present. 

S 7-9. (DMM) Basis for Identification of the Illinois Basin Extended Basement Zone.

In Section 7.3.5.1 (p. 7-33), the justification for defining this region as a distinct seismotectonic 

zone and the discussion in this section are not consistent with the criteria defined in Section 

4.3.3 for defining seismic source zones. 

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S 7-10. (CC, DMM) Default Values of Future Earthquake Characteristics in the Eastern 

Continental Crust-Atlantic Margin; Section 7.3.7.4, pg. 7-48. 

In Section 7.3.7.4 (p. 7-48), the text discussing seismicity notes that most well located 

earthquakes of the Eastern Continental Crust-Atlantic Margin are distributed throughout the 

upper 13 km of crust. Given this information, the basis for assuming that the seismogenic 

thickness should be represented by the default values is not clear. 

S 7-11. (DMM) Additional Basis for Defining the Atlantic Highly Extended Crust 

In Section 7.3.8.1 (p.7-49), under Basis for Defining Seismic Zone: Canadian seismologists 

have recognized the zone of weakness at the Atlantic Ocean margin as defined by the 

continental slope as a zone of potential seismic activity based on the location of the magnitude 

7.2 1929 Grand Banks earthquake, which occurred east of the northern tip of Nova Scotia. This 

earthquake, as well as the Baffin Bay earthquake in Canada, is supportive of the identification 

of this seismic zone. 

S 7-12. (CC, SSHAC) Clarification of Text Describing the Basis for Mmax of the Extended 

Continental Crust-Gulf Coast

In Section 7.3.9.3 (p. 7-56), Basis for Zone Mmax: The characterization and assessment of 

Mmax described in this section is unclear. First, use of the term “scenario” (meaning imagined 

or possible) can convey a lack of disciplined evaluation of the available data for characterizing 

Mmax for the zone as required by the SSHAC assessment process. Replacing “scenario(s)” 

with “alternative characterization(s)” would properly convey that the characterizations 

represent the range of uncertainty based on evaluations of the available data. Second, the third 

alternative is described as follows: “The largest observed earthquake is the potential 

paleoearthquake identified from the studies of . . . .” The use of “largest observed earthquake” 

and “potential paleoearthquake” seems incompatible. In addition, the characterization 

described here clashes with the strong conclusion stated in Section 7.3.9.5. Elaboration is 

needed better explaining the evaluations performed supporting the third alternative 

characterization. 

S 7-13. (DMM) Additional Evidence for Defining the Gulf Highly Extended Crust; 

In Section 7.3.10.1 (p. 7-59), under Basis for Defining Seismotectonic Zone, is there evidence 

of faulting in this zone as anticipated in a highly extended zone? If so, that would be additional 

evidence for defining the zone. 

S 7-14. (DMM) Evidence Regarding Characterization of the Gulf Highly Extended Crust

In Section 7.3.10.3 (p. 7-60), under Basis for Zone Mmax, there are substantive analyses that 

show the event of February 10, 2006, to have been a landslide. These analyses must be 

referenced and discussed as part of the data base for characterizing and assessing Mmax for this 

zone. 

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S 7-15. (CC,DMM) Need to Strengthen the Basis for Defining the Oklahoma Aulacogen as a 

Distinct Seismic Source Zone 

In Section 7.3.11.1 (p. 7-62), under Basis for Defining Seismotectonic Zone, the text mentions 

“default future earthquake characteristics.” This terminology has not been used systematically 

throughout Chapter 7 (with reference to Table 5.4-1), and in this section it is not clear why 

these are the primary basis for defining the seismotectonic zone versus the full set of criteria 

found in Section 4.3.3. While future earthquake characteristics are one of the criteria used to 

define distinct seismotectonic zones (see Section 4.3.3), there does not appear to be anything 

profoundly unique about the style of faulting or the strike of ruptures to support defining the 

Oklahoma Aulacogen as a distinct seismotectonic zone. The basis for defining the Oklahoma 

Aulacogen as a distinct seismotectonic zone is weak and needs to be improved. 

S 7-16. (CC) Significance of Statement in Description of Northeast Ohio Seismic Zone in the 

Midcontinent Seismic Zone 

In Section 7.3.12.1.4 (p. 7-68), for the Northeast Ohio Seismic Zone: The third bullet of the 

second paragraph is meaningless to the reader without additional description of its significance.

S 7-17. (DMM) Effects of Smoothing on Recurrence Parameters 

In Section 7.5 (p.7-71), Recurrence Parameters: The objective smoothing results in b-values 

that are low, possibly below the range of values known from world-wide experience. Yet, no 

alternative is suggested. Additional elaboration of the analyses must be provided to adequately 

inform future users of the CEUS SSC model. 

S 7-18. (DMM) Full Explanation of the Results Shown in Figures 7.5.2-9 to 7.5.2-42

Many of the data shown in Figures 7.5.2-9 to 7.5.2-42 indicate the poor fits of the realizations 

to the catalog. This is disturbing and needs to be more clearly explained in the text. Why 

doesn’t the preferred model fit the catalog data better? Only the short text in section 7.5.2 

describes these figures. The text should be enhanced to describe the fitting issues, and as a 

result there needs to be full justification of the rate and b-value maps for the seismotectonic 

zones. 

Comments by Section

Section 7.3.1.2 

This section never actually describes why the St. Lawrence Rift should be a distinct source 

zone. There is some discussion of geometry, but no well defined case for “why” (unless it is 

simply because the GSC did). 

Section 7.3.1.3

At least some mention of the implications or importance of the observations to the Kijko model 

should be provided. This comment applies to all the individual zone sub-sections. Perhaps 

consider doing it at the beginning of Chapter 7. 

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Section 7.3.2 

last bullet, p. 7-13: If the hotspot has been tracked farther to the northwest, why isn’t the 

seismic source zone extended to the northwest?

Section 7.3.2.1 

This is one of the few Seismotectonic Zone subsections that actually develop a clear summary 

for why this should be a separate zone. 

Section 7.3.3.1

This section discusses the basis for proposing the NAP zone. It states: “The basis for defining 

the NAP seismotectonic zone centers primarily on the concept that terranes of this zone formed 

outboard of the Laurentian margin after Iapetan rifting and were subsequently accreted to the 

passive margin.” This subsection is weak in terms of developing a basis for defining the NAP 

as a separate zone. The text focuses on geological arguments that are never specifically tied to 

the SSC criteria. The reader is left to infer this zone may or may not utilize a different 

Bayesian Mmax prior than adjacent regions. 

Section 7.3.4

Use of the term “IRM” changes from describing a continental margin in the first sentence of the 

introductory paragraph of Section 7.3.4 to a seismic zone later in the paragraph. This is 

confusing. Similarly, note that the labeling of the PEZ in Figure 7.3.4-1 appears to be 

incorrectly labeled as IRM.

Section 7.3.4.1.4 

Suggest that the reference to Steltenpohl et al. in Geology, June 2010, v. 38, p. 571-574 be 

added to the list in the second paragraph.

Section 7.3.4.1.6 

p. 7-27: At the end of the second paragraph of this section reference is made to “a Class C 

tectonic feature.” It would be helpful to the reader to cite where in this report the classes of the 

tectonic features are defined and thus the significance of this information to seismic source 

identification.

Section 7.3.4.1.6

p. 7-29, paragraph at top of page: The discussion of a lack of observed paleoliquefaction 

features should also be used with the appropriate qualification. Specifically, the observation 

that paleoliquefaction features provides strong evidence for past strong earthquake shaking, 

should be accompanied with a remark that failure to identify such features does not provide an 

equally strong a case for the absence of strong shaking. 

Section 7.3.5

p. 7-32: The use of “Basement” in the title of this zone does not appear to be consistent with 

the titles given to other seismotectonic zones of the CEUS. 

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Section 7.3.5.1

p.7-33, 2nd bullet: In discussing the basis for defining the IBEBZ zone the text states, “The 

southern part of the Illinois basin is one of the most structurally complex areas of the 

Midcontinent.” How this directly impacts the SSC needs to be more clearly elaborated, or 

deleted. On the following page in the next bullet the text states: “An extensive series of 

moderately dipping reflectors is present in the basement, part of which may have been 

reactivated by the 1968 mb 5.5 earthquake.” Are the reflectors then interpreted to be faults? 

Also, the 1968 earthquake may have occurred in response to reactivation of the reflectors (if 

they are in fact faults), but not vice versa. 

Section 7.3.5.2 

p. 7-34: Suggest clarification of last sentence in second paragraph with something like: “The 

margins of the volcanic layered sequences, especially to the south and west, are marked by 

prominent coincident closed-contour magnetic and gravity anomalies which are derived at least 

in part from mafic volcanic rocks and intrusions . . . .” 

Section 7.3.5.3 

pg. 7-35: In considering the Mmax of this zone it may be useful to consider the presence of 

numerous late Paleozoic ultramafic intrusions (dikes and sills) into the sedimentary section of 

this region. See, for example, Sparlin and Lewis in Geophysics, v. 59, p. 1092-1099 (1994). 

Section 7.3.6.5 

 (CC) Develop table for future earthquake characteristics in Reelfoot Rift zone; pg. 7-42. 

p. 7-42, text box: The characteristics of future ruptures in the Reelfoot Rift zone listed in the 

text box at the end of Section 7.3.6.5 should be placed in a numbered table with headings. 

Section 7.3.7 

p.7-47, first full paragraph, line 5: The text refers to the unlikelihood of a maximum magnitude 

earthquake of greater than 7 because of the paucity of paleoliquefaction features in the region. 

Could Mmax be less than 7?

Section 7.3.7.1

In the second line of the first paragraph, “large” earthquakes are specified as M > 7. Should be 

M 6.5 to be consistent with the value used elsewhere for the RLMEs.

Section 7.3.9.2.1

p. 7-52, last bullet: The point could be illustrated with reference to the appropriate magnetic 

anomaly figure.

Section 7.3.9.2.4

p. 7-55, first full paragraph: Suggest that the last sentence be modified to something like: “The 

source zone is extended north of the Southern Arkansas fault zone for several reasons:” 

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Section 7.3.10 

In the title of this section, for consistency with previously described seismic source zone, 

suggest the title of this zone be “Gulf Coast Highly Extended Crust.”

Section 7.3.11.3

This subsection is an example case where adding an additional sentence could improve the 

clarity, consistency and transparency of the document. The Bayesian approach is the only 

Mmax approach used for this zone. It would be helpful to the reader to note that specifically or 

state the Kijko approach was not used due to a high p-value. Some zones are explicit in 

describing the two approaches, some are not. 

Section 7.3.12.1.2

pg. 7-65, first full paragraph, line 4: Suggest beginning sentence with, “The deformation during 

this interval is attributed to” instead of “It is attributed to” 

Section 7.3.12.2 

p. 7-69, par. 1, line 4: Suggest adding the phrase “and recurrence characteristics” after 

“maximum magnitude probability” 

Figure 7.3.2-1 

As on similar maps in the report, Figure 7.3.2.1 should show the magnitudes of the starred 

earthquakes.

Editorial Comments and Typographical Errors 

General Comment: 

To avoid repetition of editorial comments on repeated issues throughout the text of Chapter 

7, the following issues are identified which should lead to necessary revisions throughout 

the chapter: 

The manner of describing compass directions and their hyphenation should be made 

consistent throughout the report. Note that sometimes the directions are spelled out and in 

other cases an abbreviation is used. 

Geologic time units are not used appropriately throughout the chapter. Ma is used by the 

scientific community for millions of years before the present and myr is used for millions of 

years of duration. 

Recommended that for each section that presents a different seismotectonic zone, the title 

include the acronym (e.g., Section 7.3.1 — St. Lawrence Rift (SLR). Some section 

headings already include the acronym, which is helpful to the reader in referring to maps 

and figures. 

“Aeromagnetic” is not a definitive term. Rather use “magnetic anomaly” and gravity 

should always be followed by “anomaly,” e.g., gravity anomaly and magnetic anomaly. If 

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there is no adjective before either the gravity or magnetic anomaly, it is assumed that the 

gravity anomaly is the Bouguer gravity anomaly and the magnetic anomaly is the total 

intensity magnetic anomaly. Where possible, the type of anomaly should be specified. 

Mile should be abbreviated as “mi” without a period at the end, consistent with scientific 

context. 

The first time a term is used that will be identified by an acronym, the complete term should 

be given followed by the acronym in parentheses. There are numerous acronyms in this 

chapter that are not listed in the list of acronyms near the front of the report. These will not 

all be identified in the following comments. 

Reference to Adirondacks and Appalachians in place of Adirondack Mountains and 

Appalachian Mountains, respectively, is not editorially correct. This and similar casual 

terminology should be removed from the chapter. 

Several figures cited in this chapter are neither in the draft report nor in the List of Figures. 

All cited figures and tables should be carefully reviewed. 

Magnitudes of specific earthquakes should be consistent in number of significant figures 

throughout the text. 

Format for dates should be consistent throughout the text. Avoid 10 February 1999 rather 

use February 10, 1999. 

Listing of earthquakes, references, etc. should be in a prescribed order, e.g., date, 

magnitude, etc. 

Specific Editorial (“E”) Comments and Typographical Errors: 

E 7-1 Section 7.1 Paragraph 1, line 5 – replace region with seismotectonic source zone 

E 7-2 Section 7.1 Paragraph 1, line 7 – replace event with earthquake 

E 7-3 Section 7.1 Paragraph 1, line 8 – insert tectonic between particular and province 

E 7-4 Section 7.1 Paragraph 1, line 9 – insert faulting between slip and defining 

E 7-5 Section 7.1 Paragraph 2, line 16 – replace eastern with western (?) 

E 7-6 Section 7.1 Paragraph 3, line 1 – not all seismotectonic zones represented in 

Appendices C and D 

E 7-7 Section 7.1 Paragraph 3, line 4 – replace provide an indication with specify 

E 7-8 Section 7.1 Paragraph 3, line 7 – replace looking at any of the discussions with 

reviewing the descriptions 

E 7-9 Section 7.1 Paragraph 4, line 16 – replace discussion with description 

E 7-10 Section 7.1 Paragraph 5, line 6 – replace lie with occur 

E 7-10 Section 7.1 Paragraph 6, line 5 – replace called out with identified 

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E 7-11 Section 7.1 Paragraph 5, line 9 – replace have been postulated as being with are 

postulated as 

E 7-12 Section 7.1 Paragraph 5, line 11 – replace studies are judged to be too preliminary at the 

present time with assessments are judged to be without definitive support as a result of the 

preliminary nature of the investigations 

E 7-13 Section 7.3 Paragraph 1, line 3 – replace Mid-Continent with Midcontinent 

E 7-14 Section 7.3 Paragraph 1, line 6 – NMESE not in List of Acronyms 

E 7-15 Section 7.3 Paragraph 1, line 7 – insert northwest boundary between the and Reelfoot 

E 7-16 Section 7.3.1 Paragraph 2, line 2 – separate SCRs and correlate 

E 7-17 Section 7.3.1.1.3 Paragraph 1, bullets – capitalize first word of bullets and place period 

after last bullet 

E 7-17 Section 7.3.1.1.4, pg. 7-7, third bullet, separate A and third

E 7-18 Section 7.3.1.1.4 Paragraph 2, first bullet – separate The and oldest 

E 7-19 Section 7.3.1.1.4 Paragraph 4, line 6 – remove space after hyphen 

E 7-20 Section 7.3.1.1.5 Paragraph 1, line 3 – separate from and the 

E 7-21 Section 7.3.1.1.7 Paragraph 1, line 11 – remove s between faults and associated 

E 7-22 Section 7.3.1.1.7 Paragraph 1, line 13 – separate which and continued 

E 7-23 Section 7.3.1.2 Paragraph 1, line 3 – replace has been with is 

E 7-24 Section 7.3.1.2 Paragraph 1, line 6 – remove space after hyphen 

E 7-24 Section 7.3.1.2, pg. 7-10, paragraph 1, line 3 and line 8 – separate States and faults 

E 7-25 Section 7.3.1.2 Paragraph 1, line 19 – replace asterisks with 250 

E 7-26 Section 7.3.1.1.4 Paragraph 2, line 2 – what is GSC R model?? 

E 7-27 Section 7.3.1.1.4 Paragraph 2, line 6 – remove space before Brompton 

E 7-27 Section 7.3.1.1.7, pg. 7-9, line 13 – separate which and continued 

E 7-28 Section 7.3.1.3 Paragraph 1, line 15 – separate subsidence and within 

E 7-29 Section 7.3.1.3 Paragraph 1, line 28 – spell out first time GMH is used 

E 7-29 Section 7.3.1.4, pg. 7-11, 1st line - suggest “Earthquakes in Canada are classified ....” 

should be earthquakes in southeastern Canada 

E 7-30 Section 7.3.1.4 Paragraph 1, line 13 – 5.8 is 5.75 elsewhere, use care in significant 

figures, similar problems elsewhere in report that need to be addressed 

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E 7-31 Section 7.3.1.4 Paragraph 2, line 2 – neither earthquake shown on Figure 7.3.1.1 

E 7-32 Section 7.3.2, Geologic Evidence, Paragraph 1, bullet 2 – why refer to figure here? 

E 7-33 Section 7.3.2, Geophysical Evidence, Paragraph 1, line 2 – Figure 7.3.2-3 is missing in 

report and List of Figures 

E 7-34 Section 7.3.2, Evidence for Reactivation, Paragraph 1, several lines – Capitalize Late 

and Early when part of formal age 

E 7-35 Section 7.3.2, Evidence for Reactivation, Paragraph 3, last line – replace / with and 

E 7-36 Section 7.3.2.2 Paragraph 2, line 2 – Figure 7.3.2-4 is missing from report and List of 

Figures 

E 7-37 Section 7.3.2.2 Paragraph 2, line 9 – can this information be related to a specific 

figure? 

E 7-38 Section 7.3.2.3 Paragraph 2, line 5 – Figure 7.3.2-5 is missing from report and List of 

Figures 

E 7-39 Section 7.3.2.4 Paragraph 2, line 15 – separate and20 

E 7-40 Section 7.3.3 Paragraph 1, line 1 – remove s from Appalachian 

E 7-41 Section 7.3.3 Tectonic Framework, Paragraph 3, line 5 – change to compressional 

event 

E 7-42 Section 7.3.3 Tectonic Framework, Paragraph 7, line 2 – replace million-year with myr 

E 7-43 Section 7.3.3 Seismicity Paragraph 1, line 10 – remove period after Ebel 

E 7-44 Section 7.3.3 Paragraph 2, line 3 – magnitude of June 1638 earthquake is listed as 6.5 

on page 7-19 and 5.67 on page 7-21 

E 7-44 Section 7.3.3, pg. 7-19, Seismicity section - the 1904 earthquake referred to in terms of 

mblg, shouldn’t moment magnitude be indicated as well? 

E 7-45 Section 7.3.3.3 Paragraph 2, line 5 – insert period after al 

E 7-46 Section 7.3.4.1.1 Paragraph 1, line 3 – replace valley with rift 

E 7-47 Section 7.3.4.1.2 Paragraph 1, line 3 – insert anomaly after gravity 

E 7-48 Section 7.3.4.1.2 Paragraph 2, line 7 – remove any 

E 7-49 Section 7.3.4.1.2 Paragraph 1, line 9 – replace Valley with rift 

E 7-50 Section 7.3.4.1.3 Paragraph 3, line 9 – remove Recent 

E 7-51 Section 7.3.4.1.3 Paragraph 4, last line – replace is with are 

E 7-52 Section 7.3.4.1.5 Paragraph 1, line 6 – RTG not identified 

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E 7-53 Section 7.3.4.1.6 Paragraph 5, line 6 – insert space in front of Dineva 

E 7-53 Section 7.3.2, pg. 7-13, 2nd line - currently states “This seismotectonic zone is largely 

defined by moderate seismicity, including ...” As written this contradicts the stated position 

that the model accounts for differences in seismicity by spatial smoothing. It seems more 

appropriate to say “This seismotectonic zone is characterized by moderate seismicity,.....” 

E 7-54 Section 7.3.4.2 Paragraph 1, line 3 – remove unfiltered, add Bouguer gravity before 

anomaly 

E 7-55 Section 7.3.4.2 Paragraph 1, line 5 – replace rise with anomaly gradient 

E 7-56 Section 7.3.4.2 Paragraph 2, line 6 – should PEZ be PEZ-W?? 

E 7-57 Section 7.3.4.2 Paragraph 3, line 1 – spell out PEZ-N 

E 7-58 Section 7.3.4.2 Paragraph 4, last line – replace IRM with PEZ 

E 7-59 Section 7.3.4.3 Paragraph 1, line 2 – magnitude 

E 7-59 Section 7.3.4.3, pg. 7-30, Paragraph 1 - mixed magnitudes in the section 

E 7-60 Section 7.3.4.2 Paragraph 4, line 4 – replace IRM with PEZ 

E 7-61 Section 7.3.4.4 Paragraph 4, line 4 – spelling of Pymatning?? 

E 7-62 Section 7.3.5 Paragraph 1, line 1 – delete The regions of 

E 7-63 Section 7.3.5 Paragraph 1, line 2 – delete more distant, replace presented the with 

proposed that 

E 7-64 Section 7.3.5 Paragraph 1, line 3 – delete concept and change extending to extend 

E 7-65 Section 7.3.5 Paragraph 1, line 8 – delete d from indicated 

E 7-66 Section 7.3.5 Paragraph 1, line 9 – delete of complexly deformed crust. 

E 7-67 Section 7.3.5 Paragraph 4, line 4 – be consistent in use of term for LaSalle 

anticlinorium 

E 7-68 Section 7.3.5 Paragraph 2, line 5 – insert anomaly after intensity 

E 7-69 Section 7.3.5 Paragraph 2, line 6 – insert layered between volcanic and sequences 

E 7-70 Section 7.3.6.1 Paragraph 1, bullet 1, line 4 – should be plume 

E 7-71 Section 7.3.6.1.2 Paragraph 5, line 5 – FAFC, not defined 

E 7-72 Section 7.3.6.1.2 Paragraph 8, line 8 – missing words?? 

E 7-73 Section 7.3.6. 2 Paragraph 8, bullet 3, line 5 – publication date of Pratt et al. 

E 7-74 Section 7.3.7 Geophysical Anomalies, Paragraph 2, line 5 – replace runs with extends 

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E 7-75 Section 7.3.7 Geophysical Anomalies, Paragraph 2, line 10 – remove separately 

E 7-76 Section 7.3.7 Seismicity, Paragraph 4, line 10 – should small be limited?? 

E 7-77 Section 7.3.7.2 Basis for Geometry, Paragraph 1, line 16 – BMA, identify 

E 7-77 Section 7.3.7.4, Future Earthquake Characteristics, pg. 7-48, - text refers to ECC-AM 

having the same future rupture characteristics as the AHEX zone. However, the discussion of 

the AHEX follows the ECC-AM zone. Consider placing description of characteristics in this 

section 

E 7-78 Section 7.3.8.1 Paragraph 2, line 5 – replace runs with extends 

E 7-79 Section 7.3.9 Paragraph 1, line 6 – replace represents with is 

E 7-80 Section 7.3.9.2.1 Paragraph 1, line 5 – remove any 

E 7-81 Section 7.3.9.2.1 Paragraph 1, line 7 – replace think with thin 

E 7-82 Section 7.3.9.2.1 Paragraph 2, line 6 – replace reflected with reflects 

E 7-83 Section 7.3.9.2.3 Paragraph 2, line 1 – change to In spite of this tectonic interpretation, 

E 7-84 Section 7.3.9.4 Paragraph 4, line 5 – change to that formed or were reactivated 

E 7-85 Section 7.3.9.5 Paragraph 2, line 4 – replace since with because 

E 7-86 Section 7.3.9.5 Paragraph 6, line 1 – insert the after comma 

E 7-87 Section 7.3.10 Paragraph 1, line 6 – replace represents with is 

E 7-88 Section 7.3.11.1 Paragraph 2, line 1 – replace first sentence with: The basis for defining 

the distinct future earthquake characteristics for the aulacogen is the observation of the 

characteristics of the Quaternary activity on the Meers fault, a fault within the Frontal Wichita 

fault system (see Section 6.1.4). 

E 7-89 Section 7.3.11.2 Paragraph 2, line 5 – remove any 

E 7-90 Section 7.3.12 Paragraph 1, line 2 – insert geologic between two and provinces 

E 7-91 Section 7.3.12 Paragraph 2, line 1 – replace discussion with description 

E 7-92 Section 7.3.12 Paragraph 2, line 2 – replace discussion with description 

E 7-92 Section 7.3.12.1.4 Paragraph 1, line 6 – remove any of 

E 7-93 Section 7.3.12.1.4 Paragraph 1, line 9 – replace could not with cannot 

E 7-94 Section 7.3.12.1.4 Paragraph 1, last line – delete any of 

E 7-95 Section 7.3.12.1.4 Northeast Ohio Seismic Zone, Paragraph 5, bullet 3, line 6 – change 

to consistent with one expected for a high pore-pressure... 

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E 7-96 Section 7.3.12.1.4 Northeast Ohio Seismic Zone, Paragraph 6, line 2 – replace very well 

with favorable 

E 7-97 Figure 7.3.4-1 – Indicate 1929 Attica earthquake?? 

E 7-98 Figure 7.4.1-1 – scale and size used for displaying mmzx-obs for each seismic source 

needs to be modified to better illustrate the findings 

E 7-99 – limits of information on all figures (e.g., 7.1-1 and 2) needs to be confined to the 

limits of the study area 

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CHAPTER 8 — DEMONSTRATION HAZARD CALCULATIONS USING CEUS SSC 

MODEL

General Comments 

G 8-1. (CC) Chapter 8 is the opportunity for the TI Team to explain differences in hazard 

obtained using the CEUS SSC model, the USGS seismic source model, and the COLA seismic 

source models. This has been done to a degree, but more extensive evaluations relating the 

differences in hazard to elements of the CEUS SSC model would be very valuable for future 

users. Industry stakeholders and the scientific and technical community will be looking closely 

at the demonstration hazard calculations to gain an overall understanding of the CEUS SSC 

model and whether it yields reasonable results. 

Figures such as Figures 8.2-5R through 8.2-5T for all test sites together with thorough 

evaluations of how the TI Team’s assessments of smoothing parameters impact hazard would 

be very informative. Sensitivities to the Team’s assessments of weights on the “in cluster” and 

“out of cluster” characterizations of RLME sources would also be very informative. 

G 8-2. (CC, CBR) The CEUS SSC model rates are often by a factor of two or more higher 

than the USGS and COLA models rates, over a large range of ground motions. The slopes of 

the hazard curves are more similar because they all assume the same ground motion prediction 

equations. This higher rate of ground motions compared to earlier models is not clearly 

explained in the text. This higher hazard indicates that the CEUS SSC model predicts a rate of 

earthquakes that is considerably higher than the earthquake rate predicted in the USGS and 

COLA models. The basis of these higher rates can be seen in the figures of Chapter 5 to 7 (e.g., 

6.4-7 to 6.4-16; 5.3.2-22), where the model realizations over-predicts the historical rate of 

earthquakes. These differences make one question whether the model encompasses the center, 

body, and range of the informed technical community. 

Specific Comments 

S 8-1. (CC) Explanation of CEUS Ground Motion Attenuation Model Application

The TI Team has used the 2004 EPRI ground motion attenuation model to complete 

probabilistic estimates of ground motion. Chapter 8 should provide a summary of the 

application steps that were implemented for the 2004 EPRI ground motion attenuation model.

It is particularly important that the distance measure be explained. Application of the 2004 

EPRI ground motion attenuation model could involve the use of either point source distance 

measures or extended source distance measures. If both distance measures were used, the text 

should provide an explanation of the criteria or considerations that resulted in the choice of the 

distance measure for each of the seismic sources. For those seismic sources that were modeled 

as extended ruptures, the text should describe what assumptions were made to model the 

extended rupture and to what extent epistemic uncertainty was considered (alternative extended 

rupture relationships). Without this explanation the information provided in Chapter 9 

regarding the sensitivity to certain logic tree inputs is diminished. 

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S 8-2. (DMM, CC) Questions Regarding Results of Demonstration Hazard Calculations

In the subsection labeled “CENTRAL ILLINOIS SITE” (p. 8-6, 3rd paragraph): It would be 

informative to know how much higher and over what ground motion range the CEUS SSC 

model hazard is higher. Also, what characterizations and/or assessments contained in the 

model contribute to the higher seismic hazard. 

The CEUS SSC model is almost a factor of 2 higher than USGS/EPRI-SOG models. The 

major contributor is the IBEB (Illinois Basin) zone. The New Madrid (NMFS) RLME is most 

important at 1 s SA. However, background seismicity dominates at shorter periods. Why does 

the background hazard from CEUS SSC model give significantly higher rates than were 

applied in the USGS and COLA models for short periods? At 1 s period the USGS and CEUSSSC models are much more similar because the NMFS models are much more similar. 

In the subsection labeled “CHATTANOOGA SITE” (addendum, 8/18/2010, 3rd paragraph): 

More complete evaluations and explanations relating the differences to elements of the CEUS 

SSC model would be very valuable. This comment applies to other sites as well; so, will not be 

repeated.

The CEUS SSC model hazard for the Chattanooga site is more than a factor of 2 higher in 

annual frequency of exceedance than the USGS and COLA models. At the Chattanooga site 

the ground motion hazard at e-3 to e-5 is more than a factor of 2 higher. Background sources 

contribute most to the hazard. However, the USGS ground motions are higher at 1 Hz for 

exceedances of e-4 to e-6. These results are not explained in the text. 

In the subsection labeled “HOUSTON SITE”: The CEUS-SSC model hazard at the Houston 

site is dominated by GHEX (Gulf of Mexico), which is the zone that encompasses the site. 

Contributions from other background sources are much lower. Hazard is dominated by 

background sources at all periods (except for very low ground motions at 1 s SA). The SSC 

model indicates about a factor of 2 higher annual frequency of exceedance than the USGS 

model frequencies for short periods (10 Hz and PGA) but is more similar at longer periods 

(1 Hz). This is probably because NMFS is significant at 1 Hz and the USGS and CEUS-SSC 

models are more similar for NMFS. However, the differences are not explained in the text. 

In the subsection labeled “JACKSON SITE”: For the Jackson Site, the NMFS is important at 

all frequencies. Therefore, the CEUS-SSC, COLA, and USGS models are quite similar for 

PGA, 10 Hz, and 1 Hz. 

In the subsection labeled “MANCHESTER SITE”: Similar to the other sites dominated by 

background hazard, the CEUS SSC hazard at the Manchester site is considerably higher than 

the hazard for the USGS and COLA models. The deaggregation for the Manchester site at 10 

Hz is dominated by earthquakes with magnitudes less than 6.0 and distances less than 10 km. 

The CEUS SSC deaggregation for 10 Hz at e-4 is similar to that produced by the USGS for 

PGA at 4e-4. The higher rates for the Manchester Site should be explained in the text. 

In the subsection labeled “SAVANNAH SITE”: For the CEUS SSC model at the Savannah 

site, the major contributors to the ground motion hazard are the Charleston RLME source and 

the ACCAM background source model. The CEUS-SSC, COLA, and USGS models are quite 

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similar with the CEUS-SSC model showing a little higher ground motions for a large range of 

exceedances. 

In the subsection labeled “TOPEKA SITE”: The major contributor to the background source is 

MIDC-A which encompasses the site. The next important contributors are MIDC–B, MIDC-C, 

and MIDC-D. Background seismicity dominates the hazard at PGA and 10 Hz and the NMFS 

dominates hazard at 1 Hz. The hazard curves for the CEUS-SSC, COLA, and USGS and 

similar, especially at 1 Hz. The hazard is typically higher for the CEUS-SSC model with rates 

almost a factor of two higher for a large range of ground motions. This discrepancy should be 

explained in the text. 

Comments by Section 

Order of Text, Tables, and Figures 

Material needs to be reorganized (including added materials transmitted on August 18, 2010) so 

that the order of presentation of text, tables, and figures is consistent with other chapters. 

Section 8.1 

3rd paragraph and elsewhere: The term “hard rock” can lead to confusion because it is 

unspecific and used in various meanings. Consider defining the term “CEUS Region generic 

rock,” shear wave velocity of 9200 fps, and using this term consistently throughout the chapter.

Similarly, using the term “soil” to mean the geologic section above “CEUS Region generic 

rock” can especially invite confusion because of the well-established use of this term in 

geotechnical engineering. Consider “stratigraphic column” instead. 

4th paragraph: In the first line, would “generalized” or “representative” be more accurate than 

“hypothetical”? In the last line, would “dynamic response” be more descriptive than 

“parameters”? 

Section 8.2 [including revised materials distributed on 8/18/2010] 

In the subsection labeled “All site conditions” (p. 8-5): “EPRI-SOG (1989)” should be “EPRISOG (1988)” 

Figures 8.1-4 and 8.1-5 

Are the mean amplification factors independent of the mean AFEs (e.g., at 10–4, 10–5, and 10–6)

and the resulting site’s mean uniform hazard spectra for hard rock? 

Figures 8.2-5R and 8.2-5T (Manchester Site): These figures are very important for 

understanding how smoothing affects hazard. It would be particularly useful to know the 

estimated rates of M 5 earthquakes compared with estimated b-values for the 8 objective 

smoothing realizations.

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CHAPTER 9 — USE OF THE CEUS SSC MODEL IN PSHA 

General Comments 

G 9-1. (NAR) Chapter 9 provides results that are potentially valuable for evaluating whether 

future new data or evolved knowledge require updating of the SSC model. In addition, the 

results are potentially valuable for resolving a number of seismic regulatory decision-making 

issues. The chapter is very well written, providing clear descriptions of the analyses performed 

and the results—a valuable contribution. 

G 9-2. (NAR) PPRP review comments on Chapters 1–5 include suggestions that may lead to 

modification of weights in the Master Logic Tree and hence corresponding changes in 

calculated hazard results. 

G 9-3. (NAR) It is noteworthy that, based on the comparisons provided in Chapter 8, 

differences with the USGS and EPRI-SOG (COLA) results are significantly larger than the 

precision defined in this chapter for the CEUS SSC model results at all seven test sites. Indeed, 

for ground motions in the range of 10-4 to 10-6, the results in Chapter 8 indicate differences 

sometimes more than a factor of two between the USGS and CEUS SSC models in the rate of 

exceedances and the ground motion hazard. To avoid confusion, and because it might be 

argued that all experts have had essentially the same data and knowledge basis for assessing the 

various SSC models, the report should make abundantly clear how the uncertainty (precision 

or reproducibility) of the ± 25% should be understood—or not misinterpreted.

Specific Comments 

S 9-1. (CC) Figure References in Text Need to be Corrected 

Beginning in Section 9.4.2, the referencing of figures in the text needs to be corrected (the 

counting of figures appears to be off by 40 units—e.g. “Figure 9.4-1” in the text refers to 

Figure 9.4-41). 

S 9-2. (DMM) Possibility for Simplified HID 

Section 9.3.1 discusses simplifications “to increase efficiency in seismic hazard calculations.” 

For each of the HID tables that involve five-point distributions for a Poisson recurrence model, 

it would seem that the five branches could be reduced by simply specifying the mean value of 

the gamma distribution, namely, (N + 1)/T (see Section 5.3.3.1, p. 5-36). 

S 9-3. (CC) Lack of Clarity in Notation in Section 9.4 

Some of the notation in section 9.4 is a little ambiguous. One PPRP reviewer commented that 

it took a while to understand that COVK was for the parameters GEOM, Mmax, RATE, and 

RECORD. The difference between COVT and SRSS was also found to be confusing and 

warrants clarification. Later in the chapter there are references to COVHAZ and COVHAZ wts 

COV, and COVWT , cl mean COV and CL and H. We suggest that these terms be clarified to 

be more consistent with the equations and figures. 

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Comments by Section 

Order of Text, Tables, and Figures 

Material needs to be reorganized so that the order of presentation of text, tables, and figures is 

consistent with other chapters. 

Entire Chapter 

Throughout, change “seismogenic crustal thickness” to “seismogenic thickness.” 

Section 9.1 

p. 9-1, par. 1: In line 6, change “Section 2” to “Chapter 2”; in line12, suggest replacing “that 

capture the community’s views” with “that represent the community’s views” 

Because this section is intended to be a useful “overview,” in the last paragraph it would help to 

call the reader’s attention more explicitly to the key conclusions presented in Section 9.4.3—at 

the very end of the chapter and after 96 pages. 

Section 9.2 

In the first paragraph, line 10: Change “components - that is” to “components—that is” 

Section 9.3.1 

In the first sentence: “The HIDs describing seismic sources” is confusing. There is only one 

HID. Suggestion: “In the HID, the specifications for seismic sources . . .” 

p. 9-3, first full paragraph, third sentence: Because the test sites are extensively referred to in 

the remainder of this chapter, it would be helpful at the end of this sentence to point the reader 

to a map of the seven test sites (say Figure 8.1-1). 

p. 9-3, 3rd full paragraph, last sentence: Suggest replacing “Please refer to Section 9.4” with 

“See Section 9.4” 

Section 9.3.1.10 

p. 9-41, par. 2, first sentence: Text should be revised to eliminate reference to internal

communications among the TI Team—“outlined in emails from Kathryn Hanson.” 

Sections 9.3.2 and 9.3.3 

No text provided, stated “to be written later.” 

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Section 9.4.1 and Table 9.4-1 

The text and table contain inadequate documentation insofar as the column of “Available 

studies” in Table 9.4-1 includes a mix of citations, which can be tracked, and informally 

referenced studies such as “Charleston: WLA,” “New Madrid: Youngs,” “PEGASOS study,” 

PEGASOS project.” 

Section 9.4.2 

See Comment S 9-1 regarding error in referencing figures, beginning in this section. 

First paragraph (p. 9-49), last sentence: COV is defined here. Appropriate place to introduce 

symbols for the standard deviation of hazard (H) and mean hazard (MH, or somesuch). 

p. 9-66, line 2: Change “10-4 to 10-6” to “10–4 to 10–6” 

Section 9.4.3 and Table 9.4-1 

The abbreviation “SSRS” appearing in Table 9.4-4 needs to be explained in the text. In the 

figure caption for Figure 9.4-44 one finds “srss” explained as “the square-root sum of squares 

calculation of the total COV.” Neither srss nor SRSS appears in the list of acronyms. 

Last paragraph: For clarity, it would be useful to explain where the statement “2/3 of the time” 

comes from—presumably from a normal distribution. 

It is difficult to understand why the COVs decrease in annual frequencies of exceedance greater 

than 1E-5 on Figure 9.4-53 and 9.4-57. 

The authors show at the Savannah, Chattanooga, and Columbia sites that the term “cl. Mean 

COV” is quite a bit different from the “wts COV.” Because this is not intuitive, it would be 

helpful to provide some explanation to the reader. 

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CHAPTER 10 — REFERENCES 

General Comments 

G 10-1. (CC) Content, Accuracy of List of References

The PPRP leaves the technical editing of the list of References, including systematic crosschecking with the main body of the text to the TI Team and its support staff. 

Some of our review comments on individual chapters of the main body of the text include 

specific comments on some references as either missing, to be added, or incorrectly cited (in 

particular, see PPRP review comments on Chapter 3, References, and Comment S 6-16). 

G 10-2. (CC) Single Place for All References

The PPRP believes it would be desirable to have all references cited in the report—including 

those for the Appendices—in one place, and the reader should be informed to that effect. 

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CHAPTER 11 — GLOSSARY OF KEY TERMS 

General Comments 

G 11-1. (CC) Content of Glossary

A glossary of this type usefully serves the general reader, but more effort is needed to ensure 

that “key” terms specific to the CEUS SSC report are more systematically included. (It appears 

that someone simply extracted terms from the Seismic Hazard Glossary of the 1997 SSHAC 

report, modifying a few terms and adding several new ones.)

Ideally, the author of each chapter of the report should review his/her text and identify key 

terms for inclusion in the Glossary that would (a) help readers unfamiliar with the framework 

of the CEUS SSC project and (b) assist revisiting key concepts in the report. 

Candidate Key Terms:

SSHAC Methodology 

SSHAC Assessment Level 

Stability 

Longevity

Data Evaluation Table 

Data Summary Table 

Paleoseismic/Paleoseismicity 

Liquefaction/Paleoliquefaction 

Expert Assessment 

Proponent Expert 

Evaluator Expert 

Reasonable Assurance Standard 

Participatory Peer Review 

Sensitivity Analysis 

Declustering

Magnitude, Adjusted (M*)

Conceptual SSC Framework 

SSC Model 

Probability of Activity 

Future Earthquake Characteristics 

Logic Tree 

Weight

Hazard-Informed Approach 

RLME Source 

Bayesian Approach 

Stable Continental Region 

a-value

Spatial Stationarity 

Smoothing 

Fault Slip Rate 

Hazard Calculation 

Coefficient of Variation (COV) 

[Recurrence Model—add Poisson, 

Renewal]

Probabilistic Seismic Hazard 

Analysis

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G 11-2. (CC) Geological and Other Relevant Technical Terms

For numerous geological terms used in several of the chapters that do not appear in the 

Glossary, one might refer the general reader to a standard glossary of geological terms such as: 

Neuendorf, K. K. E., Mehl, Jr., J. P., and Jackson, J. A., 2005, Glossary of Geology, 5th 

Edition, American Geological Institute, Alexandria, Virginia, 779 p. 

Another valuable glossary for reference is: 

Lee, W. H. K., and Aki, Keiiti, 2003, Glossary of Interest to Earthquake and Engineering 

Seismologists, in, Lee, W. H. K., Kanamori, H., Jennings, P. C., and Kisslinger, C., 

2003, International Handbook of Earthquake and Engineering Seismology, Part B, 

Appendix 1. 

Specific Comments 

S 11-1. (CC) Acknowledgment of Source

Because more than 85 percent (45 of 54) of the entries in this Glossary either come directly or 

have been slightly modified from the Seismic Hazard Glossary of the 1997 SSHAC report, that 

source should be acknowledged.

S 11-2. (CC) Disclaimer

Given the sponsors of the CEUS SSC project, it may be prudent to caution the reader that 

definitions may not correspond exactly to those appearing in regulatory documents of NRC or 

DOE.

Comments for Clarity and Completeness 

Active Fault, Active Source — Active Fault and Active Source can have different 

definitions (consult Lee and Aki, 2003, cited in Comment G 11-2, for definition of Active 

Fault). Consider defining these two terms separately in the Glossary.

Aleatory Uncertainty/Variability — The provided definition (not from SSHAC report) is 

a poor one for the uninformed reader. Revisit definition in SSHAC report and/or see 

definition in Robin McGuire’s 2004 EERI monograph (p. 8). 

Area Source and Background Source — These two terms have very different 

characterization for representing uncertainty in an SSC model. To avoid confusion, cross 

references should not be made. 

Distance Epistemic Uncertainty — Typo and erroneous duplicate entry for Epistemic 

Uncertainty. Delete. 

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Epistemic Uncertainty — As for Aleatory Uncertainty, the offered definition is a poor one 

for the uninformed reader. Revisit definition in SSHAC report and/or see definition in 

Robin McGuire’s 2004 EERI monograph (p. 8). 

Informed Technical (Scientific) Community — Consider alternative definition: 

A construct of the SSHAC guidance that embodies the community distribution of 

uncertainty sought by the SSHAC Methodology, independent of the Assessment Level. 

Experience implementing the SSHAC Methodology has revealed a high level of 

confusion surrounding use of the word “informed” in this construct. For this reason, the 

word “informed” has been eliminated without loss of intent of the SSHAC construct. 

Magnitude — This general definition, unrelated to a specific scale, should be labeled as 

such—given the appearance of other magnitude definitions in the Glossary. The 

explanation included in this general definition applies to some, but not all, magnitude scales 

(e.g, it doesn’t apply to coda-wave magnitude and Moment magnitude). Suggestion [see 

Bolt (1978,1988, 1993), the source that SSHAC obviously used] : 

Magnitude, General: A measure of earthquake size, classically determined by taking 

the common logarithm (base 10) of the largest ground motion recorded during the 

arrival of a seismic wave type and applying a standard correction for distance to the 

epicenter. 

Maximum Magnitude — Mmax is an assessment. Suggest replacing “that a seismic 

source is capable of generating” with “that a seismic source is assessed to be capable of 

generating”

Seismicity — Consider the more informative definition contained in Lee and Aki, 2003, 

cited in Comment G 11-2.

Seismic Source — Given the discussion on p. 4-13f, the offered definition (from the 

SSHAC report) is weak. Consider something like: 

Seismic Source: Traditionally, in a Probabilistic Seismic Hazard Analysis, a region or 

volume of the earth’s crust that has uniform earthquake potential or uniform 

earthquake-generating characteristics. In this project, unique seismic sources (faults, 

regions) are spatially defined to account for distinct differences in earthquake 

recurrence rate, maximum earthquake magnitude, expected future earthquake 

characteristics, and probability of generating earthquakes of magnitude 5 or larger. 

Technical Integrator (TI) — Consider alternative definition: 

A SSHAC term for an individual or team responsible for characterizing the technical 

(scientific) community’s knowledge and for assessing and representing the community 

uncertainty in a seismic hazard model. In this project, this was done using a SSHAC 

Level 3 assessment process.

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APPENDIX A — DESCRIPTION OF THE CEUS SSC PROJECT DATABASE 

General Comments 

G A-1. (NAR) The CEUS SSC Project has assembled and archived a comprehensive 

suite of data sets of the CEUS that are important to the characterization and assessment of 

the SSC model of the region by the TI Team and that significantly contribute to the 

community knowledge-base. Compiling and providing these data sets in a common GIS 

data format required substantial effort, for which the Project Team is commended. 

These data, for the entire CEUS SSC model region, as well as for specific subregions of 

special interest for the characterization and assessment of seismic source zones, have been 

obtained from existing data bases, digitized maps, data files, and original data. The data 

have been put into a GIS format to facilitate analysis, employing overlays of various data 

types, and they have been made available to the TI Team, the PPRP, and others in the 

project. The data files will be archived on a server that can be accessed in the future via a 

website. The data include maps of surface, bedrock, and crystalline basement geology, 

geophysical data (gravity, magnetic, and stress), results of seismic study of the crust, 

compilations of historic and pre-historic earthquake data, and previous seismic hazard 

analyses. Workshop #1 was focused on selecting the critical data sets required for the 

project and identifying the optimum data sets available to the project. 

Appendix A describes the data included in the Database and the procedures for assembling 

the data sets and making them available to the project teams. In addition, summary 

metadata “sheets” are included for 32 of the identified data 72 CEUS data bases. As part 

of the review of Appendix A, consideration also has been given to the 60 metadata files 

describing the data sets of the Database. The 60 metadata descriptions are in a separate 

digital data file which is not part of the final report or its appendices, but has been on the 

EPRI data server which is no longer in service. Future access to the metadata files via the 

website needs to be clarified and explained. In general these files are helpful in 

understanding the source, capabilities, and limitations of the data sets that are important to 

all users of the CEUS SSC data compilation. 

G A-2. (CC) The level of detail provided in Appendix A and the metadata files is 

generally satisfactory, but significant revisions are required to improve the text, update and 

complete the summary description of the data sets, complete the metadata a sheets for all 

data sets, synchronize the data sets, the metadata files, and the summary data sheets, and 

make numerous editorial changes. Suggestions are provided in the following general and 

specific comments for improving the Database and its description and the metadata files. 

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Specific Comments for Clarity and Completeness 

S A-1. The Appendix does not describe the future website, or access to it, that will make 

the data sets and the metadata available to future users. This will need to be done to enable 

the report user to access the data and metadata files. 

S A-2. There are several data sets dealing with gravity, magnetic, and geologic data of 

the same data type that are of various vintages. Data sets should be eliminated in the 

Database that have been superseded by more complete and accurate data sets. Including 

dated, out of date, data sets in the Database will cause confusion in determining which data 

set was and should be used in analyses. As a result the credibility of the results of the 

project will be enhanced by removing dated data sets. 

S A-3. A total of 32 summary metadata sheets are presented in the Appendix for the 

CEUS SSC model region, but no summary metadata sheets are provided for the remaining 

40 data sets listed in Table A-1 for specific subregions. Summary metadata sheets should 

be provided for all of the GIS layer data sets or an explanation for not preparing metadata 

for the data sets needs to be provided. Furthermore, there is not an obvious relationship 

between the summary metadata sheets and the metadata files. In the metadata file there are 

60 separate files that do not synchronize with the summary metadata sheets. It is not clear 

why there are only 60 rather than 72 representing all the data layers as in Table A-1. Note 

also that the titles of the data sets are not necessarily the same as the titles in Appendix A 

and the metadata files. This causes confusion in using the files. It would be useful to have 

a column in Table A-1 that identifies the metadata file(s) of the specific data set as they 

exist in the metadata file. 

S A-4. The prose in this appendix is in draft stage and needs clarification, reorganization, 

and improvement. A technical editor could help improve the appendix so that the resulting 

description of the efforts and the results associated with the Project Database reflect well 

on the major investment that was made. 

S A-5. All pages of the appendix should be numbered consecutively. 

S A-6. The page size maps of the data sets that are provided as part of the summary 

metadata sheets are very useful. They provide a view of the data set for use in qualitative 

analysis by the user of the report. In addition, they assist the user in making a decision 

about preparing small scale maps of the mapped parameter or in selecting regions of the 

maps for detailed analysis. Only one of the six magnetic anomaly data sets prepared for 

this project (Ravat et al., 2009) is shown, and only one of the fifteen gravity anomaly data 

sets (CEUS SSC, 2010) prepared for this project is illustrated. Please note that referring to 

the gravity anomaly data sets by CEUS SSC, 2010 as in the summary data sheets may lead 

to confusion. An alternative suggestion is to cite Keller, 2010, personal communication. 

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S A-7. Unfortunately a key to the contour interval and symbols used in several of the 

maps is not provided with the map. This seriously detracts from the usefulness of the 

maps. In the few maps that show a color bar of the mapped parameter amplitudes, the 

limits of the range are given to a precision unwarranted in the data set and have limited 

usefulness for the user. In addition, these color codes are too coarse for most uses of the 

data.

S A-8. The keywords of the metadata files need further attention. Most data sets do not 

have keywords, and keywords that are given are not consistent and comprehensive. 

Keywords are not critical but they can be helpful in directing the data user to the 

appropriate data set without laborious, extensive review of all the data sets. Will the user 

be able to search the data sets by keyword? 

S A-9. “Aeromagnetic” in the title of maps should be changed to “magnetic anomaly.” 

This is the general title that is applied to regional magnetic anomaly maps. 

S A-10. Citations in tables are not in consistent format. 

S A-11. A data file showing areas where reliable earthquake hypocenter depths are 

available would be useful. Or is it possible to show range of depths of foci for the CEUS? 

S A-12. Headers for Metadata Sheets: The repetition of “CEUS SSC Project GIS Data 

Summary” in large point size and bolded is less important to guide the reader’s eye than 

the title of what the sheet contains. Consider reformatting the header information. 

Example: 

Sheet A-1 — CEUS SSC Project GIS Data Summary 

NOAA DNAG MAGNETIC ANOMALY MAP OF NORTH AMERICA 

S A-13. Remove bracketed comments in text from previous reviewers. 

S A-14. Shaded-relief versions of selected gravity and magnetic anomaly maps (e.g., total 

magnetic intensity anomaly map, reduced to pole magnetic anomaly map, residual isostatic 

gravity anomaly map) are a significant aid in the interpretation of the geological sources of 

the anomalies, particularly the high wave-number components of the anomalies. Several 

of these shaded relief maps have been prepared, but they are not identified in the data sets. 

They should be included and the specifications of the azimuth and inclination of the light 

source used in preparing the maps should be specified on the maps and in the metadata. 

Comments by Section, Table, and Sheet 

Text: Unlabeled Introduction 

First paragraph: The first two sentences are not clear as to the goals of the database and 

the method of achieving them. The use of “function” in the first sentence leads to 

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confusion. Suggest a rewrite focusing on goals of the data sets and procedures used to 

achieve them. 

Second paragraph: Strongly suggest that the term “aeromagnetic” throughout the titles of 

data sets be changed to “magnetic anomaly.” This is the appropriate title given to regional 

magnetic anomaly maps. Delete Free-air gravity and remove Bouguer and simply use the 

term “gravity anomaly.” Also, remove DNAG and USGS. These are data sets that have 

been superseded and should be removed from the Database. The Mesozoic rift basins data 

base cannot be found as an entity in the Database. Remove the parenthetical phrase in 

Earthquake Catalog. 

In the bulleted list, note that there is no metadata file or summary for Mesozoic rift basins 

which was compiled for this study. 

Last bullet of second paragraph: Will digital presentations of the crustal scale profiles be 

available? If not, where can they be obtained for analysis? 

Last paragraph, last line: The last metadata summary sheet is A-32, rather than A-36. 

Text: Section A.1 

Last sentence of first paragraph: “The digital data compiled for the CEUS SSC Project are 

available to the public to provide transparency regarding the development of the CEUS 

SSC database.” Transparency does not seem to be an important reason for this. Rather it 

serves as a repository of data useful for largely regional seismic source zone 

characterization and assessment in the CEUS. 

Second paragraph, first line: Figure A-1 is not in the appendix. 

Second paragraph, second line: For example, some public-domain data sets cover... 

Third paragraph, bullets: Change to “Magnetic anomaly data,” “Gravity anomaly data” 

Add “Mesozoic rift basins within the ECC-AM” to the bullet list in third paragraph. 

Third paragraph, fifth bullet: Add “data” after “Maximum horizontal compressive stress” 

to be consistent. 

Third paragraph: Replace “sources” in first line by “types” or, less desirable, “class.” In 

second line, suggest: “These data layers include the following:”

Text: Section A-2 

First paragraph: Suggest that definitions of data class, theme, etc. be provided or a figure 

showing hierarchy of data. 

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First paragraph: Spell out FWLA, point out that this server is no longer available 

First paragraph, top of p. A-3: Instead of “theme,” use “type of data”? 

Fifth paragraph: All project data began at revision 0 (Rev0) and have been updated with 

consecutive revision numbers and made available via the project web site. Providing a full 

file name reference allows data to be identified if removed from the organization of the 

project Database. 

Sixth (last) paragraph: Add this sentence at end: “This server is no longer in service for 

this project.” 

Sixth paragraph: Is the “Project GIS Manager” the same as “Database Manager” identified 

in Figure 2.3-1 and Appendix G? If so, be consistent. 

Text: Section A-3.3 

Second paragraph: If the steps to review GIS data produced from non-digital data were 

sequential, it would be better to present the steps using numbers or letters rather than 

bullets. 

Second paragraph, fourth bullet: Clarify “Completion of attribute information” 

Second paragraph, last bullet: Use of the term “topology” appears to be inappropriate here 

because the term is generally used to describe a branch of mathematics. 

Text: Section A-4 

Second paragraph, line 2: ** are ?? 

Second paragraph, line 6: Summary sheet A-22 has no state boundaries. 

Second paragraph, line 7: Why not “all” rather than “majority”? What criteria were used 

to omit some? 

Second paragraph, last sentence: Why are there no metadata summary sheets for data 

covering specific regions of the study area? If they are important enough to include as a 

data set, they should be important enough to have a metadata file. Are all data sets 

included in the metadata file? If not, why not? 

Text: Section A-5 

Third paragraph, first line: Were the original or source data provided? 

Third paragraph, last line: Typo: “into other coordinate systems.” 

Text: Section A-6 

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This section is out of place, place after A-5. 

First paragraph, 3rd line: Add earthquake [information] to this list 

Second paragraph, line 5: Typo: “to identify geologic relationships” 

Table A-1 

Page 1: Where are the citations located? Are they all in the same place in the report? 

Page 1: Delete Row 1 

Page 1: Delete Row 3 

Page 1, Row 5: Need more complete description of this database and its preparation or 

refer to another section of report. 

Page 2, Row 2: Replace “Geodesy” with “Strain (GPS)” 

Page 3, Row 3: Why is this map being used, since it was replaced by Reed et al. (2005)? 

Delete. 

Page 4, Row 3: Is this the basin map referred to in the data evaluation tables? If so use 

consistent titles. 

Page 4, Row 7: Delete, superseded. 

Page 5, Row 1: Refer to Keller, 2010, personal communication 

Page 5, Rows 3 and 4: Delete, superseded 

Page 5, Row 6: How are these tied to references? Where are the metadata for these 

layers? 

Page 6, Row 2: This is also referred to as Zoback (2010). Determine appropriate reference 

and use consistently. 

Page 7, Row header: Change “Mid-Continent” to “Midcontinent” 

Page 7, Row 5: Replace “Geodesy” with “Strain (GPS)” 

Page 7: Why does the numbering of Summary Sheets stop with A-32 (in the last row of 

page 6)? 

Page 8, Rows 5 and 6: Need citations 

Page 9, Row 2: Need citation 

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Page 9, Row 3: Change “Aeromagnetic” to “magnetic anomaly” 

Sheet A-1 Delete, superseded

Sheet A-2 

Replace “aeromagnetic” with “” 

Contour interval should be given 

Show page-size maps of six data sets with bar graph for amplitude and in shaded relief if 

possible

Differentially reduced to pole, tilt derivative, etc. may not be known entities to user; 

suggest a basic reference for each of these for the interested reader 

Sheet A-3 Delete, superseded 

Sheet A-4 Increase amplitude at least twice that being shown 

Sheet A-5 

Data description: Needs range of date, also key to map symbols; as throughout report, 

moment magnitude (M) should be bolded; which earthquake catalog is referred to? The 

raw catalog, the declustered catalog, or ?? Should refer to Appendix B if this is the same 

catalog.

Sheet A-6 Identify symbols

Sheet A-7 Brighter colors needed, no extended crust identified 

Sheet A-8 Need brighter colors 

Sheet A-9 Need key to colors 

Sheet A-10 Need key to colors 

Sheet A-11 How are they keyed to source (reference)? 

Sheet A-12 Delete, superseded 

Sheet A-13 

Data description is misleading, the dashed line represents the mapped eastern limit of pre1600 Ma crust. Why not show all of Figure 2 of this reference? It puts the boundary into 

the context of the basement terranes. 

Sheet A-14 Brighten colors and provide key 

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Sheet A-15 Brighten colors and provide key 

Sheet A-16 Brighten colors

Sheet A-17 Needs key 

Sheet A-18 

Needs contour interval, high range is given to 4 decimal points which is much greater than 

precision

Sheet A-19 Needs key 

Sheet A-20 Legend of figure needs to be checked. What is basement thickness? Unclear. 

Sheet A-21 Brighten colors and provide key 

Sheet A-22 Delete, superseded 

Sheet A-23 

Brighten colors, color contour interval needed, show all figures at page size, preferably in 

shaded relief; suggest for Author that G.R. Keller be identified as the source of the data

and derivative anomaly maps . . . as in A-2 for D. Ravat. 

Sheet A-24 

To be consistent, use residual isostatic; color contour interval without range beyond 

decimal point. 

Sheet A-25 Delete, superseded 

Sheet A-26 Delete, superseded 

Sheet A-27 Tie to references?? Where will the metadata file be accessible? 

Sheet A-28 Brighten colors 

Sheet A-29 Needs key; this is also referenced as Zoback (2010) – select appropriate 

citation 

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APPENDIX B — EARTHQUAKE CATALOG 

General Comments 

G B-1. (NAR) Appendix B contains a listing of the earthquake catalog for the CEUS 

developed as part of this project. The development of the earthquake catalog is a major 

element of the source characterization and assessment in the project. The Appendix 

contains a single page of text that identifies the columnar entries in the catalog followed by 

a 273 page tabular listing of the 9800 earthquakes in the catalog. The table is well laid out 

and easy to follow. 

G B-2. (CC) It is evident that monumental efforts were required to compile this catalog, 

and the Project Team is to be applauded for these efforts. Beyond its use by TI Team 

members familiar with its contents, careful documentation and explanation is needed for 

the contents of the catalog to be understood and appropriately used by others. 

Specific Comments for Clarity and Completeness 

S B-1. Need for Introductory Text

A brief summary discussion should be added to this Appendix. This discussion should 

describe what this catalog listing actually is (i.e., final catalog with dependent events 

flagged). It would also be useful to refer the reader back to relevant sections of Section 3 

for a discussion of M*, etc.

Additional notes on depths and how ERH was estimated would also be useful in the 

introduction to the catalog.

A pointer to the appropriate Database entry would be useful. 

A catalog of non-tectonic events was developed as part of this project (mentioned in 

Section 3), where will this catalog be documented and maintained? 

S B-2. Clarity of Documentation in the Catalog Explanation 

For clarity of documentation, attention should be paid to the following: 

1. Designation of time in an earthquake catalog should be explicit. Are the times/dates in 

UTC? Local time? A mix? This is non-trivial if one tries to find the events in another 

catalog. Also, the earthquake origin times are the basis for calculation of inter-event 

times in declustering algorithms. 

2. How should the reader interpret the variable presentation of significant figures in the 

Earthquake Catalog for latitude, longitude, depth, M, and sigM? How does one 

discern available information on precision from the vagaries of spreadsheet display? 

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3. The meaning of Depth = 0 should be explained. 

4. To avoid ambiguity, ERH should be explained as “Horizontal Location Uncertainty 

(km)”. If correct that the entries for ERH contain both rough estimates and statistical 

calculations, then ERH is better described as “Estimated Horizontal Location 

Uncertainty (km)”. 

5. After ERH, entries in the Explanation change from having the first letter of all terms 

capitalized to just the first word capitalized. 

6. M , M*, and sigM should be bolded in Column 1 of the Explanation 

7. In column 1, “Flag” should be written “FLAG” as it appears in the table. 

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APPENDIX C — DATA EVALUATION TABLES 

General Comments 

G C-1. (NAR) The tables of Appendix C summarize what data were used, how the data were 

used, and the source, quality, and significance of the data in defining, characterizing, and 

assessing the CEUS seismic sources. In addition, the tables specify the availability of the data 

in GIS format. These tables are a useful supplement to the documentation of the seismic source 

zone characterization and assessment of both the RLME sources and the seismotectonic source 

zones. They will be useful to users of the CEUS SSC report, and they will also provide a guide 

to potential application of various data sets in future evaluations of the CEUS SSC model. In 

general, the tables are well prepared and presented. However, they are not without problems, 

as we proceed to explain.

Specific Comments 

S C-1. (CC, DMM) Completeness of Tables and Ambiguity About Applicability

Data Evaluation tables have been prepared for many of the identified seismic source zones, but 

not all. In Section 4.2.2 of the main report, the reader is informed (p. 4-6, first paragraph of the 

section) that, “Data Evaluation tables were developed . . . and the tables for each source

(emphasis added) are included in Appendix C.” Comparing a list of the RLME sources, the 

seismotectonic zones, and the Mmax source zones with the index of tables on the first page of 

Appendix C will leave the reader perplexed. Further, the treatment of some zones is handled 

within the Data Evaluation table for another zone (e.g., the Meers fault RLME source is 

included in the table for the OKA seismotectonic zone).

What criteria were used to select which zones were to have Data Evaluation tables? At the top 

of Table C-5.4, the labeling indicates “Default for entire CEUS SSC.” Does this mean that if a 

table is not given for a specific zone, then Table C-5.4 is the applicable table? (If this is the 

intent, note that Table C-5.4 is incomplete with regard to several data sets.) Introductory text 

should be added to eliminate these and similar questions and concerns pertaining to the Data 

Evaluation tables. All seismic source zones including Mmax zones should have a Data 

Evaluation table.

S C-2. (CC) Facilitating Use of the Data Evaluation Tables

The Data Evaluation tables are explained in the text of the report (Section 4.2.2). However, 

consideration should be given to adding a short description of the objective, organization 

(including the keying of the table numbers to the main body of the report), preparation, and 

uses of the tables in an introductory paragraph to the appendix. This will facilitate the use of 

the tables. An explanation of the content of the columns used in the tables should be also 

included in this description for stand-alone reading. Also, all pages of Appendix C should be 

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numbered consecutively, not separately for each table, to enable convenient reference—as 

opposed to having to point to a specific table and a page number within the table.

S C-3. (CC, DMM) Inconsistencies in the Tables

The Data Evaluation tables have numerous inconsistencies that should be eliminated because 

they diminish the quality and usefulness of the tables. We note the following: 

1. The titles of the tables and the identified source in the notes at the top of each table 

should be consistent with the nomenclature of the text of the report, and tables should 

be in the same sequence as the identified source is described in the text (or keyed to a 

table in the text). 

2. Although the majority of the Data Evaluation tables are also in the Data Summary 

tables (Appendix D), some are not included in the Data Summary tables and viceversa. There is no explanation for this inconsistency among tables in the 

documentation of the report. 

3. The level of information given in the tables is variable. This may be due in part to the 

information available, or it could be due to the detail that is provided by the individual 

preparing the table. Greater consistency in the level of information would be 

desirable.

4. All the tables have seven columns except for Tables 6.1.4 (OK aulacogen) and 7.3.9 

(Gulf Coast), which have eight columns. Only seven columns are described in Section 

4.2.2 (pages 4-6 and 4-7). Note that the fifth column should be “Description” rather 

than “Discussion” (there is no oral material here). Throughout the tables, references to 

“discussions” should be changed to “descriptions.”

5. Numbers in the tables are inconsistently spelled out or given in numeric form. 

Numeric form should be used for data and scoring; otherwise, numbers should be 

spelled out when referring to counts of ten or less. 

6. Geographic (compass) directions are inconsistently given in abbreviated (e.g., NE) and 

spelled-out form. 

7. Some tables have the acronyms for the subdivisions of the seismic source zone 

identified in notes at the beginning of the tables, others do not. Also several acronyms 

are not given in the List of Acronyms. 

8. Descriptions in cells are variously in sentence and non-sentence form. It may be 

useful to have both, but an effort to be consistent would be worthwhile. 

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9. The use of blanks in the tables is inconsistent. Every cell needs to have something in 

it; if nothing else, N/A for not applicable or some other notation to indicate intention. 

Otherwise, the meaning of a blank cell will be unclear. 

10. There is inconsistency in the title of column 3 among the tables. Is it “data quality” or 

“data and quality” (as in “Notes on Quality or Data”)? 

11. Use data as a plural word consistently throughout the tables.

12. Both the terms magnetic and aeromagnetic are used in the tables. The use of the term 

aeromagnetic should be changed to magnetic throughout. Aeromagnetic simply refers 

to the method of collecting the majority of the data in the file. Referring to 

“aeromagnetic” but only to “gravity” is inconsistent. 

13. Where no data are available for a particular type of data, the tables deal with this in 

different ways—sometimes the wording indicates explicitly that no data are available 

(e.g., Table C-6.1.3, p. 4; r. 3); in other places, data are just not identified. 

14. The evaluation of the quality of the data is not consistent; in some cases peer-reviewed 

publications are referred to and in others simple publications. 

Comments by Table (for Clarity and Completeness) 

(Notation: pg. = page, c = column of table, r = row of table) 

Table C-5.4 

pg. 1, descriptor (title) of 5th c: Would “significance” be a more descriptive term than 

“reliance”?

pg. 4, r. 3; c. 1: Is this the new data set from Zoback? If so, please put a date on it—

and put dates in all tables for all the data sets prepared for this project so that in 

subsequent use there will be no question of date. 

pg. 1, r. 4, 5, & 6; c. 6: Add fault to slip 

pg. 1, r. 7; c. 3: In the Charlevoix area of the St.Lawrence Rift 

pg. 2, r. 1 & 2; c. 6: Add fault slip 

pg. 2, r. 5; c. 6: Could not find where depth as a function of magnitude is described in 

report

Table C-6.1.1 

pg. 1, r. 5; c. 6: Incomplete 

pg. 1, r. 6; c. 1: Change to magnetic from aeromagnetic, here and elsewhere in tables 

pg. 2, r. 2; c. 1: Give date 

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pg. 3, r. 4; c. 1: Reinecher not in references...this holds true for many of the references 

cited in the tables...they should be included in Chapter 10 (References) 

Table C-6.1.2 

pg. 2, r. 5 & 6; c. 3: What is the significance of the term “basic”? 

6, r. 1; c. 3: What is meant by “plain sediments”? 

pg. 6, r. 5; c. 1: Should be bold and italics 

pg. 9, r. 5; c. 1: Should be bold and italics 

pg. 11, r. 3; c. 3: Replace to with two 

Table C-6.1.3 

pg. 3, r. 2; c. 6: Reference to 2002 article is incomplete (author?) 

pg. 5, r. 1; c. 6: Change to “No measurements nearby to the . . .” 

pg. 6, r. 2; c. 6: Reference to 2002 article is incomplete (author?) 

Table C-6.1.4 

Why add an eighth column? Y or N to be used in c. 8 to be consistent with rest of 

tables. 

pg. 1, r. 1; c. 4: How are faults due to hydrocarbon exploration? Change wording. 

pg. 1, r. 1; c. 5 and subsequent rows on page: What is OK aulacogen? Background? 

pg. 1, r. 2; c. 1: Bold and italics 

pg. 1, r. 3 & 4: Delete. These are data sets superseded by the EPRI data set. 

pg. 2, r. 2: Delete this data set, superseded by the EPRI data set 

pg. 3, r. 3; c. 7: Change to “within the Arbuckle” 

pg. 4; r. 2; c. 2: 1990 

pg. 4; r. 4; c. 2: What is BEG? 

pg. 7; r. 1; c. 7; “fault slip” 

Table C-6.1.5 

pg. 1; r. 2; c. 6: Change to ...are concentrated...; also ...projects to surface..

pg. 1; r. 5; c. 6: Change to ...sequences provides... 

pg. 4; r. 1; c. 3: Give map # 

pg. 5; r. 5; c. 3: Is relatively short germane? Don’t know what short is. This is not 

used where abstracts are referenced. 

pg. 6; r. 2; c. 4: Define abbreviations

pg. 6; r. 5; c. 6: Rationale or geophysical evidence? 

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pg. 8; r. 1; c. 7: What is significance of (“?”) 

Table C-6.1.6 

pg. 5; r. 2; c. 6: What is RP and ERM-SRP? ; need period after parenthesis 

pg. 12; r. 1; c. 6: What is ERRM? ERM 

Table C-6.1.7 

pg. 3; r. 5; c. 4; what is EMF_S? not in acronyms 

Table C-6.1.8 

pg. 2; r. 1; c. 6: No CFZ in acronyms 

pg. 3; r. 5; c. 6: Explain A and B; replace 

Table C-7.3.1 

pg. 2; r. 1; c. 6: Clarify the wording, “A general gradient in amplitude parallels” 

pg. 4; r. 8; c. 6: Entries; period at end of sentence 

pg. 5; r. 1; c. 6: Capitalize Mechanisms 

Table C-7.3.3 

pg. 1: Shouldn’t the title be Northern Appalachian zone, without the “s”? 

pg. 3; r. 2; c. 3: Parenthesis at end 

Table C-7.3.4 

pg. 1: In notes beneath title, need to identify the acronyms of the subdivisions of the 

zone

pg. 2; r. 4 & 5; c. 3 & 6: What is CLFS? 

Table C-7.3.9 

pg. 1; r. 3 & 4; c. 7: If considered for defining boundaries, why 0 in column 6? 

Table C-7.3.12 

pg. 1; r. 5; c. 3: Do not capitalize intensity 

pg. 2; r. 1; c. 6: Unfinished sentence 

pg. 2; r. 2; c. 6: Belongs in column 6 of row 3; why 2 in column 5 for row 2 and 1 in 

column 5 for row 3? 

pg. 5; r. 1; c. 6: Remove “yet”

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APPENDIX D — DATA SUMMARY TABLES 

General Comments 

G D-1. (NAR) The Data Summary tables of Appendix D contain a massive amount of 

information on references that include data considered by the TI Team in identifying, 

characterizing, and assessing the CEUS seismic sources. These data include all types of 

information that have a potential use in achieving these objectives. The tables provide a 

benchmark of germane data at the time of the Project, which gives transparency to the efforts of 

the TI Team and which future evaluations can augment with new sources of information. The 

tables include the citation, the title, and the data included in the reference that are relevant to 

seismic source identification and characterization. The tables are thorough and, in general, 

reasonably well prepared and presented. We proceed to point out minor problems needing 

attention before finalizing the appendix. 

Specific Comments 

S D-1. (CC) Difficulty in Relating the Appendix to the Main Body of the Report 

The labeling of the tables is not consistent with the titles and acronyms used in the main body 

of the report for the source zones, and source zone data summaries are grouped in a manner that 

makes it difficult to relate the tables to some of the specific zones. For example, the Gulf 

Highly Extended Crust zone is apparently included in Table D-7.3.9, Gulf Coast Data 

Summary. Similar situations occur in other tables of the appendix. This makes it very difficult 

to relate the tables to the source zones in the report and decreases the usefulness of the 

appendix. This inconsistency needs to be rectified. 

S D-2. (CC) Facilitating Use of the Data Summary Tables

The Data Summary tables are explained in the text of the report (Section 4.2.2). However, 

consideration should be given to adding a short description of the objective, organization 

(including the keying of the table numbers to the main body of the report), preparation, and 

uses of the tables in an introductory paragraph to the appendix. This will facilitate the use of 

the tables. An explanation of the content of the columns used in the tables should be also 

included in this description for stand-alone reading. Also, all pages of Appendix D should be 

numbered consecutively, not separately for each table, to enable convenient reference—as 

opposed to having to point to a specific table and a page number within the table.

S D-3. (CC) Inconsistencies in the Tables

The Data Summary tables have numerous inconsistencies which should be eliminated because 

they diminish the quality and usefulness of the tables. We note the following: 

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1. The titles of the tables and the identified source in the notes at the top of each table 

should be consistent with the nomenclature of the text of the report, and tables should 

be in the same sequence as the identified source is described in the text (or keyed to a 

table in the text). 

2. The level of information given in the third column, Relevance to SSC, is variable.

This may be due in part to the information available or it could be due to the detail that 

is provided by the individual preparing the table. Greater consistency in the level of 

information would be desirable. 

3. Geographic (compass) directions are inconsistently given in abbreviated (e.g., NE) and 

spelled-out form. 

4. Dates are presented in different formats. 

5. Some tables have the acronyms for the subdivisions of the seismic source zone 

identified in notes at the beginning of the tables, others do not. 

6. Column 3 descriptors are sometimes in sentences, while others are not. It may be 

useful to have both, but an effort to be consistent would be worthwhile. 

7. The use of blanks in the tables is inconsistent. Every cell needs to have something in 

it; if nothing else, N/A for not applicable or some other notation to indicate intention. 

Otherwise, the meaning of a blank cell will be unclear. 

8. Both the terms magnetic and aeromagnetic are used in the tables. The use of the term 

aeromagnetic should be changed to magnetic throughout. Aeromagnetic simply refers 

to the method of collecting the majority of the data in the file. Referring to 

“aeromagnetic” but only to “gravity” is inconsistent. 

9. The format of the references at the end of each table is inconsistent, and some 

references do not have complete information. 

10. The ordering of the citations in the tables is not consistent. Some are listed 

chronologically, while others are listed alphabetically according to the first letter of 

the family name of the senior author. 

11. Use of bold letters for subtitles in several of the tables is inconsistent. 

12. Capitalization of type of feature is inconsistent in the tables. It is suggested that the 

type of feature should not be capitalized, e.g., Commerce lineament, not Commerce 

Lineament. 

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Comments by Table (for Clarity and Completeness) 

(Notation: pg. = page, c = column of table, r = row of table) 

Table D-5.4 

pg. 1, c. 1: Period after et al. on this page and throughout tables 

pg. 4: Should Petersen et al. be included? 

Table D-6.1.1 

pg. 1, c. 3: Spell aulacogens

Table D-6.1.2 

pgs. 2 & 3, c. 3: No difference for Chapman and Beale, 2009 and 2010. Should there 

be a difference? 

pg. 5, c.3, r.2: Should be Appalachian Mountains not Appalachians, similar comment 

for other geographic features throughout tables. 

pg. 15, c.2, r.2: Why is journal listed? 

Table D-6.1.3 

pg. 1, c.3, r.2: The abbreviation for miles should be mi without a period (not mi.) —

change throughout tables 

Table D-6.1.4 

pg. 3, c.3, r.1 & 2: Replace further with farther 

Table D-6.1.5 

pg. 40, c.3, r.2: Blank—similar blanks in other tables 

Table D-6.1.9 

pg. 4, c.3, r.4: Use of the casual Appalachians and Rockies should be avoided 

pg. 12: Has horizontal line between rows missing—this occurs elsewhere in tables 

Table D-7.3.1 

pg. 4, c.2, r.2: Misspelled Quebec 

pg. 5, c.3, r.2: Is it Sutton Mountain or Sutton Mountains? Both are used in this table. 

Table D-7.3.2 

pg. 10: Reference for N.H. Sleep; misspelled mantle 

Table D-7.3.4 

pg. 9, c.3: No references for two subheadings 

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pg. 15, r.: Geophysical Investigations should be bold; similar subheading concerns 

elsewhere in tables 

Table D-7.3.7 

pg. 1: Horizontal lines needed between citations 

pg. 11: Misspelling of investigate 

Table D-7.3.9 

pg. 1 and following: Why () around citations? 

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APPENDIX E — CEUS PALEOLIQUEFACTION DATABASE, UNCERTAINTIES 

ASSOCIATED WITH PALEOLIQUEFACTION DATA, AND GUIDANCE FOR 

SEISMIC SOURCE CHARACTERIZATION 

General Comments 

G E-1. (NAR) This appendix represents a thorough and well expressed compendium of 

methodology, data, and guidance related to paleoliquefaction studies in the CEUS. The 

written content and illustrations present the data and information clearly and with a high 

degree of technical quality. Generally the documentation of effort encompassed in this 

appendix supports the related assertions made in the CEUS SSC. This work is notable not 

only because it represents a new and productive field of study that was not included in the 

earlier EPRI-SOG and LLNL projects, but also because the effort has brought sets of 

information and data that were highly varied and inconsistent into a consistent and 

coherent framework. This appendix is likely to be used as a primer on the topic for future 

researchers in paleoliquefaction, and the fulfillment of the recommendations provided 

could significantly improve the understanding of RLMEs in areas of low to moderate 

seismicity areas in the U.S. and globally. 

Specific Comments for Clarity and Completeness 

S E-1. Incorporation of the Digital Database 

It is unclear how the digital database is going to be incorporated into the final report and 

how it will be accessed in the future. It would be useful to the reader if the location was 

noted after the sentence, “The database itself is available in digital format.” 

S E-2. Recommendations for Clarification of the Digital Database

Because Section 1.1 (Database Structure) uses many technical terms related to dating that 

are very well discussed later in the document, it may be useful for many readers who are 

not well versed on the techniques if a sentence were added at the end of the first paragraph 

of the section that says, “A discussion of the various dating methods and their uncertainties 

can be found in Section 2.1.3.” 

In relation to the description of the database on page 2, a simplified figure illustrating 

parameters such as SB_THICK, SB_WIDTH, SB_LENGTH, etc. may be helpful to the 

reader. 

Similarly, a simple figure illustrating the uncertainty estimates described in the last 

paragraph of Section 1.1 is not essential, but could be very useful for the reader. 

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S E-3. Clarification of Data Contributors

At the beginning of each of the “Data Description” subsections in the discussions of 

regional datasets in Section 1.2, the authors note that “Paleoliquefaction data have been 

contributed by . . . .” It is unclear to the reader if the contributors listed represent a 

complete list of the researchers who have worked in the area or if it is a subset of 

researchers who have provided additional information specifically for this project (e.g. by 

providing 2-sigma data that were not otherwise published). 

Because this report is likely to be read by researchers not familiar with paleoliquefaction, it 

may be helpful to refer to Beta Analytic as “Beta Analytic Laboratories” or in similar 

terms. The way the text reads currently, those not familiar with the topic are likely to 

understand Beta Analytic to be a process or approach described in Talma and Vogel (1993) 

or Vogel et al. (1993). 

S E-4. Missing or Misnumbered Figures 

— There is a Figure 11a, followed by Figure 11. Presumably, the second should be 

Figure 11b. 

— Figure E28 is missing. 

— There is a Figure E-39 and a Figure E-39b. Only E-39 is noted in the text. 

— There is a Figure E-44 and an E-44b. Only E-44 is noted in the text. 

— On Figure E-50, it would be useful to note what the SL signifies in the description 

for those not familiar with that notation. 

— Figure E-51 is sideways. 

— Figures 53b and 55b are missing. 

S E-5. Additional Information and Clarification of Seismic Zones

On page 8 in the first paragraph of Section 1.1.2, there is a discussion of a lineament 

throughout the paragraph. In the next paragraph there is reference to the “Daytona Beach” 

lineament at the end of the paragraph. It is unclear whether all the discussion relates to a 

single lineament called the Daytona Beach lineament. If so, perhaps the name should be 

noted at the start of the discussion. 

The discussion of the Wabash Valley Seismic Zone should be expanded to make the report 

more complete. Neither the text, nor the figures, provides any actual dates, with the figure 

instead indicating “Event A Dates,” “Event C Dates.” The description of the dataset in the 

report should discuss these events and their dates rather than expecting the reader to go to 

the original papers. 

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On page 13, the report notes that “There is no evidence for repeated large earthquakes in 

the exposures.” This statement needs to be further explained. In what way do the data not 

meet the criteria established by the project? Because this is a hazard-significant finding for 

sites in the ALM region, the line of evidence that the features do NOT represent 

seismically-generated features should be made clear. Also, it is unclear how this bullet and 

the following bullet are different statements. 

From discussion of the Charleston Seismic Zone, it is unclear from both the text and the 

figures what the number of events and the dates of those events are. One can only tell that 

there is a historic event, and at least one other event happened. Clarification as to what the 

outcomes are in the text would be helpful to the reader. 

S E-6. Additional Guidance

It would be appropriate to include a bullet point on considerations of completeness in 

Section 3 on guidance for the use of paleoliquefaction data in SSC. 

Minor Editorial Comments and Typographical Errors 

TOC: The page number for 1.2.3 St. Louis Region is on the next line 

p. 1: There is an EPRI logo embedded on the middle of page 

Several of the page numbers have “Cited” included before the number 

p. 1: Consider changing sentence 3 as follows, “Under this task, a new 

paleoliquefaction database, including regional datasets, was created and this report was

prepared, documentation and illustrating the databases, discussing . . .” 

p. 6 and other similar sections: Some sections make reference to “Beta Analytic” and 

others to “Beta Analytic Beta Analytic” 

p. 7, first paragraph: “...that may be capable of large earthquakes (e.g., Eastern 

Margin and Commerce faults), and migration of seismicity from one part of the 

Reelfoot Rift...” 

p. 5, Sand dikes, last bullet: Typo (“as well we as soft-sediment deformation”) 

p. 19, second paragraph: “For the results of a paleoliquefaction study to be most useful 

in accessing assessing the long-term seismic hazards...” 

p. 34, par. 1, line 3: Typo (change “earthquakes parameters” to “earthquake

parameters”) 

p. 34, last paragraph: The text states that radiocarbon and OSL dating “provide age 

estimates with uncertainties of one hundred years in the best of circumstances. Dating 

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PPRPReviewComments,pageE4

techniques that provide more precise results would help to improve age estimates of 

liquefaction features and their causative earthquakes.” In section 2.1.3.2 (p. 24, par. 2), 

examples are given of reported “precision” of ± 80 radiocarbon years, ± 20 radiocarbon 

years, and ± 40 radiocarbon years.

The figures start on page E2. Presumably the page numbers will be changed for the 

final report. 

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PPRPReviewComments,pageF1

APPENDIX F — WORKSHOP SUMMARIES 

General Comments 

G F-1. (NAR) The summaries of the workshop provided in Appendix F are well-written 

accounts of the presentations and subsequent discussions that transpired. The workshop 

summaries, coupled with the agendas, participant lists, and presentations, provide 

sufficient documentation regarding the content of the workshops.

Specific Comments for Clarity and Completeness 

S F-1. Added Information for Each Workshop 

Information has been described as “what people need and want to know.” Inclusion of the 

agenda for each workshop would give the reader a useful “road map” for navigating 

through the dense narratives. Also, the list of attendees for each workshop should be 

included for complete documentation (Table 2-2, p. 2-47, provides a partial list). As an 

additional step to help those wishing to review the project in the future, we assume that 

copies of visual presentations made at the workshops will be included as part of the project 

report and will become available either as part of this Appendix or on a project Website or 

in some other conveniently accessible form. 

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PPRPReviewComments,pageG1

APPENDIX G — BIOGRAPHIES OF PROJECT TEAM 

General Comments 

G G-1. (NAR) This appendix is a straightforward compilation of biographical sketches 

for members of the CEUS SSC Project. As part of this review, individual members of the 

PPRP were asked to carefully examine their own biosketches. 

Specific Comments for Clarity and Completeness 

S G-1. Correlation and Coordination of Appendix G with Figure 2.3-1

For stand-alone reading of Appendix G, it would be useful to give the reader an overview 

of the Project Team by either pointing the reader to the CEUS SSC Project Organization 

diagram (Figure 2.3-1), say by using a footnote on p. G-1, or by reproducing the diagram 

in this appendix. The inclusion of biographies for the Sponsor Reviewers in Appendix G, 

as part of the Project Team, implies that their names should also be included in the Project 

Organization diagram. 

The presentation of names in Appendix G is a mix of alphabetical and hierarchical 

ordering. If Figure 2.3-1 is to be a guide for the reader, consider ordering names in 

Appendix G as they appear in the various boxes on the figure.

In both the Project Organization diagram and in Appendix G, the TI Team (and support 

staff) is arguably a more important component of the “Project Team” than the PPRP. 

Consider moving the PPRP box on Figure 2.3-1 to the right of the TI Team and, 

correspondingly, presenting the PPRP names last in Appendix G. A box for the Sponsor 

Reviewers could be added in the organizational chart to the right of the PPRP (and their 

biosketches could follow those for the PPRP as in the draft). 

Typographical Errors 

p. G-7: Ending period missing in last line at the end of Mark Petersen’s biosketch.

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PPRPReviewComments,pageH1

APPENDIX H — EPRI/DOE/NRC CEUS SEISMIC SOURCE CHARACTERIZATION 

PROJECT: Draft Final Seismic Source Model Hazard Input Document (HID), Dated 

 July 6, 2010 

General Comments 

G H-1. (NAR) The intent of the HID is to give future users details on how to implement the 

CEUS SSC model. It contains the logic tree structure that defines the frequency, locations, and 

sizes of future earthquakes in this region. The appendix describes how the zones are 

characterized. A description of why the TI Team chose a particular equation, occurrence rate, 

magnitude, or source geometry, or references is not given in this section of the report.

G H-2. (CC) The elements of the CEUS SSC model are clearly described in enough detail to 

support future users’ implementation of the model for PSHA at any site in the CEUS. Gaps not 

described in the July 6, 2010 draft should be described in the final revision of the appendix. 

G H-3. (CC) The PPRP’s review of the 11 chapters of the main report identified many 

opportunities to achieve greater clarity in the TI Team’s descriptions of the characterizations 

and assessments represented in the CEUS SSC model by proper and consistent use of terms. 

 These comments apply as well to the descriptions contained in Appendix H. 

Specific Comments

S H-1. (CC) Title of Appendix H

Consider changing the appendix title to: “CEUS SSC MODEL HAZARD INPUT 

DOCUMENT (HID).”

S H-2. (CC) Implementing the Variable a- and b-value Routines

To perform any hazard calculations using the HID, it would be difficult for most users to 

implement the variable a- and b-value routines described in Chapter 5. Therefore, the process 

is not open for most users to evaluate that methodology. It would be desirable that the 

computer codes be made available for these analyses. Alternatively, the TI Team could release 

the output gridded data. However, this is not the best alternative since most users would not 

understand how these numbers were generated. A third alternative is for the TI Team to revert 

to the smoothed seismicity kernel that is more intuitive to the user community. 

S H-3. (CC) Transparency of HID Tables for Recurrence

The following excerpt is reproduced from PPRP Review Comment S 6-12:

“The unalert reader (or analyst) examining the HID tables for computed annual 

frequencies for the Charleston RLMEs may potentially be confused by: (1) the inverted

order for the 5-point distributions compared to Table 5.3.3.-1, which was used to define 

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PPRPReviewComments,pageH2

the 5-point distribution; and (2) the need to refer to Tables 6.1.2-1 and 6.1.2-2 to discern 

the elapsed time since the oldest earthquake counted in the sequence. For example, 

examining “Table Charleston_HID-3,” it may escape the reader’s attention that the 5-

point distribution is not for four events in 5500 years, but rather four events in 1,524–

1,867 years (or possibly in 1,569–1,867 years). To reproduce the results in the table 

(and for virtually all the Poisson-model tables in the HID), there is no explicit 

information about the exact elapsed time that was used.”

Comments for Clarity and Completeness 

Figures 8 and 9 appear to be identical figures with different figure captions. 

p. H-19, Degree of Smoothing: The text states that, “An “Objective” approach is used to select 

the degree of smoothing.” It would be very helpful to refer back in the text where this 

approach is described. 

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PPRPReviewComments,pageI1

APPENDIX I — PPRP REVIEW COMMENTS 

General Comments 

G I-1. (NAR) This compilation of review comments usefully provides a basis for 

tracking recommendations made by the PPRP and corresponding actions promised by the 

TI Team in response. 

Specific Comments for Clarity and Completeness 

S I-1. Title of Appendix E 

Because this appendix contains both PPRP and USGS review comments, the title of the 

appendix should be changed. 

S I-2. Listing of Letters and Attachments 

In the summary of contents for the appendix, the separate listing of Attachments to PPRP 

Letter 1a as Items 1b and 1c poses a problem of consistency. PPRP Letter 2 (dated August 

15, 2008) contains a substantive Attachment A (“Key Issues for CEUS SSC Relevant to 

Workshop #1) with three labeled enclosures. Also, USGS Letter 1 (dated April 8, 2010) 

contains five attachments. In the case of these three letters with attachments, one can 

either spell everything out or simply note that these letters have attachments (perhaps 

indicating their general nature). 

S I-3. Incorrect Date in Correspondence Contents 

p. I-2, TI Team Letter 1: Error in labeling the subject of the letter (change “dated 

August 12, 2008” to “dated August 15, 2008”) 

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PPRPReviewComments,pageJ1

APPENDIX J — MAGNITUDE RECURRENCE MAPS 

General Comments 

G J-1. (NAR) Appendix J presents the recurrence maps developed for all of the 

alternative configurations of the distributed seismicity zones. A brief description of the 

organization of the maps within the Appendix is provided on the title page. Consistent 

with the care taken in the writing of Section 5.3.2 (Smoothing Approach), this appendix is 

well organized and explained—beginning with the text on the title page that provides 

helpful guidance to the reader. 

Comments for Clarity and Completeness 

Page J-1: Consider adding additional reference to specific figures in Sections 6.4 and 

7.5; suggested wording: “Mean maps and magnitude-recurrence for each source zone 

are shown in Sections 6.4 (Figures 6.4-1 through 6.4-16) and 7.5 (Figures 7.5.2-1 

through 7.5.2-42).” 

Check: Were rates indeed calculated for M > 5 or for M 5? If perchance they were 

calculated for the latter, then labels on the figures should be changed or an explanation 

can be added on the title page of the appendix.

In figure caption for Figure J-1, need closing [“] for “no separation . . .” OR simply 

delete the [“], which doesn’t appear in the captions for the following figures. 

On Figures J-17 through J-48, the header information incorrectly indicates “MES” vs. 

“MESE” (the correct acronym, according to the list of Acronyms) written in the figure 

captions. 

On Figures J-49 through J-112, the acronym “RCG” is used for Rough Creek graben 

vs. “RC” in the list of Acronyms. 

Page J-87: Realization 7 for the seismotectonic zone, wide interpretation, Rough Creek 

Graben in Mid-Continent, full magnitude weights is missing. 

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PPRPReviewComments,pageK1

APPENDIX K — SCR DATABASES USED TO DEVELOP MMAX PRIOR 

DISTRIBUTIONS 

General Comments 

G K-1. (CC) This appendix provides the database used to develop the Mmax prior 

distributions. The work done to update and refine data for the global Stable Continental 

Regions has great value and importance. However, there is no explanatory text provided 

beyond the Notes and the two tables. To help future users, as well as to enhance 

transparency, this appendix could be improved by including additional information and a 

short description of the content being included in the appendix itself, or to a reference back 

to the relevant report text. It could also be noted whether or not the database is available in 

digital form elsewhere. 

Specific Comments for Clarity and Completeness 

K-1. Information that should be considered for Appendix K 

Appendix K would benefit from including additional information for the reader to better 

appreciate where the domains and super domains are, and to better integrate with the text. 

The TI Team should considering adding the following: 

Maps showing domains and superdomains (useful files for the boundaries of these 

domains should also be included in the Project Database, with a pointer to those 

files) 

Figures displaying the Mmax-obs statistics for each of the superdomains 

Summary table of statistical analysis completed on the various superdomain 

classifications 

K-2. Clarity of Documentation 

For clarity of documentation, attention should be paid to the following: 

1. Designation of time in an earthquake catalog should be explicit. Are the 

times/dates in UTC? Local time? A mix? This is non-trivial if one tries to find the 

events in another catalog. 

2. How should the reader interpret the variable presentation of significant figures in 

Table K-1 for latitude, longitude, M, and sigM? 

3. “Extensive stress” is an unorthodox descriptor for “extensional stress”. (Google 

the two terms to see how most readers would interpret the first term.) 

4. What are the units of “Area” in Table K-2? 

5. Neither “Mx_obs” or “N > 4.5” is explicitly explained in Table K-2. 

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PPRPReviewComments,pageK2

6. Check: Is N > 4.5 indeed the number of earthquakes greater than M 4.5? Or 

perchance is it M 4.5? 

7. For the table to be self-contained, an explanation should be given for non-integer 

values of N > 4.5. 

8. The wording used to explain SDNT and SDNC in Table K-2 will trip up most 

readers. Just add a few words to make it plain English. The acronyms certainly 

aren’t intuitive, but given that they are what they are, suggestion: 

SDNT Indicates which Superdomain the domain is assigned to when TYPE 

is included in the classification 

SDNC Indicates which Superdomain the domain is assigned to when TYPE 

is not included in the classification 

130
 Via e-mail 

INFORMAL COMMUNICATION 

To: Larry Salomone 

From: PPRP

Date: October 13, 2010 

Subject: Key Issues for TI Team to be Attentive to as They Revisit the CEUS SSC Model 

and Revise the Project Report 

This informal note is to highlight key issues raised in our review comments on the Draft 

Report—to help guide the TI Team as it revisits the CEUS SSC model and revises its report 

during the next few months. Because we apparently won’t be interacting with the TI Team as it 

carries out this work, we want to communicate as clearly as possible to preclude, or at least 

minimize, any need for later corrective actions. 

Short List of PPRP’s Major Concerns

The endgame is a CEUS SSC model and report that the PPRP can endorse. Based on e-mail 

interactions and a teleconference, the following is a short list of the PPRP’s major concerns 

(numbered for convenient reference, not for priority), embedded in our review comments1

:

1. Approach to declustering and the impact on the catalog of earthquakes used to perform 

smoothing. Only one approach is used and it is not clear what impact this would or 

would not have on the catalog, and ultimately the seismicity parameters. [S 3-5; see also 

Attachment 1 here, PPRP Commentary on New Methods (or Other Methods) with a 

Weight of 1.0 and SSHAC Guidance]

2. The weights on the split between Mmax zones and Seismotectonic zones. [S 4-9] 

Note: To be clear, the PPRP recognizes that ownership of the CEUS SSC model (and 

hence the weights on the master logic tree) belongs to the TI Team. The PPRP has the 

responsibility to ensure that the distribution of the technical community’s views and 

corresponding uncertainties have been appropriately considered and reasonably represented 

in the model—and that thorough justification is provided for all weights in the model. 

3. Statistical analysis of the SCR data base and how it is used to establish the weights on 

Mmax between the prior distributions. [S 5-9, S 5-10] 



1

 We assume that the TI Team will do a responsible job of responding to our concerns regarding clarity, 

consistency, and the need for thorough technical editing. 

7
Larry Salomone October 13, 2010 

2

4. The approaches used, and weights, for assignment of Mmax to seismic source zones. 

Specifically, the TI Team considers the Kijko approach in addition to the Bayesian 

approach, and has assigned relative weights to the two approaches. [S 5-6, S 5-7, S 5-8] 

Note: Regarding Item 4, and some other important SSC model issues that did not have the 

benefit of being explicitly discussed in a workshop setting, the PPRP must judge whether 

the TI Team sufficiently understands and treats the proponent views (including the range of 

views and uncertainties).

5. The statistical analysis and approach to smoothing. Only one approach is used. The 

results from the statistical analysis directly impact the rates of seismicity considered and 

the proportion of larger to smaller events for each of the sources. [S 5-11, S 5-12, S5-

13, S 5-14, S 5-16; see also Attachment 1 here, PPRP Commentary on New Methods (or 

Other Methods) with a Weight of 1.0 and SSHAC Guidance]

6. The criteria and basis for defining seismotectonic zones, and the application of these 

criteria so that a clear definition of each seismotectonic zone is supported. [S 4-2, G 7-2, 

G 7-4] 

7. A full explanation of the causes, and implications for hazard calculations, of (a) the 

generally poor fit of the realizations of the modeled recurrence rate obtained from the 

earthquake catalog and (b) differences between the CEUS SSC model results and USGS 

and EPRI-SOG (COLA) findings. [G 8-2, S 8-2]

Note: The PPRP feels a responsibility to ensure that the characterization of earthquake 

sources is consistent with historical seismicity data, as well as with any other pertinent 

datasets, and that the final model spans the center, body, and range accepted by the 

technical community. The “best” model must not only be pleasing to the TI Team but must 

fit available data. Further, it is incumbent on the TI Team to fully understand the 

assumptions in the CEUS SSC model and to provide high confidence that the model truly 

represents the community distribution.

8. Explicit recognition of the issue raised by Lombardi (2003) regarding the incorrect use 

of the maximum likelihood method in estimating the b-value for mainshocks. The 

methodologies used by the TI Team for recurrence calculations should be carefully 

reviewed to ensure that there is no systematic bias in the maximum-likelihood estimates 

of b-values, such as criticized in the Lombardi paper. [S 5-11] 
Larry Salomone October 13, 2010 

3

We understand your desire to let the TI Team do its work before having to respond to any of 

our PPRP review comments. If you or the TI Team have questions or would like clarification 

of any of our review comments or points in this communication, please contact us. 

For the PPRP,

Walter J. Arabasz 

Tel: 801-581-7410 

arabasz@seis.utah.edu

J. Carl Stepp 

Tel: 830-833-5446 

cstepp@moment.net

Copy: PPRP Members 
Larry Salomone October 13, 2010 

4

ATTACHMENT 1 

PPRP Commentary on New Methods (or Other Methods) with a Weight of 1.0 and 

SSHAC Guidance

A principal focus of the SSHAC guidelines is the appropriate assessment of epistemic 

uncertainty in the current state of knowledge of technical issues of interest. The SSHAC 

guidelines, therefore, describe a process that is focused on accurately representing the 

“community distribution” through assessment and evaluation activities that include (1) a 

critical review of all scientifically viable alternative viewpoints and theories and (2) a series of 

structured interactive workshops, including a proponent workshop focused on assessing 

alternate methods, theories and approaches. These activities are included because it is an 

explicit goal (indeed requirement) of the SSHAC guidelines that the final model represents the 

community distribution (i.e. the center, body, and range of the viable alternatives). Typically, 

the representation of the community distribution is achieved through a logic-tree approach 

which weights the viable existing alternatives in a transparent and justifiable way. 

The SSHAC guidelines do not preclude the use of new or different approaches beyond those 

already found in the technical community. Indeed, the guidelines specifically state that the 

guidelines themselves should not be a barrier to progress and development. The guidelines also 

allow for weighting of approaches that are not simply a representation of the current view of 

the technical community; the SSHAC approach allows for evolution of thinking and is not 

simply expert elicitation. Therefore, when new approaches are introduced, the questions 

should focus on how the alternative approach is implemented in the model, consistent with 

goals and requirements of the SSHAC guidelines, and how that consistency is demonstrated. 

There are two ways in which new approaches can be incorporated into a SSHAC-based project. 

The first way is to introduce a new approach as a “proponent” approach and to add it to the 

logic tree and assign a weight based on its relative merit among the alternatives. In theory, this 

is relatively straightforward.

A second way, as chosen by the TI team in this project, is to adopt a new method and assign it a 

weight of 1.0, thereby replacing the range of alternative approaches used in the community 

with a single approach. Theoretically, this is allowable under the SSHAC guidelines as long as 

the requirement that the community distribution is effectively represented continues to be met. 

The use of a single approach must not artificially reduce the assessed epistemic uncertainty. In 

this case, the method used should not simply be another proponent model, because it is being 

treated as a “replacement” or “proxy” model that can represent the community distribution in a 

more elegant or computationally efficient way. The use of a “replacement” model comes with 

a high bar to reach in terms of showing that the SSHAC guidelines are being met. As a 

minimum, it should be demonstrated that the new approach is consistent with both the range of 
Larry Salomone October 13, 2010 

5

outcomes of traditionally accepted approaches (i.e., the community distribution), and also with 

the appropriate data that are available. 

If the new method cannot be demonstrated to appropriately represent the community 

distribution, it is difficult to judge how it is not just another proponent model that should be 

incorporated with (and not replace) other proponent methods. To simply choose a proponent 

model approach and say that is the “best” one and give it a weight of 1.0 is inconsistent with 

the SSHAC guidelines. It is acceptable for any development team to develop a model (or 

approach) that they think is the “best”— but that is different than saying that a model (or 

approach) is consistent with the SSHAC process, and it must meet a high standard. 
 Via e-mail 

INFORMAL COMMUNICATION 

To: Larry Salomone 

From: Walter Arabasz and Carl Stepp 

Date: February 23, 2011 

Subject: PPRP Feedback on CEUS SSC Working Meeting #9 

This note provides some written feedback from the PPRP on CEUS SSC Working Meeting #9, 

held at EPRI Headquarters in Palo Alto, California, on February 7–8, 2011. It summarizes 

PPRP comments made at the end of the working meeting and adds some additional perspective. 

General Comments 

Based on the TI Team discussions, the PPRP was very encouraged that its major comments on 

the initial draft of the CEUS SSC report were being addressed in an appropriate manner. We 

commend the TI Team for taking the time to revise and enhance the earthquake catalog being 

used for this project. The PPRP anticipates that this catalog will represent a major advance 

forward for the technical community. The PPRP is also encouraged that the TI Team is 

working toward closure on addressing our comments related to b-value, the approach and 

method for smoothing and earthquake-recurrence assessment, and the derivation of maximum 

magnitudes. 

Based on collective experience from the August–September 2010 review cycle of the CEUS 

SSC Draft Report, the PPRP urges the TI Team to be fully satisfied with the results and 

documentation for the next iteration of the Project report before releasing it for review. We 

expect that what we receive for review in the next cycle will have been carefully vetted, 

including careful attention to any significant discrepancies between model predictions and 

observed historical seismicity (for example, cases such as the area of St. Paul, Minnesota, in the 

July 2010, draft report).

We are pleased to learn that progress is being made on planning and arrangements for the 

Project’s Public Website. The simultaneous activation of the Public Website with the release 

of the CEUS SSC Technical Report, scheduled for December 31, 2011 (Revised CEUS SSC 

Schedule, 2/22/11) will be greatly helpful to meet user needs. 

Reminder Regarding Methods with a Weight of 1.0 and SSHAC Guidance 

After listening to a detailed description of the Penalized Likelihood Approach, the PPRP calls 

the TI Team’s attention to an attachment included in the PPRP’s Informal Communication of 

October 13, 2010, in which we distilled our major concerns on the July 31, 2010, draft report.

The attachment was labeled, PPRP Commentary on New Methods (or Other Methods) with a 

Weight of 1.0 and SSHAC Guidance. Replacing a range of alternative approaches used in the 

community with a single approach places a significant burden on the TI Team to show that 

SSHAC guidance is being met. 

8
Larry Salomone February 23, 2011 

2

Approach to Smoothed Seismicity 

The Penalized Likelihood Approach has evolved sufficiently to be accepted by the TI Team as 

the tool of choice for assessing the spatial variation of earthquake recurrence rate and b-value.

Nevertheless, the influence of factors such as spatial incompleteness remains incompletely 

understood. Thus, while the Smoothing Model is a powerful tool, it seems prudent in assessing 

the spatial variation of earthquake recurrence to incorporate considerations of variations in 

tectonic histories and properties of the seismic sources to complete the TI Team’s assessments. 

In other words, guidance by physical and tectonic insights is desirable.

The approach of establishing an initial b-value using the seismicity of the CEUS Model Region 

appears to be solid. We encourage the TI Team to consider discussing with a few selected 

seismologists their views on the variation in b-value as part of reviewing the smoothness of 

b-value maps and decisions by the TI Team related to the final sets of weights for smoothing 

parameters. 

The TI Team has a number of difficult decisions to make in the very near future regarding 

recurrence assessment and especially the smoothing parameters. Although objective 

specification of these parameters is being considered, it appears likely from the presentations at 

the meeting that "analyst-specified" parameters will significantly influence the selection 

procedure. Accordingly, it is important for the purposes of developing a consensus among the 

TI team on these parameters—and for transparency in the decision process for the end user—

that specific criteria be defined and used in the parameter-selection process so that the finally 

specified parameters be as objective as possible. We encourage vigorous internal interactions 

among the TI Team before the smoothing parameters are finalized. 

Initial Branch of the Logic Tree

One issue that was not discussed in detail at Working Meeting #9 relates to the logic-tree 

weights applied to the initial branch in the logic tree—namely, maximum-magnitude zonation 

versus seismotectonic zonation. The tables that the TI Team described using the criteria for the 

definition of zonation will improve the basis for TI Team decisions. Having said this, the TI 

Team is encouraged to review all relevant information and data as part of developing its final 

set of weights for the initial branch of the logic tree. Without having seen sensitivity results on 

this weighting, we assume that the relative weights may be important in the overall 

determination of hazard. In any case, the weights need to be well justified, and their 

justification will be carefully reviewed by the PPRP. 

Importance and Usefulness of Early Information to the PPRP 

It was clear from the working meeting that closing on the earthquake catalog, finalizing and 

implementing the maximum-magnitude approach, and executing the final smoothing and 

recurrence calculations are on the critical path to completing Chapters 3 and 5—and ultimately 

completing the hazard calculations for the seven test sites. While the June 2011 Project 

Briefing will provide the opportunity to evaluate where the project stands, final versions of 

Chapters 3, 5, and 8 will not be available before that briefing. Given this, the PPRP encourages 

the project and TI Team to provide as much pertinent material to the PPRP before that briefing. 

Such material could include electronic versions of the earthquake catalog, final intensity and 
Larry Salomone February 23, 2011 

3

magnitude-conversion relationships, the final prior distribution being used to derive maximum 

magnitude distributions, a table displaying the final weighted maximum magnitudes for each of 

the seismic sources, a set of smoothing maps for each of the sources, and the final logic tree 

with weights. 

The Stakeholder Briefing that was held February 9–10, 2011 (following Working Meeting #9) 

reinforced the expectation by the Project Sponsors that the PPRP stay engaged with the TI 

Team, as the team makes key decisions, so that the PPRP can efficiently perform their 

participatory review and potentially prevent delays in finalizing the CEUS SSC Model. 

Keeping the PPRP aware in a timely way concerning the specifics on completion of activities 8 

(final smoothing), 9 (implementation of weights and conversions to hazard), and 10 

(documentation of responses to comments on chapters 3, 5, and 8)—which are all to be 

completed well before the next scheduled Project Briefing in June 2011—will be important for 

arriving at that milestone with confidence in PPRP endorsement. 

If you need more information or clarification, please contact either of us. 

For the PPRP,

Walter J. Arabasz 

Tel: 801-581-7410 

arabasz@seis.utah.edu

J. Carl Stepp 

Tel: 830-833-5446 

cstepp@moment.net

Copy: PPRP Members 
CEUS SSC_PPRP #7a mandatory_final 

September 26, 2011 Via e-mail 

Lawrence A. Salomone 

Savannah River Nuclear Solutions, LLC 

Savannah River Site 

Building 730-4B, Room 3125 

Aiken, SC 29808 

Dear Mr. Salomone: 

Reference: Central and Eastern United States Seismic Source Characterization for Nuclear 

Facilities: “ Mandatory” PPRP Review Comments on the CEUS SSC Final Report

This letter constitutes the report of the PPRP1

 (“the Panel”) providing selected review 

comments from both Installments 1 and 2 of the Central and Eastern United States Seismic 

Source Characterization for Nuclear Facilities, Final Report (“the Final Report”). As you 

requested, the selected comments are those identified by the Panel as “mandatory”—that is, 

review comments that must be addressed by the TI Team in their final documentation of the 

Final Report. These comments were discussed with the TI Team in draft form at the PPRP 

Closure Briefing on September 7, 2011. 

Background to our PPRP Review Comments on the Final Project Report 

On August 5, 2011, we provided in draft form all of our Panel’s review comments on 

Installment 1 of the Final Report. Some of those comments were subsequently identified as 

mandatory and are now included in this formal PPRP report. The others have been 

incorporated into a separate PPRP Informal Communication that summarizes all of our Panel’s 

“non-mandatory” review comments on both Installments 1 and 2 of the Final Report. Our 

non-mandatory comments are intended chiefly to help improve the quality of the final product. 

All eight members of the PPRP (J. P. Ake, W. J. Arabasz, W. J. Hinze, A. M. Kammerer, 

J. K. Kimball, D. P. Moore, M. D. Petersen, and J. C. Stepp) participated in this peer review, 

and the review comments represent the Panel’s consensus. 

Our primary focus in reviewing Installments 1 and 2 of the Final Report has been: (1) to 

reach closure on comments made earlier on the Draft Report of July 2010; (2) to ensure 

that no substantive issues remain unresolved; and (3) to help the Project Team achieve a 

high-quality Final Report. Our overall evaluation of the CEUS SSC Project, including 

compliance with SSHAC guidance, will be addressed in our PPRP Final Letter Report 

in October 2011. 

Kudos to the TI Team and Project Manager for the 2011 Version of the Project Report

The Panel praises the TI Team—and you as the Project Manager —for the impressive 

achievement of putting together the revised 2011 version of the Project report. We fully 

appreciate the massive amount of detail that had to be dealt with. Overall, the report is of high 

1

 Participatory Peer Review Panel. For other acronyms, see the list of acronyms contained in the CEUS 

SSC Final Report. 

9
Lawrence A. Salomone September 26, 2011 

quality, remarkably comprehensive, responsive to earlier PPRP review comments on the 2010 

draft version, and clearly reflective of enormous efforts. The result is a high-quality project 

report that will support users’ implementation of the CEUS SSC Model.

Please contact us if you have questions or need more information regarding the Panel’s review 

comments.

For the PPRP,

Walter J. Arabasz J. Carl Stepp 

688 East 4129 South 871 Chimney Valley Road 

Salt Lake City, UT 84107 Blanco, TX 78606-4643 

Tel: 801-554-1845 Tel: 830-833-5446 

arabasz@seis.utah.edu cstepp@moment.net 

Copy: PPRP Members 

Sponsor Representatives 
September 26, 2011 

1

MANDATORY PPRP COMMENTS ON CEUS SSC FINAL REPORT 

 (not ordered in priority) 

1. How SSHAC Level 3 was Selected

Although there is a comprehensive description of the use and difference between SSHAC 

Level 3 and 4 in Chapter 1, there are not explicit statements on why Level 3 was selected for 

the CEUS SSC Project, who made the decision, and at what stage in the project this was 

done. These are significant items of information that should be included. They are not 

discussed in Chapter 2. 

2. Identification and Engagement of Experts

The report should provide additional discussion of how the spectrum of experts was selected 

for this project (several places within Chapter 2 and perhaps Chapter 1). While the report 

makes the point that all participants were reminded of their roles, and that many project 

participants have significant SSHAC experience, some could contend that this a closed 

process. Without additional discussion, the current text sounds like, “Trust us, we know 

what we are doing.” Specifically, we suggest a description of the steps taken by TI Team, as 

supported by the PPRP, to ensure that the participation of Resource Experts and Proponent 

Experts in Workshops #1 and #2 was appropriate and complete in order to be representative 

of the range of current scientific community interpretations, for which awareness and 

knowledge were required.

Additional discussion is required of the extended roles that certain resource experts played to 

develop explicit material for TI Team use (e.g., paleoliquefaction). Finally, the report should 

describe the extended role personnel from the U.S. Geological Survey (USGS) played in this 

project to ensure that all supportable interpretations of the scientific community were fully 

identified, evaluated and represented in the SSC model. Several USGS personnel provided 

detailed review and feedback on specific issues (e.g., the earthquake catalog, Mmax); these 

should be described. 

3. Weights to Logic Tree Branches

Referring to the discussion in Section 4.1.1.2, while it is true that the final assignments of 

weights to logic tree branches are subjective, the report needs to make clear that the weights 

represent assessments informed by the totality of the SSHAC evaluation process. Before 

weights were assigned, the TI Team heard from a properly wide range of resource and 

proponent experts, reviewed extensive technical information, created the Data Summary and 

Data Evaluation tables, and evaluated a wide range of issues with members of the 

knowledgeable broader technical community. This is the critical message that needs to be 

emphasized for supporting the final informed subjective weights. 

4. CBR of the ITC vs. CBR of the TDI

In the third sentence of Section 4.1.1.2 on p. 4-3, the text states that “the total set of logic tree 

branches and weights represent [sic] the team’s assessment of the center, body, and range of 

views of the informed technical community (see Section 2.1 for a discussion of this 

concept).” In Section 2.1, however, the reader was informed of proposed alternative wording 

referring to “the CBR of the ‘technically defensible interpretations’ (TDI), instead of CBR of 
September 26, 2011 

2

the ITC” citing the NRC (in review). If TDI is preferred, replace “of the informed technical 

community” with “of the technically-defensible interpretations.” 

In Section 2.1, in discussing the alternative wording of the TDI to replace the ITC, care 

should be taken to avoid the notion that “nothing has changed by way of perception of 

process; we have just used more acceptable wording.” The text should convey that the 

change does indeed grow out of a deeper understanding of the process and is a more clear 

expression of the fundamental concept that the SSHAC intended to convey. 

5. Evaluation of Cases A, B, and E

In Section 7.5.1 (Rate and b-Value Maps for Single Zone and Two Zones), the bases for the 

three choices of magnitude weights represented by Cases A, B, and E, are discussed, but 

there is almost no discussion of the bases and considerations that went into the evaluation 

and integration that resulted in the assessed weights. Keeping in mind that observed 

seismicity is a direct measure of tectonic strain release and that the smoothing procedure is a 

tool for representing the TI Team’s evaluation of this process—including issues such as 

uncertainty about spatial stationary of seismicity in space and time, uncertainty imposed by 

the limited observed record of earthquakes, as well as other uncertainties cited in Chapter 5 

of the report—the report needs to clearly convey the Team’s evaluation and integration 

activities that resulted in the weights on Cases A, B, and E as properly representing the TDI.

Added commentary: The following two comments on Chapter 8 are related to an 

understanding of the implications of weighting Cases A, B, and E. 

1) The Central Illinois Site shows significantly higher hazard than from the COLA or 

USGS models (Figure 8.2-1j). It seems like the primary contributor is the IBEB 

source zone. Why is the seismicity rate high in this zone compared to the catalog 

used in the 2008 USGS maps? 

2) For the Chattanooga site, Figures 8.2-2j to 8.2-2l show similar hazard between the 

USGS and CEUS SSC models for ground motion less than about 0.6 g for 10 Hz.

However, for higher ground motions the curves diverge. For 1 Hz the USGS model 

is consistently higher than the CEUS SSC model. Is this difference because of the 

Eastern TN Seismic Zone, the Mmax distribution, or something else? This is the only 

site where the contribution from the Eastern TN Seismic Zone can be checked—

hence, the interest in scrutinizing whether the CEUS SSC and USGS models are 

similar, or else the differences explained. 

Lack of table defining Cases A, B, and E: The description of smoothing in Chapter 5 is well 

written. One lapse is that the report presently lacks a defining table for Cases A, B, and E for 

the weighting of magnitude bins—clearly a critical part of the report documentation. The 

discussion of weighting of magnitude bins begins in Section 5.3.2.2.1 on p. 5-36, and the 

reader is referred to Table 5.3.2.1 [sic]. Table 5.3.2-1 includes no information on Cases A, 

B, C, D, and E discussed in the text. This same table is also referenced in Section 5.3.2.6, 

pointing the reader to Cases A, B, and E. 
September 26, 2011 

3

6. Appendix A — Description of the CEUS SSC Project Database

One PPRP member who has special expertise relating to the subject matter of Appendix A 

has made extensive efforts in reviewing both the July 2010 draft version of this appendix and 

the June 2011 revision to help improve its accuracy and technical quality. We urge diligent 

attention to the totality of the review comments on Appendix A in our companion nonmandatory PPRP review comments. The following items of response are judged to be of 

greatest importance: 

Item (e) in Comment (FR) S A-1 regarding incorrect units on some of the figure 

legends must be dealt with because the units are incorrect.

Comment (FR) S A-2 (Lack of Suitable Information on Regional Heat Flow) is 

important because of the role of these data in processes and seismogenic cristal 

thickness of the CEUS. 

Comments (FR) CC A-5, A-6, and A-8 relating to Figures A-13, A-14, and A-16, 

respectively, point out some basic problems with these figures. 

7. Region of Applicability of the SSC Model

In the first sentence of Section 1.3, the statement, “The SSC model developed for this project 

is applicable to all sites within the project study region (Figure 1.3-1)” needs to be clarified.

Sites within some distance (to be defined) of the boundary of the “study region” will require 

a site-specific SSC model that extends beyond the region boundary. A distinction must be 

made between “study region” and the region of applicability of the SSC model without the 

need to extend the model beyond the study region. 

8. AFEs for Nuclear Facilities

In the second paragraph of Section 1.1.5, PSHAs for nuclear facilities must extend from 10–3

through 10–7 AFE (see also Section 2.4.2). 

Various sections of the report should be consistent in specifying this range of importance of 

AFEs for nuclear facilities; in Chapter 9, added wording should explain the focus on AFEs of 

10–4 to 10–6 for COVs.
CEUS SSC_PPRP #7b non-mandatory_final 

 Via e-mail 

INFORMAL COMMUNICATION 

To: Larry Salomone 

From: Walter Arabasz and Carl Stepp 

Date: September 26, 2011 

Subject: PPRP Non-Mandatory Comments on Installments 1 and 2 of Final Report 

As an addition to our PPRP letter report to you on this same date, we are providing here a list of 

Non-Mandatory Comments on both Installments 1 and 2 of the Central and Eastern United 

States Seismic Source Characterization for Nuclear Facilities, Final Report (June–August 2011).

These non-mandatory comments are intended to help improve the Final Report. We understand 

that they will be handled by the TI Team as feasible and at their discretion.

Notes:

1. August 5, 2011, document now obsolete: All of our review comments on Installment 1 that 

we submitted in draft form on August 5, 2011, have subsequently been flagged as either 

“mandatory” or “non-mandatory.” The former are included in our companion PPRP letter 

report and the latter have been incorporated into this Informal Communication. Hence, the 

August 5, 2011, document is obsolete. 

2. Comprehensive Technical Editing Not Done by the PPRP in this Review Cycle: In reviewing 

the CEUS SSC Draft Report of July 31, 2010, the PPRP made diligent efforts to identify 

shortcomings in the clarity and completeness of documentation, and we offered numerous 

comments to help improve the reporting. In reviewing the revised 2011 version of the Final 

Report, we have not assumed responsibility for comprehensive technical editing, leaving that 

task to the Project Team’s support staff. Our non-mandatory review comments do, however, 

include a significant number of minor editorial comments and point out some typographical 

errors. Also, individual members of the PPRP have provided added information to the 

Project Manager to help in final-stage editing.

If you need more information or clarification, please contact either of us. 

For the PPRP,

Walter J. Arabasz 

Tel: 801-554-1845 

arabasz@seis.utah.edu

J. Carl Stepp 

Tel: 830-833-5446 

cstepp@moment.net

Copy: PPRP Members 

 Sponsor Representatives 

10
KEY TO LABELING OF PPRP REVIEW COMMENTS 

Central and Eastern United States 

Seismic Source Characterization for Nuclear Facilities 

Final Report, June–August, 2011 

Format for Numbered Comments: X Y-N

(FR) Final Report*

X Type of Comment: G (General), S (Specific), or CC (comment relating 

to clarity, completeness, or error in documentation)

Y Part of Report: 1, 2, . . . , 11 (Chapter 1, 2, . . . , 11)

A, B, . . . , K (Appendix A, B, . . . , K)

Acr = Acronyms

ES = Executive Summary

FM = Front Matter

N Sequence Number: 1, 2, . . . , n

 * The flag “(FR)” is included to indicate that the review comment applies to the 

CEUS SSC Final Report—to avoid confusion with similarly labeled PPRP review 

comments on the Draft Report of July 2010). 

Example: Review Comment (FR) G 3-1 applies to the Final Report, is a General 

Comment, applies to Chapter 3, and is the first comment of this type for that chapter. 

1
PPRPNonMandatoryReviewComments,pageFM1

FRONT MATTER

PRODUCT DESCRIPTION 

Minor Editorial Comments and Typographical Errors

In the third line of the first paragraph, the EPRI reference should be to the NRC-accepted 

report: EPRI Report EPRI-NP-4726-A (1988).

Under Keywords, change “Probabilistic seismic hazard assessment (PSHA)” to 

“Probabilistic seismic hazard analysis (PSHA)” [e.g., see Glossary in Chapter 11].

EXECUTIVE SUMMARY 

General Comments 

(FR) G ES-1. In general, the Executive Summary is complete, very informative of the Project, 

and well written. However, because this part of the report will be read by the largest number of 

readers, and ideally written as a “stand-alone” part, it should (a) strive to use language that will 

be generally understandable , (b) eliminate acronyms or at least explain them (e.g., SCR is not 

explained), and (c) avoid references. Consider including subheadings to guide the reader, and 

consider referring to particular chapters or sections of the report (as is done in some parts of the 

Executive Summary) to make it easier for the reader to focus on a topic of particular interest. 

Comments for Clarity and Completeness 

(FR) CC ES-1. (Limitations of historical seismicity record): The sentence in the last paragraph 

of page xii dealing with the relationship of the locations of small- to moderate-magnitude 

earthquakes to locations of future large earthquakes is very important. In the initial description 

of this topic in the first paragraph of Section 5.1.1, limitations to this relationship are discussed. 

It would be useful in the Executive Summary to similarly note that there are limitations to this 

relationship and also note the importance of using geology and geophysics in identifying and 

characterizing seismic source zones in cratonic regions.

It would be informative to the reader if the Executive Summary stated that the CEUS SSC Model 

is based to a large extent on the assumption, typical in PSHA studies, that spatial stationarity of 

seismicity is expected to persist for a time period of approximately 50 years. The report has a 

definite lifetime. 

(FR) CC ES-2. (“Reasonable” results): The third full paragraph of page xvi (regarding the 

seven demonstration sites) distills one of the most important parts of the report. The TI Team 

may wish to re-examine the conclusion in the last sentence that the CEUS SSC model provides 

“reasonable” seismic hazard results. Can a more definitive term be used?

Minor Editorial Comments and Typographical Errors

Page ix, 1st para., last line: Consider changing “considered” to the more precise word 

(with respect to the SSHAC process), “represented” 

2
PPRPNonMandatoryReviewComments,pageFM2

Page ix, 2nd para., line 6: EPRI (2006) . . . 2006a, 2006b, or both? 

Page xi, 1st partial para., line 2: Consider inserting “stresses in the crust and” following 

“near-surface indications of”; line 3: “stresses” should be “strains” and “identify” should 

be “quantify”; line 4: “future earthquakes” 

Page xii, 3rd para., line 1: In the word string: “the conceptual SSC framework and” 

change “and” to “, which”; line 2: instead of “identifies” use the more properly 

descriptive word “depicts”; line 3: use the more precisely descriptive word 

“interpretations” instead of “approaches”; replace “will be used” with “represent the 

range of defensible interpretations”; replace “establishes” with “depicts” and replace 

“assigned to” with “assessed for”; line 4: delete “main” 

Page xii, 1st bullet following the second full para.: Consider replacing “consideration” 

with the more properly descriptive word “representation”; 3rd bullet: Consider replacing 

“consideration of” with the more directly informative “representation of uncertainty in”; 

4th bullet: replace “consideration” with “representation” 

Page xiii, top line: Insert “uncertainty in” following “assessment” and delete “have been 

relatively”; line 10 “uses” 

Page xiv, last full para., line 8: Replace “reflects the relative degree of belief” with 

“represents the uncertainty in the interpretation”; line 12: Delete first “resulting” 

Page xvi, 3rd full para., line 9: Change “characteristics for” to “characteristics of”; last 

line: change “adequately” to “appropriately” 

Page xvii, 3rd full para., next to last line: change “10–6” to “10–7” [Note: Per discussion at

the PPRP Closure Briefing on September 7, 2011, the AFE of 10–6 is correct if the reason 

for focusing on 10–4 to 10–6 is explained in Chapter 9.] 

ACKNOWLEDGMENTS 

Depending on resolution among the sponsors for wording to be used on the title page, similar 

wording might be used for emphasis in the first sentence here. For example: “This study was 

jointly sponsored by the following three entities: . . .”

SPONSORS’ PERSPECTIVES 

No comment. 

ACRONYMS

The revised 2011 version appears to be reasonably complete (not exhaustively checked). 

3
PPRPNonMandatoryReviewComments,page11

CHAPTER 1 — INTRODUCTION 

General Comments 

(FR) G 1-1. Chapter 1 has been substantively revised from the July 31, 2010 draft. The 

current June 2011 version (Installment 1 of the Final Report) suitably responds to the PPRP’s 

earlier review comments, as summarized in the TI Team’s PPRP Comment Resolution Table.

The chapter is now well structured and relatively complete in scope. However, the PPRP has 

some continuing concerns about clarity (see Comments on Clarity and Completeness, below). 

(See also PPRP Mandatory Comments Nos. 1, 2, 7, and 8.)

Comments on Clarity and Completeness 

(FR) CC 1-1. (Clarity of wording in Section 1): Comments going to the issue of clarity of 

wording in Section 1, particularly Sections 1.1 through 1.2.2 are extensive. By agreement with 

the Project Manager, they have been made as edits in “Track Changes” format and have been 

submitted separately.

(FR) CC 1-2. (Adding helpful citations in Section 1.1.1): Although the USGS SSHAC 

implementation report and the NRC SSHAC implementation guidance (NUREG-XXXX, out 

for comment) are referenced later in the report, it would be helpful to reference them here. 

(FR) CC 1-3. (Community-based model): Section 1.1.4 is titled “Community-Based 

Region SSC Model for Nuclear Facilities.” While the concept of “community-based” has come 

up in several instances as part of broad PSHA efforts, these words could spark needless debate 

and are not necessary here.

(FR) CC 1-4. (Aid to locating key products in the report): In Section 1.4.4, consider 

referencing locations in the report where the identified key products are described. 

(FR) CC 1-5. (Website “being developed”): Mention of the project website in Section 

1.4.4.2 should not refer to development but rather the availability of the website at a specific 

address.

(FR) CC 1-6. (Use of earthquake catalog): In the last sentence of Section 1.4.4.3, we 

suggest describing that the project earthquake catalog was used in identifying and 

characterizing seismic source zones as well as for characterizing recurrence and Mmax 

parameters. 

Minor Editorial Comments and Typographical Errors

Throughout the report there is inconsistent style in the figure captions and table titles.

In some cases, only the first letter of the first word is capitalized whereas in others the 

first letters of all major words are capitalized. There is similar inconsistency in using an 

ending period at the end of figure captions and table titles. 

Some miscellaneous editorial comments and suggestions relating to Chapter 1 have been 

provided separately to the Project Manager. See also Comment (FR) CC 1-1 regarding 

suggested edits provided separately to the Project Manager. 

4
PPRPNonMandatoryReviewComments,page21

CHAPTER 2 — SSHAC LEVEL 3 ASSESSMENT PROCESS AND 

IMPLEMENTATION

General Comments 

(FR) G 2-1. Chapter 2 has been extensively revised from the July 31, 2010 draft, and we 

commend the TI Team for this important effort and for diligently responding to the PPRP’s 

earlier review comments, as summarized in the TI Team’s PPRP Comment Resolution Table.

The restructured chapter is greatly improved. To help with some further refinement, we offer 

one specific comment (see PPRP Mandatory Comment No. 2, “Identification and Engagement 

of Experts”) together with a number of comments on clarity and completeness. 

Comments on Clarity and Completeness 

(FR) CC 2-1. (Meeting of May 28): In Section 2.2 (Table 2.2-1), the meeting of May 28, 

2008, which played an important role in the project, is not included.

(FR) CC 2-2. (Section 2.3, PPRP): In describing the role of the PPRP in Section 2.3 on 

page 2-7, the last sentence should be revised to read, “PPRP responsibilities included review of 

both the Draft Project Report and the Final Technical Report developed by the TI Team.” 

Also, it seems appropriate to mention the role of the PPRP in finalizing the Project Plan, which 

was a significant and important activity of the PPRP.

(FR) CC 2-3. (Section 2.3, TI Team): In describing the TI Team in Section 2.3, consider 

mentioning the size of the TI Team. Given the unique SSHAC role of an “evaluator,” one of 

the key aspects of this project was to help train some new “evaluators,” able to lead or 

participate in future PSHAs as needed.

(FR) CC 2-4. (AFEs for nuclear facilities): In the first paragraph of Section 2.4.2, the

AFEs of interest for nuclear facilities should be 10–3 through 10–7 (see also Comment (FR)

CC 1-6).

(FR) CC 2-5. (PPRP involvement): The discussions in Sections 2.4.9 (Finalization and 

Review of SSC Draft and Final Model) and 2.5.2 (Reviews and Feedback) do not reflect the 

PPRP’s participation in identifying key issues that required resolution. For example, while the 

TI Team did continue to refine the SSC Model associated with the initial Draft Report during 

the PPRP review, the PPRP independently identified a number of critical technical issues that 

required resolution. A few minor edits in these sections could convey a better sense of the 

PPRP’s participation in the process.

(FR) CC 2-6. (Confusing descriptions in Section 2.4.10): The writing in Section 2.4.10 

contains confusing descriptions, including tense, relating to the chronology of developments, 

and there is ambiguity as to whether products described relate to the draft or final versions of 

the project report. A markup of Chapter 2, provided separately to the Project Manager, 

contains numerous suggested edits for improving the clarity of Section 2.4.10.

(FR) CC 2-7. (Another key activity for Section 2.4.10): In Section 2.4.10, as part of the 

documentation of “Key Tasks and Activities” (title of Section 2.4), consider explicit mention of 

5
PPRPNonMandatoryReviewComments,page22

the development of a “Conceptual Seismic Source Characterization Framework”—now the 

subject of Chapter 4 in the Final Report. 

(FR) CC 2-8. (Placement of PPRP closure letter in the report): The last sentence in Section 

2.5.3 on p. 2-20 now reads, “The final activity conducted by the PPRP was the development of 

its closure letter, which is appended in this report.” If our closure letter is placed after the 

Executive Summary (see Comment (FR) S I-1), this sentence will need to be revised.

(FR) CC 2-9. (Uniform data base to all experts): In Section 2.6, Item 3 (Provide a uniform 

data base to all experts) on p. 2-22, the text needs to make it clear that the Data Summary and 

Evaluation tables are viewed by both the TI Team and the PPRP as critical to the success of the 

project. This is the first project to rigorously and systematically document this information, 

and it is viewed by the PPRP as essential information to support the descriptions and discussion 

eventually found in Chapters 6 and 7. Early in the project, the PPRP encouraged the TI Team 

to create the Data Summary and Date Evaluation tables.

(FR) CC 2-10. (Confusing descriptions of the number of working meetings): In Section 2.6, 

in the first paragraph under Item 5 on p. 2-23, reference is made to “Nine multiple-day working 

meetings.” To avoid confusing the reader (given the information in Table 2.2-1 and Section 

2.4.5 describing 11 working meetings), consider writing: “Nine of the 11 working meetings 

(see Section 2.4.5) were multi-day meetings of the TI Team to review data and develop the 

SSC assessments.” Similarly, the first sentence of the second paragraph can be clarified by 

writing, “One or more members of the PPRP participated as observers in six of the nine multiday working meetings and in eight of the 11 total working meetings.” 

Minor Editorial Comments and Typographical Errors

In the third subheading within Table 2-2.2 (“Technical Experts Contacted During 

Course of CEUS SSC Project”), would it be more descriptive to replace “Contacted” 

with “Who Contributed” or “Who Were Interviewed”?

In Section 2.4.1, replace “aeromagnetic” with “magnetic” 

In the final paragraph of Section 2.4.1, it would be helpful to give the website address.

In Section 2.4.8, first paragraph, the citation “(NRC, in review)” presumably will be 

updated, together with a corresponding entry in the list of references, to point the reader 

to an identifiable source of information. 

In addition to the editorial comments listed above, a markup of Chapter 2 provided separately 

to the Project Manager includes many other editorial suggestions for improving the text. 

6
PPRPNonMandatoryReviewComments,page31

CHAPTER 3 — EARTHQUAKE CATALOG 

General Comments 

(FR) G 3-1. Revisions made to Chapter 3 in the August 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. The revised chapter, with its 43 pages of text plus 87 pages of 

tables and figures, vastly improves the documentation in the 2010 draft version, which had 13 

pages of text plus 20 pages of tables and figures to describe essentially the same subject matter. 

We commend the authors for their painstaking efforts, not only in developing the milestone 

Project catalog but also in effectively documenting and completely describing the many steps 

involved.

Comments on Clarity and Completeness 

(FR) CC 3-1. (Units of Modified Mercalli Intensity): On pp. 3-6 and 3-7, differences in MMI 

are described in terms of “degrees.” Richter (1958, p. 136) refers to “levels of intensity,” which 

is a more common descriptor in connection with the MMI scale than “degrees of intensity.” 

Consider substituting “level” for “degree” in the three occurrences on pp. 3-6 and 3-7. 

(FR) CC 3-2. (Reduced standard errors): On p. 3-28, the text states: “The value of M|mb = 

0.24 reflects the value of 0.29 obtained from the regression reduced by the average value of 

[M|M hat] = 0.16 for the earthquakes used in the regression (Equation 3.3.1-8).” Is the 

referenced equation indeed the correct one? To reproduce this result, does the reader need to 

know a value for b? In subsequent sections where a reduced standard error is described 

(§3.3.2.5, §3.3.2.6, §3.3.2.7, and §3.3.2.8) no similar reference is made to Equation 3.3.1-8 to 

guide the reader. 

(FR) CC 3-3. (Seismic source zones): The caption, or legend, on Figure 3.2-7 should explain 

the bold lines outlining the seismic source zones. Also, because the seismic source zones and 

their geometries have neither been discussed nor presented prior to Chapter 3, the caption should 

contain a note to provide an advance reference informing the reader about them. 

(FR) CC 3-4. (Description of declustering results): In the first full paragraph on page 3-39 

describing Figure 3.4-3, the reader should be cautioned of pitfalls in interpreting the figure. For 

example, the data points from EQCLUSTER plotted in the right-hand part of the figure 

(described as “the maximum distance between earthquakes assigned to a cluster”) represent a 

nearest-neighbor distance and not the same distance “window” used by Gardner and Knopoff 

(1974), i.e., the maximum distance between the largest shock in a sequence (the main shock) and 

one of its dependent events. Also, while the “average” space-time dimensions of the EPRI 

(1988) procedure can be compared with the space-time windows of Gardner and Knopoff (1974), 

the latter represent optimized envelopes to their data, not average dimensions. 

The last sentence of the paragraph, referring to Figure 3.4-3, states: “The EPRI (1988) procedure 

does identify some clusters that have a much longer duration than the published time windows.” 

Examining the left-hand side of Figure 3.4-3, this is clearly an understatement—particularly for 

parent events smaller than about E[M] 3.5. [The latter suggests that the EPRI approach is 

identifying significantly more events in the catalog as dependent events, compared to the 

Gardner and Knopoff approach—but the effects of “thinning” as opposed to “removal” have to 

7
PPRPNonMandatoryReviewComments,page32

be kept in mind.] A point that passes without comment is the fact that in their 1974 study, 

Gardner and Knopoff identified approximately one-third of their catalog as independent events. 

In contrast, more than three-fourths of the earthquakes in the CEUS SSC catalog are identified as 

independent events (Table 3.4-1). Bottom line: If correct, Table 3.4-1 is what it is, and attention 

to those results is appropriately emphasized in the subsequent paragraph. 

(FR) CC 3-5. (McLaughlin et al., 1977, and USNSN): On p. 3-43, an analysis by 

McLaughlin et al. (1997) of the USNSN is described to address the probability of detection in 

the CEUS for 1995–2008. As a matter of up-to-date reporting, the USNSN is an obsolete term 

insofar as the network has been superseded by the ANSS national backbone network of nearly 

100 stations (see http://earthquake.usgs.gov/monitoring/anss/backbone.php). The ANSS 

backbone network, including many of the original USNSN stations, was upgraded and expanded 

in 2004–2006, and many other ANSS regional network stations have been added in the CEUS 

during the last decade. Consider something like the following at the end of the first paragraph on 

p. 3-43: “During 2004–2006, the USNSN was upgraded and expanded to become the current 

ANSS backbone national network of nearly 100 stations, and many ANSS regional network 

stations have been added in the CEUS during the last decade. For our purposes, the USNSN 

analysis still serves as a useful baseline.”

Minor Editorial Comments and Typographical Errors

Pagination of the tables and figures should be sequential with the text. 

On p. 3-5, in line 5 of the last paragraph: consider changing “The magnitudes clearly line 

up” to “Nearly all the magnitudes line up” 

On p. 3-8, in the first line of the second paragraph: unclear word string: “the specific 

magnitude time reported” 

On p. 3-8, in line 5 of Section 3.2.4: change “SEUSSN, Lamont” to “SUSN, LDO” 

On p. 3-9, line 1: change “published in literature” to “published in the literature” 

On p. 3-9, in line 6 of Section 3.2.5: change “Dr. Chuck Mueller” to “Dr. Charles 

Mueller” for consistency elsewhere (e.g., p. 3-3); in this same paragraph, change “Dr.-

Talwani” to “Dr. Talwani; also in this same paragraph, in the next-to-last line: change 

“the event is considered” to “the classification is considered” 

Search the chapter globally and change (where appropriate) M to M; also, N* to N*

(multiple corrections are needed on p. 3-17). 

In the table on p. 3-12, column 1 has incorrect symbols: e.g., change 

“Number 4.0 M > 4.5” to “Number 4.0  M < 4.5” and so on (see also a similarly 

incorrect occurrence on p. 3-16). 

On p. 3-20, in the next-to-last line of the first paragraph of Section 3.3.2.2: change 

“observe value” to “observed value” 

On p. 3-22, in line 2 of the second paragraph of Section 3.3.2.3: change “in northeastern 

United States” to “in the northeastern United States” 

On p. 3-23, in line 2 of the second paragraph: delete “)” after 1997. 

8
PPRPNonMandatoryReviewComments,page33

On p. 3-40, in the fifth line from the bottom: change “imposes the ideas that” to 

“imposes the idea that” 

In Table 3.3-1, in column 2 for ML reported by GSC, should be mb = ML – 0.21 (not 21, 

typo). 

The figure captions on Figures 3.3-2 to 3.3-4 reference “Table B-X” in Appendix B; this 

should be Table B-2 (Moment Magnitudes). 

9
PPRPNonMandatoryReviewComments,page41

CHAPTER 4 — CONCEPTUAL SEISMIC SOURCE CHARACTERIZATION 

FRAMEWORK

General Comments 

(FR) G 4-1. Revisions made to Chapter 4 in the June 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. Comments on clarity and completeness for additional 

consideration are provided below. (See also PPRP Mandatory Comments Nos. 3 and 4.)

Comments on Clarity and Completeness 

(FR) CC 4-1. (Potentially problematic statement): In the second paragraph of Chapter 4 on 

p. 4-1 it is stated that “nearly all of the PSHAs developed for nuclear facilities in the CEUS 

have been conducted by members of the TI Team . . . .” This part of the sentence is not needed 

and is not the critical aspect of why the TI Team was qualified to perform this study (we 

recommend avoiding language that could be read as a bias).

(FR) CC 4-2. (Need for conceptual SSC framework): In Section 4.1, consider noting that 

the need for a conceptual SSC framework was something the PPRP encouraged the TI Team to 

develop in order to strengthen the overall basis of the SSC model. Many of the operative words 

in the three items were voiced early by the PPRP.

(FR) CC 4-3. (GPS studies and crustal strain in the CEUS): One of the more important 

scientific advances in seismic hazard studies since the mid-1980s has been the use of GPS to 

investigate current strain in the CEUS. The studies available to date have been set aside in the 

report because of the immaturity of the science and the studies—that is, in the modeling and 

also the measurements. Justification for neglecting these studies (e.g., in Section 4.1.2.2) is 

based on a few declarative statements without supporting evidence from knowledgeable experts 

in the discipline. Neglecting GPS studies would have much more credence if the report cited 

some appropriate literature or reports, e.g., the recent report prepared for the USGS on the use 

of GPS in determining the hazard in the NMSZ.

(FR) CC 4-4. (Paleoliquefaction data compilation): In Section 4.1.3, the text should 

briefly mention that after Workshop 2, the Project and the TI Team were encouraged to develop 

and complete the paleoliquefaction task to help support the final TI Team assessments. The 

paleoliquefaction data compilation represents a major accomplishment that needs to be 

emphasized more in the text.

(FR) CC 4-5. (Significant differences in hazard): On page 4-10 in the last sentence of the 

first paragraph, the text discusses the consideration of site-specific refinement of the CEUS 

SSC model “only if such refinement would lead to significant differences in hazard.” Consider 

referring the reader to the appropriate section(s) of Chapter 9 for insights on “significant 

differences” in hazard.

(FR) CC 4-6. (Four criteria for identifying seismic sources): In Section 4.1.3.3 four criteria 

are given that are used in the Project for identifying seismic sources. They are described as 

being used sequentially in the process, not simultaneously or without priority, and text on pages 

4-15 through 4-17 provide useful details on the importance and use of these criteria. However, 

10
PPRPNonMandatoryReviewComments,page42

it is never explicitly explained why the order of the criteria as listed on page 4-15 is used. Is 

there a criterion used to establish the sequential order? If so, please explain.

(FR) CC 4-7. (Details relating to Table 4.1.3-1): In Section 4.1.3.3, in the second 

paragraph on page 4-17, reference is made to Table 4.1.3-1 serving as a summary of criteria 

used in the identification of each of the seismic source zones. Please explain that the X in the 

matrix indicates that this criterion was applied, if indeed that is the case, and identify 

somewhere on the table the significance of the X. Also, note that this table does not include the 

probability of activity of tectonic features, which is one of the criteria used to identify seismic 

source zones. This needs to be clarified where the table is introduced in the text, and it would 

be helpful to include a statement to that effect in a footnote to the table; otherwise, this criterion 

(probability of activity) is lost to the identifiable criteria in the table. (See also Comment (FR)

CC 7-2).

(FR) CC 4-8. (Descriptions relating to draft vs. final model): Chapter 4 will need to be 

checked carefully for statements of technical detail that do not reflect the final model 

(described in Chapters of Installment 2, not yet available at the time of this review). For 

example, the third full paragraph on page 4-22, refers the reader to discussion in Section 5.3 

and describes approaches that do not appear to correspond to cases A, B, and E for the 

weighting of magnitude bins. 

Minor Editorial Comments and Typographical Errors

Some miscellaneous editorial comments and suggestions relating to Chapter 4 have been 

provided separately to the Project Manager.

11
PPRPNonMandatoryReviewComments,page51

CHAPTER 5 — SSC MODEL: OVERVIEW AND METHODOLOGY 

General Comments 

(FR) G 5-1. Revisions made to Chapter 5 in the August 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. (Besides the comments on clarity and completeness below, 

see also PPRP Mandatory Comment No. 5, “Evaluation of Cases A, B, and E.”) 

Specific Comments 

(FR) S 5-1. RLME Recurrence Rate Calculations 

In general, the description of the recurrence methodology is relatively brief compared to 

descriptions of methodology in other parts of the report. Given the supporting use of a single 

figure (incorrectly identified as a normalized probability density function), it’s likely that only 

knowledgeable practitioners will fully understand the details of the recurrence-rate methodology, 

particularly for the recurrence-interval approach. Treating paleoearthquake information correctly 

to calculate earthquake rates is a common requirement in PSHA. As presently described, it is 

unclear whether the recurrence-interval approach used for the Poisson case is the most 

appropriate statistical method or just one alternative (e.g., when paleoearthquake dates are 

available, it is common to observe others calculating  as the inverse of the mean inter-event 

time). 

In scrutinizing the RLME rate calculations in Chapter 6 and the HID, some key information is 

unavailable for review, notably the distribution of numerical ages for the oldest paleoearthquakes 

that propagate into the RLME Poisson recurrence-frequency distributions when the earthquakerecurrence-interval approach is used. Tabulation of these data would be useful for future readers. 

Comments on Clarity and Completeness 

(FR) CC 5-1. (AFEs for nuclear facilities): In the first paragraph of Section 5.2, the text 

states: “However, at annual frequencies of interest for nuclear facilities ( 10–4) . . .” Change 

the parenthetical statement to (10–3 to 10–7). (See PPRP Mandatory Comment No. 8, “AFEs for 

Nuclear Facilities.”)

(FR) CC 5-2. (Number of superdomains): In Section 5.2.1.1, in the last sentence of the 

second paragraph on page 5-11, the text states: “The result was 15 active (i.e., containing 

earthquakes) non-extended superdomains and 15 active extended superdomains.” These values 

are inconsistent with those on Figure 5.2.1-4; the numbers on the figure appear to be correct. 

(FR) CC 5-3. (Discrepancy between text and Figure 5.3.2-1): Text in the fourth paragraph on 

p. 5-36 is inconsistent with Table 5.3.2-1. (See PPRP Mandatory Comment No. 5, “Lack of 

table defining Cases A, B, and E.”)

(FR) CC 5-4. (Error in Table 5.2.1-6?): The Mmax values listed in Table 5.2.1-6 for 

MESE-N appear to be a five-point distribution for the Kijko results and not for the Composite 

Distribution used in the hazard calculations, as stated in the text in the second paragraph on 

p. 5-21. 

12
PPRPNonMandatoryReviewComments,page52

Minor Editorial Comments and Typographical Errors

Pagination of the tables and figures should be sequential with the text. 

Search the chapter globally and change M and MW to M. 

On p. 5-13, line 10: change “earthquaks” to “earthquakes” 

On p.5-13, in the next-to-last sentence of the second full paragraph: change “After 

evaluation the the results” to “After evaluating the results” 

On p. 5-15, in the first sentence of Section 5.2.1.1.5: change “criticiszed” to “criticized” 

On p. 5-16, in the next-to-last line of the first full paragraph: change “distributin” to 

“distribution” 

On p. 5-23 in introducing Equation 5.3.2-1, delete or change the ending words “with 

mean rate:” What follows the semi-colon is not a formulation for mean rate, it is a 

formulation for the number of earthquakes. 

On p. 5-24 in the paragraph beginning “In general”: The third sentence incorrectly states: 

“If the data are scarce, the likelihood function has a broad shape, indicating low 

uncertainty.” Substitute “high” or “large” uncertainty for “low uncertainty.” 

On p. 5-25, in the last line of the second paragraph: change “function for for” to 

“function for” 

On p. 5-26, first line: change “aren not” to “are not” 

On p. 5-26, in the last sentence of the second full paragraph: change “We note that 

expression” to “We note that the expression” 

Section 5.3.2.2.1: The zone acronym for Midcontinent-Craton defined in Table 4.2.4-1, 

and used in most of the figures in the report, is “MidC” as opposed to “Mid-C” or 

“MID-C” as written on p. 5-36. [Note: List of Abbreviations uses “Mid-C.”] 

On p. 5-32, in line 6 of Section 5.3.2.1.2: change “Equation 5.3.-18” to “Equation 

5.3.2-18” 

On p. 5-35, line 3: in “latin hypercube sampling” note that Latin Hypercube is 

capitalized on p. 5-44. 

On p. 5-36, in the first line of the next-to-last paragraph: change “Table 5.3.2-1 shows 

the five cases were” to “Table 5.3.2-1 shows the five case that were” 

On p. 5-38, in line 4 of Section 5.3.2.2.2: change “mostlikely” to “most likely” 

On p. 5-40, in the last sentence of paragraph 3: change “Nonetheless, the the” to 

“Nonetheless, the” 

On p. 5-40 in the first sentence of Section 5.3.2.3.2: consider changing “has experienced 

multiple M > 5.0 earthquakes” to “has experienced two M > 5 earthquakes” 

13
PPRPNonMandatoryReviewComments,page53

On p. 5-41, in line 4 of the third paragraph of Section 5.3.2.3.3: It appears that “0.1 

earthquake” should be “0.01 earthquake” 

On p. 5-43, in line 5 of the last paragraph: change “rate densitiy” to “rate density” 

On p.5-45, in line 3 of Section 5.3.2.6: change “but catalog of main shocks deviate from” 

to “but the catalog of main shocks deviates from” 

In Section 5.3.2.4, in the first paragraph on p. 5-43, the discussion cites Figures 5.2.3-1 

and 5.2.3-2; these appear to be incorrect figure numbers. 

The figure caption for Figure 5.3.3-1 references Equation 5.3.3-1; however, it appears 

that the results are from Equation 5.3.3-2 (the Likelihood function). 

On the second line of p. 5-46, change “1900–2001” to “1990–2001” 

On p. 5-54, in line 6 of the second paragraph of Section 5.4.4: change “conept” to 

“concept” 

On p. 5-55, in line 5 of the first paragraph: change “the criterion of D90 is correct 

interpretation” to “the criterion of D90 is the correct interpretation” 

On p. 5-55, in line 3 of the second paragraph: change “resplved” to “resolved” 

On p. 5-55, in the next-to-last line of the third paragraph: change “reprenting” to 

“represent” 

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PPRPNonMandatoryReviewComments,page61

CHAPTER 6 — SSC MODEL: MMAX ZONES BRANCH 

General Comments 

(FR) G 6-1. Revisions made to Chapter 6 in the June 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments—with one exception noted in a Specific Comment. The 

chapter is well written and complete. A few comments on clarity and completeness are 

provided below.

Specific Comments 

(FR) S 6-1. Remark on the TI Team’s PPRP Comment Resolution Table 

In the top comment on page 30 of the PPRP Comment Resolution Table, the TI Team response 

is “Revision made as suggested.” However, the title of Chapter 6 has not been changed, as 

suggested by the PPRP. The chapter title, which refers only to the Mmax zones branch, should 

recognize that the description of the RLME zones takes up ~74 of the total 79 pages of text. 

Only the final five pages of text deal with Mmax zones. 

Comments on Clarity and Completeness 

(FR) CC 6-1. (Variously described number of RLMEs): In Section 6.1, in the second 

paragraph on p. 6-1, the reader is informed: “Detailed maps of the RLME sources, along with 

their alternative geometries, are given in the individual subsections describing each of the nine

[emphasis added] RLME sources (Sections 6.1.1 through 6.1.9).” Earlier in Chapter 4 the 

Conceptual SSC Framework is outlined for the reader to include 12 RLME sources (plus 

various alternatives, Table 4.2.2.-1, p. 4-40).

For understandable reasons, the TI Team assesses and depicts various combinations of RLMEs, 

but there needs to be a clear roadmap somewhere in the report to guide the reader and avoid 

confusion about something so fundamental as the number of RLMEs in the model. (The 

reader’s first challenge is comparing the list of RLMEs in Table 4.2.2-1 to the map in Figure 

4.2.2-2—even allowing for alternative source geometries.) 

(FR) CC 6-2. (Presentation of logic trees): In Chapter 6, as well as elsewhere, figures 

showing complicated logic trees are shown with unduly small point size. In some cases, 

available white space may allow enlargement. Constraints are understood, but these nearly 

illegible figures detract from the quality of the report and will pose a challenge for many 

readers. 

Minor Editorial Comments and Typographical Errors

Some miscellaneous editorial comments and suggestions relating to Chapter 6 have been 

provided separately to the Project Manager.

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PPRPNonMandatoryReviewComments,page71

CHAPTER 7 — SSC MODEL: SEISMOTECTONIC ZONES BRANCH 

General Comments 

(FR) G 7-1. Revisions made to Chapter 7 in the June 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. The chapter is well written and overall an excellent 

presentation. Some comments to help improve clarity and completeness are provided below. 

(See also PPRP Mandatory Comment No. 5.)

Comments on Clarity and Completeness 

(FR) CC 7-1. (Basis for slip rates): In Section 7.3.7 (Extended Continental Crust—Atlantic 

Margin Zone), on p. 7-52 the basis for the slip rates cited in the last sentence of the top 

paragraph is not clear. Are these post-Cretaceous rates based on total displacement Cretaceous 

to Miocene (5.3 Ma)? Logically, given no measurable displacement in the past 5.3 Ma, the 

displacement rate for purposes of SSC model characterization is zero. 

(FR) CC 7-2. (Source zones and Pa): In the last sentence of the first paragraph of Section 

7.1 (p. 7-1), the statement is made that “A seismotectonic zone may also be defined if tectonic 

features are identified that have a significant probability of activity (Section 4.1.3.3).” It would 

be useful to the reader if these tectonic features were identified and the probability of activity 

assigned them were described. Could this be included in Table 4.1.3-1? Are any of the source 

zones as indicated in Table 4.1.3-1 based in part on the probability of activity of identified 

tectonic features in the zone—that is, they are judged to have a Pa > 0.5? 

(FR) CC 7-3. (Mid-C vs. MidC): In Section 7.2.12 (p. 7-71), the abbreviation “Mid-C” is 

used for the Midcontinent-Craton seismotectonic zone. This differs from “MidC” specified in 

Table 4.2.4-1 and used in most figures throughout the report. 

(FR) CC 7-4. (Conflicting comparison): In the third sentence of Section 7.3.1.1.7 on p. 7-

11, the title “Grenville-age dike swarms” conflicts with Cambrian age of 590 Ma of the Sutton 

Mountains.

(FR) CC 7-5. (Triggering threshold of paleoliquefaction): In the part of Section 7.3.12.1.4 

on p. 7-77 dealing with the “Nemaha Ridge–Humboldt Fault Seismic Zone,” reference is made 

in the second paragraph to the Olson et al., 2006 article indicating that available data suggest 

the triggering of paleoliquefaction features at magnitudes significantly lower than the threshold 

of M 6.5 used elsewhere in the project report for RLMEs. Should this be explained further? 

(FR) CC 7-6. (Potentially confusing figures): Figures 7.1-5, 7.1-6, and 7.1-8 superpose 

one variation (unspecified) of seismotectonic source zones upon geophysical base maps. The 

text on p. 7-2 conveys that the figures are examples of how the TI Team examined available 

geophysical data sets as part of the process of defining source zones. However, the captions for 

these figures may mislead some readers to interpret that the underlying geophysical maps 

(particularly the magnetic and gravity maps) define the boundaries of the source zones that are 

shown.

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PPRPNonMandatoryReviewComments,page72

(FR) CC 7-7. (Abbreviated figure captions): In the caption for Figure 7.5.2-1, important 

information in the second sentence is omitted in the captions for the following Figures 7.5.2-2 

and 7.5.2-3. Similarly, in the caption for Figure 7.5.2-4, important information in the second 

sentence is omitted in the captions for the following Figures 7.5.2-5 through 7.5.2-51. Figure 

captions should stand alone. Readers will miss important information unless they examine the 

first figure in each of these series. For the second series, one could write, “Error bars as in 

Figure 7.5.2-4.” 

Minor Editorial Comments and Typographical Errors

In the caption of Figure 7.1-5, “aeromagnetic” should be replaced with “total intensity 

magnetic anomaly.” In the text of this section all instances of “aeromagnetic” should be 

replaced with “magnetic.” 

Late, Early, and Middle used as adjectives to geologic time units (e.g., Paleozoic) 

should be capitalized. In the current draft the capitalization of these terms is 

inconsistent. 

In Section 7.1, the first sentence of the first paragraph on p. 7.1 should also include 

recurrence rate. 

“Appalachian Mountains” rather than “Appalachians” as in the second paragraph of 

Section 7.3.1.3. 

Should the title of Section 7.3.4 be “Paleozoic Extended Crust Zone” (as introduced in 

Table 4.2.4-1) rather than excluding the word “Crust”? 

Global search should be used to change Mw to M.

In addition to the editorial comments listed above, some miscellaneous editorial comments and 

suggestions relating to Chapter 7 have been provided separately to the Project Manager.

17
PPRPNonMandatoryReviewComments,page81

CHAPTER 8 — DEMONSTRATION HAZARD CALCULATIONS 

General Comments 

(FR) G 8-1. Revisions made to Chapter 8 in the August 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. The revised chapter greatly improves the documentation in the 

2010 draft version and provides helpful information for evaluating the CEUS SSC model. The 

reorganization of text and figures makes the chapter easy for the reader to navigate.

Specific Comments 

(FR) S 8-1. Observation Regarding Relative Hazard from the USGS and CEUS SSC Models 

There are several examples where hazard from the USGS model lies above the 85th-percentile 

fractile of hazard from the CEUS SSC model. For example, for the Chattanooga site, comparing 

Figures 8.2-2b and 8.2-2k for 1 Hz rock hazard shows that the USGS curve is much higher than 

the 85th-percentile fractile of the CEUS SSC model.

Comments on Clarity and Completeness 

(FR) CC 8-1. (Terse information): On p. 8-2, in the last sentence of the top paragraph, how 

were the standard deviations ranging from 0.07 to 0.25 calculated to include “the effect of 

uncertainties in VS versus depth and in soil parameters”? 

Minor Editorial Comments and Typographical Errors

In the captions for Figures 8.2-1c, 8.2-2c, 8.2-3c, etc., delete “Hz” in “PGA Hz rock 

hazard”

The authors can consider whether they wish to report the VS profiles (Figures 8.1-2 and 

8.1-3) in units of ft and fps or in m and m/sec; the latter are used in the text (Section 8.1) 

as the primary units for VS.

As written, the last paragraph of Section 8.2 on p. 8-3 seems to apply to “Figures ee, ff, 

and gg,” To better guide the reader, insert a header before this important paragraph such 

as “Sensitivity to in-cluster and out-of-cluster assumption:”

In the paragraph 4 of Section 8.2.2 on p. 8-5, change “but at approximately 0.6 g and 

0.3 g” to “but above approximately 0.6 g and 0.3 g” 

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PPRPNonMandatoryReviewComments,page91

CHAPTER 9 — USE OF THE CEUS SSC MODEL IN PSHA 

General Comments 

(FR) G 9-1. Revisions made to Chapter 9 in the August 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. The revised chapter adds helpful information for 

implementing the CEUS SSC model and for understanding sensitivities in the model.

(FR) G 9-2. The revised Section 9.4.3 markedly improves guidance on understanding the 

precision in seismic hazard estimates and how the results presented should be interpreted. After 

going through extensive detail on COVs, presented in about 91⁄2 pages of text and 34 figures, the 

reader arrives at Section 9.4.3 to learn that the critical information for the conclusions is 

contained in the minimum observed COVMH values. The reader should be prepared at the outset 

for this detail in order to pay attention as the relevant information unfolds. For example, a 

simple informative statement could be added at the end of Section 9.4.1.

Comments on Clarity and Completeness 

(FR) CC 9-1. (Precision and weights): In the second paragraph of Section 9.4.2.2, there is the 

statement: “It is notable that weights on alternatives are generally given to one-decimal-place 

precision, and that while these weights indicate quantitative preferences on alternatives, an 

independent evaluation by another investigator might assign somewhat different weights.” This 

sentence leaves unclear whether it is the precision with which weights are quantified or the 

different weights that different evaluators would assess, or both that are being evaluated. The 

distinction is conceptually important since the precision of the weights is a matter of how precise 

qualitative assessments typically are or can be quantified, while the difference in weights 

assessed by two TIs using the same data and SSHAC process is a matter of the limiting precision 

of the SSHAC Methodology itself.

(FR) CC 9-2. (Basis for following SSHAC guidelines): In the first paragraph of Section 9.1 

on p. 9-1, the text refers to a SSHAC Level 3 process and states that “all the required steps were 

taken to implement the letter and the spirit of the SSHA guidelines (Budnitz et al., 1997).” The 

next sentence then refers the reader to [Chapter] 2. Consistent with Chapter 2, consider 

expanding the sentence containing “all the required steps were taken” to refer not only to 

Budnitz et al. (1997) but also to the draft NUREG.

(FR) CC 9-3. (Sections 9.3.2 and 9.3.3): Sections 9.3.2 and 9.3.3 are missing—for reasons 

explained in the text (“to be written later”).

(FR) CC 9-4. (Section 9.4.2.2): The addition of Equation 9-5 and associated discussion on 

p. 1-13 is particularly helpful. On this same page, the cluster model is referred to. It seems like 

the authors should at least provide a reference (e.g., Toro and Silva) and possibly an equation.

(FR) CC 9-5. (Seismogenic crustal thickness and hazard calculations): The text and figures 

(e.g., Figure 9.3-18 through 20) address sensitivity to seismogenic crustal thickness. Revisiting 

Section 5.4.4, there does not appear to be discussion of how seismogenic crustal thickness is 

used in the calculation of hazard. How are ruptures distributed with depth? [Reviewer’s note: If 

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PPRPNonMandatoryReviewComments,page92

this is clearly stated somewhere else in the report, then this comment can be disregarded.

Otherwise, some discussion is appropriate.]

(FR) CC 9-6. (Description of figures vs. actual content): The amount of text and the number 

of figures devoted to COVs invites the interested reader to carefully examine the material 

presented. When reference is made to a figure, the reader will be confused if he/she observes 

something different than described. Two examples:

In the last paragraph of Section 9.4.2.1 appearing on p. 9-11, the conclusion is drawn 

from Figures 9.4-1 through 9.4-3—for area sources—that “typical COVMH will range 

from 0.15 at a mean annual frequency of 10–4 to perhaps 0.25 [emphasis added] at a 

mean annual frequency of 10–6, with a wide variation in that range.” This statement 

cannot be squared with the range of values observed on Figures 9.4-1 through 9.4-3 

unless “typical” is explained. On Figure 9.4-2, there are many COV values at 10–6 in 

the 0.3 to 0.45 range, and in Figure 9.4-3 (bottom), half the COV values at 10–6 are

> 0.25.

Text in the middle of p. 9-13 states: “From Figures 9.4-4 through 9.4-6, the COVMH for 

annual frequencies in the range of 10–4 to 10–6 is 0.25 to 0.4, with a minimum of 0.25.” 

Given the curves on Figure 9.4-4 and 9.4-6, why not “0.25 to 0.45”? 

Minor Editorial Comments and Typographical Errors

In Section 9.1, in line 6 of the first paragraph on p. 9-1, change “Section 2 describes” to 

“Chapter 2 describes” 

On p. 9-1, at the end of line 1 in the second paragraph: consider changing “to calculate 

seismic hazard at locations of nuclear facilities” to “calculate seismic hazard for nuclear 

facilities” 

The second sentence of Section 9.4 states: “Once a PSHA is completed, it is expected 

that new data, models, and methods will emerge within the technical community.” [This 

makes is sound like new information is expected to arise immediately, once the PSHA is 

completed.] Suggestion: “After a PSHA is completed, it is expected that new data, 

models, and methods will subsequently emerge within the technical community.” 

In Table 9.4-1, in column 3 relating to site response: Clarify whether EPRI (2005) refers 

to EPRI (2005a), EPRI (2005b), or both in the list of references. 

In Section 9.4.2.1, the last paragraph on p. 9-10 (continuing on p. 9-11) refers to Figures 

9.4-3a and 9.4-3b. However, Figure 9.4-3 contains no “a” and “b” parts; the figure 

caption refers only to “top” and “bottom.” Text needs to be revised to avoid confusion.

In Section 9.4.2.3, on p. 9-15 (third paragraph, line 2): change the parenthetical reference 

from “Figure 9.4-13” to “Figure 9.4-12.” In the following sentence, consider writing: 

“The reason is that the 1 Hz hazard curves (Figure 9.4-13) show . . .” 

In Section 9.4.2.3 the abbreviation GMPE [presumably, for ground-motion prediction 

equations] is used on pp. 9-16 and 9-17. The abbreviation is not included in the list of 

Abbreviations and Symbols, and a prior definition of the abbreviation couldn’t be found 

in either Chapter 9 or Chapter 8. 

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PPRPNonMandatoryReviewComments,page101

CHAPTER 10 — REFERENCES 

General Comments 

(FR) G 10-1. Content, Accuracy of List of References

The PPRP leaves the technical editing of the list of References, including systematic crosschecking with the main body of the text to the TI Team and its support staff. 

Comments on Clarity and Completeness 

(FR) CC 10-1. (Some missing references): The following citations encountered in the text of 

Installment 2 are not included in list of references in Chapter 10. No systematic attempt was 

made to identify missing references. 

p. ix: (NRC, 2011)

p. 3-37: (Reasenberg, 1985)

p. 5-25: Utsu (1965)

p. 5-29: (Fukuda and Johnson, 2008) 

ubiquitous in Chapter 5: EPRI-SOG (1986) 

p. 5-37, p. 5-44, and elsewhere: EPRI-SOG (1988); [a 1988 citation abbreviated (EPRI) 

appears in the list of references, but not (EPRI-SOG).] 

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PPRPReviewNonMandatoryComments,page111

CHAPTER 11 — GLOSSARY OF KEY TERMS 

General Comments 

(FR) G 11-1. Revisions made to Chapter 11 in the August 2011 installment of the Final 

Report suitably respond to the PPRP’s earlier review comments. The revised glossary is a great 

improvement over the 2010 draft version and will provide helpful information for many 

readers.

Comments for Clarity and Completeness 

(FR) CC 11-1. (Definitions still to be added): The following definitions still need to be 

added to the Glossary:

a-value (This term is used in many places in the final report; the companion term, 

b-value, is suitably described.)

Database, Data Set (There was agreement at the PPRP Closure Briefing on September 

7, 2011, that these terms would be added to the Glossary.) 

22
PPRPNonMandatoryReviewComments,pageA1

APPENDIX A — DESCRIPTION OF THE CEUS SSC PROJECT DATABASE 

General Comments 

(FR) G A-1. The PPRP stated in its review of the July 2010 draft of this appendix (see the TI 

Team’s PPRP Comment Resolution Table) that “The CEUS SSC Project has assembled and 

archived a comprehensive suite of data sets of the CEUS that are important to the 

characterization and assessment of the SSC model of the region by the TI Team and that 

significantly contribute to the community knowledge-base.” In our July 2010 review, 

numerous general and specific comments were made aimed at helping to improve Appendix A. 

Appendix A in the June 2011 installment of the Final Report is notably improved, both 

editorially and with regard to clarity and completeness. Nonetheless, further improvements in 

quality can still be made. To this end, we offer a few specific comments, and we also offer 

numerous editorial comments on the metadata summary sheets that accompany the figures of 

the CEUS-scale data layers.1

Specific Comments 

(FR) S A-1. Remarks on the TI Team’s PPRP Comment Resolution Table

The TI Team’s PPRP Comment Resolution Table pertaining to Appendix A generally provides 

a useful and positive summary of the revisions made to the report in response to the PPRP 

comments on the July 2010 draft report. However, there are the following exceptions:

a. In our original Comment S A-1 the suggestion was made to clarify for the reader the 

availability of and access to datasets and metadata on the Project website. This suggestion 

is not commented upon or adopted in the revision. The website address of the project and 

links to the metadata files should be presented in the introduction to this appendix. 

b. In our original Comment S A-4 the suggestion was made to have a technical editor review 

Appendix A. However, the response to this suggestion apparently did not extend in the 

revision to the metadata summary sheets. These sheets still need review by a technical 

editor. 

c. Our original Comment S A-10 noted that the citations in the tables were not in consistent 

format. This has not been addressed in the metadata summary sheets. Note the varied use 

of italics. 

d. In our original Comment S A-11 a suggestion was made to include a data file showing areas 

where reliable earthquake hypocenter depths are available. No response to this comment is 

given in the resolution table. Such a data file (or map) would be useful in validating the 

probabilities placed on the seismogenic crust thickness in Table 5.4-2 (July 2010 draft 



1 In order to help the Project Team in its technical editing of Appendix A, a fundamentally important appendix, we 

include the complete comments made by one diligent PPRP reviewer. Separately, additional editorial comments 

on Appendix A, made by this same reviewer, are being provided to the Project Manager. 

23
PPRPNonMandatoryReviewComments,pageA2

report). The seismogenic crustal thickness is identified in Section 7.1 of the June 2011 

version of the report as a criterion for defining seismotectonic zones. Thus, supporting 

information on this criterion is particularly important. 

e. In our original comment on Sheet A-20 the suggestion was made to check the legend of the 

figure. Here and in the case of other sheets, this has generally been done, but problems still 

remain. For example, the units used in the horizontal and vertical derivatives of the gravity 

anomalies are incorrect. The units have to be mGals/length unit, either km or m. The units 

of the similar magnetic anomaly maps should also be checked to be certain that the 

nT/length unit is correct. Other editorial suggestions for Appendix A are being provided 

separately to the Project Manager. 

(FR) S A-2. Lack of Suitable Information on Regional Heat Flow 

A regional heat flow dataset, which can provide important information on crustal properties and 

tectonic activity, is not included in the data compilation of the CEUS SSC, despite being 

identified as a potential database in the preliminary evaluation of data significant to recognizing 

and mapping seismic source zones in the CEUS. For example, the January 9, 2009, file of 

database status recognizes both the University of Michigan (Henry Pollack) and the Southern 

Methodist University (David Blackwell) maps of the heat flow of North America that include 

the CEUS region, but neither of these are included in the final datasets. What is included is the 

heat flow point data in the USGS Crustal Database (Sheet A-13, Figure A-15). Unfortunately, 

this database includes only six heat flow values in the entire CEUS. Thus, this database is of 

limited value, if any, to mapping seismic source zones. It can be assumed that the data points 

in this file are relatively recent updates to the US heat flow database.

It needs to be emphasized that even a heat flow map that shows minimal variation over a region 

has tectonic significance. Thus, even though heat flow over the CEUS is not highly variable, 

the dataset should be included in the project. A metadata file was prepared in the CEUS SSC 

project for the University of Michigan’s global 1993 heat flow dataset (File: 

NorthAmerica_HeatFlow_R0_20080617). However, the Southern Methodist University map is 

dated 2004 (it is an update of the GSA DNAG heat flow map, 1993) and thus should be used if 

possible because it is the most recent dataset. It is recommended that Figure A-15 be removed 

because of its limited utility. 

Comments on Clarity and Completeness2

(FR) CC A-1. (Consistent labeling desirable): The GIS Layer/File Name in column 2 of 

Table A-1 should be consistent with titles of the Metadata Summary Sheets. They are not for at 

least two of the Data Theme entries for Tectonic Features.

(FR) CC A-2. (Reference to Ravat et al., 2009): In Table A-1 for Data Theme entitled 

Magnetic on page A-11 and the associated Metadata Summary Sheets and Figures, the 

reference is to the Ravat et al.’s USGS Open-File Report dated 2009. That reference is only 

appropriate for the original total magnetic intensity anomaly data as shown on Figure A-40, 

page A-80, and the associated shaded relief maps. All subsequent derived magnetic anomaly 



2

 See footnote 1 for additional information. 

24
PPRPNonMandatoryReviewComments,pageA3

data sets and figures (e.g., differentially reduced to pole magnetic anomaly data shown on 

Figure A-42) should refer to personal communication from Ravat. The processed derived data 

as provided by Ravat is not included in the USGS Open-File Report. 

(FR) CC A-3. (Geon): The term Geon is used in the legend of a figure in Appendix A. 

Because, this is not a widely known term, we suggest that Geon be added to Glossary.

(FR) CC A-4. (Figure A-6): The addition of a Source number reference on the cross-sections 

shown in Figure A-6 would greatly help the user of the dataset.

(FR) CC A-5. (Figure A-13): Just what is shown on Figure A-13 is unclear. Is crustal 

thickness or basement thickness presented? The statement is made in the legend that the labels 

are basement thickness, but the title of the figure refers to crustal thickness. Which are the 

symbols for the sediment thickness? The label indicates that the sediment thickness is not 

given, but the symbol identification indicates that they are. The legend and title are confusing.

(FR) CC A-6. (Figure A-14): Referring to Figure A-14 (and Summary Sheet A-13), why 

does the title refer to both P- and S-wave velocity, but the legend indicates that only P-wave 

velocities are shown. One can presume that the velocities refer to average velocity of the crust. 

Is that correct? If so, modification of the title to indicate this would be appropriate.

(FR) CC A-7. (Figure A-49): On Figure A-49 there is no indication of the COCORP lines in 

south Texas. Should they be there as in a preliminary copy of this figure? 

(FR) CC A-8. (Figure A-16): Comparison between Figure A-16 (Sediment thickness derived 

from USGS Crustal Database), page A-52, and the figure of the same data presented by Walter 

Mooney on page 6 of his handout at Workshop #1 indicates significant discrepancies. Are 

these only caused by differences in contour interval? This should be checked to verify the 

information shown in Figure A -16 and the associated dataset. 

25
PPRPReviewNonMandatoryComments,pageB1

APPENDIX B — EARTHQUAKE CATALOG 

General Comments 

(FR) G B-1. Revisions made to Appendix B in the August 2011 installment of the Final 

Report suitably respond to the PPRP’s earlier review comments. Once again, the PPRP 

commends the TI Team on the monumental efforts that went into compiling the earthquake 

catalog.

Minor Editorial Comments and Typographical Errors

Section B.3, Page B-3, cites Equations 3.3-9 and 3.3-10; the correct citation is 

Equations 3.3.1-9 and 3.3.1-10. 

26
PPRPNonMandatoryReviewComments,pageC1

APPENDIX C — DATA EVALUATION TABLES 

General Comments 

(FR) G C-1. Revisions made to Appendix C in the June 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments, with one exception, noted below as a Specific Comment. 

A few items for improved clarity are offered for consideration by the Project Team. 

Specific Comments 

(FR) S C-1. Remark on the TI Team’s PPRP Comment Resolution Table

Our original Comment S C-1, reproduced on p. 50–51 in the PPRP Comment Resolution Table,

stated in its final sentence that “All seismic source zones including Mmax zones should have a 

Data Evaluation table.” The corresponding resolution column in the table states that “All 

seismic sources have an applicable Data Evaluation table.” Nonetheless, no evaluation tables 

could be found in Appendix C for the Mmax zones, and these tables are not identified in the 

listing of tables in the introductory text to Appendix C. 

Comments on Clarity and Completeness 

(FR) CC C-1. (Explanation of labeling of the Data Evaluation tables): It would be helpful to 

explain that the labeling of the Data Evaluation tables is keyed to a specific chapter and section 

where the corresponding source zone is described and discussed—e.g., Table C-7.3.3 is keyed 

to Section 7.3.3, Northern Appalachian Zone (NAP).

(FR) CC C-2. (Potential confusion about “No Table”): The entry in the index on page C-1 

indicating “[No Table C-7.3.11]” may confuse some readers. An explanation of the labeling 

scheme for the tables, suggested in Comment (FR) CC C-1 above, would help clarify the 

matter. 

(FR) CC C-3. (Reader-friendly guide to locating information): To help the reader locate a 

specific Data Evaluation table, it would be helpful if the index on page C-1 (and perhaps also 

the Table of Contents) included page numbers for finding the table for a specific source zone. 

27
PPRPNonMandatoryReviewComments,pageD1

APPENDIX D — DATA SUMMARY TABLES 

General Comments 

(FR) G D-1. Revisions made to Appendix D in the June 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. A few items for improved clarity are noted below for 

consideration by the Project Team. 

Comments on Clarity and Completeness 

(FR) CC D-1. (Explanation of labeling of the Data Summary tables): It would be helpful to 

explain that the labeling of the Data Summary tables is keyed to a specific chapter and section 

where the corresponding source zone is described and discussed—e.g., Table D-7.3.3 is keyed 

to Section 7.3.3, Northern Appalachian Zone (NAP).

(FR) CC D-2. (Potential confusion about “No Table”): The entries in the index on page D-1 

indicating “[No Table . . .]” may confuse some readers. An explanation of the labeling scheme 

for the tables, suggested in Comment (FR) CC D-1 above, would help clarify the matter. 

(FR) CC D-3. (Absence of Data Summary tables for the Mmax source zones): Why are there 

no Data Summary tables for the Mmax seismic source zones? Include or explain their 

omission in appropriate text in an introduction to Appendix D (see also Comment (FR) S C-1).

(FR) CC D-4. (Reader-friendly guide to locating information): To help the reader locate a 

specific Data Summary table, it would be helpful if the index on page D-1 (and perhaps also the 

Table of Contents) included page numbers for finding the table for a specific source zone.

(FR) CC D-5. (Intentional or accidental repetition?) Page D-34 repeats pages D-31, and

D-36 repeats D-33. 

(FR) CC D-6. (Mix-up in Tables D-7.3.1 and D-6.1.9): Pages D-119 to D-145, ostensibly 

Table D-7.3.1 and identified in the header as a Data Summary table for the St. Lawrence Rift, 

are a repeat of pages for the Wabash Valley RLME given in Table D-6.1.9. 

(FR) CC D-7. (Inconsistent labeling of magnitude): Both M and Mw appear in the table 

descriptions. For consistency with the rest of the report, M should be used (unless some 

magnitude scale other than moment magnitude is referred to). 

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PPRPNonMandatoryReviewComments,pageE1

APPENDIX E— CEUS PALEOLIQUEFACTION DATABASE, UNCERTAINTIES 

ASSOCIATED WITH PALEOLIQUEFACTION DATA, AND GUIDANCE FOR 

SEISMIC SOURCE CHARACTERIZATION 

General Comments 

(FR) G E-1. This appendix represents a thorough and well expressed compendium of 

methodology, data, and guidance related to paleoliquefaction studies in the CEUS. Revisions 

made to Appendix E in the June 2011 installment of the Final Report, as summarized in the TI 

Team’s PPRP Comment Resolution Table, fully address the PPRP’s earlier review comments.

The only need for further attention is the item noted below. 

Comments on Clarity and Completeness 

(FR) CC E-1. (Figure E-6): Incorrect figure? It appears that the figure provided as Figure E6 is Figure E-5 repeated. The two figures have different captions. 

Minor Editorial Comments and Typographical Errors 

Miscellaneous editorial comments and suggestions, provided separately to the Project Manager, 

include several comments on Appendix E. 

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PPRPNonMandatoryReviewComments,pageF1

APPENDIX F — WORKSHOP SUMMARIES 

General Comments 

(FR) G F-1. This appendix remains basically unchanged from the July 2010 draft. As the 

PPRP commented in its earlier review (see the TI Team’s PPRP Comment Resolution Table),

“The summaries of the workshop provided in Appendix F are well-written accounts of the 

presentations and subsequent discussions that transpired.” The only remaining issue is a clear 

instruction to the reader about the availability and location of companion materials for 

understanding the summaries (see Comment (FR) S F-1 below).

Specific Comments 

(FR) S F-1. Remark on the TI Team’s PPRP Comment Resolution Table 

 In our review comments on the July 2010 draft (see TI the TI Team’s PPRP Comment 

Resolution Table), the PPRP suggested that it would be helpful to add the agenda and list of 

participants for each workshop, and we noted our assumption that copies of visual presentations 

made at the workshops would become available in some conveniently accessible form. The TI 

Team’s Comment Resolution Table (response to Comment S F-1) states: “No change. The 

workshop agendas and lists of participants, as well as copies of all presentations, will be 

provided on the Project website.”

Because the extra information is important for understanding of context, as well as for 

completeness of documentation, there should be a clear instruction to the reader—perhaps as a 

footnote to the title of Appendix F—that for each workshop the agenda, list of participants, and 

copies of all presentations can be accessed on the Project website.

Minor Editorial Comments and Typographical Errors 

Because tables consistently appear at the end of all other parts of the report, the placement of 

Table 1 after the narrative for Workshop and #2 and before the narrative for Workshop #3 may 

confuse some readers. Perhaps a footnote to the Appendix title on p. C-1 could be added 

stating something like: “Note that references and any tables for each workshop appear at the 

end of that workshop’s summary.”

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PPRPNonMandatoryReviewComments,pageG1

APPENDIX G — BIOGRAPHIES OF PROJECT TEAM 

General Comments 

(FR) G G-1. The revised Appendix G suitably responds to the PPRP’s review comments on 

the July 2010 draft, as summarized in the TI Team’s PPRP Comment Resolution Table.

Appendix G remains a straightforward compilation of biographical sketches for members of the 

CEUS SSC Project. The addition of an introduction gives the reader a helpful overview and 

provides guidance for understanding the grouping and ordering of the individual biographies. 

Minor Editorial Comments and Typographical Errors 

In the biographical sketch for Tom J. Mulford, there is the following word string:

 “. . . has had extensive interface with utilities around the world, including the U.S. 

Nuclear Regulatory Commission (NRC) . . .” 

In the syntax, “including” refers to “utilities”; because the NRC is not a utility, this 

sentence needs to be reworded. 

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PPRPNonMandatoryReviewComments,pageH1

APPENDIX H — CEUS SSC MODEL HAZARD INPUT DOCUMENT (HID) 

General Comments 

(FR) G H-1. The revised HID usefully includes more cross-references to text and figures in 

the report to help guide the user, and it appears to be complete. Three members of the PPRP 

will eventually be using the HID at their respective agencies (USGS, NRC, and DFNSB), but it 

wasn’t feasible for them to implement the HID before completing this review. The adequacy of 

the HID remains to be verified by these and other users in the near future.

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PPRPNonMandatoryReviewComments,pageI1

APPENDIX I — PPRP AND USGS REVIEW COMMENTS1

General Comments 

(FR) G I-1. Revisions made to Appendix I in the June 2011 installment of the Final Report, 

as summarized in the TI Team’s PPRP Comment Resolution Table, suitably respond to the 

PPRP’s earlier review comments. Three matters needing further attention are described below. 

Specific Comments 

(FR) S I-1. Placement of PPRP Closure Letter in CEUS SSC Final Report

As discussed with the Project Team at the PPRP Briefing on June 22, 2011, the PPRP 

recommends that its Final Letter Report, to be delivered to the Project Manager in October 

2011, appear in the CEUS SSC Final Report immediately following the Executive Summary. 

We believe that executive readers will be eager to know how the PPRP views the project and 

its outcome, and that this information should be readily accessible—rather than in Appendix I.

(Note that the last sentence on p. 2-20, referring to the location of the PPRP’s closure letter in 

the report, would need to be revised.)

(FR) S I-2. PPRP Review Comments to be Included in Appendix I

As also discussed with the Project Team at the PPRP Briefing on June 22, 2011, it is our 

expectation that the following PPRP report be included in Appendix I: 

Letter dated October 4, 2010, to Mr. Salomone: Central and Eastern United 

States Seismic Source Characteristics for Nuclear Facilities: PPRP Review 

Comments on CEUS SSC Draft Report of July 31, 2010. 

The above letter, although lengthy, provides full context for our review comments and gives the 

reader a sense of the extent and incisiveness of the PPRP’s review. Insofar as the TI Team’s 

PPRP Comment Resolution Table is partly repetitious, the latter might appear only on the 

Project website. We assume that, after they are finalized in September 2011, the PPRP’s 

combined review comments on Installments 1 and 2 of the CEUS SSC Final Report will also be 

included in Appendix I.

(FR) S I-3. Inclusion of Two PPRP Informal Communications in Appendix I

Despite their designation, we request that two specific PPRP “Informal Communications” be 

included in Appendix I. The following two communications contain important perspectives at 

critical junctures of the project, and we believe that they warrant inclusion in the Project’s 

formal documentation: 

Memorandum dated October 13, 2010, to Mr. Salomone: Key Issues for TI Team to be 

Attentive to as They Revisit the CEUS SSC Model and Revise the Project Report. 

Memorandum dated February 23, 2011, to Mr. Salomone: PPRP Feedback on CEUS 

SSC Working Meeting #9.



1

 Some comments here regarding the content of Appendix I are superseded by later decisions made with 

the Project Team after the PPRP Closure Briefing on September 7–8, 2011. 

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PPRPNonMandatoryReviewComments,pageJ1

APPENDIX J — MAGNITUDE-RECURRENCE MAPS FOR ALL 

REALIZATIONS AND ALL SOURCE-ZONE CONFIGURATIONS 

General Comments 

(FR) G J-1. Revisions made to Appendix B in the August 2011 installment of the Final 

Report suitably respond to the PPRP’s earlier review comments. Reviewers cannot be 

certain that each map is the correct one corresponding to the caption, but the maps appear 

to be logical in terms of degree of smoothing, and so on.

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PPRPNonMandatoryReviewComments,pageK1

APPENDIX K — SCR DATABASES USED TO DEVELOP MMAX PRIOR 

DISTRIBUTIONS 

General Comments 

(FR) G K-1. The addition of explanatory text, figures, and cross-references to relevant 

sources of information all greatly improve this revised 2011 version of the Appendix K.

No further comments. 

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PPRPNonMandatoryReviewComments,pageL1

APPENDIX L — QUALITY ASSURANCE 

General Comments 

(FR) G L-1. Appendix L is a new appendix that was not contained in the 2010 version of 

the Draft Project Report. The PPRP offers one specific comment that deals with the 

transparency (or lack thereof) in merely citing the previous EPRI-SOG verification efforts 

as adequate verification for several key pieces of software. 

Specific Comments

(FR) S L-1. Adequate Verification of Software

On page L-4, a discussion of the use of Verified Computer Programs indicates that the two 

principal computer codes used in the development of the earthquake catalog are 

EQCLUST and EQPARAM. The text asserts that “both of these programs were part of the 

verification program of the EPRI-SOG” study. These programs and the associated 

results/documentation of the EPRI-SOG verification effort have not been publicly 

available. The CEUS SSC Project Team should strongly consider reproducing/placing the 

relevant portions of the EPRI-SOG verification documentation on the Project website. 

This would significantly improve the transparency and completeness of the CEUS SSC 

documentation.

36
PPRP Comment Response Table 

I-1 

Comment Summary of Revisions to Report 

CHAPTER 1—INTRODUCTION General Comments G 1-1. (NAR) This chapter is well structured and introduces the reviewer to all elements 

of this complex project report. The chapter usefully discusses the need for communitybased studies and comparisons with other approaches. Here and throughout this Draft 

Report, we recognize the great effort that has gone into the writing and documentation, and we commend the TI Team for its diligent efforts to distill and report a massive amount of detail. Mindful of the criteria we have been given to guide our critical review (see cover letter), we proceed to specific comments. 

Comment noted and appreciated. 

S 1-1. (SSHAC) Justification for Using the SSHAC Level 3 Assessment Process A key issue related to the selection of the SSHAC assessment level, specifically a Level 4 assessment versus Level 3, relates to the ability of the selected experts to act as impartial evaluators―the perceived higher level of assurance provided by Level 4 comes with significant additional costs, some of which are associated with making sure the use of experts or expert teams as impartial evaluators is being done properly. The Hanks (2009) 

Open File reports notes, appropriately, that most geosciences experts are quite inexpert in one or more of several matters important to higher level SSHAC assessments. But generally, they are not experienced evaluators of uncertainty, given competing 

hypotheses and interpretations that require evaluation using diverse sets of geological, geophysical, and seismological data. This particular point needs to be brought out more in the draft report, both here and in Chapter 2.Experience has shown, even for some projects that have claimed SSHAC Level 4 assessment, that the actual success of experts or expert teams as evaluators has been limited. At the present time for the CEUS it may be that the technical community is best able to implement a SSHAC Level 3 assessment (high confidence that a TI Team can be 

selected to act as impartial evaluator) versus a Level 4 assessment. While some could view this point as less important, it is a key point that those outside the project (other agencies, ACRS, others) must appreciate and understand. 

Based on cumulative experience using the SSHAC Methodology, particularly given the time constraints, we have confidence that this project can be successfully implemented using a SSHAC Level 3 assessment versus Level 4. 

Explanation added regarding why Level 4 projects cost more and take more time than Level 3 studies. We are unaware of any Level 4 projects that have not been successful with regard to the experts acting as evaluators. 

S 1-2. (CC, SSHAC) Clear Communication is Essential: Chapter 1 and Entire Report Keeping in mind that words are the stuff of thought and that clear communication of thought is essential, especially for regulatory guidance documents intended for long term use, usages of words and terms must clearly and accurately convey the concepts that are being described. It is also essential that the words and terms be used in their proper meaning consistently throughout the report.The practice of using nuanced words as synonyms contributes to a lack of essentialclarity. For example, throughout Chapter 1 the word “study” is used interchangeably in multiple meanings. In most instances “study” is used to mean either “project” or “assessment”; it is used in its proper meaning in only a few instances, for example in subsection 1.4.4.4. Serious miscommunication will result from incorrectly using the word “study” to convey the activities that constitute a SSHAC assessment process—or that constitute a “SSHAC Study Level 3 Approach” or a “SSHAC Study Level 3 Methodology,” 

Changes made to clarify the use of “study,” “project,” and “assessment.” We agree with the term “SSHAC assessment process” and text has been revised accordingly. However, the term “Study Level” is given in the SSHAC Guidelines and cannot be easily changed by this report without confusion. For clarity, SSHAC Study Levels are always indicated with capital letters. Use of “event” has been clarified or revised.

11
PPRP Comment Response Table 

I-2 

Comment Summary of Revisions to Report 

which are alternatively used when referring to the SSHAC assessment process. The word “study” does not properly communicate the complex activities and processes that constitute the SSHAC Methodology or SSHAC assessment process. These activities together constitute a structured assessment process that involves compilation of the state of scientific and technical knowledge, compilation of datasets, evaluations of state of practice, and finally, assessments that represent the integrated knowledge of the scientific community and the community’s knowledge uncertainty as represented in the logic tree of the SSC model.It should be kept in mind that the SSHAC assessment process is accepted by the Nuclear Regulatory Commission (NRC) as the current state of practice for a technical process whereby seismic hazard models are assessed. Thus, it has the same standing as a consensus standard (ASCE Standard 43-05, for example). It is incorporated into the Agency’s accepted seismic regulatory procedures (Regulatory Guide 1.208) for demonstrating compliance with the seismic regulation 10 CFR Part 100.23; it also is accepted by the Department of Energy (DOE) as part of the Agency’s seismic safety policies and regulatory procedures.We emphasize that it is essential to clearly establish in Chapter 1 that the SSHAC Methodology is an assessment procedure that is accepted by the NRC and the DOE for developing seismic hazard models that are, in turn, accepted as providing reasonable assurance, consistent with these Agency’s seismic safety decision-making practice, of 

compliance with their seismic safety regulations and policies. Reasonable assurance is expressed in the outcome of using the SSHAC Methodology as the representation of the center, body and range of scientific community knowledge. In order to clearly convey the fact that the assessment of the CEUS SSC model has been accomplished through implementation of an accepted structured assessment process, we believe that the terminology “SSHAC Level 3 assessment process” should be adopted and used 

consistently throughout the CEUS SSC Report, notwithstanding use of alternative terminology in other documents. This would require extensive technical editing.Similarly, a careful edit should be performed, replacing the words “study/studies,” which do not properly apply when describing the activities performed in the CEUS SSC Project, with “project” or “assessment,” as appropriate. As examples, “LLNL study” and “EPRISOG study” are properly “LLNL Project” and EPRI-SOG Project.” Although the term “SSHAC Study Level” has been used in past documents, we recommend use of the term “SSHAC assessment process” in order to clearly convey the complex activities performed in the CEUSSSC Project.The word “event” is used confusingly to mean “earthquake” throughout this chapter and the report. While it can be argued that the usage is understood in context, regulatory documents, which are intended to be used for an extended time by many people having differing backgrounds, require clarity. Consider making a blanket change of the word “event” to“earthquake” where appropriate. Comments by Section Section 1.1 1st paragraph: Consider replacing the 2nd sentence with:“As such, the CEUS SSC model replaces regional seismic source models for this region that are currently accepted by the Nuclear Regulatory Commission (NRC) for satisfying the requirements of the seismic regulation, 10 CFR Part 100.23, for assessing uncertainty 

Revisions made to text as suggested. 
PPRP Comment Response Table 

I-3 

Comment Summary of Revisions to Report 

in seismic design bases. These include the Electric Power Research Institute–Seismicity Owners Group (EPRI-SOG) model (EPRI, 1988) and the Lawrence Livermore National 

Laboratory (LLNL) model (Bernreuter et al., 1989).” 

This change would require some additional editing of the paragraph.Note that the proper reference to the EPRI-SOG Project is EPRI (1988). The date should 

be corrected in the References. Note also, that EPRI (1989) contains hazard 

computations at the SOG utility’s NPP sites. This report was not submitted to NRC for review. (See also Comments by Section for Chapter 3, under References.) 2nd paragraph: Consider replacing the 2nd sentence with:“The project used a SSHAC Level 3 assessment process in order to assure compliance with the requirements of seismic regulations that uncertainties in the model have been properly quantified, evaluating the range of views and interpretations of the technical community.”And add to the end of the paragraph: “These models are expected to be adopted as part of the seismic safety regulatory guidance, replacing the EPRI (2004, 2006) models.” Section 1.1.1 “Studies” should be replaced with “Projects” here and throughout the report when referring to the EPRI-SOG and LLNL projects. 

Revisions made as suggested. 

Section 1.1.2 “Studies” should be replaced with “Expert Elicitation Projects.” In the 1st paragraph, consider replacing sentences 4 through 6 with:“These included the EPRI-SOG and LLNL projects.1 Although both of these large projects relied on assessments by multiple experts, there were significant technical and procedural differences between the two, and there were large differences in the hazard results obtained at many common sites compared by the two projects. The formation of SSHAC was motivated by the need to understand these differences and to develop guidance acceptable for meeting the requirements for seismic safety regulation of nuclear facilities for assessing uncertainty in seismic hazard models”. This change would require editing of the subsection as needed to be consistent.Typo: In the first sentence of paragraph 2, change “time if their issuance” to “time of their issuance” 

Revisions made as suggested. 

Section 1.1.3 

Suggested wording change in the first sentence: “just as important as the basis of the 

technical assessments.” In the subsection heading: “SSHAC Methodology” or “SSHAC 

Guidance.” 

At the top of p 1-3, the sentence, “As will be discussed in Section 2.2, the roles and 

responsibilities that a SSHAC process defines for all project participants must be scrupulously adhered to throughout the process to ensure its success” is overstated. Section 2.2 makes no mention that “scrupulous adherence” is a condition for success. Suggestion:“The roles and responsibilities of participants in the CEUS SSC project were explicitlydefined, consistent with SSHAC guidelines for a successful Level 3 assessment project (see Section 2.2), and were diligently followed.” 

Revisions made as suggested. 
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Section 1.1.4 “Study” should be replaced with “Project” or “CEUS SSC Model”; edit the subsection as needed for consistency.Suggested word change in paragraph 2, line 2: “The CEUS SSC model is based on acomprehensive, transparent, and traceable process, . . .” In the last sentence of paragraph 1, given the purpose of the CEUS SSC project (as described in the following paragraph), it seems strange to mention the DNFSB explicitly but not the NRC in this first general statement. Suggestion: “Standardization at a regional level will provide a consistent basis for computingseismic hazard, which will assist regulators such as the NRC [acronym defined earlierin section 1.1] and the Defense Nuclear Facilities Safety Board (DNFSB) in their oversight of nuclear facilities.” 

Revisions made as suggested. 

Section 1.1.5 In the last line of paragraph 1 on p. 1-3, change “participated or observed the CEUS SSC 

Project” to “participated in or observed the CEUS SSC Project.”

Differences from USGS National Seismic Hazard Mapping Project: In the 1st paragraph on p. 1-4, the quoted AFEs should be verified. The national seismic hazard maps and USGS PSHA work is for AFEs in the range of 10-2 to 10-4 (building code maps are developed for an AFE of 4.04 x 10-4), and the CEUS SSC results will provide results for 

AFEs in the range of 10-3 to 10-6 for design purposes. 

In the same paragraph, lines 6 and 7, suggested wording change: “critical safety requirements of these facilities” rather than “the robustness of these facilities.” [Delete comma preceding period at the end of this sentence.]In the same paragraph, line 11, suggested wording change: “hypotheses and parameter values are included where appropriate”In the same paragraph, line 12, consider changing “witnessed in the paleoseismic record” to “observed in the paleoseismic record” 

Revisions made as suggested. 

Section 1.2.1 Consider replacing the section heading with “Regional Seismic Source Model that Represents Current Knowledge and Data Uncertainties of the Technical Community” (see Comment S 1-1). In paragraph 2, line 1, consider changing “proper” to “appropriate.” The last sentence of this section discusses the possibility that local sources can be used to refine the CEUS SSC model for site-specific application. We suggest that this sentence be deleted. Any 

change to the CEUS SSC model will need to be evaluated in terms of the PSHA distance influence for that change. Thus, what constitutes a local SSC model change versus a regional SSC model change is somewhat vague. The SSC report should recognize that site-specific studies are required but be silent on what happens if these studies indicate 

an SSC model change. NRC and others will have to decide what to do with any recommended SSC change (the distance extent to which that change must apply) and whether updates to calculations for “regions” are necessary. 

Consideration given to suggested revisions; revisions made to text to reflect the intent of the suggestions. 

Section 1.2.2 The section heading should be changed to “Conducted Using the SSHAC Level 3 Assessment Process,” and edit the section to be consistent with the change (see 

Revisions made to text as suggested, except that terminology of SSHAC Study Levels is kept for clarity.
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Comment S 1-1). In paragraph 1, consider replacing the 3rd sentence with: “For regional seismic hazard models intended for use at many sites, the higher assessment levels provide the level of assurance required by the regulators for future use in seismic safety decision-making.”

In paragraph 2, line 9, suggested wording change: “the success of these assessment

levels is the implemented process followed, which . . .” Third paragraph: Time and costs are issues that the regulatory agencies are committed to take into account, but reasonable assurance of safety as required by the seismic safety regulations and regulatory safety practice are primary. This section should be edited to 

reflect this understanding. Consider replacing the first sentence of this paragraph with: “Selection of a SSHAC assessment level depends on the scope and complexity of the required evaluations and the intended use of the assessed seismic hazard model.” 

At the end of the paragraph consider adding the sentence: “Moreover, after severalyears experience using the SSHAC Methodology, a Level 3 assessment is now accepted for developing regionally-applicable seismic hazard models intended for use over an extended time as the starting basis for computing PSHAs at multiple sites.” Section 1.2.3 In paragraph 1, line 3, suggested wording change: “a SSHAC process should not be subject to significant change without new hazard-critical scientific findings.” Suggested wording change in paragraph 2, line 2: “Although these findings may lead to” Suggested wording change in paragraph 2, line 3: “. . . it is likely that the assessment will remain viable, avoiding the need for an extensive revision.”In paragraph 2, third sentence: The text states, “Longevity means that the model will last for several years before requiring a significant revision or update.” The last sentence in the paragraph states, “It is expected that the longevity for studies such as the CEUS SSC Project will be at least 10 years before there will be the need for a significant revision.” To avoid confusion, the wording defining longevity should be sharpened. 

Revisions made as suggested. 

Section 1.2.4 The section heading should be changed to “Interface with Ground Motion Models”Use of the words “debate” and “interaction” in the 2nd paragraph, do not properly convey 

the role of the workshops for implementing the assessment process. Consider

replacing the last two sentences of the paragraph with:“The TI Team brought together a panel of ground motion experts constituted of proponents of the range of available models in a series of three workshops, structured to gain a common understanding of the uncertainties in the modeling approaches and to structure the evaluation and assessment process for representing the uncertainty distribution of the technical community.” The subsection should make clear that the Expert Panel represented the range of community ground motion modeling knowledge for the CEUS.Suggested wording change in paragraph 2, line 8: “The TI Team interacted with theExpert Panel to . . .” 

Revisions made to text as suggested. 

Section 1.3 As discussed in Comment S 1-1, the word “study” does not convey the activities and 

The term “study region” is commonly used for seismic hazard analyses, while “model region” is not clear and not common. We will continue to use the term 
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processes that constitute the SSHAC Methodology. The section heading should be changed to “CEUS SSC Model Region.”Regarding the 4th sentence of paragraph 1: Are there any contributing sources that are in oceanic crust?In this same paragraph, the text incorrectly (or at least misleadingly) states that “On the north and southwest, the study region extends a minimum of 322 km (200 mi.) from the U.S. borders with Canada and Mexico.” Examination of Figure 1.3.1 shows that the SSC model region extends 200 mi. into Mexico only along the Gulf Coast. It does not generally extend 200 miles into Mexico “on the southwest.” 

study region when talking about the region depicted on the figure. Change made to sentence regarding boundary.

Section 1.4 “Study” should be changed to “Project” in the section heading (see Comment S 1-1). 

Revision made as suggested. 

Section 1.4.1 In the section heading, use of the word “Complete” is not clear, and the word “Study” is misleading. Section heading should be changed to “Seismic Source Model Region.” Need to introduce the three stages of the SSC Model assessment: In section 1.4.1, the reader should be informed that the SSC Model was developed in three stages—the sensitivity SSC Model, the preliminary SSC Model, and the final SSC Model. This can be done effectively at the end of this section—prior to Chapter 2 where the terms appear for 

the first time on p. 2-19 unexplained. 

In paragraph 1 (see line 10), the text states, “sources of repeated large-magnitude earthquakes (M ≥ 6.5) earthquakes (RLMEs) are identified . . .” The rationale for selecting 

the threshold of M 6.5 for RLMEs should be explained. 

In this same paragraph, next-to-last line, change “and the forecast future occurrences” to 

“and the forecast of future occurrences” 

Kijko Methodology as “State-of-the-Art”: On p. 1-9 in the first paragraph, the text describes “two methods for assessing Mmax: a Bayesian methodology . . . and the Kijko methodology that is state-of-the-art within the technical community.” The latter assertion 

raises questions about the Kijko methodology vis-à-vis the project. If state-of-the-art, then 

why was the methodology only considered at a late stage of the project (see p. 2-44) and 

why was it not identified at the USGS Mmax workshop as state-of-the-art? Suggestion for 

a broad-brush statement needed here: “. . . and a well-founded mathematical procedure 

that estimates Mmax based on seismic data (where sufficient) only for the source being considered.” 

“Complete” deleted; term Study Region is specific to the mapped area (see comment response to Section 1.3)Discussion of the three stages added to Section 1.4.4.Explanation added by M6.5 used for RLME.Revisions regarding the Kijko method made as suggested.

Section 1.4.2 In the 3rd line, consider changing “third party” to “future user” In this same paragraph, lines 10–11, consider changing “for a project” to “for seismic hazard analysis at a specific site.” 

Revisions made to text as suggested. 

Section 1.4.4.2 In the 4th sentence, suggested word change: “Where applicable, GIS data layers were 

developed, and this included new geophysical data compilations developed specifically for the project.” 

Revisions made to text as suggested. 

Section 1.4.4.3 In line 4, change “all events up through 2009” to “all earthquakes through 2008.” The 

Revisions made to text as suggested. 
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project catalog (Chapter 3) extends through the end of 2008. In line 7, suggested word change: “a number of historical earthquakes were reviewed in order to develop reliable moment magnitudes for these shocks.” Section 1.4.4.4 In the title of this section elsewhere in the report, paleoseismicity data tends to be used 

loosely as synonymous with paleoliquefaction data. Paleoliquefaction data are a subset of 

paleoseismicity data, which notably include results of geological trenching of active faults, such as for the Meers and Cheraw faults. The report includes varied types of paleoseismic data, and correct terminology is important for clarity.

Consider replacing the first sentence of this section with: “Because of the emerging use and significance of paleoliquefaction data in the CEUS, part of the scope of the project was a compilation of these data and development of written guidance for representing uncertainty in evaluations and interpretations of the data to estimate the locations, occurrence times, and magnitudes of causative earthquakes.” 

Revisions made to text as suggested. 

Section 1.4.4.5 The first sentence of the second paragraph is awkwardly worded. Suggestion: “This report contains an evaluation . . .” 

Revisions made to text as suggested. 

CHAPTER 2—SSHAC LEVEL 3 PROCESS AND IMPLEMENTATION General Comments G 2-1. (CBR, CC) This chapter contains generally informative and valuable background 

information, but it does not adequately achieve the goal of explaining the chapter heading for a number of reasons: (1) the chapter is not organized effectively, with too much discussion of history that, in its present form, distracts from a necessary focus on this project1; (2) there is not enough discussion of what the TI Team did to ensure that they were objective evaluators to “represent the center, body, and range of the technical interpretations that the larger informed technical community (ITC) would have if they were to conduct the study”; and (3) the discussion of the workshops needs to be enhanced to describe what the TI Team did to ensure that (a) the workshops focused on the right issues (completeness), (b) the workshop goals were met, and (c) the experts who attended the workshops were appropriate and sufficient for the purpose of defining the 

community knowledge and associated uncertainties. 

History discussion removed. Additional discussion provided of the activities associated with the evaluation process, including the need for all TI Team members to assume the role of expert evaluators, and the potential for removal of Team members who were not able or willing to assume the evaluator roleAdditional discussion provided regarding workshops and approaches to ensuring their success, including providing the proponent experts with a list of 

questions prior to the workshop to ensure that the proponents focused on the hazard-significant issues. 

G 2-2. (CC) The discussion regarding a “SHAC Level 3 process” and the concept of the “informed technical community” (ITC) is of great importance for substantiating key claims about the implementation and results of the CEUS SSC project. But, it is marred by imprecise wording that may contribute to confusion or invite argument. Our Comment S 1-2 (clear communication) applies equally to Chapter 2, and we offer additional specific comments to help strengthen the logic underpinning key claims in this chapter. 

Extensive revisions to the discussion of the ITC made throughout to make it consistent with NRC (2011), which will be issued shortly. 

Specific Comments S 2-1. (CC, SSHAC) Explaining the Goals of the Chapter Writing always involves individual choice, and there are different ways to explain the goals of the Chapter at the outset. In the following example text2 an attempt is made to give the reader a road map—intentionally with a regulatory framework in mind: 

Most of the suggested passage was included in the revised text. Use of the term “community distribution” is maintained in this discussion because it is 

specifically defined in the SSHAC guidelines. 
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The goals of this chapter are, first, to describe the SSHAC Level 3 assessment process and how it was implemented to assess the CEUS seismic source characterization (SSC) model and, second, to demonstrate that the implementation was accomplished in compliance with the SSHAC guidance. The SSHAC developed guidance for four levels of implementing an assessment, depending on the degree of uncertainty and contention 

involved and the intended use of the seismic hazard model.3

The SSHC guidance emphasizes that, independent of the implementation level, the goal of a SSHAC assessment is “to represent the center, the body, and the range of thetechnical interpretations that the larger informed technical community would have if they were to conduct the study” (SSHAC, 1997, p. 21). The “center, the body, and the range” is taken to mean a representation of the uncertainty in the technical community’s knowledge, referred to by the SSHAC as “the community distribution.” The latter, as a representation of the uncertainty in the technical community’s knowledge, can be termed “the community uncertainty distribution.” A proper representation of the community uncertainty distribution appropriately meets the requirements of the NRC’s seismic regulation, 10 CFR 100.23The SSHAC recommended that a Level 3 or a Level 4 assessment process be used for complex assessments, the products of which have high public importance and attract public scrutiny, such as regional seismic hazard models intended to be used over a sustained time period as base-case models for site-specific PSHAs. Such models require 

the highest level of assurance that the community uncertainty distribution has been 

properly represented. For this project, the decision was made to use a SSHAC Level 3 assessment process.4 The CEUS SSC Project arrived at this decision based on experience gained with implementations of the SSHAC guidance, which has shown that a properly executed Level 3 assessment process can provide a level of assurance of meeting the SSHAC goals comparable to that of Level 4, which is much more costly to implement.This chapter begins with a discussion of the fundamental SSHAC goal of representing the center, body, and range of the technical community’s knowledge, including why this goal was developed. This is followed by a discussion of how the SSHAC Level 3 assessment process has been implemented by the CEUS SSC Project, including the roles of keyparticipants, project organization, key activities, and participation of the Participatory Peer Review Panel (PPRP). S 2-2. (CC, SSHAC) “Capture” and the Informed Technical Community

We caution the TI Team that repeated use of the word “capture”—a highly nuanced term 

as it relates to the center, body, and range (CBR) of the technical interpretations of the ITC—may confound clear thinking. 

In its 1997 report, the SSHAC most often uses the words “represent” or “a representation of” for actions relating to “the center, the body, and the range of technical interpretations that the larger informed technical community would have if they were to conduct the study” (SSHAC, p. 21).5 In Chapter 2, the dominant action word used for the CBR is “capture,” emphasized, for example, by the headings for sections 2.1.2 and 2.1.2.2. Coppersmith et al. (2010)6 use “capture” (at least 17 times) in the context not only of the CBR but variously in terms of capturing uncertainty, capturing insights, capturing the community distribution, capturing rate of occurrence and randomness, and so on. The problem with capturing the CBR of technical interpretations of the ITC, as opposed to 

Capture replaced by represent, although both terms are used interchangeably in the SSHAC report. One downside to the use of “represent” is the mistaken notion that the TI Team merely attempts to reflect or mirror the views of the community (i.e., a poll), in the same way that a politician represents his constituency. The “informed” aspect of the definition of the ITC is important, was defined specifically in SSHAC, and is emphasized in the text. All of the discussion of these issues has been made consistent with NRC (2011), which 

will be issued in the near future.
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representing them, is that it invites critical scrutiny of what may have been left out, not fully preparing the reader for the need to understand important concepts dispersed elsewhere in the report—notably, identification and due consideration of alternative views, 

allowance not to include views judged to have an insignificant effect on the hazard, and the integration function performed by the TI Team in its role of assessing and 

representing the CBR of the ITC. S 2-3. (CC) Claim that CEUS SSC Robustly Implemented SSHAC Guidance On p. 2-1, par. 2, the text states: “These sources, as well as projects conducted prior to the development of SSHAC guidance, offer confirmation that the CEUS SSC process was a robust implementation of both the “spirit” and the “letter” of the law, namely SSHAC.”It is illogical to say that prior sources “confirm” a later “robust implementation.” And it is misleading to refer to SSHAC guidelines as “the law.” The astute reader will compare the claim made in this introductory part of Chapter 2, with the conclusion eventually reached in section 2.1.2.3 (p. 2-23), where one finds wording such as “addressed adequately,” “preponderance of evidence,” and “reasonable assurance.”Suggestion:“These sources, as well as projects conducted prior to the development of SSHAC guidance, provide a basis for concluding that the CEUS SSC assessment process followed in a robust way both the “spirit” and the “letter” of SSHAC guidance. Theend result is reasonable assurance that the CEUS SSC final model achieves the primary goal intended by the SSHAC guidelines.” 

Revisions made to merely state that the SSHAC assessment process, as given in the SSHAC guidelines, was followed.

S 2-5. (CC) Historical Context and Evolution of Use of Expert Assessment (Section 2.1.1) The length of this subsection detracts from this chapter. While this section is informative, Sections 2.1.1 through 2.1.2.2 and Table 2-1 could be moved to an appendix, with a short 

summary provided here. Also, the text (specifically in Section 2.1.2) and Table 2-1 would 

be improved if the authors provided their thoughts on how well the experts or expert 

teams did as evaluators for those projects that were completed at a SSHAC Study Level 

4. It is our impression that results are mixed in this regard. If the authors agree, this should be discussed and noted.

In order to completely chronicle the origins of the NRC’s probabilistic seismic hazards program, it should be stated that during the mid to late 1970s, the Advisory Committee on Reactor Safeguards (ACRS) persistently urged the NRC to undertake research aimed at quantifying the uncertainty embodied in SSEs derived following the requirements of the seismic regulation 10 CFR Part 100, Appendix A, which had been adopted in 1973. The ACRS also urged the NRC to undertake a parallel program with the aim of quantifying the margin embodied in the NRC’s seismic design criteria and procedures. In response, the NRC developed and funded a seismic margins research program and, a short time later, a seismic hazard research program, both conducted by the Lawrence Livermore National Laboratory (LLNL). The seismic hazard research program adopted from the decision analysis community the structure and formalism of classic expert elicitation processes. 

The entire section has been removed. A comparable section appears in the NUREG on SSHAC implementation (NRC, 2011), which is a more appropriate 

venue.

S 2-6. (CC, SSHAC) “Capturing” the Center, Body, and Range (Section 2.1.2)Consider changing “Capturing” to “Representing” in the section title.As a lead-in to Section 2.1.2, consider this example text (see also Comment S 2-4): 

Much of the suggested wording has been added in the text. 
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Reasonable assurance is the standard for reaching administrative decisions about public safety across the spectrum of hazards to which the public is exposed. Regulations, regulatory guidance, regulatory review, and administrative hearings all invoke the standard of reasonable assurance. Regulations state the safety requirements, regulatory guides provide guidance for technical methods and procedures that are accepted for demonstrating compliance with applicable regulations, regulatory review providesreasonable assurance that regulatory guidance has been properly implemented, and an administrative hearing determines whether the safety conclusions are supported by preponderance of the evidence developed by the regulatory review process.In this safety decision-making process the SSHAC assessment process is a technical process accepted in the NRC’s seismic regulatory guidance for reasonably assuring that uncertainties in data and scientific knowledge (stated by the SSHAC as the center, body, and range of views of the informed scientific community) have been properly represented 

in seismic design ground motions consistent with the requirements of the seismic regulation 10 CFR Part 100.23. 

S 2-7. (CC) “Standard of Proof” (Section 2.1.2.1)

Better wording for the title of section 2.1.2.1 would be “The Reasonable Assurance Standard,” which is the primary focus of this subsection. The claim made in the fourth sentence of this subsection that, “there is no need for such proof” is out of place (the 

claim is explained later in the second paragraph).Based on arguments made in our Comment S 2-5, we recommend deletion of the entire 

first paragraph of this subsection and revision of the remainder. The standard of proof is reasonable assurance, and reasonable assurance is demonstrated by proper implementation of the NRC’s regulatory decision-making procedures. In the instance of 

the CEUS Project reasonable assurance that the CEUS SSC Model represents the center, body, and range of the views (prefer knowledge) of the scientific community is 

demonstrated by proper implementation of the SSHAC Level 3 assessment process. 

The entire section has been removed. 

S 2-8. (CBR, SSHAC) Evidence That CEUS SSC Project Has Captured the Informed Technical Community (Section 2.1.2.2)Adherence to the SSHAC guidelines is necessary evidence, but it is not sufficient to show that the CBR of the technical community has been represented in the assessment. How can sufficient evidence be obtained? Certainly that is not easy, but sufficiency can be approached by peer review of the report. That is what the review of the draft report by the PPRP, the USGS, and supporting parties is doing. These parties are judging the completeness of the process carried out by the TI Team. The question is, do these reviews achieve the goal of evaluating the results of the process? This will be a subjective appraisal. It would be well for the report to discuss the subjectivity of the evaluation and the role of reviews in the evaluation. This subjectivity is acknowledged in Section 2.1.2.1 [Standard of Proof] in the description of the technical community as a “hypothetical community” and the regulatory use of reasonable assurance. The idea that the technical community is hypothetical is contrary to seismic regulatory principles and practice (see our Comment S 2-5). There is a very 

real technical community that has developed the evidence and views regarding specific topics that are important to seismic source characterization and assessment in the CEUS. This community does not consider themselves to be hypothetical. 

Section has been modified extensively. The remaining section is intended to show that the recommended steps in a SSHAC assessment process (as given in the SSHAC guidelines) have been followed. 
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S 2-9. (CC) PPRP Attendance at the Eight Working Meetings of the TI Team: The report contains differing statements about the attendance of PPRP observers at the TI Team Working Meetings:“All of the working meetings were observed by one or more members of the PPRP.” (p. 2-20) “[The PPRP] participated in many TI Team working meetings to plan and review the 

process and progress of the project.” (p. 2-36) “One to three representatives from the 

PPRP attended the working meetings in order to observe the deliberation and technical assessment processes.” (p. 2-42) For the record, PPRP attendance was as follows:WM # 1WM # 2 Hinze, Kammerer, Kimball WM # 3 Ake, PetersenWM # 4WM # 5WM # 6 Ake, SteppWM # 7 Ake, Arabasz, Kimball WM # 8 Kammerer 

Revisions made to indicate PPRP attendance at seven of the ten working meetings.

Comments by Section Chapter 2 (Title)In order to emphasize that the CEUS SSC Project implemented an assessment process, were commend the Chapter title be changed to: SSHAC LEVEL 3 ASSESSMENT PROCESS AND IMPLEMENTATION (see Comments S 1-1 and S 1-2). Chapter 2 (Introductory Text)Spell out PPRP when it is first used in report.Section 2.1p. 2-2, par. 3, line 3: “the data that applies” (inconsistency: data used as singular here;

plural elsewhere in report)

Section 2.1.1par. 1: The text states, “The SSHAC report was written in response to an evolution of expert risk assessment methodologies that had been conducted for purposes of probabilistic risk analyses during the previous three decades.” According to the footnote on p. 34, the only identified studies predating the SSHAC report that dealt with risk were the WASH-1400 study and the NUREG-1150 study; all the other studies dealt 

with hazard. 

Section 2.1.1.1 p. 2-5, par. 3, line 1: Change “The EPRI-SOG study” to “In the EPRI-SOG Project” p. 2-7, next-to-last par.: “and offered a prophecy for future guidance:” What exactly is prophesied in the subsequent quoted text? Suggestion: “and future guidance wasenvisioned” Section 2.1.1.2p. 2-10, par. 2, line 7: Suggest replacing “third party” with “future user” 

All specific comments led to text revisions, except as noted: Sections 2.1.1, 2.1.1.1, 2.1.1.2, 2.1.2, and 2.1.2.1 have been deleted.Comment regarding Sections 2.4.3 and 2.4.4: the workshop summaries are included in the report in Appendix F; the presentations will be made available 

on the project website after issuance of the final report
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p. 2-11, par. 2, line 3: Suggest replacing “gone up” with “increased” p. 2-11, par. 2, second sentence: There is unclear phrasing in the second half of this critical sentence. The difference between the PEGASOS results and the older results were shown to be due to “an appropriate treatment of the ground motion aleatory variability and an error in the calculations in the previous hazard studies (NAGRA, 2004, Section 8.4.2).” Was the treatment appropriate in the older studies or in PEGASOS?p. 2-11, par. 2, line7: “to discredit the study” — Clarify which study is being referred to.

p. 2-11, par. 3, line 11: Change “TI” to “TI Team” 

p. 2-11, par. 3, line 2: Because ESP and COL appear in the list of Acronyms, consider

writing, here at their first mention in the text, “Early Site Permits (ESPs) and Combined Construction and Operating License (COL) applications”

p. 2-11, par. 3: The narrative of what happened in the EPRI (2004) Level 3 process is confusing. The text describes that “A small TI Team was responsible for the assessments and a panel of resource experts/proponents provided their views of the existing ground motion models and their applicability to the CEUS.” Subsequent text describes the problem of the experts not taking ownership of the resulting composite model. As written, why would “resource experts/proponents” be expected to take ownership? In the EPRI (2004) Project, the TI Team requested that the Resource Expert Panel endorse the assessed model. The Panel did not challenge the implementation of the assessment process, but persisted in the role of proponent experts, insisting that their proponent model should have more weight.Suggestion:“A lesson learned in the project was that if broad expertise is needed to perform the TI

role of representing complex technical views of the informed technical community, then a small TI Team may not suffice. In the case of the EPRI (2004) assessment, the panel of ground-motion experts was not charged with the TI role, but they were asked to 

review and endorse the assessed ground motion model; individual members of the panel persisted in acting as proponents, advocating higher weighting of their individual 

proponent models. Subsequent Level 3 . . .” 

p. 2-11, par. 3, last line: Suggest replacing “claim” with “accept: p. 2-11, last paragraph, line 6: Suggest deleting “developing” p. 2-12, line 1: Typo. Change “significance advances” to “significant advances” Section 2.1.2par. 1, third sentence: What is meant by “many of the technical issues that drive seismic hazard . . . are rare?” Suggestion: Delete “rare and”Section 2.1.2.1par. 1: See Comment S 2-3 regarding the notion of “capturing the informed technical community.” If the authors insist on using “capture,” for clarity at least describe capturing the views or technical interpretations of the informed technical community— not the jargon of “capturing the informed technical community.”p. 2-17, par. 1, last line: Typo. “have the like highest likelihood” p. 2-17, par. 3: It will be helpful to clarify for the reader that what is “not yet available” is 

not the article written by Coppersmith et al. (2010) but rather the NUREG document discussed in Coppersmith et al. (2010). Suggestion: “to develop a NUREG-series 
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document (see Coppersmith et al., 2010).” Section 2.1.2.2In the discussion of Item 3 (Provide a uniform data base to all experts), mention should be made of the development of the seismicity catalog.p. 2-19, par. 2, last sentence: What “will provide a valuable methodology step for future 

Study Level 3 projects” isn’t “these tables” but rather something like “the structure of these tables.”

On p. 2-19 near the end of the next-to-last paragraph, the reader encounters, for the first 

time, “the development of the sensitivity SSC model, the preliminary SSC model, and the final SSC model”—terms which aren’t explained until the bottom of p. 2-20. These are 

fundamentally important for the reader to understand. A good place to introduce the reader to these terms would be at the end of Section 1.4.1, explaining that the SSC model was developed in three stages.p. 2-19, last par.: For complete documentation (useful for future readers) give the dates 

of the maximum magnitude workshop in Golden, Colorado, and the CEUS workshop in

Memphis, Tennessee.

p. 2-20, Item 5. Elicit SSC judgments from experts: The text describes eight workingmeetings of the TI Team and goes on to state that “Each working meeting was structured around a particular aspect of the project, as follows:”—but ten bullets follow, not eight. To 

compound the problem, a different list of eight bullets later appears on p.2-41 to describe 

the focus of the eight meetings. On p. 2-37 under the header TI 

Team, mention is made of nine working meetings. Section 2.1.2.3Where are the conclusions regarding the selection of the study level—an important part of 

the process?

Section 2.3par. 3: Change “TI Lead” to “TI Team Lead” consistent with the organizational chart inFigure 2.3-1. p. 2-37, par. 2: To soften jargon, consider replacing “Technical Integrator (TI) Team” with “Technical Integration (TI) Team”Section 2.4.2par. 1, line 9: Text states, “annual frequencies of interest (e.g., 10–4 to 10–7/yr) for nuclear facilities.” Executive Summary states 10–4 to 10–6/yr. Section 2.4.3The text should describe what was done to identify resource experts for Workshop #1and the approach used to ensure that the experts who participated in the workshop were appropriate and sufficient.Sections 2.4.3 and 2.4.4 It would be helpful to have more references to the workshop information in the appendices, particularly the workshop summaries and the presentations.Section 2.4.4The text should describe what was done to identify proponent experts for Workshop #2

and the approach used to ensure that the experts who participated in the workshop were 
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appropriate and sufficient. DRAFTInstallment 2, PPRP Review Comments, page 2-11 Section 2.4.8A short summary of the purpose of the Data Summary and Data Evaluation tables and the use that was made of them would be informative here.Section 2.4.9.1The HID is a valuable document. It would be useful here to expand on its purpose and to note specifically that this document is meant for the analyst—providing clarity about the 

model to be implemented and obviating the need to distill the model from the full report. This document helps assure that implementation of the model (which is sometimes 

challenging) is as intended.Section 2.4.9.2First sentence: This sentence appears to be the objective of the report. Suggest that it be moved forward or reappear in an appropriate place in Chapter 1.Table 2-2 Under “Other Technical Experts . . .” there are duplicate entries for Al-Shukri and Mueller 

To avoid confusion about the listing of names in this table, delete “Other” in “Other Technical Experts” because some of the experts are also listed in the first two categories of the table. 

CHAPTER 3 — EARTHQUAKE CATALOG General Comments G 3-1. (NAR) This chapter summarizes the project approach to developing the earthquake catalog for use in the CEUS seismic source model. The process followed in this project is similar to many others in that it consists of three basic elements: (1) assembly of available, relevant sources of earthquake data into a single, magnitudeconsistent earthquake catalog; (2) identification of dependent events; and (3) evaluation 

of catalog completeness.

No response required. 

G 3-2. (NAR) Chapter 3 is arranged logically as it describes the goals for earthquake catalog development (Section 3.1), the compilation of available data from continental and regional scale catalogs as well as special studies (Section 3.2), development of various relationships to convert all earthquake size estimates to moment magnitude (Section 3.3), catalog declustering (Section 3.4), and catalog completeness (Section 3.5).

No response required. 

G 3-3. (NAR) It is appropriate to emphasize that, the comments below notwithstanding, the catalog that has been developed for this project represents a major achievement and 

is a real step forward for the entire seismic hazard community. It is a major improvement 

over previous catalogs in that it incorporates more regional catalogs and has developed moment magnitude estimates for all the earthquakes. The efforts of the TI Team, together those of collaborators from the USGS and the Geological Survey of Canada (GSC), are to be commended. The detailed and thorough approach followed has led to a product that will be widely used. The TI Team, USGS, and GSC staff should consider producing something in the open literature that documents this work. The development of a specific catalog for non-tectonic events in this region may not seem like an interesting product, 

Listing of non-tectonic events included in Appendix B 
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but for practitioners in this field it will be very useful (especially if it is maintained over time). Having said the above, in order to achieve a clear and complete description of the efforts that went into developing the catalog and of the results, Chapter 3 needs to be improved, as we proceed to explain.G 3-4. (CC) The text and explanation of figures in Section 3.3 are too terse. The knowledgeable practitioner may be able to “read between the lines” or infer the meaning of unexplained dashed and dotted lines on many of the figures, but the documentation for this project report must be clear and complete for all readers.

Section 3.3 greatly expanded 

G 3-5. (CC) This chapter would be enhanced by a description of the problems associated with obtaining useful focal depths in the region, limitations on focal-depth resolution, and 

general observations or conclusions regarding the depth of earthquake foci in the CEUS.

Section on focal depth data added 

Specific Comments S 3-1. (CC) Non-PPRP Review Comments Section 3.1 documents the emphasis placed on the earthquake catalog as it provides the basic earthquake rate information that “drives” the seismic hazard model for most of the CEUS. This section describes the process of compiling the relevant catalogs and data sources and summarizes the rationale for returning to the basic data sources for magnitude or intensity data. A brief synopsis on review of the catalog by other interested and experienced seismologists is contained in Section 3.1.3. However, no mention is made of any results, comments, or changes due to those reviews (hence uncertainty whether suggested changes were implemented in the final catalog). Will those review comments (particularly those of the USGS) be part of the project documentation in any form? They do not appear as an Appendix. Will they be documented in project files in a form that could be retrieved by interested individuals?

Section 3.1.3 added to describe main review comments and actions taken as a result

S 3-2. (CC) Clarity and Completeness in Figures The meaning of different line symbols is incompletely explained on several of the magnitude conversion figures. On Figures 3.3.1-1 and 3.3.1-2, the addition of an added 

point to extend the regression to lower values needs more explanation and justification. On Figure 3.3.4-1, the labeling in the Explanation of “CEUS dependent catalog” makes 

the content on the figure ambiguous. The text on p. 3-11 states that “the catalog of 

earthquakes” is shown on the figure—but two sentences later, the text states, “Therefore, 

dependent earthquakes (foreshocks and aftershocks) must be identified . . . .” So 

“dependent catalog” can be read as the catalog of dependent events.

Text greatly expanded in Section 3.3 to clarify figures. 

S 3-3. (CC) Corrected Moment Magnitudes from Atkinson Section 3.3 provides the summary of the development of the various conversions of earthquake size measures (instrumental magnitude or macro-seismic observations) to 

moment magnitude. This step is essential to ensure consistent earthquake counts and compatibility with modern ground motion prediction equations. Section 3.3.1.1 describes the first of the specific instrumentally determined moment magnitude studies utilized (Atkinson, 2004). To make it clear to the reader how the conversion was carried out, additional detail should be added to 3.3.1.1. This additional discussion will ensure that the other 3.3.1.x sections are clear. For instance, for events that are used from Atkinson’s study, our understanding is that her estimated M values are “corrected” to moment 

magnitudes consistent with the results of waveform inversion studies for those events. If this is not what was done, considerably more detail must be supplied as the correction process is not clear to the PPRP.

Additional discussion added to explain process 
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S 3-4. (CC) Approximate vs. Instrumentally Determined Moment Magnitudes In Section 3.3.1, second paragraph, the text notes that some “moment magnitude estimates were obtained from three studies that determined M by approximate methods . 

. . .” As part of the project documentation, it would be helpful to identify these earthquakes in a table (presumably, the number involved is manageable). Also, to aid future users of the catalog, and for transparency, instrumentally determined moment magnitudes in the Earthquake Catalog should be flagged—ideally in Appendix B, or in files available to 

interested parties.

Listing of approximate moment magnitudes added to Appendix B 

S 3-5. (DMM, U, CBR, CC) Sensitivity of Recurrence or Hazard to Choice of Declustering 

Method

Section 3.4 provides a discussion of the approach used to perform declustering of the magnitude-corrected earthquake catalog. Because the PSHA formulation used for area 

source zones relies on the assumption of earthquake occurrences following a Poisson process, it is necessary to identify any dependent events in the catalog and remove them prior to performing any rate calculations. A number of different approaches have been used in the past to perform declustering analyses in major seismic hazard studies. The work of Gardner and Knopoff (1974), Reasenberg (1984), and Reasenberg and Jones (1989) have been widely used. The Gardner and Knopoff technique, as well as similar region-specific methods (Urhammer, 1986; Gruenthal, 1985), rely on removing events 

within fixed magnitude-dependent time and distance windows about a “main” earthquake. 

The method developed by Reasenberg defines variable space-time windows for 

individual event clusters using statistical tests and related to a particular model of aftershock occurrence.In contrast, the approach that has been used in the CEUS-SSC study is a stochastic approach developed in the mid-1980s as part of the EPRI-SOG Project. Section 4.3 cites 

EPRI (1988) as the source document for this approach to declustering, this reference is missing from the reference list (see note on EPRI references below). The EPRI approach begins by treating each earthquake as a main event and then evaluates the rate of earthquake occurrences within a “local window” about the main event and compares that rate to that within an “extended window,” i.e., one larger in space-time dimension. If the 

rate of earthquakes within the local window is significantly higher (based on an unspecified statistical test) than within the extended window, then smaller events are 

removed within the local window until the rate approaches the extended window (“background”) rate. However, in regions of low seismic activity, stable estimates of rate in the larger window can be problematic and hence lead to biasdue to the unwarranted removal of events.The PPRP has several specific concerns related to the approach taken to declustering of the catalog used in the CEUS SSC Project:1. The lack of clear documentation. The discussion of declustering in Section 3.4 is less than one page long. The discussion and development of the EPRI declustering algorithm contained in EPRI (1986, Vol. 1, Pt. 2, Sections 3 and 4) runs to more than 20 pages and is not trivial to follow. EPRI (1988) contains a thorough discussion of the various declustering approaches and the assumptions associated with each. The EPRI declustering method was designed to minimize the number of assumptions required about the clustering process. The description of the adopted declustering methodology in Chapter 3 needs to be significantly expanded.2. Given that the declustering fundamentally alters the number of earthquakes in the catalog for calculations of recurrence—and thus hazard, more discussion is warranted 

1. Explanation of declustering method expanded 2. The effect of the declustering method is examined by including a comparison with results obtained by Gardner Knopoff as implemented by USGS. Differences are small.3.More discussion added to declustering section4. That is correct, there is variability in cluster length as a function of magnitude. The “classical” methods ignore this effect while the EPRi approach recognizes it5. There are assessments/conjectures in the literature for very long aftershock sequences for earthquakes in the CEUS in the literature, but these do not enjoy widespread support in the technical community. The comparisons shown in the revised report indicate similar results to the Gardner-Knopoff approach 
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about associated uncertainty. What are the implications if a different method were used (e.g., the Gardner and Knopoff method, which reportedly produces 15 percent fewer dependent events and thus more main events)? In the case of the EPRI-vs.-Gardner and 

Knopoff comparison, were smaller magnitude bins systematically more affected? This issue of uncertainty associated with declustering methodology could be addressed in one of two ways: (1) sensitivity studies displaying the impact that this assumption has on recurrence relationships or hazard results, or (2) explicit consideration of alternative 

declustering models each with an appropriate weight. If sensitivity calculations aren’t explicitly made, can experience from other PSHAs be used to amplify on uncertainties associated with the choice of the declustering method? Also, because any declustering algorithm is sensitive to the choice of declustering parameters used, some discussion is warranted about the efforts made in the earlier EPRI Project to determine suitable parameters for the CEUS.3. EPRI (1988) is in the open literature. However, it is difficult to obtain, not widely used outside a small number of individuals, and in the view of the PPRP, not uniquely representative of the CBR of the ITC. If it is the position of the TI Team that in fact theEPRI declustering approach is superior to all other approaches and the only approach that should be considered, then that needs to be more clearly articulated and documented. In point of fact, the EPRI approach has been used only by a few of the teams in the Yucca Mountain PSHA and in updates to the EPRI-SOG seismic source model used for recent COL/ESP applications. The seismic source characterization teams in the PEGASOS project used either the Gardner and Knopoff approach or variants thereof, or a modified version of the Reasenberg approach. Most other seismic hazard studies for critical facilities in the US have used similar approaches to those in PEGASOS. Alternative approaches to declustering should be examined, documented, and if warranted considered for inclusion in the present study to satisfy the goal of capturing the CBR of the ITC.4. Figure 3.4-1 displays the results using the EPRI (1988) procedure, showing dependent 

event time and distance windows for events down to about M* = 2.5. Are these 

considered large events? Note: definition of main, large, and independent earthquakes 

needs to be clearly articulated in this section. If the PPRP is interpreting these figures properly the estimated time windows for many individual small (M* < 4) events are 

significantly longer than time windows for many individual larger (M* from 5.5 to 6) events. 

For M* just below 

5, the time window ranges from 4 days to about 6.5 years. The PPRP questions if that range would be endorsed by the broader community of observational seismologists. Based on the information provided, it is not clear whether these outcomes are unique to the model selected, and whether the model properly models the uncertainty associated with identifying dependent events.S 3-6. (DMM, CC, U) Catalog Completeness Section 3.5 describes the approach used to assure catalog completeness in the CEUS SSC Project. The methodology used for catalog completeness is that developed in the EPRI-SOG Project and works with the uniform magnitude, M*. The EPRI approach defines spatially discrete zones that have uniform levels of magnitude completeness and 

defines magnitude specific probabilities of detection (PD) in each. For the CEUS SSC Project, the TI Team augmented the completeness regions used in the earlier EPRI study slightly to address additional catalog information and to properly cover the current study region. 

Additional description of the completeness approach is provided. Discussion of the alternative approaches is included
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Many of the same comments made regarding Section 3.4 can be made regarding Section 3.5. The lack of detail and clarity make a proper evaluation of this section virtually impossible. The sole reliance on reference to the EPRI documents as the technical basis fails to meet the standard of documentation required in a study of this scope. It is not discussed in this section, but the probability of detection thresholds defined and shown in Table 3.5-1 were derived by simultaneously maximizing the log likelihood functions for PD 

as well as the “a” and “b” values in the earlier EPRI approach. Based on our reading of Section 5 it is not clear if the same approach was used in the current study. As with the discussion of declustering, there are alternative methods for performing completeness 

assessments in the literature and those should at least be discussed and evaluated. The PD and equivalent time period of completenessmethodology used is quite powerful as it maximizes the number of events used from the 

declustered catalog. However, it needs to be more completely described and evaluated against alternative methodologies if it is to be the sole approach used.

Comments by Section Entire ChapterThe word “study” should be replaced with “project” throughout the chapter where used in as part of the designation of an integrated assessment project; e.g., “EPRI-SOG Project”, 

“this project”, and so on.

Section 3.1Suggestion: The reader would find a summary preceding this to be helpful.Sections 3.1.1 through 3.2.2Numerous acronyms are unexplained and do not appear in the list of acronyms. These include:SUSN, NEIC, PDE (p. 3-1), ISC, ANSS (p. 3-3), CERI (p. 3-4), NEDB (p. 3-5) Section 3.1.1p. 3-1, par. 2, line 1: Change “CGS” to “GSC” Section 3.1.3line 3: Typo. “Therefore, and an important part of the catalog development process was review by seismologist seismologists with extensive knowledge . . .” line 7: Affiliation for Martin Chapman as “Virginia Technological University” is incorrect. The school is called either Virginia Tech or Virginia Polytechnic Institute and State University (see http://www.vt.edu/).Section 3.2 p. 3-3, 1st paragraph: It would be helpful to give an example of the numbering scheme as 

it is not entirely obvious how the scheme will appear in the summary catalog.

Section 3.2.1p. 3-3, 1st paragraph, line 3: Typo. Change “and primary earthquake listing” to “and the

primary earthquake listing”)

p. 3-3, 2nd paragraph: EPRI (1988) reference is missing. (Please see comment on EPRI 

references below.)

Section 3.2.3p. 3-4, 1st paragraph: Typo in line 3? (“locations and/or depths”?); in line 6, change “Boatwrigth” to “Boatwright”p. 3-4, 2nd paragraph: Typos. Change “catalog” to “catalogs”; “are area” to “an area”); “The second is” to “the second was” (for consistency with tense in preceding sentence). Section 3.2.4p. 3-4, 3rd line: Reference to Section 3.2.4 should be to 3.2.3 

Correction made 3.1Brief summary added at beginning of chapter3.1.1-3.2.2 Acronyms explained as introduced CGS fixedFixedNumbering scheme explainedSection rewrittenFixedScheme explained. 
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Section 3.2.5 The scheme for assigning order of preference to events located south of the US-Canada 

border is not clear. We assume that all the regional networks have equal weight and events located near New Madrid would default to CERI or St Louis University, and if in New Jersey would default to Lamont Doherty. If not, this needs to be made clearer.

Section 3.3.1.1line 5: Typo. Change “over estimates” to “overestimates”Section 3.3.1.3Typos. In line 2, change “an coda wave technique” to “a coda wave technique”); in line 4, change “abet” to “albeit”Section 3.3.2.1Define fN, and FNSection 3.3.2.25th line and equation 3.3.2-3: Missing word and typo. “The Johnston (1996) relationship is 

reasonably consistent with the project data. Also, is Equation 3.3.2-3 the Johnston (1996) 

relationship, and is that what was actually used? Not clear as written.

Sections 3.3.3.1 and 3.3.3.2Unclear whether the locally-weighted least-squares fit or a constant offset model was used in the conversions between MN and mbLg to moment magnitude M, as shown on 

Figures 3.3.3-1 and 3.3.3-2. 

Section 3.3.3.2Add a sentence after the equation indicating the variables ZCAN and Z1995 are as defined in Section 3.3.3.1.Section 3.3.3.3Suggestion: “The A third mb body-wave magnitude scale (mb) is also more commonly used in the US than in Canada . . . .” Also note that mbLg is used in this section when it should be mb. Perhaps add a reference for robust regression.Section 3.3.3.5 Typo in first sentence. Should be surface-wave magnitude (MS) not “local magnitude ML”; 

the same error is in equation 3.3.3-5. 

Section 3.3.3.8The discussion of unknown magnitude (MU) is not clear. For any given earthquake, how was the decision made as to which conversion should be used?Section 3.3.4p. 3-10, line 3: Typo. Change “Section s” to “Sections” p. 3-10: Following equation 3.3.4-1, the reference to σE[M|X] should perhaps indicate this 

is illustrated by the confidence interval for the mean shown on Figures 3.3.1-1, 2, 3 etc. 

for example. We suggest that equations 3.3.4-2 and 3.3..4-3 be double checked as 

comparison with equations 3-8 and 3-9 in Vol.1. Pt.2 of the EPRI-SOG report indicates 

some discrepancies. Since the corrected magnitudes are ultimately used to derive the “bvalue” one may wish to comment on the sensitivity (or hopefully lack thereof) to the “bvalue” used in equation 3.3.4- 3. In equation 3.3.4-4 the σ2 M|M instrumental is not clear. 

Is it the 0.1 value assigned to the instrumentally determined values referenced in the 

paragraph above equation 3.3.4-1? p. 3-10, last paragraph: The text states, “As discussed in EPRI (1988) uncertainty in the 

magnitude estimates and its propagation through the magnitude conversion process introduces a bias in the estimated earthquake recurrence rates.” It would be helpful to the general reader to add some explanatory detail, rather than placing the burden on the reader seek another publication to understand the purpose or basis of the information that 

Section 3.3 rewritten to address comments and add additional clarification
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follows. Section 3.4p. 3-11, par.1,line 6: The text states, “The standard method of creating a catalog of independent earthquakes developed by Gardner and Knopoff . . . .” It is misleading to describe the Gardner and Knopoff procedure as “the standard method.” Researchers in earthquake statistics outside the U.S. would likely use Ogata’s well-established epidemictype aftershock sequence (ETAS) model as the basis for declustering.p. 3-11, par. 1, next-to-last sentence: In the report, “large” earthquakes are defined as M 

≥ 6.5, so it is confusing to write “and distance interval about a large earthquake.” Suggestion: “and distance interval about a relatively large earthquake.”

p. 3-11, par. 1, last sentence: The text states, “If the rate of earthquakes is significantly 

higher than the background rate . . . , then earthquakes are removed until the rate 

becomes consistent with the background rate.” Does this mean that a few earthquakes that would clearly be declared as aftershocks, say by Gardner and Knopoff, remain in the final catalog in order to match the background rate? In other words, is the declustered catalog not strictly a catalog of main shocks?p. 3-11, par. 2, second sentence: For clarity (because Figure 3.4-1 contains two plots), 

consider writing, “The data points in the two plots represent the length in days of 

individual clusters and the maximum distance between earthquakes assigned to a cluster, respectively.”p. 3-11, par. 3, first sentence: Typo. Change “European earthquake” to “European earthquakes”p. 3-11, par. 3, last sentence: The narrative describing that the EPRI procedure identifies 

about 15 percent more dependent events may confuse readers examining Figure 3.4-1. 

For clarity, consider cautioning the reader not to confuse numbers of dependent events with the number of data points for dependent-event parameters associated with individual 

clusters on Figure 3.4-1. 

Section 3.5First sentence: Typo. Change “EPRI SOG” to “EPRI-SOG” p. 3-12, par. 2, line 6: Could not find Figure 8-1 in Report; what is the basis for the boundaries of the completeness regions? For example, how were the boundaries of Region 15 defined, which is one of the new regions? Is there a rationale for including both the Gulf of Mexico and Florida offshore in the same completeness region?p. 3-12, 4th paragraph: The terms PENB, PENA and WEDT are not defined. p. 3-12; 6th par., line 2: The text states, “in the time period 1995 to 2008” but in Table 3.5-

1 the limiting year is 2009.

FiguresLabeling of page numbers on pp. 3-31, 3-32, and 3-33 needs to be corrected. Figures 3.3.1-1 through 3.3.1-3 Add more detail to the figure captions, and indicate the 1:1 line and the 90% confidence interval for the mean. Typo in Figure 3.3.1-2: (1994) not (19944). Figure 3.3.2-1

Lots of lines on the figure with no explanation in the figure caption. What exactly is 

approximate M in this figure? Figure 3.3.4-1 Is the map of epicenters south of Florida complete to the shown boundary of the study 

region? If not, explain justification for neglecting these. Was the Caribbean seismicity 

catalog accessed to determine earthquakes in the study region?Figure 3.4-1 

Section rewritten 3.4 to better explain the EPRI method and address commentsSection 3.5 rewritten to address comments and add greater explanationFigures for section 3.3 have been redone Caribbean seismicity not included 
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The text should comment on the very large disparity in cluster duration and spatial dimension for similar magnitudes. Virtually all readers will be left with distrust of the methodology based on these results, absent any additional discussion.ReferencesEPRI (1988) is missing from reference list.EPRI reports need to be properly referenced (see next page).This is how the EPRI reports are referenced in the CEUS/SSC report: Electric Power Research Institute (EPRI), 1986, Seismic Hazard Methodology for the Central and Eastern United States: Volume 1, Part 2, Methodology (Revision 1): Final Report, EPRI-NP-4726-A-1(1). Electric Power Research Institute (EPRI), 1989, Probabilistic Seismic Hazard Evaluations at Nuclear Power Plant Sites in the Central and Eastern United States: Resolution of the Charleston Earthquake Issue: EPRI Technical Report EPRI NP-6935-D. The references below are how the EPRI Project documents are referenced in the

PEGASOS report.

EPRI-SOG 1986: Seismic Hazard Methodology for the Central and Eastern United States, Electric Power Research Institute NP-4726A, Volumes 1-11. EPRI 1989: Probabilistic Seismic Hazard Evaluations at Nuclear Power Plant Sites in the Central and Eastern United States, Electric Power Research Institute NP-4726, 9 v. The PPRP suggests the proper reference is the following: EPRI-SOG 1988: Seismic Hazard Methodology for the Central and Eastern United States, Electric Power Research Institute NP-4726A, Revision 1, Volumes 1-11. The EPRI-SOG Project was completed and submitted as “EPRI NP-4726” in 10 volumes 

to the NRC for review as a topical report. The review was completed in 1988. The report number designation “4726-A, Revision 1” identifies that the report has been revised in 

response to NRC’s review and that it is accepted by NRC for future use for licensing submittals and contains the NRC’s Review Report and Acceptance Letter. Volume 11 is the NRC’s requests for additional information and EPRI’s responses. The above noted inconsistency is indicative of the problem with just broadly referencing the EPRI documents within this chapter of the report and the attendant issues with transparency and availability. The PPRP has two systemic recommendations regarding utilization of methods from the EPRI-SOG Project and citations. First, be much more specific when referencing the EPRI studies (i.e. volume, section etc.). Second, the TI Team should strongly consider reproducing and expanding the discussions and developments in the EPRI-SOG report in the CEUS-SSC report. This will enhance clarity 

and transparency and facilitate utilization of some of the methods by the broader community.

Other references either missing from Chapter 3 and/or that probably should have been citedGardener, J.K. & Knopoff, L. 1974: Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian? Bull. Seism. Soc. Am. 64, 1363-1367. 

Grünthal, G. 1985: The up-dated earthquake catalogue for the German Democratic 

Republic and adjacent areas – statistical data characteristics and conclusions for hazard 

assessment. In: Proceedings 3rd International Symposium on the Analysis of Seismicity 

and Seismic Risk, Czech. Ac. Sc., Prague, 19-25. 

Reasenberg, P.A. 1985: Second-order moment of central California seismicity. J. Geophys. Res. 90, 5479-5495. Reasenberg, P., and L. M. Jones (1989), Earthquake hazard after a mainshock in California, Science 243, 1173–1176. 

EPRI reference fixed to 1988Additional references cited as appropriate
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Stepp, J.C. 1972: Analysis of completeness of the earthquake sample in the Puget Sound area and its effect on statistical estimates of earthquake hazard. Proceedings of the International Conference on Microzonation 2, 897-910.CHAPTER 4—CONCEPTUAL SSC FRAMEWORK General Comments G 4-1. (CBR, CC) Chapter 4 describes the Conceptual SSC framework. This chapter is 

generally well-written, organized in a logical format, and responsive to early PPRP 

recommendations for creating a structured systematic approach to SSC, including the establishment of criteria for defining seismic sources. However, it is incumbent on the TI Team to document how these criteria were used to define seismic source zones. While the PPRP appreciates the role that informed judgment has on assessing weights for various branches of the logic tree, these weights must have a documented basis. In response to the PPRP April 7, 2010 letter, the TI agreed that project documentation must provide a detailed (emphasis added) discussion of the criteria that were used to identify seismic sources and a justification for all logic tree branches and weights. 

To aid in the description of the criteria for identifying seismic sources, Table 4.1.3-1 has been added. Also, text has been added in Section 4.1.3 stating 

where the detailed descriptions are given of the technical bases for identifying each source (in Chapters 6 and 7). Also, each discussion of alternatives in the logic tree and their associated weights has been reviewed to ensure that it provides ample detail for the reader to understand the technical bases for the branches and weights of the logic tree. 

G 4-2. (NAR) The development of Data Evaluation and Data Summary Tables has been extremely important with respect to making the seismic source characterization process more transparent and complete (see detailed comments on these tables). These types of tables represent a foundation upon which future SSC seismic hazard evaluations can be efficiently built. This is particularly true for seismic source characterization projects that have a broad regional extend. The TI Team is to be commended for taking the time to create these tables. The tables include an unprecedented level of information that external reviewers can use to understand the assessments that have been made and represented in the logic trees. An important point that was developed in Section 4.2.2 was that the Data Summary and Evaluation Tables are not intended to replace the documentation of the SSC effort but to supplement it. 

No revisions necessary. 

Specific Comments S 4-1. (CC) Terminology The nuanced words “study,” “capture,” and “event” are used throughout Chapter 4, contributing to a lack of clarity. We recommend replacing with words that convey the specific contextual meaning: that is, replacing “study” with “project” or “assessment” as appropriate; “capture” with “represent” as appropriate; and “event” with “earthquake” as appropriate. 

Revisions made to text, as appropriate. 

S 4-2. (CBR) Master Logic Tree and Representing the Community Distribution The assessment of a conceptual tectonic framework is ultimately represented in the master logic tree as the weights applied to branches of this logic tree (major alternatives related to the overall tectonic framework). Interactions with the broad scientific community in Workshops #1 and #2, and the scientific knowledge base developed through these interactions, informed: (a) the TI Team’s assessments for the conceptual tectonic framework, (b) the TI Team’s evaluations of the hazard significance of various seismic source characterization issues (Section 4.3.2), and (c) development of criteria for defining seismic sources (Section 4.3.3).For assessment of SSC models of this regional extent, it is now clear to the PPRP that it 

Evidence that the data evaluation process developed for this project and the methodology for identifying seismic sources can result in a full SSC model is the CEUS SSC model itself. Linkages are made (or enhanced) between the 

use of the data tables to assist in the evaluation and integration process, as well as the linkage between the seismic source criteria and their application for the sources identified in the assessment. The PPRP is the fundamental group in a SSHAC assessment process to provide feedback on all technical and process issues, including whether or not the conceptual SSC framework advanced in this project is reasonable. Importantly, the SSC process is a hazard-related activity and, in addition to the PPRP, the TI Team received 
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could have been useful to have additional feedback of the conclusions discussed in Section 4.3.2 and the criteria discussed in Section 4.3.3 to enhance confidence that this 

information can be used (i.e., appropriately represents the CBR of the ITC) to create a detailed SSC logic tree. From a generic perspective, this should be considered a lesson learned, recommended for Level 3 assessment projects of broad regional extent, to 

directly link the overall development of the seismic source assessment logic tree with a broader segment of the ITC. The TI Team is strongly encouraged to consider whether additional feedback with a targeted group of subject experts is warranted. 

valuable input from the USGS regarding potentially applicable data and approaches to identifying seismic sources.

S 4-3. (SSHAC) Level 3 Assessment Process In the first paragraph of Chapter 4, the text states that the justification for the use of a SSHAC Level 3 assessment process is given in the CEUS SSC Project Plan. While the project plan did discuss the selection of the assessment level, this project report must demonstrate that execution of this assessment level is appropriate, resulting in a high quality product consistent with the requirements for seismic regulatory decision-making. 

We suggest that this sentence be deleted. 

Sentence has been deleted, as suggested. 

S 4-4. (CBR, CC) “Generic” Data Evaluation (Section 4.2.1) 

The development of Table 4-3 and the discussion of this table are beneficial to this report. 

The text would be strengthened if at the end of this section the TI Team discussed how they developed the numbers in the table. Specifically past PSHA experience, results from Workshop #2, and discussions with a wide range of people who are part of the ITC were all used to make these assessments (See Comment S 4-2). Finally, there should be 

discussion of how the numbers were or were not used to guide the weights ultimately assigned on the logic tress.

Additional discussion added to clarify the dual purposes of data identification and evaluation. The generic table is described more fully and its role of helping to document the identification of data based on potential indicators of seismic sources. The bases for the weights are discussed and they provide a basis for documenting the current thinking regarding the relative importance of potential indicators and the relative usefulness of various types of data to address the indicators. They also provided a means of prioritizing the data compilation efforts toward those data that have the highest potential usefulness in the SSC process. They are not used in any quantitative sense, nor do they have a direct relationship to the weights given in the logic trees. 

S 4-5. (CC) Logic-Tree Branches and “Credible” Alternatives (Section 4.1.1.1)

In Comment S 1-2, caution was raised about the use of particular wording that may lead 

to confusion or invite argument. We offer a similar caution here about declaring that only 

“credible” alternatives are included in the logic tree. Having to defend the assertion of zero credibility in the case of excluded alternatives can become a red herring. The nature of the TI Team’s assessment of a representation of the views of the ITC is explained at 

great length in Chapter 2. Allowance is made for excluding an alternative view or parameter based on the judgment that its relative weighting would lead to an insignificant effect on the hazard. When discrete probability distributions are used to represent the 

center, body, and range of a continuous distribution, it is recognized that the distributions have tails of low-to-zero probability. Instead of having to assess exactly where the zero 

bounds are, acceptable practice allows representing the significant mass of the distribution. We recommend removing “credible” from the section title. 

“Credible” is not used in the section title. The term “non-credible” is replaced by “alternatives that are not technically defensible.” The discussion of the exclusion of non-credible branches of the logic tree is motivated by problems 

that have emerged in PSHA projects where it was felt that including very lowweighted alternatives would provide a means of handling outlier and 

controversial models and parameter values. In one such project, the total number of end branches exceeded 1027, thus leading to excessive run times 

for calculations (~one month) and limited sensitivity analyses. Analysis of the hazard significance of the branches allowed for the vast majority of them to be “pruned” or “pinched” based on a lack of hazard significance. It is felt that, rather than trim branches after the fact, making an attempt to eliminate noncredible alternatives could lead to similar reductions in scale during the 

development of the trees.

S 4-6. (CC) Methodology for Identifying Seismic Sources (Section 4.3) This section would be improved if there were a discussion how Workshop #2 was used to guide the TI Team in terms of developing a methodology for identifying seismic sources. 

Text added to explain usefulness of WS2 to source identification process. 

S 4-7. (CC, SSHAC) Hazard-Informed Approach: Section 4.3.1 In the last paragraph on page 4-10, the following statement is very confusing, seemingly 

in conflict with SSHAC guidance, and likely to create controversy:

“Rather, it reminds us that the purpose of the CEUS SSC Project is to develop a seismic 

The point of the sentences is to indicate that the SSC process is part of a hazard analysis and is not a mechanism for answering research questions. First sentence was modified and second sentence deleted. 
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source model to be used in a seismic hazard analysis, and not to attempt to answer or even capture the larger technical community’s questions about SCR earthquake causative mechanisms. The exceptions are those cases where a hypothesis might have profound implications on the geometry, Mmax, or recurrence for a seismic source such that it would affect the hazard results.”Perhaps the intent is to convey the fact that the CEUS SSC Project is an assessment based on existing knowledge rather than an attempt of advance knowledge or resolve competing arguments. The two sentences could be removed without loss of continuity. In 

any case, some clarification is essential. 

S 4-8. (CC) Criteria for Defining Seismic Sources (Section 4.3.3) 

It would be appropriate and helpful here to note that geological and geophysical studies of the crust since the 1980s have provided little significant new information about tectonic features and the geological history of the region that may have a bearing on evaluation of seismic hazards. The only possible exception is the improved understanding of the Illinois basin extended zone and its features. However, paleoliquefaction studies have been 

useful in defining and characterizing seismic source zones. 

Sentences added as suggested. 

S 4-9. (CBR) Weights on the Two Conceptual Models (Section 4.4.1) One of the critical logic tree assessments is the weights on the two conceptual models used to represent classes of seismic sources. Section 4.3.3 establishes criteria for assessing seismic sources while Section 4.4.1 provides a description of the logic tree elements. This section does not develop a strong argument for the weights assigned, particularly the strong preference assigned to the seismotectonic zone branch. Additionally, it is not clear where the TI Team demonstrates that the development of seismotectonic zones leads to hazard significant changes in the model. The text states that the development of seismotectonic zones allows for more relevant information on the characteristics of future earthquakes (the third criteria in the sequence defined in section 4.3.3)—but this seems to be a TI Team judgment, as opposed to a documented evaluation and assessment. Section 4.1 (Item #3) makes the point that a methodology for identifying seismic sources that takes into account defensible criteria is a critical attribute of this project, but the project must demonstrate that the TI Team has properly executed these criteria. Perhaps some type of summary table can be prepared to synthesize how the criteria distinguish between seismic sources.The weight assessed for the seismotectonic branch has increased from 0.33 (August 2009, when three branches were considered) to 0.60 (March 2010) to 0.8 (July 2010 and the draft report). The PPRP notes that these weights could be viewed as somewhat counter to the overall ITC trend that has been documented in the USGS National Seismic Hazard Maps (three cycles including regional workshops) and not necessarily a logical outcome from Workshop #2 of this project. At a minimum, the TI Team needs to bolster their arguments for the weights assigned. The PPRP encourages careful consideration of this issue and the potential need for adjusting the weights toward more parity between the two overall SSC models. 

Table 4.1.3-1 has been added, along with associated text, to summarize the criteria that have been used to identify each seismic source. Reference is made to hazard sensitivity studies (which will be included in Section 8) that show little sensitivity to the choice of the “seismotectonic zones” or the “Mmax zones” branches of the logic trees. The comment regarding changes to the weights of the alternative models are misleading and irrelevant. As discussed in the report, refinements to all components and weights in the model were encouraged throughout the project and there was no imposed requirement that weights not change or that alternative branches not be added or removed as the model integration process progresses. The weights on the alternative branches for the conceptual approach are, in fact, a judgment made by the TI Team. Similar approaches have been used by the SSC community for various hazard studies, but the weights are not intended to reflect a poll of what others have done. Rather, the important consideration is the ability of each model to incorporate important seismic source information. Additional text has been added explaining the bases for 

the weights on these alternative models. 

S 4-10. (CBR, CC) Mmax Zones Logic Tree (Section 4.4.1.2) 

The discussion of the magnitude weighting provides no explanation or basis for the weights. The same holds true for the approach to spatial distribution of seismicity rates (smoothing). PPRP comments on these weights are provided in Chapter 5. Once these 

These assessments are addressed in the applicable sections of Chapter 5 and applicable cross-references are made. 
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comments are addressed these discussions should, at a minimum, refer to specific sections in Chapter 5, and be enhanced to summarize the basis as appropriate. S 4-11. (DMM) Table 4-3 (p. 4-41) Does “(4) Rift Basins” overlap with “(2) Extended Margins”? Does this include basins formed as a result of regional extension in a Highly Extended Terrain such as theTriassic grabens of the EUS? A comprehensive description of continental rift structures is presented by Olsen and Morgan (Continental Rifts: Evolution, Structure, Tectonics, Elsevier, 1995; Chapter 1). Does “(4) Rift Basins” also overlap with “(5) Failed Rift (Paleozoic and younger)” as in the Oklahoma aulacogen? A failed arm of a rift is a branch of a triple junction that did not develop into an ocean basin. A paleorift that has been reactivated by compressional deformation is an aulacogen, e.g., Oklahoma aulacogen. Does (4) include Precambrian continental rifts that were reactivated in later Precambrian time? Why is “(5) Failed Rift” rated lower than (4) if the Failed Rifts are limited to the Phanerozoic? The Oklahoma failed rift (aulacogen) has the Meers fault,while Recent faulting is not observed on Triassic graben faults, to the best of our knowledge. 

No doubt many of the items identified “overlap” and should not be considered as mutually exclusive. The goal of Table 4-3 (now Table 4.1.2-3) is to identify 

potential indicators of seismic sources (all of those shown have been proposed in the community) for the purpose of identifying the types of data that can address them. Thus, fine-scale definitions of each indicator are not 

necessary for purposes of defining the applicable data.

Comments on Sections Chapter 4 (title and introductory text)Consider spelling out SSC in the title of chapter.In the first sentence of par. 1, suggested wording change: “for use in future PSHAs.” In next-to-last line of par. 1: Typo. “how that the framework” On p. 4-1, last sentence: Consider changing “the master logic tree that is the backbone of 

the SSC model” to “the master logic tree of the SSC model” 

Section 4.1In Item #3, line 1: Consider replacing “that takes into account” with “that is based on”; in line 2, consider replacing “takes advantage of” with “incorporates”; in line 3, “identifies” instead of “captures.”Section 4.1.1To more clearly represent the activities described in this section and in the report as a whole, we recommend changing the title of Section 4.1.1 to “Logic Tree Approach to Representing Alternatives and Assessing Uncertainties,” conveying that the alternatives represent the center, body, and range of scientific community’s knowledge and that the assessed uncertainties represent the community uncertainty distribution.On page 4-2, last paragraph, line 3: Consider replacing “identifying” with “representing; 

also in line 10 of the same paragraph. 

On page 4-3, 1st paragraph, last line: Consider changing “that express the relative credibility of the alternatives” with “that represent an assessment of the relative credibility of the alternatives”On page 4-3, last paragraph, line 7: Consider replacing “those assessments that are judged” with “those assessed alternatives”; see also Comment S 4-5). On page 4-4, first full paragraph, line 1: Consider replacing “considered” with “assessed 

to be”; in line 2, consider replacing “degree of belief” with “assessment”; in line 7, consider replacing “and not worthy of” with “so did not warrant”; in the last line, consider replacing “assigned” with “assessed.” 

Revisions made to text as suggested except as noted here. Section 4.2 (now Section 4.1.2) has been rewritten for clarity. SCR is defined per Johnston et al. (1994)
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On page 4-4, 2nd full paragraph, line 2: Consider replacing “assigned to” with “assessed for”; in line 6, consider replacing “the TI Team considered the available data” with “the TI Team evaluated the alternatives using available data”; in line 13, consider replacing “the weights assigned to” with “the weights assessed for.”On page 4-4, 2nd full paragraph, line 5: When writing that “there is rarely a quantitative 

basis for assigning these weights,” it should be made clear that this refers to the assessment of subjective probabilities. The CEUS SSC methodology uses five-point 

distributions to represent quantified continuous distributions of selected parameters. Section 4.2On page 4-5, 2nd paragraph, line 1: Consider changing “an attempt was made to provide 

more structure and transparency” with “more structure and transparency has been provided”; in the next-to-last line, replace “study” with “evaluations and assessments of 

the TI Team”

Section 4.2.1First paragraph, line 3: Consider replacing “as the technical community evolves its thinking regarding” to “as the knowledge of the technical community evolves regarding” On page 4-5, first bullet, line 7-8: Consider replacing “which is an SCR” with “which geologically is constituted of SCR crust”Section 4.2.2On page 4-7, last paragraph, 2nd paragraph: The text states that “errors in the data generally exceed the signal” (data referring to geodetic data). It is suggested that this be changed to “errors in the data may exceed the signal.”Section 4.3First paragraph, line 2: Consider replacing “three decades in SSC” with “three decades in assessing SSCs”; in line 3: consider changing “community” to “scientific community”; in 

line 4, consider replacing “a regional PSHA that can be applied” with “a regional SSC assessment that can be applied; in line 5: consider replacing “requires that a methodology include” with “requires that the assessment include”; in the last line, 

consider replacing “across the study region” with “throughout the regional SSC model.” In the last paragraph on p. 4-8, Regulatory Guide 1.208 is mentioned with respect to guidance for commercial reactors. ANS Standards 2.27 and 2.29 provide similar guidance for other nuclear facilities, and this should be recognized.In the first paragraph on p. 4-9, the message conveyed by the first sentence is not clear. 

Consider replacing the word “intuitive” with “subjective” or “common practice.” 

Section 4.3.1The meaning of the first sentence is not clear and it seems to be inconsistent with the content of the paragraph. It could be deleted, as the following sentence seems to properly introduce the content of the paragraph. Add Pa to List of Acronyms.Section 4.3.3On page 4-14, next-to-last paragraph, line 3: Consider replacing “captured by” with “obtained from”; in the last paragraph, line 7, replace “reasonable assessment” with “reasonable interpretation” On page 4-15, 3rd full paragraph, line 4: Replace “PSHAs” with “seismic hazard models” 
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On page 4-16, first partial paragraph, lines 4-5: Consider replacing “Because the CEUS SSC Project is a regional study and not a site-specific study,” with “Because the CEUS 

SSC Project developed a regional SSC model rather than site-specific one,” 

Section 4.4.1It would be useful to start this discussion with recognition that RLME sources areidentified based on well defined evidence for Late Quaternary or Holocene direct evidence of repeated large magnitude earthquakes. Also when discussing the 8th node of the logic tree, the discussion needs to be enhanced, consistent with the information shown on the logic tree figure.Section 4.4.1.1On page 4-18, the text refers to Table 4.4.1.1-3, which is not included in the report. Rather it appears to be labeled Table 4-6, which is included in the body of the text of the 

chapter. We suggest that this numbering be corrected, that the tables be numbered in a consistent manner, and that a List of Tables be included in the report. 

On page 4-19, 1st paragraph: In the first sentence, make it clear that the issue is “the temporal clustering of large magnitude earthquakes.”Section 4.4.1.2 Page 4-20, last paragraph: In the second sentence beginning, “For the CEUS SSC Project . . .” need a connector (“and” or a semi-colon) at the start of the last clause (e.g., 

“and the prior distributions from that study were reassessed.”).

On page 4-21, second paragraph, suggest moving up the last sentence “As discussed in 

Section 6.2...” prior to the sentence that lists the weights assigned to the logic tree branches.

Four additional review comments relate to the discussion in the second paragraph on p. 4-21: 1. Two alternative locations of the Mesozoic and younger separation branch are identified: the wide and the narrow. Unfortunately, no map is provided for the location of the narrow zone. Reference is made to Figure 4.4.1.2-3 in line 6, which is presumably this 

map, but it is missing from the report as well as the List of Figures. 

2. Figure 4.4.1.2-2 is labeled as showing the narrow Mesozoic alternative, but instead it 

shows the wide alternative.

3. Note that the caption of Figure 4.4.1.2-2 is not complete in the List of Figures. All captions in the List of Figures should be checked against those given on the figures. 4. The boundary of the project area shown on Figure 4.4.1.2-2 and subsequent figures of 

this chapter are not the same as shown in the defining figure of the boundary, Figure

1.3-1, and in Figure 4.4.1.1-2. Apparently the boundary in these figures has been 

modified to incorporate identified seismic source zones in Canada, which is the northeastern segment of the project area. Inconsistent project area boundaries should be avoided to prevent confusion. 

Section 4.4.1.3In the first paragraph, change “shown on Figures 4.4.1.3-2 through 4.4.1.3-7” to “shown 

on Figures 4.4.1.3-2 through 4.4.1.3-5” 

Tables and FiguresThe order of presentation of text, tables, and figures needs to be standardized in all 
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chapters. In this chapter, the order is different than in preceding chapters. Table 4-3 Page 4-39, last row: Assumed the intended wording is small r recent, not capital R Recent. Perhaps a more definitive and less confusing word could be used—perhaps 

Phanerozoic?

Page 4-42, first row: Suggest replacing “Orientation” with “Fault orientation” Page 4-42, third row: Suggest adding “High-resolution seismic reflection” in third column. CHAPTER 5—SSC MODEL: OVERVIEW AND METHODOLOGY 

General Comments G 5-1. (CC) Chapter 5 provides an overview of the SSC model and some of the methodologies used within that model. This section is generally well written and provides a good description and summary of a number of the technical elements of the SSC model. The work that the TI Team completed to update the SCR database, performing new statistical analyses, and updating prior distributions is an important contribution to 

improving assessment of maximum magnitudes. However, some specific elements of the model and/or documentation thereof are problematic in the PPRP’S view. Significant changes or additional justifications may be warranted. 

No revisions necessary. Significant changes have been made throughout the chapter.

G 5-2. (CC ) In addition to the PPRP review, to ensure thorough review of the many equations contained in the report, the PPRP recommends that all knowledgeable members of the TI Team carefully examine all equations, especially equations in sections that they were not tasked to write. 

Reviewed as suggested. 

Specific Comments S 5-1. (DMM, CC) Implications of Kafka’s Studies for Spatial Smoothing Section 5.1 provides a well-written overview of the approach to spatial and temporal models of earthquake occurrence in the current CEUS-SSC model. Section 5.1.1 describes the TI team interpretation that the spatial pattern of observed seismicity provides predictive information about the spatial distribution of future moderate-to-large 

magnitude earthquakes. The PPRP notes that the studies by Kafka (2007, 2009, and Workshop #2) indicate this is generally (emphasis added) the case. Various versions of the cellular seismology results presented by Kafka suggest that much (55–85%), but not 

all, seismicity is predicted by the spatial occurrence of past earthquakes. This suggests that the report should at least discuss the possibility of specifying a very high level of 

smoothing within source zones. This is utilization of subjective rather than objectively defined smoothing parameters that would specifically define a seismicity floor in some regions. 

Sentences added to Section 5.1.1 indicating that a range of smoothing parameters has been included in the logic tree in order to represent a range of variations in the spatial distribution of future recurrence rates, including an option that leads to relatively uniform rates throughout the seismic source. It is also noted that the penalized maximum likelihood approach used does not require a floor in rate, unlike the kernel approach.

S 5-2. (SSHAC, CC) Inconsistency With Principles of Seismic Hazard Model Assessment In Section 5.1.2, par. 3, second sentence, the statement: “The TI Team has taken a very 

cautious approach, however.” conveys a clear violation of the SSHAC guidance principals for seismic hazard model assessment; namely the goal to represent the center, body, and range of the community scientific knowledge. An explanation is required. It would be made clearer if “assumed” were replaced with “used” in the last line of this paragraph (and if the awkward sentence were inverted). 

The sentence has been removed. Other sentences modified to indicate that distributed seismic source zones are modeled using exponential distribution of magnitudes and Poissonian recurrence behavior.

S 5-3. (DMM, CC) Inadequate Description of the Assessment Process In Section 5.1.2, the last paragraph on p. 5-3 (continuing on p. 5-4) is critically important, 

as it introduces the reviewer to the TI Team’s assessment of temporal clustering, 

Revisions made as suggested. Clarification is added to indicated that the TI Team evaluated the data that exists for each RLME and then assessed the appropriate approach to modeling recurrence. Because this section is 
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arguably the most uncertain assessment for the CEUS SSC model. For example, the topic is introduced with the weak statement, “consideration was given to” instead of wording such as “assessed,” which links directly to the SSHAC guidance. With similar effect, “considered” is used in line 4, where the word “assessed” would more accurately convey the appropriate action and at the same time connect with the SSHAC guidance. In line 5 continuing on line 6, the physical process would be explained more clearly if the words “based on the concept of” were deleted, leaving the sentence to read: “The physical underpinning of a renewal model is a quasi steady state . . . .” In line 10, it would be clearer to change “concept” to “physical process.” Werecommend that this paragraph be rewritten, expanding the discussion to convey the state of scientific knowledge about an earthquake cycle in which strain is released as clustered large earthquakes. The most relevant data appear to be the absence of measurable levels of strain accumulation in the Charleston and New Madrid seismic zones, where the short-term geodetic strain rates are in apparent conflict with interpretations of “in-cluster” rates of occurrence of large earthquakes. 

intended to be merely an introduction to key concepts, the reader is referred to the applicable sections regarding RLME recurrence methodology and the specific assessments regarding Charleston and New Madrid RLME recurrence.

S 5-4. (CC) Weak Support for Conclusion In the first paragraph of Section 5.1.3, the last two sentences, beginning with “The TI Team reviewed . . .” convey an evaluation and conclusion of the TI Team that is greatly important for the CEUS SSC model assessment. Yet support for the strong conclusion seems general and weak. Consider elaborating on the basis for the conclusion. For example, the last sentence begins with “With a few exceptions . . . .” Describe the data that permitted the exceptions and describe how the data were used in the assessments. 

Additional discussion added to indicate that there are no exceptions and the appropriate model given the limited data in the CEUS is recurrence of RLMEs and that of distributed seismicity sources.

S 5-5. (DMM, CBR, CC) Maximum Earthquake Magnitude Assessment Section 5.2 describes the methodology for assessing maximum magnitude (Mmax) that was used in the CEUS-SSC Project. The text notes that the maximum magnitude earthquake for any given source zone in regions of low-to-moderate seismicity (such as 

the CEUS) happens rarely, relative to the period of observation. As a result, the record of historical seismicity provides information, but rarely hard constraints, on the sourcespecific Mmax value. This fact has led to the investigation of global tectonic analogues to 

address this issue. The scheme for assessment of Mmax in the CEUS-SSC Project 

incorporated the uncertainties in both conceptual models and the parameters within models. The approach utilized in the CEUS-SSC Project provides a quantitative and repeatable process for estimating Mmax that is easily updatable if new information becomes available.The discussion of the development of the Bayesian Mmax approach in Section 5.2.1.1 is generally clear and guides the reader through the development of the approach. The PPRP believes that the significant effort invested by the Project in the update and reinvestigation of the global SCR database was worthwhile. This refinement represents a significant advancement for the community. However, the PPRP notes there are points that require further clarification and assessments that require additional justification as noted in the following two comments. 

No response required. 

S 5-6. (DMM, CBR, CC) USGS Mmax Workshop and Mmax Approaches Considered In Section 5.2.1, the discussion of the evaluation of alternative approaches to Mmax in the CEUS, lacks any meaningful discussion of the USGS workshop on this topic (Wheeler, 2009), and does not strongly support the TI Team’s selection of Mmax approaches beyond the Bayesian approach. The approach developed by Kijko is not the only viable alternative discussed as part of the USGS workshop. Additionally, the approach developed by Kijko was not given much support in the USGS workshop, 

Additional reference made to the Wheeler (2004) to indicate the problems with statistical approaches that rely on large sample sizes. Although the TI Team considered the summary of approaches given in the Wheeler report, the Team was charged with doing more than merely identifying the pros and cons of any given approach. The Team’s conclusion was that there are only two viable approaches: those that rely on analogues and those that use the observed seismicity. The Bayesian approach formalizes the use of analogues, and 
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needing additional study before it becomes commonly used in PSHAs. This section should provide more discussion of the USGS Mmax workshop and the Mmax approaches considered by the TI Team, and why they are, or are not, selected for assessment. 

provides for updating using observed seismicity. The Kijko approach (the option choosen for application to the CEUS project) uses observed seismicity and an assumption of exponentiality. 

S 5-7. (DMM, CC) “Kijko Approach” — Terminology and Description Defining how this approach or procedure will be referred to in the report and appropriate 

attribution for its origin need to be established upon first mention. In section 5.2.1 (pg. 5-6, paragraph 3), two alternative approaches are described for estimating Mmax: the 

Bayesian procedure and “the Kijko (2004) procedure.” Later in section 5.2.1-2 (pg. 5-15), 

the first sentence states: “The Kijko approach (Kijko and Graham, 1998; Kijko, 2004) . . .” In referring to the “Kijko approach,” misleading statements are made. On pg. 5-7 

(paragraph 1, last sentence), the text states, “However, the approach relies on the assumption that the distribution of earthquake magnitudes follows a doubly truncated exponential distribution.” Later on pg. 5-15 (section 5.2.1.2, paragraph 1, first sentence), 

the text repeats that the approach is based on the simple assumption that “the distribution of earthquakes in a region follows a doubly truncated exponential distribution.” In Kijko (2004, pg. 1) the reader plainly finds:

“This paper provides a generic equation for the evaluation of the maximum earthquake magnitude mmax for a given seismogenic zone or entire region. The equation is capable 

of generating solutions in different forms . . . . It includes the cases (i) when earthquake magnitudes are distributed according to the doubly-truncated Gutenberg-Richter relation, 

(ii) when the empirical magnitude distribution deviates moderately from the GutenbergRichter relation, and (iii) when no specific type of magnitude distribution is assumed.” 

The report modified to refer consistently to the Kijko (2004) approach. While many of the concepts were introduced in Kijko and Graham (1998), Kijko (2004) introduces the methodology for developing a distribution for Mmax that was used in the CEUS SSC Project. The PPRP is correct. Kijko indicated that multiple magnitude distribution forms can be accommodated. The report was modified to indicate this and to justify why the selection option was utilized. 

S 5-8. (DMM, CBR) “Kijko Approach” — Justification of Weighting Adding to Comment S 5-7 on the TI Team’s use of the “Kijko approach” (Section 5.2.1.1), 

this is an approach that was not identified in the any of the CEUS-SSC workshops as a 

potential approach. Further, the approach was not discussed in detail at the 2009 USGS Mmax workshop. The Kijko approach is one that is represented by the form: Mmax = Mmax obs +Δ. At the USGS Mmax workshop this class of methods was given little 

credence. However, the discussion was mostly focused on models that specified a fixed magnitude increment for Δ (0.5 magnitude unit, for example). Kijko’s approach is different in that it utilizes a statistical assessment of seismicity in the region of interest to obtain 

estimates of Δ (and uncertainties). The approach(es) developed by Kijko have not seen wide usage. The PPRP endorses the utilization of an alternative approach that uses zone-specific data for estimation of this important parameter, but notes that the 

assignment of equal weights to the Kijko KSB approach and the Bayesian global tectonic analog approach may be inconsistent with the CBR of theITC. Inspection of the results suggests the Kijko method is only used when it agrees with the Bayesian results. (See also earlier Comment S 5-5 and Comment S 5-10 below regarding the justification of the relative weighting of approaches.)The P(mu>8.25) threshold of 0.5 does not seem unreasonable, but it does lead to the question of sensitivity of the final distribution to that choice. If P(mu>8.25) were set to 0.25 or 0.75 what effect would that have on the number of zones for which the Kijko result would be used?The choice of M 4.8 for the lower bound of the Kijko approach needs additional discussion. This leads in some cases (see Section 7) to non-zero probability assigned to 

Mmax branches of M < 5.25 in large source areas. The PPRP is not convinced this result 

is consistent with the ITC. It will certainly provoke discussion and hence should be 

justified to the maximum extent practicable. 

The statement that the Kijko approach is a Max observed plus delta is an over simplification. The Kikjo approach defines a distribution for Mmax. The basic 

formulation produces equations for the mean of that distribution, which could be considered a max_obs plus delta. However, looking at it in this way, one could also consider the Bayesian approach to be a mean plus delta if one computed the mean of the posterior. 

The PPRP is correct in that the Kijko approach has not seen wide usage. However, as discussed in the response to comment S-5-10, there do not appear to be many options for a repeatable and readily updatable Mmax assessment method for large source zones. The TI team selected the ones that were judged viable for application in this context.It is true that the weight on the Kijko approach is correlated with the similarity in the Kijko and Bayesian results. This has to do with data. The more data there is in a source zone, the more the Bayesian prior is modified by the likelihood function. That likelihood function has a shape similar to the distribution for Mmax produced by the Kijko method implemented in the CEUS SSC project. Also as the amount of data increases in a source, the Kijko method gets more weight. Therefore, when there is a lot of data, it is not surprising that the two methods produce similar results.The revised model imposed a minimum Mmax of 5.5 for all sources 
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S 5-9. (DMM, CBR, CC) Bayesian Mmax Approach The discussion of the updated domain dataset analyses in Section 5.2.1.1 (and subsections) is confusing and lacks sufficient information to fully understand what was done. The text states that Table 5.2.1-1 list Mesozoic and younger extended superdomains, yet the table appears to list all ages of extended superdomains (and Table 5.2.1-2 is for all ages of non-extended superdomains). Without listing the actual p-values 

of the statistical tests it is difficult to appreciate the improvements that are being 

discussed as you assess subsets of the data. Given that Appendix K only provides tables of the SCR Mmax databases, more specifics should be provided in this section (see also Comments on Appendix K – more detail needs to be provided there also). It is suggested 

that there be a displayed, on one or more figures, the Mmax-obs distributions for the 

various classes being compared. Was an assessment made of the impact for using an alternative choice for the lower cutoff of magnitude for each of the domains (such as M 5 

or M 5.5)? 

Statistical analyses are good, but not necessarily the only basis for assigning weights to the prior distributions. It seems clear that the Mean Mmax between the two-priors is likely 

to be important from a PHSA perspective (7.1 versus 6.35). The text states that a 

stronger weight (0.6) is not assigned to the two priors because the statistical significance of the separation is not strong. Assignment of relative weights should consider the seismologic views of the ITC in addition to any statistical significance—based on the text, 

the TI Team seems to be making the statistics the primary consideration. Discussion at the USGS Mmax workshop and the public workshops held to support the National Seismic Hazard Maps could suggest that the ITC would put more emphasis on the “twopriors” model (the TI Team’s intuitive judgment). The OpenFile Report from the USGS Mmax workshop should be reviewed in this context, along 

with pertinent discussion from Workshop #2. A stronger basis for assigning relative weights is needed.The description of the methodology to assess Mmax for all seismic sources contains a discussion of the role of the RLME sources in the assessment. The report suggests that a potential problem is that the global SCR database includes events from RLME sources (e.g., New Madrid) and that the Bayesian approach is being applied to non-RLME sources (p. 5-7). It seems that this methodology assumes that all RLME’s have been identified in the current model. Otherwise, the model does not consider RLME’s that may be found in the future. The report should explicitly describe how the model accounts for non-identified RLME’s that may have maximum magnitudes the size of New Madrid or 

Charleston. 

More details on the development of the priors are provided in the revised report.No impact was made of the choice of lower cutoff for each domain. However, a minimum Mmax is now used for all applications to assess of MmaxThe USGS Mmax workshop did not deal explicitly with the issue of the relative weights that should be applied to alternative prior distributions using the Bayesian approach. Nor was there any formal “consensus” in exactly what prior distributions should or could be used with the Bayesian approach. As noted in the text, the lack of strong statistical significance between the separate and the combined priors provides input to the judgment that there is not a strong technical basis for giving either alternative strong weight. The updated distributions all contain the possibility that Mmax values could be as large as 1811,1812 or 1886 

S 5-10. (CBR) Weights for the Alternative Mmax Approaches (Section 5.3.1.3) Given the TI Team’s noted high regard for the Bayesian approach, it is difficult to understand why the Kijko approach was assigned equal weight under any circumstances (large number of larger earthquakes). Discussion at the USGS Mmax workshop and the discussion at the regional workshops to support the National Seismic Hazard Maps would suggest that the ITC gives considerably more weight to the global tectonic analog/Bayesian approach. Beyond the Bayesian approach, there were several potential approaches considered at the USGS workshop, thus it is not clear why the TI Team selected the Kijko approach as the only alternative. The Mmax distributions shown in the report appear to be bi-modal in some cases. The TI Team has not properly discussed and 

justified the weights assigned to the alternative Mmax approaches. 

The TI team is not aware of other quantitative and repeatable procedures for estimation of Mmax other than the Bayesian approach or the Kijko approach other than assigning an arbitrary delta value to the observed Mmax or developing a direct subjective assessment. The Team is not opposed to use of a direct subjective assessment but felt that methods that could readily be updated in the future when new information becomes available are preferable. 

S 5-11. (DMM, U, CC) Approach to Earthquake Recurrence Assessment An effort was made to improve the clarity in section 5.3.2 by providing more 
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Section 5.3 describes the approach to earthquake recurrence assessment used in the Project. This section is generally well-written (given the complexity of the topic) but could 

certainly benefit from the inclusion of additional steps in the derivations and from additional discussion in some places (we elaborate in following comments). 

A fundamental assumption of the methodology used in the CEUS-SSC Project (and most 

others as well) is that the magnitudes of earthquakes in the corrected catalog can be represented as exponential variables -β(m-m0)). 

Lombardi (BSSA, 2003, vol. 93, no. 5, pp. 2082–2088) argues that main shocks (i.e., those in the “corrected” catalog) do not satisfy this assumption. Lombardi suggests a different density function for the use with these main events that depends not only on β 

but on N (the number of events) as well. In fact, her comparisons utilizing Southern California data suggest much lower b-values for main shocks than for all the events in the 

catalog. The PPRP suggests that some discussion of these alternative assumptions be included in the report—and that the methodology used by the TI Team be checked, vis-àvis implications of the Lombardi paper, to ensure that there is no systematic bias in the 

maximum-likelihood estimates of b-values. 

background. We have also examined the Lombardi paper and concluded that the issues identified in that paper do not affect the results of this study. A section was added (Section 5.3.2.6) that discusses the paper and its practical implications.

S 5-12. (DMM, CBR, CC) Smoothing to Represent Spatial Stationarity (Section 5.3.1) The argument is presented in this section that the penalized likelihood approach to spatial smoothing of seismicity is superior to other approaches and the only method to be considered in the CEUS-SSC Project. The PPRP does not find this argument to be adequately supported by the report as written in its present form. Keeping in mind that the objective of the SSHAC Level 3 process is to represent the CBR of the ITC, we note that, other than one or two members of the TI team, no other members of the technical community are utilizing the penalized likelihood approach to perform smoothing of observed seismicity. The overwhelming majority of the community is utilizing either a fixed-kernel or adaptive-kernel approach to smoothing. The kernel approaches are conceptually much simpler and easier to implement and, as a result, yield enhanced transparency. The PPRP notes that in Section 5.2.1 (p. 5-7, 2nd paragraph) the report states, “[I]t was 

decided that for representing the center, body, and range of views of the informed technical community, the assessment would need to include alternative conceptual 

models for Mmax.” The PPRP wonders if one were to replace “Mmax” with “smoothing technique” in this statement, why the argument presented in Section 5.2 would not apply in Section 5.3. The penalized likelihood method, as developed in the EPRI-SOG Project 

and in the present report, possesses some very positive attributes. Some are briefly discussed in Section 5.3.1 but developed more fully in Section 5.3.2.4. It would enhance clarity to refer the reader to Section 5.3.2.4 in Section 5.3.1. 

While the TI Team recognizes that the selection of the smoothing option requires expert judgment, the text goes on to note that “The smoothing operation within the distributed seismicity zones results in variations of a- and b-values over scales that were judged by 

the TI Team to be reasonable . . . .” The report has not provided an adequate basis for making this statement. The text does not compare the computed smoothing results to other studies, and does not point to any explicit data that indicates that the seismicity parameters fall within a reasonable range. 

Discussion added to justify the use of the penalized maximum likelihood approach to smoothing and to present the argument that all smoothing approaches are based on the same conceptual model of spatial stationarity. The penalized maximum likelihood approach developed for the CEUS SSC project is a refinement of the EPRI-SOG approach, which is part of an SSC 

model endorsed in Reg Guide 1.208 and has seen common use throughout the technical community in every Combined Operating License application 

filed to date. Section 5.3.2.4 provides the bases for selecting the approach over the other kernel approaches and reference to it is added to Section 5.3.1. The point of the quoted statement is that the selection of smoothing parameters is subjective and an assessment made by the TI Team. The technical considerations that were part of that assessment are given in Section 5.3.2.4.Calculations were also performed for a few source zones using a kernel approach with objectively selected adaptive kernel size (using a completely different objective approach). The resulting map is presented in Section 5.3.2.4. Visual comparisons indicate a very good agreement, except in regions of very low seismicity, where Gaussian kernel approaches are known to be problematic. 

S 5-13. (DMM, CC) Penalized Likelihood Function — Differences with EPRI-SOG? In Section 5.3.2.1 the model for the penalized likelihood function for recurrence parameters is formally developed. Many aspects of the approach appear to be similar to those of the EPRISOG Project. It would be useful to specify the differences in the present 

The new Section 5.3.2.5 contains a detailed comparison of the approach used in this study and the penalized likelihood. This discussion covers all the differences identified by the PPRP.
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approach relative to the EPRI-SOG Project. The PPRP identifies the following differences (or at least this section of the current report is not clear enough to be sure if these are in fact differences relative to the EPRI-SOG Project): 1. One of the attributes of the EPRI-SOG model was the simultaneous solution of recurrence parameters and incompleteness. On pg. 5-23 the text states the probability of 

detection (PD) values are calculated in Section 3.3.3 (typo-this should be Section 3.5). 

This statement plus the remainder of Section 5.3.2.1 give the appearance that PD is calculated independently and no longer simultaneously solved for.

2. The smoothing functions are now analytically determined (objective estimates) as opposed to the general, judgment-based smoothing specified by the expert teams in the 

EPRI-SOG study. 

3. The use of the Monte Carlo-Markov Chain simulation approach to develop alternative 

maps in the present study as opposed to the parametric bootstrapping used in the EPRISOG study.

4. The use of quarter-degree cells instead of one-degree cells and only using the cells 

that share sides (4 nearest neighbors instead of 8). 

S 5-14. (DMM, CBR, CC) Model for the Penalized Likelihood Function — Need for ScrutinyThe development of the statistical approaches used in this Section 5.3.2.1.1 should undergo independent review either using an appropriately qualified member of the TI Team or an outside expert. It is not sufficient to simply provide a description of the approach used. To facilitate a thorough and transparent review, the software developed should be made available for use in the review process.The text implies that selecting a small cell dimension, more cells, is an improvement relative to larger cell dimensions. It is not clear, from a seismologic perspective, considering the short historic record, why this would be the case. Review of the alternative recurrence maps (Appendix J) suggests that there are broad areas where the rates of M > 5 are effectively zero, there is wide variation (several orders of magnitude) in 

rates and b-values between alternatives, with generally lower b-values (< 0.8). It is not 

clear how the choice of cell dimension may have impacted these observations.

This section has not adequately demonstrated how the method chosen quantitatively compares to other methods such as the kernel approach. While section 5.3.2.4 provides some discussion, it is not sufficient by itself to support the sole use of the method chosen. It appears that the TI Team is using the argument that b-values are not constant within a 

“larger” seismic source.

The variation (or lack of variation) of b-values is subject to considerable discussion within 

the ITC. What is the basis for supporting the position that the variation of b-values is 

consistent with the views of the ITC?The weights on the reduced-weight option for the magnitude intervals listed on Table 5.3.2-1 are not properly discussed and justified. Presenting only two figures as a 

demonstration that the approach is not sensitive to these weights is not compelling. What was the basis for assigning these weights to each of the magnitude intervals?

A few additional aspects in Section 5.3.2.1 could certainly be clarified further to enhance readability and understanding: • The reader is challenged to derive 5.3.2-11 from 5.3.2-9. • What is the basis for eight alternative maps as opposed to four or ten?• Section 5.3.2.3 is not clear enough to understand the generation of the alternative maps from the eigenvalues and eigenvectors of the covariance matrix Sx. 

The software will be made available to the reviewers, as already indicated in 

the project plan.

In principle, smaller cell dimensions are preferable because they allow finer spatial resolution. The absence of earthquakes in an individual cell does not create a problem because the penalty functions that promote smoothness in fact create a larger “effective cell size.” Tests on the MIDC_A zone with objective smoothing indicate similar results for cell sizes of 0.25, 0.5, and 1 degree. The objective smoothing compensates for the cell size by arriving at solutions with smaller   (i.e., smaller differences between adjacent cells) 

for the smaller cell sizes. 

In the opinion of the TI team, the source-level comparisons shown in Chapters 

6 and 7, the comparisons for smaller regions shown in Sections 5.3.2.3, and the comparison to the kernel approach in Section 5.3.2.4 provide sufficient support for the decision to adopt the penalized likelihood approach as the sole method for source-zone recurrence calculations. In addition, the choice of 

cases A, B, and E samples a broad range of assumptions regarding degree of smoothness or roughness. As indicated earlier, the choice between the penalized-likelihood approach and kernel approach is a choice between statistical tools; the conceptual model for both approaches is the same.The spatial variation of the b value is indeed a topic of much discussion. The TI Lead canvassed several seismologists who have thought about b and its spatial variation, but did not receive any useful guidance in this regard. The TI team felt that, given the large size of some of these source zones, it was preferable not to adopt a constant b as an a-priori assumption. In the end, the 

objective-smoothing approach arrived at maps with a mild spatial variation in b 

(except in SLR). 

The choice of magnitude weights has changed: we now use cases A, B, and E. The revised report contains a discussion in Section 5.3.2.2.1 of why other 
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cases were eliminated and how the weights to cases A, B, and E were assigned by the TI Team.Regarding Eqs. 5.3.2-11 and 5.3.2-9 (now 5.3.2-15 and 5.3.2-13), 5.3.2-11 is 

not derived from 5.3.2-9. The latter represents the likelihood of the recurrence 

parameters in all cells, while the former represents one of the penalty functions that are introduced to promote smoothness between cells.

Regarding the choice of eight alternative maps, the following paragraph was added at the end of Section 5.3.2.1.3: “The initial implementation of this approach required that the number of realizations be a power of 2 because the first few epsilons were sampled using two-point distributions. This number was set to 8 because 4 was considered insufficient and 16 imposed a high computational burden for the hazard calculations. In the present Latin Hypercube implementation, the restriction of a power of 2 no longer exists, but the choice of eight realizations was retained. Tests indicate that 8 realizations, together with Latin Hypercubes, provide an adequate representation of the mean and fractiles of the hazard.” Regarding the eigenvalue decomposition, Section 5.3.2.1.3, the text was modified in the hope that it will improve clarity. In essence, the eigenvalue analysis and the Karhunen –Loève expansion are utilized to generate realizations of a random vector with the desired covariance properties. This technique is used in many disciplines. 

S 5-15. (CBR, CC) Application of the Smoothing Model (Section 5.3.2.2) 

In Section 5.3.2.2, no basis is given for weights on b-value priors. The alternatives are 

shown to be unimportant later, indicate that fact in this section to avoid confusion over the lack of basis for weights. 

Those weights were preliminary weights, simply for the purpose of the sensitivity analysis. This potential misunderstanding was removed in the revised report.

S 5-16. (DMM,CBR, CC) Constant b-value Kernel Approaches Section 5.3.2.4 discusses the constant b-value kernel approaches to smoothing of seismicity. The PPRP believes that significantly more discussion and comparisons are needed to justify the use of a sole unity-weighted branch in the logic tree for this important choice of model. We note that one of the strengths of the penalized likelihood approach, relative to the fixed b-value approaches, is the ability to allow for coupled rate 

and b-value behavior within sources. However, the results shown in Figures 5.3.2-3 and 

5.3.2-5 suggest the penalized likelihood approach with the CEUS data yields very high 

smoothing levels on the b-value. In other words, the data may be insufficient to make a 

strong case between variable and fixed b-value approaches at the seismic source level—

thus significantly reducing one of the strengths and justifications for the penalized 

likelihood approach. Additional comparisons with the fixed bvalue kernel smoothing 

approaches are warranted. 

As indicated earlier, the TI team felt that, given the large size of some of these source zones, it was preferable not to adopt a constant b as an a-priori assumption. As indicated in Section 5.3.2.4, the penalized likelihood approach has other advantages over the kernel approach (besides the spatial variation in b). The most important of these are the ability to produce spatially varying estimates of the uncertainty in b and the presence of a natural floor in areas of very low seismicity. A comparison to the kernel approach was added in Section 5.3.2, and it shows a good agreement. Please see the response to 5.5-14 for additional discussion of the issues raised in this comment.

S 5-17. (DMM, CC) Seismogenic Crustal Thickness In the title and text of Section 5.4.1.4, the term should be “seismogenic thickness” not “seismogenic crustal thickness.” The statement that the focal depth distributions of well studied earthquakes established the basis for the assessment of seismogenic thickness is overly generalized. This section goes on to note that the base of the seismogenic zone is identified as lying near the base of observed focal depths at about the 95th-percentile 

depth; review of the depths listed in the updated earthquake catalog would suggest that a 

The term “seismogenic crust” is commonly used and text is added to indicate that it is synonymous with seismogenic layer or seismogenic zone.The approach used has been modified to be based on the D90 of high-quality 

focal depths for all seismic sources. Text is added to present the approach and to define its technical basis.
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depth of 13 km may not be consistent with recorded data. If there are specific “wellstudied” earthquakes used to establish the TI Team’s assessment, these should be listed 

and summarized. Later in Chapter 6 when discussing the assignment of crustal thickness to specific seismic source zones, the report appears to ignore the stated intent that observed focal depths at about the 95th-percentile depth is an important consideration. 

Chapters 6 and 7 will be made consistent with this approach and reported values consistent with those in Table 5.4.1-2. 

S 5-18. (CC) Relationship of Rupture to Source Zone Boundaries In Section 5.4.1.7, the discussion of strict versus leaky source boundaries is not clear. While it is recognized that TI Team judgment is important here, it seems that some type of systematic approach would be appropriate. It may be important to note that the assumed rupture dimension relationships establish limits that must be explicitly considered in assigning strict versus leaky, and that this constraint is considered on a case-by-case basis. Otherwise it is not clear why some RLME sources move from strict to 

leaky, given the defined boundary. The same is true for difference between seismotectonic source zones—why are some leaky and some strict? 

Explanation added regarding the bases for leaky versus strict boundaries. It is also noted that all sources have sufficient dimensions to accommodate the ruptures consistent with their assessed magnitudes.

S 5-19. (CC) Assessment of Future Earthquake Characteristic In Section 5.4, the introduction of Table 5.4-2 invites discussion before the reader has a 

chance to read the specifics related to each seismic source in Chapters 6 and 7. It is suggested that this table be split into two tables that can be provided as useful summaries at the end of Chapters 6 and 7, respectively, for the sources zones discussed in those chapters. In this way, the reader will have had the benefit of understanding the TI Team’s basis for the source-specific weights that are assigned. 

Having all of the assessed characteristics for all seismic sources directly in the section where the approach is discussed has value and Table 5.4.1-2 is 

retained. Chapters 6 and 7 have been structured so that they are consistent in format and discuss the bases for the future earthquake characteristics. All of those discussions now refer the reader to Table 5.4.1-2, for clarity. 

Comments by Section Entire Chapter 5Throughout Chapter 5, we recommend that “event” not be used as a synonym for “earthquake.”In order to achieve the needed clarity for a regulatory document, we recommend making a blanket search to replace “event” with “earthquake” where that meaning is the case. Other instances of confusing uses of synonyms are identified elsewhere in the following comments.Section 5.1.1First sentence: Replacing “led to the belief” with “led to acceptance” would be clearer (note that in line 4 the word “conclusion” is used).On p. 5-2, par. 2, line 9: Suggest replacing “secondary effects” with “liquefaction phenomena associated with them” In the same paragraph, line 10: Suggest replacing “paleoseismic events” with “paleoearthquakes interpreted using the distribution of liquefaction phenomena”In the same paragraph, last line: Replace “studies” with “SSC model assessments”On p. 5-2, par. 3, line 3: Change “EPRI-SOG study” to “EPRI-SOG Project” In the same paragraph, line 8: Suggest replacing “capturing” with “representing”In the same paragraph, line 10: Change “in EPRI-SOG” to “in the EPRI-SOG Project” Sections 5.1.2In the first paragraph, line: Change “PSHA” to “SSC model assessments” In the same paragraph, last line: Change “PSHAs” to “SSC model assessments”On p. 5-3, par. 2, line 9: Change “CEUS SSC study” to “CEUS SSC Project” Section 5.1.3In the second paragraph, suggest rewording the first sentence to read: “Another area of ongoing research with potential implications for recurrence behavior relates to geodetic strain rate measurements.” 

Event changed to earthquake in most cases. Revisions made as suggested.

Section 5.2 Revised as suggested. 
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In the first line of the second paragraph: Consider deleting “issue” and change “EPRISOG study” to “EPRI-SOG Project” Section 5.2.1In the first sentence of the first paragraph: Suggest replacing “calls for” with “incorporates” Section 5.2.1.1On p. 5-11, sequential paragraphs describe the results of performing Student’s t-test as 

yielding “a very high probability (p-value),” then “a lower p-value,” and then “a further 

reduction in the p-value.” But the p-values are not given! Finally, the fourth paragraph reports the results of an additional step that “yielded a p-value of 0.14.” The other pvalues also need to be reported and documented for the reader to evaluate whether the extended and non-extended superdomain classifications are statistically significant. Section 5.2.1.1.1In the first paragraph, line 4: Consider replacing “known stress” with “known characteristics of tectonic stress”In the next paragraph, first sentence: Change “study area” to “model region” Section 5.2.1.1.2In the first sentence: Consider replacing “applicable” with “appropriate”; change “study

region” to “model region”

Section 5.2.1.1.3In the first sentence: Replace “assigned” with “assessed”In the same paragraph, line 3: Consider replacing “an intuitive” with “our subjective”Section 5.2.1.1.4In the second sentence, line 2, delete “likely”; in line 3, change “For this study” to “For this project”Section 5.2.1.2In the last line of the first paragraph: Consider deleting “possible” (or explain) On p. 5-16, in the second full paragraph, line 4: Consider deleting “relatively” (or explain) 

On p. 5-16, in the last full paragraph, line 6: Replace “decided” with “assessed”; in the last 

sentence of this same paragraph, consider replacing “the following key assumptions are made in the application of” with “the following constraints are placed on the application of” On p. 5-17, first bullet: Replace “accounted for” with “assessed” 

On p. 5-17, third bullet: Consider replacing “regard for” with “reliance on” Section 5.2.1.3In the first paragraph, line 3: Consider replacing “assigning weights to” with “weighting”

In the same paragraph, lines 4 and 6: Consider replacing “assigned” with “assessed”

Section 5.2.1.4In the first paragraph, line 5: Consider replacing “assigned” with “assessed”On p.5-18, in the partial paragraph at the top of the page: Consider replacing “assigned” 

with“assessed”

On p. 5-18, first full paragraph, lines 3 and 7: Consider replacing “assigned” with “assessed”On p. 5-18, second full paragraph, line 3: Consider replacing “assigned to” with “assessed 

for”

Table 5.2.1.1 Does the last row contain numbers of earthquakes “Greater than M 4.5” or ≥ M 4.5? Figures 5.2.1-7 and 5.2.1-8 Typo in legend. Change “Disribution” to “Distribution”

Revised as suggested.P values given in revised reportRevised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.Revised as suggested.≥ M 4.5 Revised as suggested. 
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Section 5.3.1 In the last paragraph on p. 5-19, line 9: Replace “study region” with “CEUS SSC model 

region”

On p. 5-20, first full paragraph, last sentence: Consider replacing: “were judged by the TI 

Team to be reasonable, given the technical community’s views” to “were judged by the TI 

Team to represent the technical community’s views”

Section 5.3.2.1.1 Regarding m0 and the definition of ν: Is ν in fact calculated for m > m0 or m ≥ m0 (e.g., 

McGuire, 2004; Weichert, 1980)? If calculated as the latter, then corrections should be made to equation 5.3.2-1 (and associated text on pg. 5-20), on pg. 5-29 (paragraph 2, 

line 2), and perhaps elsewhere. On p. 5-21, third line from the top of the page: Change “This study” to “This project” On p. 5-22, par. 4, line 2: Consider replacing “one may wish to assign lower weights to 

lower magnitudes” with “the assessment may result in a lower weight on lower 

magnitudes”In this same paragraph, second sentence: Consider replacing this sentence with “For instance, the magnitude-recurrence law may deviate from exponential, or the magnitudeconversion models or completeness model may be less reliable for lower magnitudes.”

On p. 5-22, last paragraph, line 1: Consider replacing “considered” with “incorporated” 

On p.5-23, par. 1, line 5: Change reference to “Section 3.3.3” to “Section 3.5”On p. 5-25, last full paragraph: Consider replacing “are specified by the expert teams on 

the basis of judgment” to “are assessed by the expert teams on the basis of their evaluations”

On p. 5-26, first text line at the top of the page: Change “study” to “project” On p. 5-26, first full paragraph, line 4: Consider replacing “refer to” with “formulate” On p. 5-26, par. 3: In line 1, change “Equation 13” to “Equation 5.3.2-13”; in line 2, consider changing “a characterization” to “an assessment”; in lines 7–8, consider replacing “An additional, practical requirement is that one must represent the epistemic uncertainty by means of a small number of ” with “An additional practical requirement is that epistemic uncertainty must be represented. This can be accomplished by means of a small number of “On p. 5-27, par. 3, line 4: Change “Equation 15” to “Equation 5.3.2-15” 

The term “study region” is common usage and well-understood, so it is retained.Considerable additional discussion added on the issue of the community’s views regarding spatial stationarity and smoothing. During the evaluation phase, the larger community’s views were evaluated. During the integration phase, the SSC model was built and that includes the smoothing decisions. So, it is correct to say that the assessment belongs to the TI Team, having given due consideration to the community’s views. We use m>mo and we corrected the equations and text accordingly. In theory, this is not important for a continuous random variable. Because magnitude are not quite continuous, it has a moderate effect in practice (note: most changes to 5.3.2 were made after Aug. 7 version) Change made in a number of places Change madeChange made.Change was considered but it was not incorporated.Change made.Change made.“refer to” was changed to “write”Change made using slightly different wording.Change made. 
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On p. 5-27, par. 4, lines 7–8: Typo. “maps of to represent” Section 5.3.2.2.1On p. 5-29, second bullet: Change “in EPRI-SOG” to “in the EPRI-SOG Project” and change “study region” with “SSC model region”Section 5.3.2.2.2 On p. 5-31, first full paragraph, line 6: Replace “assigned” with “assessed”; in line 7, consider deleting “reflected”Section 5.3.2.3Last line: Consider replacing “small-scale” with “local” The first example used to examine model results in parameter space needs to be more explicit in describing how the expected earthquake counts in the polygons are derived. It would also be helpful to discuss the data error bars for the magnitude bins with no events. The figure captions for these figures need additional information. Section 5.3.2.3.1On p.5-32, par. 2, line 1: It is an overstatement to claim that Figures 5.3.2-20 and 5.3.2-

21 show a “very close” agreement between model and data. In the following paragraph, “good agreement” is claimed between model and data for results shown on Figures 5.3.2-22 and 5.3.2-23. Admittedly, such statements are qualitative, but don’t stretch the 

reader’s credulity.Section 5.3.2.4In the first paragraph, first sentence, change “this study considered” to “this project evaluated”; in line 3, change “considered” to “evaluated”; in line 4, change “study” to “project” In the second paragraph, line 2, change “has been specified subjectively” to “has been assessed subjectively”On p. 5-34, next-to-last paragraph, line 6: Consider changing “idea” to “understanding”

Section 5.3.3.1

Equation 5.3.3-2 should be checked. The N! in the denominator appears to be an error. 

Because the normalization procedure used to generate the probability density function for λ isn’t explained, it’s not evident why the y-axis values are so low (0.00, 0.02, 0.04). 

Rescaling the x-axes of both plots would be helpful to avoid the awkward labeling of 5e05, etc., making it easier to read the plots. Checking the five discrete levels on the CDF 

points to an error in Table 5.3.3-1: The value of cumulative probability in column 1, row 1 

can’t be 0.304893(other values in the table suggest it should be 0.034893).

Section 5.3.3.1.3First paragraph: In the first sentence, consider replacing “is generally used to represent 

uncertainty in the inputs” to “is used to represent uncertainty in the SSC model “inputs”; in the last sentence, change “CEUS project” to “CEUS SSC Project”

Section 5.3.3.1.3In the section title, consider changing “Estimation” to “Assessment” 

Change made. Change made.N/A. Section was almost entirely re-written. Change made.Explanations added. Error bars no longer shown for bins with no data.Statements are consistent with revised results.Change made.Change made. Other changes made as suggested.
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Section 5.3.3.1.3On p. 5-39, par. 3, line 1: Note that a 50-year life is stated elsewhere On p. 5-39, last line: Missing word. Insert “on the time before present” Section 5.3.4 In the section title, consider “Assessment of RLME Magnitude Distribution” First paragraph: In the first sentence, consider deleting “are intended to”; in line 6, change “study” to “project; in line 7, consider deleting “set to be”; in the last sentence, consider substituting “is” for “was chosen as”Section 5.4 (and Tables 5.4-1 and 5.4-2 Some additional discussion is required to explain the bases for the development of weights for the characteristics (or improved cross-referencing). On p. 5-41, par. 1, line 5: Consider deleting “a consideration of” On p. 5-41, par 2, line 7: Consider replacing “considering” with “evaluating” Section 5.4.1First paragraph: In line 3, consider replacing “considered” with “evaluated”; in lines 7–8, 

consider rewording the last clause to read: “the assessed values in column 2 of the table are based on assessments by the TI Team of the default characteristics that represent the current state of scientific knowledge”

Section 5.4.1.3In the first sentence: Consider rewording to read: “information about the characteristics of 

earthquake sources, modeled as finite faults in much the same manner as earthquake sources are modeled in the WUS.”

In line 6, consider replacing “in light of” with “using”In the last line: Consider deleting “largely” (or explain) and replacing “consideration” by “evaluations”Section 5.4.1.4In line 2: Consider deleting “upper” (or explain)In line 4: Replace “study” with CEUS SSC Model”On p. 5-43, first partial paragraph at top of page: In line 1, consider replacing “some” with 

“a high”; in line 2, replace “study” with “CEUS SSC Model”

Section 5.4.1.5In line 5: Replace “capture” with “represent”; in line 6, consider rewording to read: “The relationship used (Somerville et al., 2001)”In the last line: Replace “study” with “assessment” Section 5.4.1.6In line 2: Consider replacing “a consideration” with “an evaluation”In line 4: Replace “assumed to be equidimensional” to “assessed to be equidimensional” and change “For progressively larger areas” to “For progressively larger rupture areas”

In line 6: Consider deleting “it was assumed that”

In line 10: Consider deleting “assumed to be”In line 11: The NAGRA approach should be explained, as reviewers are unlikely to have this report.In the last line: Consider replacing “associated with” with “of” Section 5.4.1.7In line 1: Consider replacing “Assuming” with “For”, and “assumed to have” by “defined 

Referencing to Chapters 6 and 7 has been added to indicate that the technical bases for the weights are included in those chapters. Also, Chapters 6 and 7 have been made consistent and each section refers to applicable future earthquake characteristics.“Study region” is common terminology and has been kept. All other revisions made as suggested.
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by” In line 2: Replace “defined” with “represented”In line 5: Replace “assigned to” with “assessed for”

CHAPTER 6—SSC MODEL: Mmax ZONES BRANCH General Comments G 6-1. (NAR) The core of the TI Team’s assessment of the Mmax zones approach within 

the CEUS SSC model is described in this chapter. As such it is a critical chapter 

understanding of the assessment by future users. The TI Team has described an immense amount of data together with its evaluations of these data in characterizing and assessing this branch of the CEUS SSC model; in doing so the TI Team generally has described the assessment in sufficient scope and detail to inform future users of the model. 

No revision necessary. 

G 6-2. (CBR, U) Chapter 6 is generally well written. The discussion of each of the RLME sources is laid out logically providing a general description of the source, localizing feature(s), geometry, recurrence, and maximum magnitude. However, the basis for some of the assessments is not clearly articulated. Some specific examples are mentioned below, but the PPRP recommends the TI Team review all the subsections with an eye to improving the clarity and strength of the bases for assessments. For example, it is not always clear why one source is using the generic seismogenic crustal thickness assumptions while others are not. The same holds true for differences in assessed weights for clustered behavior. Another example is the empirical relationships used to derive magnitudes given assumed dimensions for seismic sources. To the extent possible, the TI Team needs to clearly establish their overall approach to assessing these weights; in some instances additions to Chapter 5 should be considered to establish the basic approach to how the TI Team decided to modify generic weights, or what generic data (discussed in Workshop #2?) influence the assignment of weights to individual seismic sources.

The bases for all assessments have been reviewed and revised as necessary for clarity.Explanation has been added for the assessed future earthquake characteristics and for assessed weights for clustered behavior. Dimensions of seismic sources have been checked to be sure they are compatible with the dimensions implied by the empirical relationships.The technical bases for all weights have been reviewed to ensure completeness and clarity. There are no “generic weights” for the assessments; all weights must be discussed and supported. Perhaps the comment refers to the “default” future earthquake characteristics; Discussion added to Section 5.4 regarding the use of the default characteristics or source-specific assessments and Table 5.4-2 

added summarizing the source assessments. 

G 6-3. (CC) In the 3rd paragraph of Section 6.1 the report states: “By identifying the RLME sources and including them in the model, there is no implication that the set of RLME sources included is, in fact, the total set of RLME sources that might exist throughout the study region.” This sentence and the remainder of the paragraph make a very important point about a fundamental assumption included in this model. This point 

needs to be articulated, specifically in Section 4 of the report as well.

The point is made in Section 4 of the report, as suggested. 

Specific Comments S 6-1. (CC, SSHAC) Achieving Clarity Necessary for Future User The importance of Chapter 6 for informing future users of the CEUS SSC model places a heavy demand on the TI Team to clearly document its assessment. As a framework for achieving necessary clarity of documentation, it may be useful for the TI Team to keep in mind the steps involved in implementing the SSHAC assessment process: (1) compiling the community knowledge; (2) compiling the relevant data; (3) evaluating the community’s knowledge, understanding the community’s uncertainty, and characterizing alternatives for assessment; and (4) assessing weights for the alternatives representing the 

Documentation of the technical bases for the assessments has been reviewed and revised as appropriate.Suggested wording for Section 6.1 incorporated as suggested.
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community uncertainty. Generally the TI Team has provided very thorough documentation of steps 1 and 2 in this chapter. Documentation of steps 3 and 4 is often less clear. Much of the lack of clear presentation can be attributed to misuse of terms. This is particularly evident in descriptions of the TI Team’s assessments where many different words (define, characterize, modeled, given, constrain, allowed, chosen, assign, assumed ...) are used for assessment. In addition to conflicting meanings, the impact of using words with such diverse meanings for the core SSHAC methodology requirement, namely “assessment,” is that they undermine the essential discipline that a SSHAC assessment requires. Other instances of misuse of terms coupled with lack of completeness in descriptions detract from the reviewers’ understanding of the evaluations performed and weaken the usefulness of the document for future users. Consider as an example the following edited first paragraph of Section 6.1 compared to the original.By definition, RLME sources are the locations of repeated (more than one) large magnitude (M ≥ 6.5) earthquakes in the historic and (or) paleoearthquake record. Because of the rarity of repeated large-magnitude earthquakes relative to the period of

historical observation, evidence for these earthquakes comes largely from the

paleoearthquake record. For example, paleoearthquakes identified by interpretations of paleoliquefaction features and fault displacement (paleoseismic) studies combined with those in the historical record result in the catalog of large-magnitude earthquakes in the 

central New Madrid region and at Charleston. At Charlevoix, RLMEs are observed in the historical record and are supplemented by the paleoearthquake record. For the

Meers and Cheraw faults as well as the Wabash Valley source, there are no large magnitude earthquakes in the historical record. The RLMEs for these sources are characterized by evaluating repeated surface-faulting displacements identified in trenches across the faults and, for the Wabash Valley source, by interpretations of the geographic distribution of paleoliquefaction features. S 6-2. (CC) Improving the link to the Data Summary and Data Evaluation Tables Prior to discussing specific seismic sources, the reader should be reminded that the information in the Data Summary and Data Evaluation tables provides a comprehensive assessment of the current information related to each seismic source. It is the PPRP’s view that external readers and reviewers of the CEUS report need to be at least familiar with those tables prior to objectively commenting on the TI Team’s assessment. This section would also benefit from a brief discussion of how the earthquake recurrence for 

RLME sources was modeled, specifically how the lower-bound magnitude for integration 

for these sources was established by the TI Team. 

Discussion added to Section 6.1 as suggested. 

S 6-3. (DMM, CC, U) Earthquakes of M ≥ 6.5 in the Charlevoix RLME 

The first paragraph in Section 6.1.1 describes two historical earthquakes of M ≥ 6.5 (one 

of M 7 in 1663 and one of M 6.5 in 1870). The reader is then pointed to the Charlevoix 

RLME logic tree (Figure 6.1.1-2) which has branches for the “Events/Data” node that do 

not appear to include the two historical earthquakes in the stated event count for M ≥ 6.5 

(e.g., “3 eqs in 9.5– 11.2 kyr”). Section 6.1.1.2 goes on to describe paleoearthquakes, 

including one “historic” paleoearthquake with “a bracketed age of at least 540 yr BP.” These descriptions need to be clarified for the reader to understand the basis of rate information. To appearances, the RLME rate information and calculated uncertainties for Charlevoix in 

Text clarified to indicate that the 1663 and 1870 earthquakes are RLMEs. Tuttle’s historical paleoearthquake could be either of these. Therefore two prehistoric earthquakes occurring at 5,000 and 10,000 years B.P. are the other two RLME events.Updated and revised recurrence calculation section clarifies how the historical earthquakes are used.
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the HID (Appendix H, Section 5.2) do not account for the two historical earthquakes in 1663 and 1870—only the paleoearthquakes. (For an example of better clarity, see the logic tree and HID tables for the Charleston RLME, where the reader is explicitly informed with labeling such as “1886, A, B, C” that the count includes one historical earthquake and three paleoearthquakes.) Adding to the problem of event counts, the text in Section 6.1.1.2 (first sentence of par. 2) states that “Tuttle and Atkinson (2010) provide evidence for at least three Holocene paleoearthquakes in Charlevoix with M ≥ 6.2 . . . .” If 6.2 is not 

a typo, then an assessment has to be made for how many of those events were of M ≥ 

6.5 (or explain assumptions). 

S 6-4. (U, DMM, CBR, CC) Unclear Interpretation Impacting Uncertainty In Section 6.1.1.2, par. 3, the third sentence states, “Focal mechanisms for earthquakes of magnitude ≥ 3 show reverse faulting, whereas smaller-magnitude earthquakes indicate 

some strike-slip and normal faulting, suggesting that local stress conditions affect rupture 

style (Lamontagne and Ranalli, 1997).” This indicates that there is a local source of tectonic stress. If this is the intent, the interpretation would be in conflict with the community’s knowledge and would require additional evaluation of uncertainty. 

Current literature (Baird et al., 2009) indicates that the Charlevoix RLME is attributed to the interaction of the impact crater and rift faults. Introductory text clarifies the local stress discussion.

S 6-5. (CC, DMM) Charlevoix—Geometry and Style of Faulting 

In the fourth paragraph of Section 6.1.1.2, while discussing the geometry and style of faulting for the Charlevoix RLME, the report indicates that future ruptures for this source are modeled as randomly-oriented thrust faults with dips between 45 and 60 degrees in 

either direction. Later on p. 6-6 the report indicates the RLME boundaries should be 

treated as leaky with ruptures permitted to extend beyond the source boundaries. There are a number of questions that arise in interpreting these statements that apply to several 

other RLME sources as well. The preceding paragraphs of the section describe fault orientations derived from small magnitude earthquakes. Keeping in mind the fact that a RLME source is for large (M ≥ 6.5) earthquakes and hence requires large rupture areas, 

the applicability of these results for small magnitude earthquakes needs to be carefully explained.

For the RLME sources it is not clearly explained what assumptions are being made regarding the recurrence model, i.e. is it Mmax ± 0.25 magnitude unit about each of the four identified Mmax values (noted briefly in Section 5)? This would be a “perfectly characteristic” or maximum-moment type model. This represents the epistemic uncertainty in Mmax plus the aleatory variability in the future occurrence of each of the characteristic events. The “interaction” between the lower ranges of magnitudes for the characteristic RLME source that will overlap with the upper end of the truncated exponential distribution being applied for the Mesozoic Extended Mmax source zone needs to be explained. This point is true for all the RLME sources. Since Charlevoix is the first of the RLME sources described, the TI Team should clearly explain these issues in this section. 

Text clarified to use reverse for dips between 45 and 60 degrees. Paragraph added at end of section 6.1 to address issue of combining RLMEs with their host seismic source.

S 6-6. (CC) Charlevoix—Maximum Magnitude In the last paragraph of Section 6.1.1.3, the discussion of boundary dimensions leading to the TI Team’s conclusion that the boundary is leaky requires more discussion. Given the assigned Mmax values, are the boundary dimensions too small to fit these magnitudes fully within the boundaries? To the extent possible quantitative discussion should be provided. 

The discussion of the boundary amplified to provide quantitative reasons for assigning them as leaky
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S 6-7. (DMM, CC) Unclear Logic for Performing Assessment In the first paragraph of Section 6.1.2.1, the meaning of “time periods of interest” as used is not clear. Is it the projected life of an NPP, the projected life of the CEUS SSC model, a geologic time period? In any case it is not clear how “time periods of interest” influences an assessment of whether tectonic strain release in the Charleston area is in or out of a cluster. Moreover, the TI Team must explain its evaluation, characterization, and assessment of the community’s knowledge about tectonic driving forces and the physics of tectonic strain release in a clustered sequence of large earthquakes at about 500-year 

intervals in the absence of any measurable strain deformation. Otherwise, the reviewer and potential future user of this report will not be able to understand the basis for the assessment. 

Text revised for clarity and to delete phrase “time periods of interest”. 

S 6-8. (CBR, U) Charleston—Evidence for Clustered Behavior In Section 6.1.2.1, the TI Team’s assessment of “in” or “out” of a cluster requires more justification. While the TI Team appropriately discusses the evidence of long-term versus short-term behavior, the fact remains that there is direct evidence of repeatedlarge earthquakes in the Holocene and little if any direct evidence that we are at the end of a cluster. Perhaps there needs to be some type of generic discussion of this issue in

Chapter 5, with Workshop #2 providing the ITC background to characterize and assess this issue. Otherwise the assessment that we are at the end of a cluster seems to come across as somewhat arbitrary versus informed assessment. What is different between 

Charleston and other RLME sources such as Cheraw? 

Generic discussion added to Ch. 5 regarding the issue of assessing clustered behavior.

S 6-9. (CC) Charleston—Geometry and Style of Faulting 

In Section 6.1.2.3, the discussion of boundary dimensions leading to the TI Team’s 

conclusion that the boundary for the three source geometries is either strict or leaky requires more discussion. Given the assessed Mmax values, are the boundary dimensions too small to fit these magnitudes fully within the narrow source boundary relative to the other two source definitions? To the extent possible, quantitative discussion should be provided. The TI Team’s assessment of using the default values for seismogenic crustal thickness requires additional justification. While all of the references cited for seismogenic crustal thickness are within the range for the default values, several suggest more preference (higher weight?) for values between about 15 and 20 km. Given this, the basis for assessing a weight of 0.4 to a seismogenic crustal thickness of 13 km is not clear. 

Seismogenic crustal thickness distribution revised. Discussion expanded to provide additional rationale and justification for Narrow and Local source configurations. 

S 6-10. (CC) Charleston—Weights for Charleston Narrow and Regional Sources In Section 6.1.2.3.1, the discussion of the basis for the weight assessed for the Charleston Local Source seems well developed. However, the discussion for the relative weighting of the Charleston Narrow and Regional sources is not clear. 

Text revised to provide additional rationale for weights on Narrow and Regional source configurations. 

S 6-11. (U, DMM, CBR, CC) Contextual use of the term “microseismicity”

In Section 6.1.2.3.1, first paragraph, the use of the term “microseismicity” potentially leads to confusion about tectonic processes. “Seismicity” is defined in terms of the spatial and temporal occurrence of earthquakes, a generally accepted measure of space-time 

tectonic strain release in earthquakes. The term “microearthquake” is now generally accepted to mean an earthquake of M ≤ 3. But the PPRP is not aware of a community definition of the term “microseismicity.” Consequently, the TI Team needs to explain its use of the term in the context of this evaluation. For example, is “microseismicity” used to 

The term “microseismicity” has been removed from section. 
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mean “seismicity of microearthquakes,” possibly implying a strain cycle process that is different from that implied by “seismicity”? The discussion should clearly convey how the TI Team evaluates “microseismicity” as one of the four observations cited as the basis for assessing the “Charleston Local source zone”? S 6-12. (CC, DMM) Charleston—Recurrence 

Given the uncertainty in length and completeness of the paleoliquefaction record and

interpreted number of separate episodes, and the very general description of the process used to develop recurrence values contained in Section 5.3.3, the PPRP strongly encourages the TI Team to include a step-by-step example of the application of the procedure used for at least one of the RLME sources. This should include additional figures and text. This will significantly improve clarity and transparency. Consider the following criticisms, some of which apply to recurrence calculations and corresponding HID tables for other RLMEs:In Section 6.1.2.5, the recurrence method is noted to be “based solely on inter-event times estimated from the paleoliquefaction record.” What this section fails to communicate clearly to the reader—especially amid the elaborate analysis and description of those inter-event times— is that the methodology used to calculate the annual frequency of earthquakes of M ≥ 6.5 (Section 5.3.3.1.2) ultimately uses only the 

elapsed time since the oldest event in the sequence and the number of events counted. The Charleston RLME logic tree (12th node), for example, points the reader to the HID tables. Referring to those tables, it will not be readily evident to the reader that the key pieces of information are N and the elapsed time since the oldest earthquake in the sequence of N events. Also, given that the oldest earthquakes (Table 6.1.2-1) 

have an age specified by a range, an explanation is needed whether (or how) that uncertainty was addressed.The unalert reader (or analyst) examining the HID tables for computed annualfrequencies for the Charleston RLMEs may potentially be confused by: (1) the inverted order for the 5-point distributions compared to Table 5.3.3.-1, which was used to define 

the 5-point distribution; and (2) the need to refer to Tables 6.1.2-1 and 6.1.2-2 to discern 

the elapsed time since the oldest earthquake counted in the sequence. For example, examining “Table Charleston_HID-3,” it may escape the reader’s attention that the 5- 

point distribution is not for four events in 5500 years, but rather four events in 1,524– 1,867 years (or possibly in 1,569–1,867 years). To reproduce the results in the table (and 

for virtually all the Poisson-model tables in the HID), there is no explicit information about 

the exact elapsed time that was used. To add to the confusion, the text does not explain what the age ranges listed in Tables 6.1.2-1 and 6.1.2-2 represent. Do they represent the 

mean ± 2 sigma from the probability distributions in Figure 5.3.3- 2? 

As the reader progresses to the BPT renewal model there are terse descriptions of the weighting (without justification of the weights) and cross reference to Section 5.3.3 for methodology—but the text does not provide any discussion of the results. How do the BPT results compare to those for a Poisson model? Do they make sense? 

Discussion of these issues added to Ch. 5 on the methodology for assessing recurrence for RMLE sources. 

S 6-13. (CC) Charleston—Time Period for Recurrence 

In Section 6.1.2.5.2 the discussion of the completeness period of the paleoliquefaction 

record (at least the last three sentences) seems equivocal. However, the weight assessed for the shorter completeness period, 0.8, indicates a strong preference; additional 

Text revised to provide additional clarity and rationale for relatively high weight on shorter completeness period.
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discussion seems required to justify the strong weighting. S 6-14. (U, CC) Clear Representation of the Community’s Knowledge for CharacterizingAlternatives and UncertaintiesThe discussion in Section 6.1.2.5.3 calls attention to the need for clear representation of the community’s knowledge and uncertainty as the basis for characterizing alternatives in the logic tree and for assessing the community uncertainty distribution. We offer the following edited paragraph as an example for comparison with the original paragraph:The ninth branch of the Charleston logic tree represents alternative characterizations of 

the community’s knowledge and the TI Team’s assessment of the community uncertainty for recurrence of large earthquakes in the Charleston Seismic Zone, developed as part of the CEUS SSC Project (Figure 6.1.2-1). Alternative interpretations 

of the distribution of liquefaction features include a total of four large earthquakes in the past approximately 2,000 years and between four and six large earthquakes in the past approximately 5,500 years. The alternative characterizations represented in the logic tree are based on (1) interpreted length of the paleoliquefaction record; (2) interpretedtypes of constraining ages; and (3) evaluations of the area distribution andinterpretations of which prehistoric liquefaction features were caused by large magnitude earthquakes centered in the Charleston area and which were caused bymoderate-magnitude local earthquakes. The clarity of this section could be greatly improved by technical editing to better link the descriptions of the current knowledge with characterizations of alternatives in the logic tree and with the assessment of the community uncertainty distribution. 

Text revised for clarity as recommended. 

S 6-15. (CC) Cheraw Fault—Evidence for Temporal Clustering 

In Section 6.1.3.1, the discussion of weights assigned to in or out of a cluster requires 

additional discussion given the statements that there is no evidence to indicate that this source is out of a cluster. It is not clear what the differences are for this source relative to other sources, such as Charleston as an example. 

Text modified to change weights from 0.8 to 0.9 for ‘in cluster’ and 0.2 to 0.1 for ‘out of cluster’ based on the lack of evidence to support a ‘out of cluster’ behavior.

S 6-16. (CC, U) Cheraw Fault—Magnitude In Section 6.1.3.3, p. 6-19, the discussion of relationships used to estimate magnitude from fault area includes “Somerville et al. (2001).” At various places in the Project report the citations for this relationship include Somerville et al. (2001), Somerville et al. (2005), and Somerville and Saika (2000). This needs to be double-checked and a validated reference cited (the Somerville references are in the gray literature and difficult to find, and the basis of the citation was not evident). A verifiable citation and reference need to be included in the Project database.On page 6-20, in the discussion of maximum and average displacement for the Cheraw fault the report notes: “There is insufficient information to establish whether the displacement per event measured at the sole trench 

site (emphasis added) along the Cheraw fault represents average or maximum values.” In the last sentence of this paragraph, the report concludes the values are maximum values. The conclusion does not seem to follow from the discussion in the paragraph as 

written. 

There is uncertainty regarding whether the displacement/event recorded at the site represents an average or maximum value for the fault as a whole. Revisions to text have been made to clarify uncertainty in the estimated range of average and maximum slip per event at the site. The Mmax distribution assigned to the Cheraw encompasses the range of M (6.8-7.2) suggested by 

displacements suggested by these revised estimates. Table 6.1.3-1 has been 

added to show the range of estimated magnitudes from different empirical 

relationships.

S 6-17. (CC) Meers Fault—Clustered Behavior In Section 6.1.4.1, the explanation of weights assessed for in or out of a cluster requires additional discussion, given the statements that there is no evidence to indicate that this 

Additional discussion was added to Chapter 5 regarding the evaluation of clustering behavior for RLMEs.
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source is out of a cluster. It is not clear what the differences are for this source relative to other sources such as Charleston as an example. S 6-18. (DMM) Meers Fault—Discussion of Potentially Relevant Data 

In Section 6.1.4.2, potentially relevant data for the assessment are not discussed. 

Specifically, the Meers fault is located on the sector of the boundary of the Wichita uplift that has greatest structural relief by a wide margin. The magnitude of the structural relief between the Wichita Mountains and the Anadarko Basin is the source of a very large gravity gradient indicating significant induced stress across the northern Wichita 

Mountains frontal fault system along this sector. A discussion of these potentially important data should be included for perspective.Also, is “Arbuckle-Wichita-Amarillo uplift” a proper usage? A reference to the source of 

this usage is needed. 

The section in question discusses the “localizing feature” branch of the logic tree. The presence of a gravity gradient was not used to argue whether the Meers-like activity should be localized on the fault or allowed to occur throughout the aulacogen. Also, a gravity gradient does not necessarily say anything about the state of stress on a fault system. The gravity gradient is used in helping to define the geometry of the zone and is discussed elsewhere in the section.A-W-A is a name used in the literature. See references in data summary table 

(e.g., Perry 1989). There is no need to cite a reference in the text just for this naming convention; the intention and meaning of the name is clear in the existing text. 

S 6-19. (CC, U) Meers Fault—Localizing Feature In Section 6.1.4.2, it is not made clear in the discussion of the potential for the occurrence of Meers-like ruptures in the Oklahoma Aulacogen why “only one Meers-like structure is 

active within the aulocogen at a time.” 

Added “This interpretation is based on the fact that there is no evidence of Quaternary activity on other faults within the aulacogen.”

S 6-20. (DMM, CC, U) Meers Fault—Geometry and Style of Faulting In Section 6.1.4.3, on page 6-24: When Meers-like earthquakes are allowed to migrate off 

the fault they are limited to occurring within the OKA. How are the earthquakes within the OKA to be modeled? The next paragraph suggests the strike to be N60W (parallel to the Amarillo- Wichita-Arbuckle uplift) with a dip between 40 and 90 degrees. However (and 

this comment holds for several of the other RLME sources), it is not clear how the analyst should model this situation. As a series of fictitious parallel faults distributed throughout the appropriate portion of the OKA? If so, how many are appropriate? This answer will clearly be determined by the location of the site of interest relative to the source. What was assumed by the hazard analysts for the demonstration and sensitivity calculations? On pages 6-24 and 6-25: The discussion indicates there is a significant amount of 

uncertainty in the appropriate H/V values to assign to the displacement observations. It does not seem as if this uncertainty is represented in the final recurrence values for the Meers RLME. Additional clarification seems necessary. On p. 6-24, third paragraph: The assignment of seismogenic thickness for the Meers fault 

source based on one reference seems to be inconsistent with how this parameter has been assessed for other seismic sources including Charleston. Consistency in 

assessment of each of the branches of the logic tree is an important consideration. If outside reviewers see inconsistencies in the assessment of weights for the logic tree branches, then their confidence in the overall assessment may be weakened. 

 Details of the source model implementation are provided in the HID. Recurrence for the Meers fault is based on the record of discrete faulting offsets in the trenches and does not depend on H/V ratios.The methodology for assessing seismogenic thickness for all seismic sources is the same and is discussed in Section 5.4

S 6-21. (CC, U) Meers Fault—RLME Magnitude In Section 6.1.4.4, the use of four seismic source dimension relationships to characterize and assess magnitude for this seismic source contrasts with the approach to other seismic sources. It is not clear why the Meers source is any different than other seismic sources to justify these differences. A consistent approach to characterizing and assessing magnitude based on source dimensions seems to be appropriate. There does not appear to be any unique property of the Meers fault that would justify using rupture 

Unlike most of the other RLME sources, the Meers fault is a discrete mapped fault, thus allowing fault-specific characteristics to assist in the assessment of 

RLME magnitude. 
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area relationships for the Meers fault but not other RLME sources such as Charlevoix, Charleston, or Cheraw. S 6-22. (CBR, CC) New Madrid—RLME Magnitude In Section 6.1.5.3, the use of unpublished information (Hough and Page) needs careful consideration. Has the paper been accepted for publication? Additionally, the text discusses the use of the characteristic earthquake recurrence model. Other sections of the text indicate that the characteristic earthquake recurrence model is not being used.

The Hough and Page manuscript has now been published: Hough, S. E., and M. Page (2011), Toward a consistent model for strain accrual and release for the New Madrid Seismic Zone, central United States, J. Geophys. Res., 116, 

B03311. 

References to the characteristic model have been deleted from this discussion. The model includes epistemic uncertainty in the average size of the RLME earthquakes, plus aleatory variability in the size of next earthquake of one-quarter magnitude unit. Section 5.3.3 has been modified to clarify this 

approach. 

S 6-23. (CBR, CC) New Madrid—Recurrence Section 6.1.5.4 presents an insufficient basis for the assessed weights for the two alternative recurrence models characterized. The text should refer to Workshop #2 for discussion of this topic and present more information to justify the weight assessed for the renewal recurrence model. 

Additional discussion of the basis for the weights added to the discussion of recurrence models in Section 5.3. 

S 6-24. (CBR, CC) Reelfoot Rift—Eastern Rift Margin Fault, Evidence for Temporal 

Clustering: Section 6.1.6.2

In Section 6.1.6.1, for this seismic source, the TI Team has assessed non-clustered behavior with a weight of 1.0. The evidence for this assessment is stated to be insufficient information on the number or timing of earthquakes. This contrast with other RLME sources where the main issue pertained to evidence of short-term versus long-term behavior and the logic that short-term rates cannot extend through extended time frames. 

That logic also appears to apply to the ERMF. The TI Team needs to develop a consistent approach to assessing clustered versus non clustered behavior. 

The text has been revised to state... “The available data regarding number and timing of recent earthquakes and long term slip rates for the ERM sources are not sufficient to evaluate whether the ERM RLME sources exhibit evidence for temporal clustering. Therefore, this branch of the tree is not applicable to the Reelfoot Rift ERM_S and ERM_N RLME sources.

S 6-25. (CBR, CC) Reelfoot Rift—Marianna Zone, Evidence for Temporal Clustering 

In Section 6.1.7.1, the text states, “It also is unclear whether some of the paleoliquefaction features are due to earthquakes on the Eastern Rift Margin (ERM, 

RLME) source . . . .” Given this statement, it is not clear why this seismic source has a probability of activity of 1.0. The discussion and justification of the weight for temporal clustering need to be strengthened. Similarly, the basis for characterizing the seismic source boundary is “leaky” needs to be improved.

The size and number of features in the Marianna area suggest that most if not all of the liquefaction features are due to a local source rather than a more distant ERM source. It is acknowledged however that some of the paleoliquefaction features in the Marianna area could be related to an earthquake on the ERM. The text has been modified to clarify that there is evidence of a local source. Tuttle (WS #2) and others have suggested that seismicity migrates within the RRZ on a 5-15 kyr time frame. The apparent clustering of events in the early 

Holocene and lack of recognized events in the late Holocene has been postulated to support this concept (i.e., that the locus of activity is currently in the NMSZ rather than in the Marianna region). A statement regarding this concept has been added to support the 0.5 (in versus out) of a cluster weight assigned to this source. 

The ‘leaky’ boundary acknowledges that the location of the source of the earthquakes giving rise to the Marianna features is uncertain. 
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S 6-26. (CC) Reelfoot Rift—Marianna Zone, Geometry and Style of Faulting 

In Section 6.1.7.2, last paragraph, the probability distribution on seismogenic thickness is different than the default distribution. Given this, the text should provide more details on 

the number of well-located earthquakes in this source and how they are used to establish 

a distribution on seismogenic thickness that is different than the default values.

The seismogenic thickness distribution in the Reelfoot rift is based on recent analysis and relocation of earthquakes using an improved velocity models for the northeastern part of the rift (Shumway, 2008) and along the eastern margin (Chiu et al., 1997). These studies indicate that the best located events lie within the upper 16-17 km of the crust. Therefore, this distribution rather 

than the default distribution was used. 

S 6-27. (CBR, CC) Reelfoot Rift—Commerce Fault, Evidence for Temporal Clustering 

In Section 6.1.8.1, the text notes that the liquefaction and secondary faulting used to 

document Holocene events may be related to strong ground motion from earthquakes occurring elsewhere in the Reelfoot Rift. Given this statement, it is not clear why this seismic source has a probability of activity of 1.0. The basis for assessing a weight of 1.0 to nonclustered behavior is not clear.

The text has been revised to state... “The available data regarding number and timing of recent earthquakes and long term slip rates for the Commerce RLME source is not sufficient to evaluate whether the Commerce RLME source exhibits evidence for temporal clustering. Therefore, this branch of the tree is not applicable to this source. 

S 6-28. (CC) Reelfoot Rift—Commerce Fault, Geometry and Style of Faulting In Section 6.1.8.2, last paragraph, the basis for characterizing the northwest and southeast boundaries of the seismic source as fixed and the northeast and southwest boundaries as “leaky” is not clear.

The northwest and southeast boundaries, which are defined by the general limits of the CGL as defined by Hildenbrand are sufficiently wide enough to cover the zone of surface faulting that has been identified by various 

researchers. There has been less work to define the northeastern and 

southwestern extent of the zone of Quaternary deformation and the geophysical lineament can be traced in both of these directions beyond the limits of the paleoseismic investigations. Therefore, the TI team judged that leaky boundaries would serve to represent the greater uncertainty in the possible extension of ruptures along the CGL. 

S 6-29. (CC) Wabash Valley—Temporal Clustering: Section 6.1.9.1 In Section 6.1.9.1, the basis for the weight of 1.0 on “in a cluster” needs to be improved and to be consistent with the bases for this assessment for all RLME seismic sources. 

The last sentence of Section 6.1.9-1 has been revised to read...“Therefore, this branch of the tree is not applicable to the Wabash Valley RLME source.” 

S 6-30. (DMM, CC) Wabash Valley—Future Ruptures 

On pages 6-59 and 6-60 there is no specific discussion of how the future ruptures are to 

be modeled. The text refers to Table 5.4-1 (should be Table 5.4-1 and 5.4-2). But as 

noted previously, additional guidance for the hazard analyst would be useful. 

The appropriate table callout should be Table 5.4-2 (not both Tables 5.4.1 and 5.4-2). The text is modified accordingly. The information provided in Table 5.4-2 and the associated discussion in the 

Section 5.4 text should be sufficient input for the hazard analyst. 

S 6-31. (CC) Wabash Valley—Alternative Mmax Zones In Section 6.2, the discussion of alternative Mmax zones only discusses the Bayesian approach to Mmax estimation and its relevance to source zone characterization. The consistency of the results using the Kijko method should be discussed as well. 

The results derived from the Kijko approach are now discussed. 

S 6-32. (CC) Criteria for Definition of Boundary—Mesozoic Extended Narrow Zone 

In the last sentence of Section 6.2.1.1 on p. 6-64, the text states: “These observations 

support the weight of 0.8 that this geometry represents crust extended in the Mesozoic.” The PPRP does not feel the section make the case well. A series of well written observations are presented, but the relevance of the observations to source 

characterization and specifically to a weight of 0.8 is not clearly articulated. This same comment applies to the other sections on Mmax zones. 

Section 6.2 has been rewritten to better outline criteria used to differentiate MESE versus NMESE crust and more directly relate the weight assigned to the wide versus narrow geometries to these criteria.

S 6-33. (CBR, U) Comparison of Recurrence Parameters to Catalog Two additional cycles of model-building and hazard feedback were conducted 
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As discussed in Section 6.4.2, Figures 6.3-7 through 6.3-16 (should be corrected to read 6.4-7 through 6.4.16) show that the recurrence model for the large seismic source zones 

tends to overestimate the rates for magnitudes 5 or higher. What does this mean to the TI Team? A systematic trend such as the one discussed, should be questioned in detail by the TI Team in terms of evaluating whether all assumptions of the analysis are appropriate. The consistent overestimates of the rates suggest that assumptions related to smoothed seismicity may need to be adjusted to provide a better match between the recurrence model and observed seismicity. The PPRP strongly believes additional discussion and investigation is warranted regarding these results. 

following the draft report, thus providing the TI Team the opportunity to question and review the recurrence results, both those related to recurrence plots and to spatial smoothing of recurrence parameters. The PPRP was an observer during these working meetings and briefings. The results are now 

judged by the TI Team to be reasonable relative to the observed rates from the catalog.

S 6-34. (CR, DMM, U) Need for TI Team Assessment of Spatial Variation of Rate and bvaluesThe results of the recurrence-rate analysis presented in Section 6.4 clearly show that TI 

Team assessments of priors on rate and b-values are required. The derived b-values in 

particular appear to be almost entirely below the range of values supported by studies world-wide over many years. We recommend that the Project arrange to further evaluate 

this analysis. 

As suggested, such analyses occurred and changes were made to the recurrence model. Discussion of the recurrence methodology is given in 

Chapter 5.3. 

Comments by Section Chapter 6 (Title) Given that 60 of the 70 pages in this chapter deal with RLME sources, the chapter title should be changed to something like, SSC MODEL: MMAX ZONES BRANCH AND RLME SOURCES. 

Revision made as suggested. 

Chapter 6 (Introductory text) In the introductory paragraph at the top of p. 6-1, after the second sentence, it would be 

helpful to most readers to repeat a very helpful description that appeared on p. 4-16f in 

Section 4.4.1:

The “Mmax zones” model involves the direct use of observed seismicity by spatial smoothing of distributed seismicity and the inclusion of RLMEs that are defined primarily by paleoseismic evidence. The “seismotectonic zones” model involves the use of additional tectonic data to define the spatial distribution of future events. 

Revision made as suggested. 

Section 6.1.1 p. 6-2, 2nd paragraph: Regarding “(source IRM in the R model)”: we assume this refers to 

the Canadian study; clarification is needed.

p. 6-2, 3rd paragraph: The phrase “investigations undertaken for the . . .” probably should 

be “investigations evaluated . . . ” The PPRP believes only evaluations were performed. Section 6.1.1.2

Note: There are two sections labeled 6.1.1.2—one on p. 6.4 and one on p. 6-6. On p. 6.4, in paragraphs 3 and 4, “thrust” and “reverse” are used inconsistently vis-à-vis 

the definition provided in the Glossary for “Fault, Thrust” (< 45°) and “Fault, Reverse” (> 45°).

On p. 6-6, 2nd paragraph, next-to-last sentence: “. . . favors three events to four based on 

field observations.” A citation would be helpful. 

Revisions and clarifications made as suggested. 

Section 6.1.2.1 In last sentence of the first paragraph, the reader is referred to a non-existent Section 

- Text revised to provide correct subsection call-out (5.1.2). 
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5.3.3.6. In scanning Chapter 5, it’s not clear that there is a “definition” of the temporally clustered earthquake model.On p. 6-8, 2nd full paragraph: No justification is given for weights on whether the Charleston RLME is “in” or “out” of a cluster.Section 6.1.2.5.3 p. 6-14, last paragraph, line 10: Typo. (see See Appendix E . . .). Section 6.1.2.5.4 The use of “occurrence model” in the section title and text is at odds with “recurrence model” used predominantly throughout the text (easily verified by a global search for “recurrence model,” which shows repeated instances of “Renewal vs. Poisson recurrence models”) and in the Glossary. There is at least one other appearance of “occurrence model” in the text (Section 4-19, p. 4-20, beginning of second full paragraph). “Occurrence” rates/probability also appears in Section 5.3.3.2 and should be corrected globally.Section 6.1.2.4.3p. 6-13, 2nd paragraph: “The UCSS magnitudes and weights . . . .” UCSS not defined. 

- Generic discussion of in vs. out of cluster to be added to Ch 5. - Typo corrected - Text revised to replace term “occurrence model” with “recurrence model”.

- “UCSS” is typo. Deleted. 

Section 6.1.3.2 p. 6-19, 3rd paragraph: The weights assigned to the two dip cases sum to a value greater 

than one.

Section 6.1.3.4p. 6-21, second full paragraph, line 3: The term “interval-based approach” is ambiguous 

and potentially misleading. The data used are the number of earthquakes in a specified time interval (e.g., Figure 6.1.1-2, 7th node), not the interval between earthquakes, as 

some readers might assume.p. 6-21, fourth full paragraph, line 1: Consider replacing “occurrence rates” with “recurrence rates”p. 6-21, 4th full paragraph: Typo in cited recurrence values: 200, 350, and 500 years, 

should be k-years. 

Change (0.5) to (0.4). The approach used to model recurrence for the Cheraw fault is intervalbased. The text and description in this section have been modified to clarify 

this. 

Years changed to kyr

Section 6.1.4.5 2nd par., line 4: Typo. Change “500,00 years” to “500,000 years” 

Changed 

Section 6.1.5 In the Table on the top of p. 6-33: The note for the 1811-1812 earthquakes indicates 138 

yr BP ± 100 yr. As written, suggests the uncertainty is 100 years; this needs to be clarified.

Section 6.1.5.3p. 6-39, last paragraph: The text references Table 6.1.5-3 which appears to be missing. 

Section 6.1.5.4

p. 6-41, first full paragraph, last sentence: Replace “only includes of all three” with “only 

includes the alternative of all three components”

p. 6-41: The paragraph containing equation 6.1.5-1 is not clear. The use of the equation 

needs to be explained within the source characterization scheme. 

Text (and table will be modified to discuss in detail the analysis, data used, and resultsTable 6.1.5-3 will be included in the final report p. 6-41 (first full paragraph) sentence corrected as suggested. p. 6-41—deleted the last paragraph that included the equation. 

Section 6.2.1.2 Section 6.2.1.2 has been rewritten. Typo comment is thus obsolete See 
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p. 6-66, 2nd full paragraph line 9: Typo. (** mi) Section 6.3line 4: Typo. “source( described...” Section 6.3.1p. 6-69, first full paragraph, line 9: Reference is made to “the 1882 earthquake”; this event 

is not in the table on the previous page and there is no context. Adding a short descriptive sentence for clarity would help the reader.

Section 6.4.1 In the first line, change “Figures 6.3-1 through 6.3-6” to “Figures 6.4-1 through 6.4-6” Section 6.4.2In the first line, change “Figures 6.3-7 through 6.3-16” to “Figures 6.4-7 through 6.4-17” 

Figure 6.1.1-1 

Two of the large earthquakes are incorrectly labeled: 1663/2/5 is labeled M=3.71 (text in 

Section 6.1.1 says “M 7”; 1791/12/6 is labeled M 5.5 (text in Section 6.1.1 says “M 5.8). 

The labeled magnitude for only one of the other three large earthquakes corresponds exactly to the text in Section 6.1.1. 

Figure 6.1.1-2 In the Charlevoix RLME logic tree, the header for the 10th node should be changed from “Earthquake Occurrence Model” to “Earthquake Recurrence Model” (see comment on Section 6.1.2.5.4).Figure 6.1.2-1 In the Charleston RLME logic tree, the header for the 10th node should be changed from “Earthquake Occurrence Model” to “Earthquake Recurrence Model” (see comment on Section 6.1.2.5.4).Figure 6.1.2.4Figure 6.1.2-4 shows the three zones along with the magnitude and gravity anomalies. It 

is not clear how these zones were delineated based on these geophysical data. 

Figure 6.1.3-1 In the Cheraw RLME logic tree, under Recurrence Method, the uppermost branch should more correctly be labeled “Earthquake Count in Time Interval” (as for the Charlevoix RLME logic tree instead of “Inter-event Times.” Figure 6.1.3-1 In the Meers RLME logic tree, under Recurrence Method, the upper and lower branches should more correctly be labeled “Earthquake Count in Time Interval” (as for the Charlevoix RLME logic tree) instead of “Inter-event Times.” In the corresponding HID tables (Table MEERS_HID-2 and HID-3), information on the data set (N events, T time) 

should usefully be provided, as in Table Marianna_HID-2. 

Figure 6.1.5-1 In the logic tree for the NMFS RLME source, under Equivalent Annual Frequency, references to the HID tables should be labeled NMFS instead of NMF. Under Events/Data, the labeling of “1811–1812, 1450 AD, and 900 AD” is difficult to relate to the 

dates in the table presented at the top of p. 6-33 (for example, 900 AD corresponds to 

1110 yr BP—but in the table one finds “1,050 yr BP ± 150 yr). Exactly which elapsed time 

was used in Table NMFS_HID-2? (In that table, information on the data set (N events, T 

revised Section 6.2.1.2 Figure 6.1.1-1 labeled modified. Figure 6.1.6-2 The star represents paleoseismic investigation sites. This will be added to the explanation.Tables 6.1.5-1, 6.1.5-2, and 6.1.5-3 will be included in the final draft. Logic tree labeling of approaches made consistent throughout Clear descriptions of the data used for each RLME recurrence calculations are provided in each section along with tables of the results.
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time) should usefully be provided, as in Table Marianna_HID-2. Figure 6.1.6.2What are the yellow stars on the figure? No explanation in legend or caption.Figures 6.4-1 through 6.4-6 Consider adding a note to the caption explaining what the mean maps are.Tables 6.1.5.1, 6.1.5.2, and 6.1.5.3 missing Table 6.1.5-1 discussed on page 6-32 is missing. Table 6.1.5-2 discussed on page 6-37 

is missing. Table 6.1.5-3 discussed on page 6-39 is missing. 

CHAPTER 7—SSC MODEL: SEISMOTECTONIC ZONES BRANCH General Comments G 7-1. (NAR) In this chapter, as in Chapter 6, the TI Team has described and evaluated 

an immense amount of data and information and deserves praise for its efforts. The chapter addresses the “seismotectonic zones” branch of the master logic tree, as developed in Chapter 4 and portrayed in Figure 4.4.1-11 (and companion figures 

referenced therein). The TI Team’s assessment is supported by Data Evaluation and Data Summary tables in Appendices C and D. This conceptual branch of the logic tree splits into two source groups—seismotectonic zones and the independent RLME sources, 

described in Chapter 6. Chapter 7 deals only with the twelve seismotectonic zones and their seismic characteristics. 

No revisions required. 

G 7-2. (CBR, CC) A significantly higher weight is assessed for the seismotectonic zones branch relative to the “Mmax zones” branch. As stated in Section 4.4.1 on p. 4-17: “A higher weight (0.8) is assigned to the seismotectonic zones branch than the Mmax zones branch (0.2) because the seismotectonic zones branch allows for more relevant information on the characteristics of future earthquakes to be included in the model.” This information is the subject of the majority of Chapter 7. However, no full explanation or validation is presented in the introduction to this chapter to support the decision on the specific weights assessed for the two conceptual approaches at the front end of the master logic tree. A description of the justification of the weights would be an important and useful addition to the chapter. 

The discussion of the basis for weights has been bolstered in Section 4.2.1. It is not appropriate to repeat that discussion in Chapter 7, but reference is made back to Section 4.2.1. 

G 7-3. (CC, DMM, U) Although the chapter provides an abundance of geological detail, it fails to make a compelling case for identifying many of the seismotectonic zones as 

separate sources distinct from the larger Mmax zones described in Chapter 6. Considering the weight that is given to this branch (0.8), it is especially important that the definition of each of the seismotectonic zones be very clear and well supported with 

convincing evidence. Unfortunately, a persuasive case is not developed for the identification of several of the zones described in this chapter. 

Each section of Chapter 7 includes a summary of the bases for identifying the seismotectonic zone, and the criteria that define each zone are summarized in Table 4.1.3-1. Each section has been reviewed and revised, as necessary, to 

ensure that the bases for the seismotectonic zones are adequate and clear. 

G 7-4. (CC, DMM) The identification of the zones appears to be made largely on the basis of isolating regions of differing geological and tectonic histories that may have little direct relevance to the SSC characterization criteria that are specified in Section 4.3.3 (p. 4-14). 

These criteria are : (1) earthquake recurrence rate, (2) maximum earthquake magnitude, (3) expected future earthquake characteristics (e.g., style of faulting, rupture orientation, depth distribution), and (4) probability of activity of tectonic feature(s). The latter criterion was not used in developing the CEUS SSC model (Section 7.1, pg. 7-1), but no 

The bases for identifying the seismic source zones in the CEUS SSC model indeed come from the four criteria. The statement that the fourth criterion was not used is incorrect and has been removed. Examples of the application of 

the criterion are the Meers fault and Cheraw fault. Discussions of the bases for identifying each of the seismotectonic zones have been revised to tie the discussion back to the four criteria, as applicable. As suggested, Table 4.1.3-1 

has been added to summarize how the Mmax zones and the seismotectonic 
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justification is given for not addressing this criterion. Furthermore, there is no uniform or systematic description of the application of the first three criteria which allow ready identification of the merits of the zones and which permit comparison among zones. Additional information pertaining to how the sources meet the defining criteria and more systematic organization of the content of the description of the zones would increase the 

rigor of the decisions reached in the report and their presentation. A summary table specifying the critical information that identifies each source zone based on criteria described in Chapter 4 would be helpful in organizing the information and comparing 

source zones. 

zones relate to the four seismic source identification criteria. 

G 7-5. (CC) Chapter 7 includes an impressive compilation of information and interpretations representing the range of relevant current knowledge of the scientific community. The scope and detail of this information are important in identifying and 

characterizing the seismotectonic zones and will be of great value to future users of the CEUS SSC Model. This information is well supported by comprehensive and timely references to the scientific literature. The level of detail is generally consistent throughout the description of the zones, but unfortunately the organization of the descriptions is not consistent. For example, some source zones have initial sections dealing with Background, others with Geologic Evidence, and still others with Basis for Defining Seismotectonic Zone. This lack of consistency in the description of the identified zones is 

an impediment to the review and comparison of the zones and needs to be corrected. The uneven descriptions appear to be due, in part, to multiple authorship, and some subsections apparently have not been updated since the application of the Kijko Mmax procedure in the Project. Some updating and rewriting appears warranted to alleviate these problems. 

The sections have been organized to be comparable section to section. 

G 7-6. (CC) The level of detail in this chapter is high, which will be useful in future seismotectonic studies within the CEUS. However, this level of detail will make it difficult for those readers of the report not well versed in the geology and geography of the region or the geologic time scale to comprehend the significance of the detail. Thus, to support the detail it would be advisable to (1) add maps that identify the location of geologic features, (2) provide more geologic terms in the glossary, and (3) accompany the glossary with a geologic time scale. Additionally, the descriptions of the seismotectonic zones should be reviewed to determine if some of the more specialized terminology, e.g., essexite, T-axes, Neoproterozoic, can be eliminated or simplified so that they can be meaningful to the spectrum of users of the report. 

Locations referred to in the text have been added to the maps, terms have been added to the glossary, and a geologic time scale has been added to the glossary. Terminology has been simplified wherever possible to avoid unnecessary jargon.Figures 7.3.1-2, 7.3.2-2, -3 added. Labels for places discussed in text added 

to all relevant figures; deleted mention of specific alkaline rocks, including 

essexite in Section 7.3.2.1.Deleted mention of T-axes in section 7.3.1.4 

G 7-7. (CC, SSHAC) As with previous chapters, this chapter could be greatly improved by a thorough technical edit. There are numerous editorial modifications required to achieve 

consistency in presentation, remove editorial errors, and improve clarity. Special attention should be given to clearly describing the bases for characterizing alternatives represented in alternative branches of the logic tree. Also, consideration should be given to describing the basis for the assessed weights for alternative characterizations representing the community uncertainty. Finally, care must be exercised to use words in their correct 

meaning, avoid casual terminology, and use terms that properly convey the essential activities of characterization of alternatives and assessment of the community uncertainty. 

All sections have been reviewed and revised relative to describing all branches of the logic tree and the technical bases for the weights assigned to each branch.

G 7-8. (DMM) The Data Summary Tables of Appendix D are an important supplement to the descriptions of the seismotectonic zones. Unfortunately there appear to be omissions in Appendix D so that supporting information is not consistently available for this draft 

All Data Summary tables are now included in Appendix D. 
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chapter. This will need to be remedied in revision of the report. Additional comments on Appendix D are given in a review of that segment of the report. 

Added key references from text to Date Evaluation tables. 

Specific Comments S 7-1. (CC) Suggestion for Rewrite of Introductory Paragraph The introduction to Chapter 7 could be improved with significant editing. Consider the following as an example. As discussed in Section 4.3, the Conceptual Framework for assessing the CEUS SSC model is characterized by two alternative branches of the master logic tree: the Mmax zones branch and the seismotectonic zones branch. The seismotectonic zones branch, which is assessed a higher weight of 0.8 versus 0.2 for the Mmax zones branch,subdivides the CEUS SSC region according to differences in the seismic source assessment criteria described in Section 4.3.3. A common element of both the Mmax zones and the seismotectonic zones branches is the RLME sources. Because thepaleoearthquake data that indicate the presence, location, and size of the RLMEs are essentially independent from data used to assess seismotectonic sources, the RLMEbranch is present in both models. An overview of the approaches for characterizationand assessment of the zones is in Section 7.3. 

Revision made using most of suggested example. 

S 7-2. (DMM) Need for Specifics Regarding Geologic Conditions that Affect Mmax The first paragraph of Section 7.1 (p. 7-1) describes how the seismotectonic zones branch relates to Mmax. The basic premise is that regional differences in characteristics related to Mmax and/or future earthquake characteristics are best dealt with by identifying source zones of uniform properties. A region may possess characteristics that would lead to a different Mmax than adjacent regions, including a different prior distribution or different maximum observed earthquake. Mmax was described in Chapter 5, but it would be helpful to the users of the report for the authors to present examples of specific physical properties of the zones (e.g., thinner crust, lithospheric strength characteristics, aulacogens) and describe why these different conditions might result in different Mmax distributions. This information would help to sharpen the need for, and the significance of, the detailed information in the subsequent text which define Mmax and future earthquake characteristics. 

Examples and discussion added to Section 7.1 to illustrate the manner in which the zones were identified and how they differ from one another. The methodologies for assessing Mmax are described in Section 5.2. As discussed therein, the only physical characteristic that is important for the Mmax assessment is whether or not the zones show evidence of Mesozoic or younger extension. Otherwise, the differences in future earthquake characteristics of the various zones are described in Section 5.4 and summarized in Table 5.4-2. There is no explicit connection between these characteristics and Mmax.

S 7-3. (CC) Description of Charlevoix RLME Source; Section 7.3.1.1.3, pg. 7-6. In Section 7.3.1.1.3 (p. 7-6), the description of the Charlevoix RLME seismic source (which is assumed to exist as a distinct seismic source) as part of justifying the St. Lawrence Rift (SLR), confuses the understanding of whether the SLR is a distinct seismotectonic zone. Part of the confusion relates to how the project is using historic earthquakes as part of the development of recurrence and maximum magnitudes. Are the historic earthquakes assigned to the SLR, even though they may be located within the boundaries of the Charlevoix RLME source? 

Text in Section 6.1.1 and 7.3.1 clarified to indicate which earthquakes are considered RLMEs. Text in Section 7.3.1.1 introduces Charlevoix and other portions of the SLR seismotectonic zone such as the Ottawa-Bonnechere graben, Saguenay graben, and lower St. Lawrence as crust within SLR that exhibits varying rates of seismicity.

S 7-4. (DMM) Significance of Vp/Vs Ratio On p. 7-14 of Section 7.3.2, under Geophysical Evidence, what is the significance of results from teleseismic receiver functions described in last sentence of this section? 

Eaton et al. (2006) do not interpret the result of variable Vp-Vs ratio: “Finally, region 3 is an area of thin crust (<38km) and variable VP/VS ratio. This area is entirely located northeast of the Ottawa–Bonnechere graben, a postGrenvillian extensional feature that formed during the opening of the Iapetus ocean (ca. 0.7Ga; Kamo et al., 1995). It is interesting to note that region 3 appears to coincide with the Western Quebec Seismic Zone (Fig. 14), an area 
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of relatively intense intraplate seismicity.” It could be judged that variable Vp-Vs ratio could be attributed to intrusion of 

mafic rocks into felsic host rock, but the authors have not made that interpretation. 

S 7-5. (DMM) Evidence for Separating the Northern Appalachian Seismic Zone from the Paleozoic Extended ZoneIn Section 7.3.3.2 (p. 7-20), under Basis for Zone Geometry: The separation of the Northern Appalachian seismic zone (NAP) from the similar Paleozoic Extended zone (PEZ) to the south appears to be largely based on the location of the Triassic Hartford basin. However, a linear connection of the eastern boundaries of these zones would include only a small segment of the northern extent of the basin as shown in Figure 7.3.7-1 similar to the situation observed farther south along the boundary of the PEZ. Is the termination of the NAP being driven by the studies of Adams et al. in defining the seismic source zones of Canada? 

Boundaries of PEZ-N modified on the west to follow the NY-AL lineament and the western boundary of the Hartford Basin. The southern boundary of the NAP seismotectonic zone follows the northern boundary of the Hartford basin. 

S 7-6. (DMM) Future Earthquake Characteristics; In Section 7.3.3.4 (p. 7-21), under Future Earthquake Characteristics for the Northern Appalachian seismotectonc zone, the text notes that all earthquakes with known depths are relatively shallow, but goes on to use the default depth distribution for the seismic source. The basis for assigning the depth distribution for distinct seismic sources, including the NAP, should be based on a common approach to using earthquakes with known depths. Otherwise, assignment of the default depth distribution lacks rigor. Also note that a search of Chapter 5 shows no “default depth” term. 

All estimates of seismogenic crustal thickness have been assessed using the same approach, as described in Section 5.4.

S 7-7. (DMM) Background of the Paleozoic Extended Zone In Section 7.3.4.1, the text needs to make clear that the Giles County Seismic Zone, the Eastern Tennessee Seismic Zone, and the Clarendon-Linden Fault System, are not unique from a seismotectonic perspective. Otherwise it is not clear why these features are not considered distinct seismic source zones. 

Text reorganized to include large regional data and conceptual framework in the background section and specific seismological characteristics of zones of historically elevated seismicity within subsections.

S 7-8. (DMM) Basis for Western Margin of the Paleozoic Extended Zone In Section 7.3.4.2 (p. 7-29), under Basis for Zone Geometry: A reentrant of the Paleozoic 

Extended seismic zone extends into the craton in the vicinity of Kentucky, moving the western margin of the zone farther west. There is no support for this feature in the text of 

the report. The reference in the report that is used most extensively in defining the western margin is Wheeler (1995), but his studies did not indicate this reentrant; rather his margin to this zone in essentially a straight line through this region. A strongly 

supported description of the cause of this feature is needed or it should be eliminated. No references are cited to provide an indication that this feature is present. 

Geometry of PEZ alternatives have been redrawn. The western boundary of PEZ_N follows the NY-AL. Crust northwest of the NY-AL lineament appears 

to have behaved as a rigid, somewhat coherent block, and its sharp boundary against the anomaly implies the edge of this competent block (Steltenpoh et al., 2010). Crust of the reentrant in the vicinity of Kentucky consists of the 

Rome Trough and is now included in the PEZ-W alternative geometry. The 

Rome trough is an Cambrian graben that appears to be related to reactivation of the NY-AL lineament (Stetlenpohl et al., 2010) or the East Continent Rift 

Basin (Drahovzal, 1997; Stark, 1997).

S 7-9. (DMM) Basis for Identification of the Illinois Basin Extended Basement Zone. In Section 7.3.5.1 (p. 7-33), the justification for defining this region as a distinct seismotectonic zone and the discussion in this section are not consistent with the criteria defined in Section 4.3.3 for defining seismic source zones.

The arguments for defining the IBEB as previously stated primarily address magnitude and future earthquake characteristics (i.e., allows for use of both MESE and NMESE Mmax priors; specification of future earthquake characteristics based on analysis of seismicity in southern Illinois, basement and Paleozoic structural trends).The higher rate of seismicity in this region may stem from some of the same 
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mechanisms proposed for the adjacent NMSZ/Reelfoot rift region to the south. This also suggests that the IBEB is different from the surrounding craton regions. 

S 7-10. (CC, DMM) Default Values of Future Earthquake Characteristics in the Eastern Continental Crust-Atlantic Margin; Section 7.3.7.4, pg. 7-48. In Section 7.3.7.4 (p. 7-48), the text discussing seismicity notes that most well located earthquakes of the Eastern Continental Crust-Atlantic Margin are distributed throughout 

the upper 13 km of crust. Given this information, the basis for assuming that the seismogenic thickness should be represented by the default values is not clear. 

The weights on the default values of 13, 17, and 22 km have been modified to place a higher weight on shallower depths for the ECC-AM. The weights of 

0.6, 0.3, and 0.1 result in a slightly shallower mean seismogenic depth than the default weights of 0.4, 0.4, and 0.2. 

S 7-11. (DMM) Additional Basis for Defining the Atlantic Highly Extended Crust In Section 7.3.8.1 (p.7-49), under Basis for Defining Seismic Zone: Canadian seismologists have recognized the zone of weakness at the Atlantic Ocean margin as defined by the continental slope as a zone of potential seismic activity based on the location of the magnitude 7.2 1929 Grand Banks earthquake, which occurred east of the 

northern tip of Nova Scotia. This earthquake, as well as the Baffin Bay earthquake in Canada, is supportive of the identification of this seismic zone. 

We agree that the occurrence of the two mentioned earthquakes could be used to argue for the presence of a zone of weak crust. However, following our methodology for defining seismic zones, the occurrence of the earthquakes, and/or the arguments for a weaker crust, are not criteria for defining zones, so they are not discussed within this section of the report. 

S 7-12. (CC, SSHAC) Clarification of Text Describing the Basis for Mmax of the Extended Continental Crust-Gulf Coast In Section 7.3.9.3 (p. 7-56), Basis for Zone Mmax: The characterization and assessment 

of Mmax described in this section is unclear. First, use of the term “scenario” (meaning imagined or possible) can convey a lack of disciplined evaluation of the available data for characterizing Mmax for the zone as required by the SSHAC assessment process. 

Replacing “scenario(s)” with “alternative characterization(s)” would properly convey that the characterizations represent the range of uncertainty based on evaluations of the available data. Second, the third alternative is described as follows: “The largest observed earthquake is the potential paleoearthquake identified from the studies of . . . .” The use of “largest observed earthquake” and “potential paleoearthquake” seems incompatible. In addition, the characterization described here clashes with the strong conclusion stated in Section 7.3.9.5. Elaboration is needed better explaining the evaluations performed supporting the third alternative characterization. 

Revised as suggested with the exception of comments regarding paleoliquefaction. There is no strong evidence of repeated earthquakes in the 

ALM area, but there is potential evidence of one paleoliquefaction event. 

Also, we don’t see the incompatibility in using a potential paleoearthquake as 

the largest observed earthquake. Including this possibility is part of capturing 

the uncertainty in the largest observed earthquake. Changed to “alternate characterizations”

S 7-13. (DMM) Additional Evidence for Defining the Gulf Highly Extended Crust; 

In Section 7.3.10.1 (p. 7-59), under Basis for Defining Seismotectonic Zone, is there 

evidence of faulting in this zone as anticipated in a highly extended zone? If so, that would be additional evidence for defining the zone. 

There is no evidence of seismogenic Quaternary faulting within this zone. 

S 7-14. (DMM) Evidence Regarding Characterization of the Gulf Highly Extended Crust 

In Section 7.3.10.3 (p. 7-60), under Basis for Zone Mmax, there are substantive analyses 

that show the event of February 10, 2006, to have been a landslide. These analyses must be referenced and discussed as part of the data base for characterizing and assessing Mmax for this zone. 

Added discussion of this event, but note that there has not been any research published in peer-reviewed journals that demonstrates that the event was a 

landslide, and all available literature is listed in the data summary tables.

S 7-15. (CC,DMM) Need to Strengthen the Basis for Defining the Oklahoma Aulacogen as aDistinct Seismic Source ZoneIn Section 7.3.11.1 (p. 7-62), under Basis for Defining Seismotectonic Zone, the text mentions “default future earthquake characteristics.” This terminology has not been used 

The basis for defining the zone follows from the methodology outlined in Section 4.1.3.3. The description of this methodology has been modified for 

clarity.
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systematically throughout Chapter 7 (with reference to Table 5.4-1), and in this section it is not clear why these are the primary basis for defining the seismotectonic zone versus the full set of criteria found in Section 4.3.3. While future earthquake characteristics are one of the criteria used to define distinct seismotectonic zones (see Section 4.3.3), there does not appear to be anything profoundly unique about the style of faulting or the strike of ruptures to support defining the Oklahoma Aulacogen as a distinct seismotectonic zone. The basis for defining the Oklahoma Aulacogen as a distinct seismotectonic zone is weak and needs to be improved. S 7-16. (CC) Significance of Statement in Description of Northeast Ohio Seismic Zone in the Midcontinent Seismic ZoneIn Section 7.3.12.1.4 (p. 7-68), for the Northeast Ohio Seismic Zone: The third bullet of 

the second paragraph is meaningless to the reader without additional description of its significance.

Text added to clarify this statement. Additional discussion provided of age and location (significance) of the sand 

pit exposure. 

S 7-17. (DMM) Effects of Smoothing on Recurrence Parameters In Section 7.5 (p.7-71), Recurrence Parameters: The objective smoothing results in bvalues that are low, possibly below the range of values known from world-wide experience. Yet, no alternative is suggested. Additional elaboration of the analyses must be provided to adequately inform future users of the CEUS SSC model. 

Recurrence has been reassessed based on the Final SSC model and there is a reasonable match between the observed recurrence and the predicted recurrence based on the objective model.

S 7-18. (DMM) Full Explanation of the Results Shown in Figures 7.5.2-9 to 7.5.2-42 

Many of the data shown in Figures 7.5.2-9 to 7.5.2-42 indicate the poor fits of the 

realizations to the catalog. This is disturbing and needs to be more clearly explained in the text. Why doesn’t the preferred model fit the catalog data better? Only the short text in section 7.5.2 describes these figures. The text should be enhanced to describe the fitting issues, and as a result there needs to be full justification of the rate and b-value maps for 

the seismotectonic zones. 

The recurrence based on the Final SSC model shows reasonable fits between the realizations from the model and the observed counts.

Comments by Section Section 7.3.1.2This section never actually describes why the St. Lawrence Rift should be a distinct source zone. There is some discussion of geometry, but no well defined case for “why” (unless it is simply because the GSC did).Section 7.3.1.3At least some mention of the implications or importance of the observations to the Kijko model should be provided. This comment applies to all the individual zone sub-sections. 

Perhaps consider doing it at the beginning of Chapter 7. 

SLR seismotectonic crust separates crust initially rifted in the Paleozoic and subsequently reactivated during the Mesozoic into one zone with a maximum magnitude distribution derived from a Mesozoic and younger prior. Text in section 7.3.1.1 better introduces subsections describing portions of the SLR seismotectonic zone that display different geological or seismological characteristics and seismicity rates.Text added giving results from Kijko approach. Discussions of the Kijko 

approach are a part of section 5.2. 

Section 7.3.2 last bullet, p. 7-13: If the hotspot has been tracked farther to the northwest, why isn’t the 

seismic source zone extended to the northwest? 

Section 7.3.2.1This is one of the few Seismotectonic Zone subsections that actually develop a clear summary for why this should be a separate zone.Figure 7.3.2-1 As on similar maps in the report, Figure 7.3.2.1 should show the magnitudes of the starred earthquakes. 

Moved discussion of Ma and Eaton (2007) indicating that seismic portion of the hotspot track corresponds to the transition from kimberlitic dikes to plutons. Also, Figure 7.3.2-2 shows that the hotspot track northwest of the seismic zone is aseismic. Labels added.
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Section 7.3.3.1 This section discusses the basis for proposing the NAP zone. It states: “The basis for defining the NAP seismotectonic zone centers primarily on the concept that terranes of this zone formed outboard of the Laurentian margin after Iapetan rifting and were subsequently accreted to the passive margin.” This subsection is weak in terms of developing a basis for defining the NAP as a separate zone. The text focuses on geological arguments that are never specifically tied to the SSC criteria. The reader is left to infer this zone may or may not utilize a different Bayesian Mmax prior than adjacent regions. 

Clarified section to illustrate why a Paleozoic and younger Mmax prior does not apply and why a Mesozoic and younger prior does. Further tectonic and seismological arguments are used to distinguish between ECC-AM which also 

has a Mesozoic and younger prior. 

Section 7.3.4 Use of the term “IRM” changes from describing a continental margin in the first sentence of the introductory paragraph of Section 7.3.4 to a seismic zone later in the paragraph. This is confusing. Similarly, note that the labeling of the PEZ in Figure 7.3.4-1 appears to 

be incorrectly labeled as IRM.

Section 7.3.4.1.4Suggest that the reference to Steltenpohl et al. in Geology, June 2010, v. 38, p. 571-574 

be added to the list in the second paragraph.

Section 7.3.4.1.6p. 7-27: At the end of the second paragraph of this section reference is made to “a Class 

C tectonic feature.” It would be helpful to the reader to cite where in this report the classes of the tectonic features are defined and thus the significance of this information to seismic source identification.

Section 7.3.4.1.6p. 7-29, paragraph at top of page: The discussion of a lack of observed paleoliquefaction 

features should also be used with the appropriate qualification. Specifically, the observation that paleoliquefaction features provides strong evidence for past strong earthquake shaking, should be accompanied with a remark that failure to identify such 

features does not provide an equally strong a case for the absence of strong shaking. 

Restricted usage of IRM as a concept of the Iapetan rifted margin. Discussions based on this reference have been added throughout the section. Statement deletedStatement added.

Section 7.3.5 p. 7-32: The use of “Basement” in the title of this zone does not appear to be consistent 

with the titles given to other seismotectonic zones of the CEUS.

Section 7.3.5.1p.7-33, 2nd bullet: In discussing the basis for defining the IBEBZ zone the text states, “The southern part of the Illinois basin is one of the most structurally complex areas of the Midcontinent.” How this directly impacts the SSC needs to be more clearly elaborated, or deleted. On the following page in the next bullet the text states: “An extensive series of moderately dipping reflectors is present in the basement, part of which may have been reactivated by the 1968 mb 5.5 earthquake.” Are the reflectors then interpreted to be faults? Also, the 1968 earthquake may have occurred in response to reactivation of the reflectors (if they are in fact faults), but not vice versa.Section 7.3.5.2p. 7-34: Suggest clarification of last sentence in second paragraph with something like: 

“The margins of the volcanic layered sequences, especially to the south and west, are 

marked by prominent coincident closed-contour magnetic and gravity anomalies which 

p. 7-32: The names applied to the various zones reflect both geographic and geologic information. The IBEB zone is defined in part on its structural and tectonic setting that influenced our characterization of Mmax priors. Evidence for reactivation of extensional structures in the Precambrian basement was considered in this assessment; hence, this was included in the name assigned to the zone.p. 7-33: Additional text has been added to the observations used to define the IBEB as a seismotectonic zone. The mid-crustal reflectors are interpreted to be faults 

and the revised text clarifies the terminology.

p. 7.34 Sentence modified as suggested. p. 7-35: A summary of the article to the Data Summary table for the Illinois 

Basin-Wabash Valley has been added. The Omaha intrusive mentioned is 
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are derived at least in part from mafic volcanic rocks and intrusions . . . .” Section 7.3.5.3pg. 7-35: In considering the Mmax of this zone it may be useful to consider the presence 

of numerous late Paleozoic ultramafic intrusions (dikes and sills) into the sedimentary section of this region. See, for example, Sparlin and Lewis in Geophysics, v. 59, p. 1092-1099 (1994). 

actually in the WV RLME source zone. 

Section 7.3.6.5 (CC) Develop table for future earthquake characteristics in Reelfoot Rift zone; pg. 7-

42.p. 7-42, text box: The characteristics of future ruptures in the Reelfoot Rift zone listed 

in the text box at the end of Section 7.3.6.5 should be placed in a numbered table with headings. 

This table is being deleted from the revised text. Reference made instead to Table 5.4-2. 

Section 7.3.7 p.7-47, first full paragraph, line 5: The text refers to the unlikelihood of a maximum magnitude earthquake of greater than 7 because of the paucity of paleoliquefaction features in the region. Could Mmax be less than 7?Section 7.3.7.1In the second line of the first paragraph, “large” earthquakes are specified as M > 7. Should be M ≥ 6.5 to be consistent with the value used elsewhere for the RLMEs. 

p. 7-47: The statement reflects the interpretations made by Obermeier and McNulty (1998). It is possible that the paucity of paleoliquefaction data could suggest that the largest mid-late Holocene event could be even smaller than 

M7, but it would more difficult to support that conclusion. 

7.3.7.1: In this context, “large” earthquakes refer to the M≥7 events in Mesozoic and younger extended crust observed in the global earthquake catalog compiled as part of the Johnston et al (1994) EPRI study. At the time of that study, the only stable continental earthquakes of M≥7 had occurred in 

Mesozoic and younger extended crust. The use of “large” was not intended to reflect the same definition of RLME. To avoid any confusion the text is modified and the term “large” is removed. 

Section 7.3.9.2.1 p. 7-52, last bullet: The point could be illustrated with reference to the appropriate magnetic anomaly figure. Section 7.3.9.2.4p. 7-55, first full paragraph: Suggest that the last sentence be modified to something like: 

“The source zone is extended north of the Southern Arkansas fault zone for several reasons:” 

Reference to figure added. Suggested change made. 

Section 7.3.10 In the title of this section, for consistency with previously described seismic source zone, suggest the title of this zone be “Gulf Coast Highly Extended Crust.” 

Revision made as suggested. 

Section 7.3.11.3 This subsection is an example case where adding an additional sentence could improve the clarity, consistency and transparency of the document. The Bayesian approach is the only Mmax approach used for this zone. It would be helpful to the reader to note that specifically or state the Kijko approach was not used due to a high p-value. Some zones 

are explicit in describing the two approaches, some are not. 

Revision made as suggested. 

Section 7.3.12.1.2 pg. 7-65, first full paragraph, line 4: Suggest beginning sentence with, “The deformation 

during this interval is attributed to” instead of “It is attributed to”

Section 7.3.12.2 

The text modified as suggested. p. 7-69 This suggestion was not adopted. The Mmax prior is the primary 
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p. 7-69, par. 1, line 4: Suggest adding the phrase “and recurrence characteristics” after “maximum magnitude probability” 

distinguishing characteristic for delineating this zone. 

Editorial Comments and Typographical Errors General Comment:To avoid repetition of editorial comments on repeated issues throughout the text of Chapter 7, the following issues are identified which should lead to necessary revisions throughout the chapter:• The manner of describing compass directions and their hyphenation should be made consistent throughout the report. Note that sometimes the directions are spelled out and in other cases an abbreviation is used.• Geologic time units are not used appropriately throughout the chapter. Ma is used by the scientific community for millions of years before the present and myr is used for millions of years of duration.• Recommended that for each section that presents a different seismotectonic zone, the title include the acronym (e.g., Section 7.3.1 — St. Lawrence Rift (SLR). Some section

headings already include the acronym, which is helpful to the reader in referring to maps and figures.

• “Aeromagnetic” is not a definitive term. Rather use “magnetic anomaly” and gravity should always be followed by “anomaly,” e.g., gravity anomaly and magnetic anomaly. If there is no adjective before either the gravity or magnetic anomaly, it is assumed that the gravity anomaly is the Bouguer gravity anomaly and the magnetic anomaly is the total intensity magnetic anomaly. Where possible, the type of anomaly should be specified. • Mile should be abbreviated as “mi” without a period at the end, consistent with scientific context.• The first time a term is used that will be identified by an acronym, the complete term should be given followed by the acronym in parentheses. There are numerous acronyms in this chapter that are not listed in the list of acronyms near the front of the report. These will not all be identified in the following comments.• Reference to Adirondacks and Appalachians in place of Adirondack Mountains andAppalachian Mountains, respectively, is not editorially correct. This and similar casual terminology should be removed from the chapter.• Several figures cited in this chapter are neither in the draft report nor in the List of Figures. All cited figures and tables should be carefully reviewed. • Magnitudes of specific earthquakes should be consistent in number of significant figures throughout the text.• Format for dates should be consistent throughout the text. Avoid 10 February 1999 rather use February 10, 1999.• Listing of earthquakes, references, etc. should be in a prescribed order, e.g., date, magnitude, etc.Specific Comments:E 7-1 Section 7.1 Paragraph 1, line 5 – replace region with seismotectonic source zone

E 7-2 Section 7.1 Paragraph 1, line 7 – replace event with earthquake 

E 7-3 Section 7.1 Paragraph 1, line 8 – insert tectonic between particular and province 

Revisions made as suggested unless otherwise noted below:E 7-63: Text deleted or modified as suggested, replaced with ‘adjacent’ E 7-67: Text checked—La Salle anticlinal belt is used throughout E 7-71: no change needed. FAFC explained in paragraph 2 of this section

E 7-72: 

Sentence revised to add ‘Pleistocene deformation’ after the word ‘late’ E 7-73: Reference corrected to Pratt (2009) E 7-91 no change needed. Discussion is an appropriate term 
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E 7-4 Section 7.1 Paragraph 1, line 9 – insert faulting between slip and defining E 7-5 Section 7.1 Paragraph 2, line 16 – replace eastern with western (?) E 7-6 Section 7.1 Paragraph 3, line 1 – not all seismotectonic zones represented in Appendices C and DE 7-7 Section 7.1 Paragraph 3, line 4 – replace provide an indication with specify E 7-8 Section 7.1 Paragraph 3, line 7 – replace looking at any of the discussions with reviewing the descriptionsE 7-9 Section 7.1 Paragraph 4, line 16 – replace discussion with description E 7-10 Section 7.1 Paragraph 5, line 6 – replace lie with occur E 7-10 Section 7.1 Paragraph 6, line 5 – replace called out with identified DRAFTInstallment 3, PPRP Review Comments, page 7-11E 7-11 Section 7.1 Paragraph 5, line 9 – replace have been postulated as being with are 

postulated as

E 7-12 Section 7.1 Paragraph 5, line 11 – replace studies are judged to be too preliminary 

at the present time with assessments are judged to be without definitive support as a 

result of the preliminary nature of the investigationsE 7-13 Section 7.3 Paragraph 1, line 3 – replace Mid-Continent with Midcontinent E 7-14 Section 7.3 Paragraph 1, line 6 – NMESE not in List of Acronyms E 7-15 Section 7.3 Paragraph 1, line 7 – insert northwest boundary between the and ReelfootE 7-16 Section 7.3.1 Paragraph 2, line 2 – separate SCRs and correlate E 7-17 Section 7.3.1.1.3 Paragraph 1, bullets – capitalize first word of bullets and place 

period after last bullet

E 7-17 Section 7.3.1.1.4, pg. 7-7, third bullet, separate A and third E 7-18 Section 7.3.1.1.4 Paragraph 2, first bullet – separate The and oldest E 7-19 Section 7.3.1.1.4 Paragraph 4, line 6 – remove space after hyphen E 7-20 Section 7.3.1.1.5 Paragraph 1, line 3 – separate from and the E 7-21 Section 7.3.1.1.7 Paragraph 1, line 11 – remove s between faults and associated 

E 7-22 Section 7.3.1.1.7 Paragraph 1, line 13 – separate which and continued 

E 7-23 Section 7.3.1.2 Paragraph 1, line 3 – replace has been with is E 7-24 Section 7.3.1.2 Paragraph 1, line 6 – remove space after hyphen E 7-24 Section 7.3.1.2, pg. 7-10, paragraph 1, line 3 and line 8 – separate States and faultsE 7-25 Section 7.3.1.2 Paragraph 1, line 19 – replace asterisks with 250 E 7-26 Section 7.3.1.1.4 Paragraph 2, line 2 – what is GSC R model?? E 7-27 Section 7.3.1.1.4 Paragraph 2, line 6 – remove space before Brompton E 7-27 Section 7.3.1.1.7, pg. 7-9, line 13 – separate which and continued E 7-28 Section 7.3.1.3 Paragraph 1, line 15 – separate subsidence and within E 7-29 Section 7.3.1.3 Paragraph 1, line 28 – spell out first time GMH is used E 7-29 Section 7.3.1.4, pg. 7-11, 1st line - suggest “Earthquakes in Canada are classified 
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....” should be earthquakes in southeastern Canada E 7-30 Section 7.3.1.4 Paragraph 1, line 13 – 5.8 is 5.75 elsewhere, use care in significant figures, similar problems elsewhere in report that need to be addressedE 7-31 Section 7.3.1.4 Paragraph 2, line 2 – neither earthquake shown on Figure 7.3.1.1 

E 7-32 Section 7.3.2, Geologic Evidence, Paragraph 1, bullet 2 – why refer to figure 

here?E 7-33 Section 7.3.2, Geophysical Evidence, Paragraph 1, line 2 – Figure 7.3.2-3 is missing in report and List of Figures

E 7-34 Section 7.3.2, Evidence for Reactivation, Paragraph 1, several lines – Capitalize 

Late and Early when part of formal age

E 7-35 Section 7.3.2, Evidence for Reactivation, Paragraph 3, last line – replace / with andE 7-36 Section 7.3.2.2 Paragraph 2, line 2 – Figure 7.3.2-4 is missing from report and List 

of Figures

E 7-37 Section 7.3.2.2 Paragraph 2, line 9 – can this information be related to a specific 

figure?

E 7-38 Section 7.3.2.3 Paragraph 2, line 5 – Figure 7.3.2-5 is missing from report and List 

of Figures

E 7-39 Section 7.3.2.4 Paragraph 2, line 15 – separate and20 E 7-40 Section 7.3.3 Paragraph 1, line 1 – remove s from Appalachian E 7-41 Section 7.3.3 Tectonic Framework, Paragraph 3, line 5 – change to compressional 

event

E 7-42 Section 7.3.3 Tectonic Framework, Paragraph 7, line 2 – replace million-year with 

myr

E 7-43 Section 7.3.3 Seismicity Paragraph 1, line 10 – remove period after Ebel E 7-44 Section 7.3.3 Paragraph 2, line 3 – magnitude of June 1638 earthquake is listed 

as 6.5

on page 7-19 and 5.67 on page 7-21 E 7-44 Section 7.3.3, pg. 7-19, Seismicity section - the 1904 earthquake referred to in terms of mblg, shouldn’t moment magnitude be indicated as well?E 7-45 Section 7.3.3.3 Paragraph 2, line 5 – insert period after al E 7-46 Section 7.3.4.1.1 Paragraph 1, line 3 – replace valley with rift E 7-47 Section 7.3.4.1.2 Paragraph 1, line 3 – insert anomaly after gravity E 7-48 Section 7.3.4.1.2 Paragraph 2, line 7 – remove any E 7-49 Section 7.3.4.1.2 Paragraph 1, line 9 – replace Valley with rift E 7-50 Section 7.3.4.1.3 Paragraph 3, line 9 – remove RecentE 7-51 Section 7.3.4.1.3 Paragraph 4, last line – replace is with are E 7-52 Section 7.3.4.1.5 Paragraph 1, line 6 – RTG not identified E 7-53 Section 7.3.4.1.6 Paragraph 5, line 6 – insert space in front of Dineva E 7-53 Section 7.3.2, pg. 7-13, 2nd line - currently states “This seismotectonic zone is largely defined by moderate seismicity, including ...” As written this contradicts the stated position that the model accounts for differences in seismicity by spatial smoothing. It 
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seems more appropriate to say “This seismotectonic zone is characterized by moderate seismicity,.....”E 7-54 Section 7.3.4.2 Paragraph 1, line 3 – remove unfiltered, add Bouguer gravity before anomalyE 7-55 Section 7.3.4.2 Paragraph 1, line 5 – replace rise with anomaly gradient E 7-56 Section 7.3.4.2 Paragraph 2, line 6 – should PEZ be PEZ-W?? E 7-57 Section 7.3.4.2 Paragraph 3, line 1 – spell out PEZ-N E 7-58 Section 7.3.4.2 Paragraph 4, last line – replace IRM with PEZ E 7-59 Section 7.3.4.3 Paragraph 1, line 2 – magnitude E 7-59 Section 7.3.4.3, pg. 7-30, Paragraph 1 - mixed magnitudes in the section E 7-60 Section 7.3.4.2 Paragraph 4, line 4 – replace IRM with PEZ E 7-61 Section 7.3.4.4 Paragraph 4, line 4 – spelling of Pymatning?? E 7-62 Section 7.3.5 Paragraph 1, line 1 – delete The regions of E 7-63 Section 7.3.5 Paragraph 1, line 2 – delete more distant, replace presented the with 

proposed that

E 7-64 Section 7.3.5 Paragraph 1, line 3 – delete concept and change extending to extendE 7-65 Section 7.3.5 Paragraph 1, line 8 – delete d from indicated E 7-66 Section 7.3.5 Paragraph 1, line 9 – delete of complexly deformed crust. E 7-67 Section 7.3.5 Paragraph 4, line 4 – be consistent in use of term for LaSalle anticlinoriumE 7-68 Section 7.3.5 Paragraph 2, line 5 – insert anomaly after intensity E 7-69 Section 7.3.5 Paragraph 2, line 6 – insert layered between volcanic and sequencesE 7-70 Section 7.3.6.1 Paragraph 1, bullet 1, line 4 – should be plume E 7-71 Section 7.3.6.1.2 Paragraph 5, line 5 – FAFC, not defined E 7-72 Section 7.3.6.1.2 Paragraph 8, line 8 – missing words?? E 7-73 Section 7.3.6. 2 Paragraph 8, bullet 3, line 5 – publication date of Pratt et al. E 7-74 Section 7.3.7 Geophysical Anomalies, Paragraph 2, line 5 – replace runs with extendsE 7-75 Section 7.3.7 Geophysical Anomalies, Paragraph 2, line 10 – remove separately 

E 7-76 Section 7.3.7 Seismicity, Paragraph 4, line 10 – should small be limited?? 

E 7-77 Section 7.3.7.2 Basis for Geometry, Paragraph 1, line 16 – BMA, identify E 7-77 Section 7.3.7.4, Future Earthquake Characteristics, pg. 7-48, - text refers to ECCAM having the same future rupture characteristics as the AHEX zone. However, the 

discussion of the AHEX follows the ECC-AM zone. Consider placing description of 

characteristics in this sectionE 7-78 Section 7.3.8.1 Paragraph 2, line 5 – replace runs with extends E 7-79 Section 7.3.9 Paragraph 1, line 6 – replace represents with is E 7-80 Section 7.3.9.2.1 Paragraph 1, line 5 – remove any E 7-81 Section 7.3.9.2.1 Paragraph 1, line 7 – replace think with thin 
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E 7-82 Section 7.3.9.2.1 Paragraph 2, line 6 – replace reflected with reflects E 7-83 Section 7.3.9.2.3 Paragraph 2, line 1 – change to In spite of this tectonic interpretation,

E 7-84 Section 7.3.9.4 Paragraph 4, line 5 – change to that formed or were reactivated

E 7-85 Section 7.3.9.5 Paragraph 2, line 4 – replace since with because 

E 7-86 Section 7.3.9.5 Paragraph 6, line 1 – insert the after comma E 7-87 Section 7.3.10 Paragraph 1, line 6 – replace represents with is E 7-88 Section 7.3.11.1 Paragraph 2, line 1 – replace first sentence with The basis for defining the distinct future earthquake characteristics for the aulacogen is the observation of the characteristics of the Quaternary activity on the Meers fault, a fault within the Frontal Wichita fault system (see Section 6.1.4).E 7-89 Section 7.3.11.2 Paragraph 2, line 5 – remove any E 7-90 Section 7.3.12 Paragraph 1, line 2 – insert geologic between two and provinces

E 7-91 Section 7.3.12 Paragraph 2, line 1 – replace discussion with description 

E 7-92 Section 7.3.12 Paragraph 2, line 2 – replace discussion with description E 7-92 Section 7.3.12.1.4 Paragraph 1, line 6 – remove any of E 7-93 Section 7.3.12.1.4 Paragraph 1, line 9 – replace could not with cannot E 7-94 Section 7.3.12.1.4 Paragraph 1, last line – delete any of E 7-95 Section 7.3.12.1.4 Northeast Ohio Seismic Zone, Paragraph 5, bullet 3, line 6 –

change to consistent with one expected for a high pore-pressure... 

E 7-96 Section 7.3.12.1.4 Northeast Ohio Seismic Zone, Paragraph 6, line 2 – replace 

very well with favorable

E 7-97 Figure 7.3.4-1 – Indicate 1929 Attica earthquake?? E 7-98 Figure 7.4.1-1 – scale and size used for displaying mmzx-obs for each seismic source needs to be modified to better illustrate the findings E 7-99 – limits of information on all figures (e.g., 7.1-1 and 2) needs to be confined to the 

limits of the study area 

CHAPTER 8 — DEMONSTRATION HAZARD CALCULATIONS USING CEUS SSC MODELGeneral Comments G 8-1. (CC) Chapter 8 is the opportunity for the TI Team to explain differences in hazard 

obtained using the CEUS SSC model, the USGS seismic source model, and the COLA seismic source models. This has been done to a degree, but more extensive evaluations relating the differences in hazard to elements of the CEUS SSC model would be very 

valuable for future users. Industry stakeholders and the scientific and technical community will look be looking closely at the demonstration hazard calculations to gain an overall understanding of the CEUS SSC model and whether it yields reasonable results. Figures such as Figures 8.2-5R through 8.2-5T for all test sites together with thorough evaluations of how the TI Team’s assessments of smoothing parameters impact hazard would be very informative. Sensitivities to the Team’s assessments of weights on the “in cluster” and “out of cluster” characterizations of RLME sources would also be very informative. 

Additional discussion of releases for differences at each site
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Comment Summary of Revisions to Report 

G 8-2. (CC, CBR) The CEUS SSC model rates are often by a factor of two or more higher than the USGS and COLA models rates, over a large range of ground motions. The slopes of the hazard curves are more similar because they all assume the same ground motion prediction equations. This higher rate of ground motions compared to earlier models is not clearly explained in the text. This higher hazard indicates that the CEUS SSC model predicts a rate of earthquakes that is considerably higher than the earthquake rate predicted in the USGS and COLA models. The basis of these higher rates can be seen in the figures of Chapter 5 to 7 (e.g., 6.4-7 to 6.4-16; 5.3.2-22), where the model realizations over-predicts the historical rate of earthquakes. These differences make one 

question whether the model encompasses the center, body, and range of the informed 

technical community. 

Hazard curves for CEUS SSC model match other curves better. 

Specific Comments S 8-1. (CC) Explanation of CEUS Ground Motion Attenuation Model Application The TI Team has used the 2004 EPRI ground motion attenuation model to complete probabilistic estimates of ground motion. Chapter 8 should provide a summary of the application steps that were implemented for the 2004 EPRI ground motion attenuation model. It is particularly important that the distance measure be explained. Application of the 2004 EPRI ground motion attenuation model could involve the use of either point source distance measures or extended source distance measures. If both distance measures were used, the text should provide an explanation of the criteria or considerations that resulted in the choice of the distance measure for each of the seismic sources. For those seismic sources that were modeled as extended ruptures, the text should describe what assumptions were made to model the extended rupture and to what extent epistemic uncertainty was considered (alternative extended rupture relationships). Without this explanation the information provided in Chapter 9 regarding the sensitivity to 

certain logic tree inputs is diminished. 

Text modified to include this revision 

S 8-2. (DMM, CC) Questions Regarding Results of Demonstration Hazard Calculations In the subsection labeled “CENTRAL ILLINOIS SITE” (p. 8-6, 3rd paragraph): It would be 

informative to know how much higher and over what ground motion range the CEUS SSC model hazard is higher. Also, what characterizations and/or assessments contained in the model contribute to the higher seismic hazard.

The CEUS SSC m del is almost a factor of 2 higher than USGS/EPRI-SOG models. The 

major contributor is the IBEB (Illinois Basin) zone. The New Madrid (NMFS) RLME is 

most important at 1 s SA. However, background seismicity dominates at shorter periods. Why does the background hazard from CEUS SSC model give significantly higher rates than were applied in the USGS and COLA models for short periods? At 1 s period the USGS and CEUS SSC models are much more similar because the NMFS models are much more similar. In the subsection labeled “CHATTANOOGA SITE” (addendum, 8/18/2010, 3rd paragraph): More complete evaluations and explanations relating the differences to elements of the CEUS SSC model would be very valuable. This comment applies to other sites as well; so, will not be repeated.The CEUS SSC model hazard for the Chattanooga site is more than a factor of 2 higher in annual frequency of exceedance than the USGS and COLA models. At the Chattanooga site the ground motion hazard at e-3 to e-5 is more than a factor of 2 higher. 

Background sources contribute most to the hazard. However, the USGS ground motions are higher at 1 Hz for exceedances of e-4 to e-6. These results are not explained in the 

text. 

Revised comparisons are described Explained revised comparison
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Comment Summary of Revisions to Report 

In the subsection labeled “HOUSTON SITE”: The CEUS-SSC model hazard at the Houston site is dominated by GHEX (Gulf of Mexico), which is the zone that encompasses the site. Contributions from other background sources are much lower. Hazard is dominated by background sources at all periods (except for very low ground motions at 1 s SA). The SSC model indicates about a factor of 2 higher annual frequency of exceedance than the USGS model frequencies for short periods (10 Hz and PGA) but is more similar at longer periods (1 Hz). This is probably because NMFS is significant at 1 Hz and the USGS and CEUS-SSC models are more similar for NMFS. However, the differences are not explained in the text. In the subsection labeled “JACKSON SITE”: For the Jackson Site, the NMFS is important at all frequencies. Therefore, the CEUS-SSC, COLA, and USGS models are quite similar 

for PGA, 10 Hz, and 1 Hz.

In the subsection labeled “MANCHESTER SITE”: Similar to the other sites dominated by 

background hazard, the CEUS SSC hazard at the Manchester site is considerably higher than the hazard for the USGS and COLA models. The deaggregation for the Manchester site at 10 Hz is dominated by earthquakes with magnitudes less than 6.0 and distances less than 10 km. The CEUS SSC deaggregation for 10 Hz at e-4 is similar to that 

produced by the USGS for PGA at 4e-4. The higher rates for the Manchester Site should 

be explained in the text. 

In the subsection labeled “SAVANNAH SITE”: For the CEUS SSC model at the Savannah site, the major contributors to the ground motion hazard are the Charleston RLME source and the ACCAM background source model. The CEUS-SSC, COLA, and USGS models 

are quite similar with the CEUS-SSC model showing a little higher ground motions for a 

large range off exceedances.

In the subsection labeled “TOPEKA SITE”: The major contributor to the background source is MIDC-A which encompasses the site. The next important contributors are MIDC–B, MIDC-C, and MIDC-D. Background seismicity dominates the hazard at PGA and 10 Hz and the NMFS dominates hazard at 1 Hz. The hazard curves for the CEUSSSC, COLA, and USGS and similar, especially at 1 Hz. The hazard is typically higher for the CEUS-SSC model with rates almost a factor of two higher for a large range of ground 

motions. This discrepancy should be explained in the text.

Explained revised comparison No comment requiredNo comment requiredNo comment requiredExplained revised comparison

Comments by Section Order of Text, Tables, and FiguresMaterial needs to be reorganized (including added materials transmitted on August 18, 2010) so that the order of presentation of text, tables, and figures is consistent with other chapters. Section 8.13rd paragraph and elsewhere: The term “hard rock” can lead to confusion because it is unspecific and used in various meanings. Consider defining the term “CEUS Region generic rock,” shear wave velocity of 9200 fps, and using this term consistently throughout the chapter. Similarly, using the term “soil” to mean the geologic section above “CEUS Region generic rock” can especially invite confusion because of the wellestablished use of this term in geotechnical engineering. Consider “stratigraphic column” 

instead. 

Revised accordinglyNo revision requiredNo revision required 
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Comment Summary of Revisions to Report 

4th paragraph: In the first line, would “generalized” or “representative” be more accurate than “hypothetical”? In the last line, would “dynamic response” be more descriptive than “parameters”?Section 8.2 [including revised materials distributed on 8/18/2010]In the subsection labeled “All site conditions” (p. 8-5): “EPRI-SOG (1989)” should be “EPRISOG (1988)”Figures 8.1-4 and 8.1-5 Are the mean amplification factors independent of the mean AFEs (e.g., at 10–4, 10–5, 

and 10–6) and the resulting site’s mean uniform hazard spectra for hard rock? 

Figures 8.2-5R and 8.2-5T (Manchester Site): These figures are very important for 

understanding how smoothing affects hazard. It would be particularly useful to know the estimated rates of M 5 earthquakes compared with estimated b-values for the 8 objective 

smoothing realizations. 

No revision requiredDiscuss revised comparisons

CHAPTER 9 — USE OF THE CEUS SSC MODEL IN PSHA General Comments G 9-1. (NAR) Chapter 9 provides results that are potentially valuable for evaluating whether future new data or evolved knowledge require updating of the SSC model. In addition, the results are potentially valuable for resolving a number of seismic regulatory decision-making issues. The chapter is very well written, providing clear descriptions of 

the analyses performed and the results—a valuable contribution. 

So noted. 

G 9-2. (NAR) PPRP review comments on Chapters 1–5 include suggestions that may lead to modification of weights in the Master Logic Tree and hence corresponding changes in calculated hazard results. 

Changes in logic trees, such as the weights associated with the seismotectonic zones versus the Mmax zones approach, have been propagated into the seismic hazard results. 

G 9-3. (NAR) It is noteworthy that, based on the comparisons provided in Chapter 8, differences with the USGS and EPRI-SOG (COLA) results are significantly larger than the 

precision defined in this chapter for the CEUS SSC model results at all seven test sites. Indeed, for ground motions in the range of 10-4 to 10-6, the results in Chapter 8 indicate 

differences sometimes more than a factor of two between the USGS and CEUS SSC models in the rate of exceedances and the ground motion hazard. To avoid confusion, and because it might be argued that all experts have had essentially the same data and knowledge basis for assessing the various SSC models, the report should make abundantly clear how the uncertainty (precision or reproducibility) of the ± 25% should be understood—or not misinterpreted. 

Paragraph added at end of Section 9.3 

Comments by Section Order of Text, Tables, and FiguresMaterial needs to be reorganized so that the order of presentation of text, tables, and figures is consistent with other chapters.Entire ChapterThroughout, change “seismogenic crustal thickness” to “seismogenic thickness.” Section 9.1p. 9-1, par. 1: In line 6, change “Section 2” to “Chapter 2”; in line12, suggest replacing 

“that capture the community’s views” with “that represent the community’s views”

Because this section is intended to be a useful “overview,” in the last paragraph it would help to call the reader’s attention more explicitly to the key conclusions presented in Section 9.4.3—at the very end of the chapter and after 96 pages. Section 9.2In the first paragraph, line 10: Change “components - that is” to “components—that is” 

Order is consistent with presentation in Chapters 6 and 7. As discussed in Section 5.4, the use of the term “seismogenic crustal thickness” is consistent with common usage and is maintained.Changes made as suggested.
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Comment Summary of Revisions to Report 

Section 9.3.1 In the first sentence: “The HIDs describing seismic sources” is confusing. There is only one HID. Suggestion: “In the HID, the specifications for seismic sources . . .”p. 9-3, first full paragraph, third sentence: Because the test sites are extensively referred 

to in the remainder of this chapter, it would be helpful at the end of this sentence to point the reader to a map of the seven test sites (say Figure 8.1-1). 

p. 9-3, 3rd full paragraph, last sentence: Suggest replacing “Please refer to Section 9.4” 

with “See Section 9.4”

Section 9.3.1.10p. 9-41, par. 2, first sentence: Text should be revised to eliminate reference to internal communications among the TI Team—“outlined in emails from Kathryn Hanson.” Sections 9.3.2 and 9.3.3 No text provided, stated “to be written later.”Section 9.4.1 and Table 9.4-1 The text and table contain inadequate documentation insofar as the column of “Available studies” in Table 9.4-1 includes a mix of citations, which can be tracked, and informally 

referenced studies such as “Charleston: WLA,” “New Madrid: Youngs,” “PEGASOS study,” PEGASOS project.”

Section 9.4.2See Comment S 9-1 regarding error in referencing figures, beginning in this section. First paragraph (p. 9-49), last sentence: COV is defined here. Appropriate place to introduce symbols for the standard deviation of hazard (σH) and mean hazard (MH, or some such).p. 9-66, line 2: Change “10-4 to 10-6” to “10–4 to 10–6” Section 9.4.3 and Table 9.4-1 The abbreviation “SSRS” appearing in Table 9.4-4 needs to be explained in the text. In 

the figure caption for Figure 9.4-44 one finds “srss” explained as “the square-root sum of 

squares calculation of the total COV.” Neither srss nor SRSS appears in the list of acronyms. 

Last paragraph: For clarity, it would be useful to explain where the statement “2/3 of the time” comes from—presumably from a normal distribution.It is difficult to understand why the COVs decrease in annual frequencies of exceedance greater than 1E-5 on Figure 9.4-53 and 9.4-57. The authors show at the Savannah, Chattanooga, and Columbia sites that the term “cl. Mean COV” is quite a bit different from the “wts COV.” Because this is not intuitive, it would be helpful to provide some explanation to the reader.

Revised as suggestedRevised as suggested Revised as suggestedRevised as suggestedOthers responsible. Text must be written by MACTEC or EPRI for how to ftp access informationCitations were corrected to specify the sourcesFigures renumbered.Introduction of symbols was added Superscripts changedAbbreviation was removed from textStatement removedRevised as suggestedRevised as suggested
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Comment Summary of Revisions to Report 

APPENDIX A—DESCRIPTION OF THE CEUS SSC PROJECT DATABASE General Comments The CEUS SSC Project has assembled and archived a comprehensive suite of data 

sets of the CEUS that are important to the characterization and assessment of the SSC model of the region by the TI Team and that significantly contribute to the community knowledgebase. Compiling and providing these data sets in a common GIS data format required substantial effort, for which the Project Team is commended. These data, for the entire CEUS SSC model region, as well as for specific subregions of special interest for the characterization and assessment of seismic source zones, have been obtained from existing data bases, digitized maps, data files, and original data. The data have been put into a GIS format to facilitate analysis, employing overlays of various data types, and they have been made available to the TI Team, the PPRP, and others in the project. The data files will be archived on a server that can be accessed in the future via a website. The data include maps of surface, bedrock, and crystalline basement geology, geophysical data (gravity, magnetic, and stress), results of seismic study of the crust, compilations of historic and pre-historic 

earthquake data, and previous seismic hazard analyses. Workshop #1 was focused on selecting the critical data sets required for the project and identifying the optimum data sets available to the project.

Appendix A describes the data included in the Database and the procedures for assembling the data sets and making them available to the project teams. In addition, summary metadata “sheets” are included for 32 of the identified data 72 CEUS data 

bases. As part of the review of Appendix A, consideration also has been given to the 60 metadata files describing the data sets of the Database. The 60 metadata descriptions are in a separate digital data file which is not part of the final report or its appendices, but has been on the EPRI data server which is no longer in service. Future access to the metadata files via the website needs to be clarified and explained. In general these files are helpful in understanding the source, capabilities, and limitations of the data sets that are important to all users of the CEUS SSC data compilation.

The level of detail provided in Appendix A and the metadata files is generally satisfactory, but significant revisions are required to improve the text, update and complete the summary description of the data sets, complete the metadata a sheets for all data sets, synchronize the data sets, the metadata files, and the summary data sheets, and make numerous editorial changes. Suggestions are provided in the following general and specific comments for improving the Database and its description and the metadata files. 

Report was revised to clarify that data will be part of future project website for delivery of data/metadata.

Specific Comments for Clarity and Completeness S A-1. The Appendix does not describe the future website, or access to it, that will 

This will be provided. 
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make the data sets and the metadata available to future users. This will need to be done to enable the report user to access the data and metadata files. S A-2. There are several data sets dealing with gravity, magnetic, and geologic data ofthe same data type that are of various vintages. Data sets should be eliminated in the Database that have been superseded by more complete and accurate data sets. Including dated, out of date, data sets in the Database will cause confusion in determining which data set was and should be used in analyses. As a result the credibility of the results of the project will be enhanced by removing dated data sets. 

Older data sets removed from the database, as suggested. 

S A-3. A total of 32 summary metadata sheets are presented in the Appendix for the CEUS SSC model region, but no summary metadata sheets are provided for the remaining 40 data sets listed in Table A-1 for specific subregions. Summary metadata 

sheets should be provided for all of the GIS layer data sets or an explanation for not preparing metadata for the data sets needs to be provided. Furthermore, there is not an obvious relationship between the summary metadata sheets and the metadata files. In the metadata file there are 60 separate files that do not synchronize with the summary metadata sheets. It is not clear why there are only 60 rather than 72 

representing all the data layers as in Table A-1. Note also that the titles of the data 

sets are not necessarily the same as the titles in Appendix A and the metadata files. This causes confusion in using the files. It would be useful to have a column in Table 

A-1 that identifies the metadata file(s) of the specific data set as they exist in the 

metadata file. 

Report was revised to provide metadata summary sheets for only the CEUSscale data. Summary sheets for zone-specific data were not prepared because these data were typically digitized from a published figure.

S A-4. The prose in this appendix is in draft stage and needs clarification, reorganization, and improvement. A technical editor could help improve the appendix so that the resulting description of the efforts and the results associated with the Project Database reflect well on the major investment that was made. 

Updated text. 

S A-5. All pages of the appendix should be numbered consecutively. S A-6. The page size maps of the data sets that are provided as part of the summary 

metadata sheets are very useful. They provide a view of the data set for use in qualitative analysis by the user of the report. In addition, they assist the user in making a decision about preparing small scale maps of the mapped parameter or in selecting regions of the maps for detailed analysis. Only one of the six magnetic anomaly data sets prepared for this project (Ravat et al., 2009) is shown, and only one of the fifteen gravity anomaly data sets (CEUS SSC, 2010) prepared for this 

project is illustrated. Please note that referring to the gravity anomaly data sets by CEUS SSC, 2010 as in the summary data sheets may lead to confusion. An alternative suggestion is to cite Keller, 2010, personal communication. 

The goal of the summary sheets was to provide an easily-accessible review of the database contents and individual regional-scale data layers rather than 

a detailed presentation of every derivative of every layer. However, we have developed figures for each of the data layers in the CEUS and their 

derivatives where there is a metadata summary sheet.

S A-7. Unfortunately a key to the contour interval and symbols used in several of the maps is not provided with the map. This seriously detracts from the usefulness of the maps. In the few maps that show a color bar of the mapped parameter amplitudes, the limits of the range are given to a precision unwarranted in the data set and have limited usefulness for the user. In addition, these color codes are too coarse for most uses of the data. 

Explanations, labels, scale bars and other typical map elements have been provided for the figures in the appendix where appropriate. Because of the scale of information presented in the figures not all features can be shown clearly, or exhaustive legends developed.

S A-8. The keywords of the metadata files need further attention. Most data sets do not have keywords, and keywords that are given are not consistent and comprehensive. Keywords are not critical but they can be helpful in directing the data 

A keyword dictionary will not be available as part of the metadata for each data layer. 
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user to the appropriate data set without laborious, extensive review of all the data sets. Will the user be able to search the data sets by keyword? S A-9. “Aeromagnetic” in the title of maps should be changed to “magnetic anomaly.” This is the general title that is applied to regional magnetic anomaly maps. 

Updated text. 

S A-10. Citations in tables are not in consistent format. Updated text. S A-11. A data file showing areas where reliable earthquake hypocenter depths are available would be useful. Or is it possible to show range of depths of foci for the CEUS?

Although such a map would be useful, it is not currently available, nor is it easily developed without significant study of station distributions, instrumentation details, etc.Analysis of depths (including figures) will be added to Chapter 3. 

S A-12. Headers for Metadata Sheets: The repetition of “CEUS SSC Project GIS Data 

Summary” in large point size and bolded is less important to guide the reader’s eye than the title of what the sheet contains. Consider reformatting the header information. Example:

Sheet A-1 — CEUS SSC Project GIS Data Summary NOAA DNAG MAGNETIC ANOMALY MAP OF NORTH AMERICA 

Updated sheets. 

S A-13. Remove bracketed comments in text from previous reviewers. Updated text. S A-14. Shaded-relief versions of selected gravity and magnetic anomaly maps (e.g., total magnetic intensity anomaly map, reduced to pole magnetic anomaly map, residual isostatic gravity anomaly map) are a significant aid in the interpretation of the geological sources of the anomalies, particularly the high wave-number components 

of the anomalies. Several of these shaded relief maps have been prepared, but they are not identified in the data sets. They should be included and the specifications of the azimuth and inclination of the light source used in preparing the maps should be specified on the maps and in the metadata. 

Hillshades (shaded relief) were created for the magnetic and gravity anomaly derivatives where possible to provide an added visual aid to the interpretation of these data. Some of the data layers have limited data ranges and were not appropriate for hillshade creation without significant exaggeration. Summary sheet text for gravity and magnetic data, were modified to note that the hillshades (shaded relief) layers exist and their parameters. This information was also included on the figures where a hillshade was displayed.

Comments by Section, Table, and Sheet Text: Unlabeled IntroductionFirst paragraph: The first two sentences are not clear as to the goals of the database and the method of achieving them. The use of “function” in the first sentence leads to confusion. Suggest a rewrite focusing on goals of the data sets and procedures used to achieve them.Second paragraph: Strongly suggest that the term “aeromagnetic” throughout the titles of data sets be changed to “magnetic anomaly.” This is the appropriate title given to regional magnetic anomaly maps. Delete Free-air gravity and remove Bouguer and 

simply use the term “gravity anomaly.” Also, remove DNAG and USGS. These are data sets that have been superseded and should be removed from the Database. The Mesozoic rift basins data base cannot be found as an entity in the Database. Remove the parenthetical phrase in Earthquake Catalog.

In the bulleted list, note that there is no metadata file or summary for Mesozoic rift basins which was compiled for this study.Last bullet of second paragraph: Will digital presentations of the crustal scale profiles be available? If not, where can they be obtained for analysis?Last paragraph, last line: The last metadata summary sheet is A-32, rather than A-36. 

Updated text. Mesozoic basins have been included as five separate data layers, each corresponding to the interpretation of the source author. Metadata and a metadata summary sheet have been included for these layers. Digital representations of the crustal scale profiles are not included in the database.

Text: Section A.1 Last sentence of first paragraph: “The digital data compiled for the CEUS SSC Project 

Updated text. 
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are available to the public to provide transparency regarding the development of the CEUS SSC database.” Transparency does not seem to be an important reason for this. Rather it serves as a repository of data useful for largely regional seismic source zone characterization and assessment in the CEUS.Second paragraph, first line: Figure A-1 is not in the appendix. Second paragraph, second line: For example, some public-domain data sets cover... 

Third paragraph, bullets: Change to “Magnetic anomaly data,” “Gravity anomaly data” Add “Mesozoic rift basins within the ECC-AM” to the bullet list in third paragraph. 

Third paragraph, fifth bullet: Add “data” after “Maximum horizontal compressive stress” to be consistent.Third paragraph: Replace “sources” in first line by “types” or, less desirable, “class.” In second line, suggest: “These data layers include the following:” Text: Section A-2 First paragraph: Suggest that definitions of data class, theme, etc. be provided or a figure showing hierarchy of data.First paragraph: Spell out FWLA, point out that this server is no longer availableFirst paragraph, top of p. A-3: Instead of “theme,” use “type of data”? Fifth paragraph: All project data began at revision 0 (Rev0) and have been updated with consecutive revision numbers and made available via the project web site. Providing a full file name reference allows data to be identified if removed from the organization of the project Database.Sixth (last) paragraph: Add this sentence at end: “This server is no longer in service for this project.” Sixth paragraph: Is the “Project GIS Manager” the same as “Database Manager” identified in Figure 2.3-1 and Appendix G? If so, be consistent. 

Updated text. Notes added regarding the class/theme as used in database and text. The FWLA server was only for project use, not long-term use. No 

need to note this in the text as requested in the comment. Title renamed as 

“Database Manager” as originally noted in the project work plan.

Text: Section A-3.3 Second paragraph: If the steps to review GIS data produced from non-digital data weresequential, it would be better to present the steps using numbers or letters rather than bullets.Second paragraph, fourth bullet: Clarify “Completion of attribute information”Second paragraph , last bullet: Use of the term “topology” appears to be inappropriate here because the term is generally used to describe a branch of mathematics. 

Updated text. The term “topology” used in GIS refers to data layers with defined relationships between their component points, lines and polygon features. 

Text: Section A-4 Second paragraph, line 2: ** are ??Second paragraph, line 6: Summary sheet A-22 has no state boundaries. Second paragraph, line 7: Why not “all” rather than “majority”? What criteria were usedto omit some?Second paragraph, last sentence: Why are there no metadata summary sheets for data covering specific regions of the study area? If they are important enough to include as a data set, they should be important enough to have a metadata file. Are all data sets included in the metadata file? If not, why not? 

Updated text. See above comments about metadata summary sheets vs. 

layer metadata.
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Text: Section A-5 Third paragraph, first line: Were the original or source data provided? Third paragraph, last line: Typo: “into other coordinate systems.” 

Updated text. 

Text: Section A-6 This section is out of place, place after A-5. First paragraph, 3rd line: Add earthquake [information] to this list Second paragraph, line 5: Typo: “to identify geologic relationships” 

Updated text. 

Table A-1 Page 1: Where are the citations located? Are they all in the same place in the report? Page 1: Delete Row 1 Page 1: Delete Row 3Page 1, Row 5: Need more complete description of this database and its preparation or refer to another section of report.Page 2, Row 2: Replace “Geodesy” with “Strain (GPS)”Page 3, Row 3: Why is this map being used, since it was replaced by Reed et al. (2005)? Delete.Page 4, Row 3: Is this the basin map referred to in the data evaluation tables? If so use consistent titles.Page 4, Row 7: Delete, superseded.Page 5, Row 1: Refer to Keller, 2010, personal communicationPage 5, Rows 3 and 4: Delete, supersededPage 5, Row 6: How are these tied to references? Where are the metadata for these layers?Page 6, Row 2: This is also referred to as Zoback (2010). Determine appropriate reference and use consistently.Page 7, Row header: Change “Mid-Continent” to “Midcontinent” Page 7, Row 5: Replace “Geodesy” with “Strain (GPS)”Page 7: Why does the numbering of Summary Sheets stop with A-32 (in the last row 

of page 6)?

Page 8, Rows 5 and 6: Need citationsPage 9, Row 2: Need citation Page 9, Row 3: Change “Aeromagnetic” to “magnetic anomaly” 

Text has been updated. Citations are presented in the report. Citations used in Table A-1 are the same, or same style, as those in the report. Older data that have been superseded with new data in this database have been removed. Data layers 

that were incorporated into the CEUS paleoliquefaction database have been removed from the rest of the database where earlier presented as separate layers.

Sheet A-1 Delete, superseded Sheet A-2 Replace “aeromagnetic” with “” Contour interval should be givenShow page-size maps of six data sets with bar graph for amplitude and in shaded relief ifpossibleDifferentially reduced to pole, tilt derivative, etc. may not be known entities to user; suggest a basic reference for each of these for the interested reader Sheet A-3 Delete, superseded 

Updated sheets as appropriate. 
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Sheet A-4 Increase amplitude at least twice that being shown Sheet A-5 Data description: Needs range of date, also key to map symbols; as throughout report, moment magnitude (M) should be bolded; which earthquake catalog is referred 

to? The raw catalog, the declustered catalog, or ?? Should refer to Appendix B if this is the same catalog.

Sheet A-6 Identify symbols Sheet A-7 Brighter colors needed, no extended crust identified Sheet A-8 Need brighter colors Sheet A-9 Need key to colors Sheet A-10 Need key to colors Sheet A-11 How are they keyed to source (reference)? Sheet A-12 Delete, superseded Sheet A-13 Data description is misleading, the dashed line represents the mapped eastern limit of 

pre- 1600 Ma crust. Why not show all of Figure 2 of this reference? It puts the 

boundary into the context of the basement terranes.Sheet A-14 Brighten colors and provide key Sheet A-15 Brighten colors and provide key Sheet A-16 Brighten colors Sheet A-17 Needs key Sheet A-18 Needs contour interval, high range is given to 4 decimal points which is much greater than precisionSheet A-19 Needs key Sheet A-20 Legend of figure needs to be checked. What is basement thickness? Unclear.Sheet A-21 Brighten colors and provide key Sheet A-22 Delete, superseded Sheet A-23 Brighten colors, color contour interval needed, show all figures at page size, preferably in shaded relief; suggest for Author that G.R. Keller be identified as the source of the data and derivative anomaly maps . . . as in A-2 for D. Ravat. Sheet A-24

To be consistent, use residual isostatic; color contour interval without range beyond decimal point.

Sheet A-25 Delete, superseded Sheet A-26 Delete, superseded Sheet A-27 Tie to references?? Where will the metadata file be accessible? Sheet A-28 Brighten colors Sheet A-29 Needs key; this is also referenced as Zoback (2010) – select appropriate 

citation 
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APPENDIX B — EARTHQUAKE CATALOG General Comments Appendix B contains a listing of the earthquake catalog for the CEUS developed as part of this project. The development of the earthquake catalog is a major element of the source characterization and assessment in the project. The Appendix contains a single page of text that identifies the columnar entries in the catalog followed by a 273 page tabular listing of the 9800 earthquakes in the catalog. The table is well laid out and easy to follow. It is evident that monumental efforts were required to compile this catalog, and the Project Team is to be applauded for these efforts. Beyond its use by TI Team members familiar with its contents, careful documentation and explanation is needed for the contents of the catalog to be understood and appropriately used by others. 

Greater detail on contents of catalog added to Chapter 3 and to Appendix B 

Specific Comments for Clarity and Completeness S B-1. Need for Introductory Text A brief summary discussion should be added to this Appendix. This discussion should describe what this catalog listing actually is (i.e., final catalog with dependent events flagged). It would also be useful to refer the reader back to relevant sections of Section 3 for a discussion of M*, etc. Additional notes on depths and how ERH was estimated would also be useful in the introduction to the catalog.A pointer to the appropriate Database entry would be useful.A catalog of non-tectonic events was developed as part of this project (mentioned in 

Section 3), where will this catalog be documented and maintained? 

Summary added, including description of list of non-tectonic event Catalog will be on Project web site. Maintenance in the future is beyond the scope of this project, but discussions with the USGS as a possible repository are in progress 

S B-2. Clarity of Documentation in the Catalog Explanation For clarity of documentation, attention should be paid to the following:1. Designation of time in an earthquake catalog should be explicit. Are the times/dates in UTC? Local time? A mix? This is non-trivial if one tries to find the events in another 

catalog.

2. How should the reader interpret the variable presentation of significant figures in theEarthquake Catalog for latitude, longitude, depth, M, and sigM? How does one discern available information on precision from the vagaries of spreadsheet display? 3. The meaning of Depth = 0 should be explained.4. To avoid ambiguity, ERH should be explained as “Horizontal Location Uncertainty (km)”. If correct that the entries for ERH contain both rough estimates and statistical calculations, then ERH is better described as “Estimated Horizontal LocationUncertainty (km)”.5. After ERH, entries in the Explanation change from having the first letter of all terms capitalized to just the first word capitalized. 6. M , M*, and sigM should be bolded in Column 1 of the Explanation 7. In column 1, “Flag” should be written “FLAG” as it appears in the table. 

Discussion added of entries 

APPENDIX C—DATA EVALUATION TABLES General Comments G C-1. (NAR) The tables of Appendix C summarize what data were used, how the data 

were used, and the source, quality, and significance of the data in defining, 

Comment noted and appreciated. 
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characterizing, and assessing the CEUS seismic sources. In addition, the tables specify the availability of the data in GIS format. These tables are a useful supplement to the documentation of the seismic source zone characterization and assessment of both the RLME sources and the seismotectonic source zones. They will be useful to users of the CEUS SSC report, and they will also provide a guide to potential application of various data sets in future evaluations of the CEUS SSC model. In general, the tables are well prepared and presented. However, they are not without problems, as we proceed to explain. Specific Comments S C-1. (CC, DMM) Completeness of Tables and Ambiguity About Applicability Data Evaluation tables have been prepared for many of the identified seismic source zones, but not all. In Section 4.2.2 of the main report, the reader is informed (p. 4-6, first 

paragraph of the section) that, “Data Evaluation tables were developed . . . and the tables for each source (emphasis added) are included in Appendix C.” Comparing a list of the RLME sources, the seismotectonic zones, and the Mmax source zones with the index of tables on the first page of Appendix C will leave the reader perplexed. Further, the treatment of some zones is handled within the Data Evaluation table for another zone (e.g., the Meers fault RLME source is included in the table for the OKA 

seismotectonic zone).What criteria were used to select which zones were to have Data Evaluation tables? At the top of Table C-5.4, the labeling indicates “Default for entire CEUS SSC.” Does this 

mean that if a table is not given for a specific zone, then Table C-5.4 is the applicable 

table? (If this is the intent, note that Table C-5.4 is incomplete with regard to several data 

sets.) Introductory text should be added to eliminate these and similar questions and concerns pertaining to the Data Evaluation tables. All seismic source zones including 

Mmax zones should have a Data Evaluation table. 

Data Evaluation for Meers fault / OKA RLME combined because when Meers is out of cluster, RLME allowed within larger OKA source.The list of tables on the cover sheet for Appendix C was expanded to indicate the applicable table for each RLME and Seismotectonic zone. All seismic sources have an applicable Data Evaluation table. In some cases, the same table is used for multiple sources and the applicable sources are listed at the top of the table. Table C-5.4 is different from the 

other tables because it is referring specifically to the assessment of future earthquake characteristics (Section 5.4). Thus, the reference to “Default for entire CEUS SSC” is specifically for future earthquake characteristics, as discussed in Section 5.4.

S C-2. (CC) Facilitating Use of the Data Evaluation Tables The Data Evaluation tables are explained in the text of the report (Section 4.2.2). However, consideration should be given to adding a short description of the objective, organization (including the keying of the table numbers to the main body of the report), preparation, and uses of the tables in an introductory paragraph to the appendix. This will facilitate the use of the tables. An explanation of the content of the columns used in the tables should be also included in this description for stand-alone reading. Also, all 

pages of Appendix C should be numbered consecutively, not separately for each table, to enable convenient reference—as opposed to having to point to a specific table and a 

page number within the table. 

Revisions made as suggested. 

S C-3. (CC, DMM) Inconsistencies in the Tables The Data Evaluation tables have numerous inconsistencies that should be eliminated 

because they diminish the quality and usefulness of the tables. We note the following: 1. The titles of the tables and the identified source in the notes at the top of each table should be consistent with the nomenclature of the text of the report, and tables should

be in the same sequence as the identified source is described in the text (or keyed to a table in the text).

2. Although the majority of the Data Evaluation tables are also in the Data Summary tables (Appendix D), some are not included in the Data Summary tables and vice versa. There is no explanation for this inconsistency among tables in the documentation of the 

1. Revisions made as suggested. 2. Explanation added in Section 7.1; a new Table 7.1-1 shows which Appendix C and D table numbers are associated with each of the seismotectonic zones. 3. Modifications made with an objective of achieving greater consistency in the level of information.4. Modifications made so that all tables have seven columns. “Discuss” is defined as “to consider or examine by argument, comment, etc.” and is the 
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report. 3. The level of information given in the tables is variable. This may be due in part to the information available, or it could be due to the detail that is provided by the individual preparing the table. Greater consistency in the level of information would be desirable. 4. All the tables have seven columns except for Tables 6.1.4 (OK aulacogen) and 7.3.9 (Gulf Coast), which have eight columns. Only seven columns are described in Section 4.2.2 (pages 4-6 and 4-7). Note that the fifth column should be “Description” rather than 

“Discussion” (there is no oral material here). Throughout the tables, references to “discussions” should be changed to “descriptions.” 

5. Numbers in the tables are inconsistently spelled out or given in numeric form.Numeric form should be used for data and scoring; otherwise, numbers should be spelled out when referring to counts of ten or less. 6. Geographic (compass) directions are inconsistently given in abbreviated (e.g., NE) and spelled-out form. 7. Some tables have the acronyms for the subdivisions of the seismic source zone identified in notes at the beginning of the tables, others do not. Also several acronyms are not given in the List of Acronyms.8. Descriptions in cells are variously in sentence and non-sentence form. It may be useful to have both, but an effort to be consistent would be worthwhile.9. The use of blanks in the tables is inconsistent. Every cell needs to have something in it; if nothing else, N/A for not applicable or some other notation to indicate intention.Otherwise, the meaning of a blank cell will be unclear.10. There is inconsistency in the title of column 3 among the tables. Is it “data quality” or “data and quality” (as in “Notes on Quality or Data”)?11. Use data as a plural word consistently throughout the tables.12. Both the terms magnetic and aeromagnetic are used in the tables. The use of the term aeromagnetic should be changed to magnetic throughout. Aeromagnetic simply refers to the method of collecting the majority of the data in the file. Referring to “aeromagnetic” but only to “gravity” is inconsistent.13. Where no data are available for a particular type of data, the tables deal with this in different ways—sometimes the wording indicates explicitly that no data are available (e.g., Table C-6.1.3, p. 4; r. 3); in other places, data are just not identified. 14. The evaluation of the quality of the data is not consistent; in some cases peerreviewed publications are referred to and in others simple publications. 

formal treatment of a topic in speech or writing. We believe that the term “Discussion”, as used in the Data Evaluation tables, is more accurate than the term “Description”, so no change has been made. 5.Revisions made as suggested 6. Modifications were made to abbreviate compass directions in the tables. 7. Modifications made for consistency; List of Acronyms has been expanded.8. Modifications made with an objective of achieving greater consistency in using non-sentence (or notes) form. 9. Modifications made with an objective of achieving greater consistency. 10. Revisions made; the proper heading for column 3 is “Notes on Quality of Data”11. Revisions made as suggested.12. Revisions made as suggested.13. Modifications made with an objective of achieving greater consistency. 14. Modifications made with an objective of achieving greater consistency. 

Comments by Table (for Clarity and Completeness) (Notation: pg. = page, c = column of table, r = row of table) Table C-5.4 • pg. 1, descriptor (title) of 5th c: Would “significance” be a more descriptive term than “reliance”?• pg. 4, r. 3; c. 1: Is this the new data set from Zoback? If so, please put a date on it—

and put dates in all tables for all the data sets prepared for this project so that in 

subsequent use there will be no question of date.• pg. 1, r. 4, 5, & 6; c. 6: Add fault to slip• pg. 1, r. 7; c. 3: In the Charlevoix area of the St. Lawrence Rift 

Reliance is a better descriptor; “significance” would be some measure of importance, but “reliance” describes how much the TI Team used the information in their assessments.Revisions made as suggested or to clarify.
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• pg. 2, r. 1 & 2; c. 6: Add fault slip • pg. 2, r. 5; c. 6: Could not find where depth as a function of magnitude is described in 

report 

Table C-6.1.1 • pg. 1, r. 5; c. 6: Incomplete• pg. 1, r. 6; c. 1: Change to magnetic from aeromagnetic, here and elsewhere in tables • pg. 2, r. 2; c. 1: Give date• pg. 3, r. 4; c. 1: Reinecher not in references...this holds true for many of the references cited in the tables...they should be included in Chapter 10 (References) 

• Removed reference to specific value from project catalog • changed to magnetic • no date given for gravity dataset;• Replaced reference with Heidbach et al., 2008 as a global change. 

Table C-6.1.2 • pg. 2, r. 5 & 6; c. 3: What is the significance of the term “basic”?• 6, r. 1; c. 3: What is meant by “plain sediments”?• pg. 6, r. 5; c. 1: Should be bold and italics• pg. 9, r. 5; c. 1: Should be bold and italics • pg. 11, r. 3; c. 3: Replace to with two 

Revised as suggested. 

Table C-6.1.3 • pg. 3, r. 2; c. 6: Reference to 2002 article is incomplete (author?)• pg. 5, r. 1; c. 6: Change to “No measurements nearby to the . . .”• pg. 6, r. 2; c. 6: Reference to 2002 article is incomplete (author?) 

Revised to address comments 

Table C-6.1.4 • Why add an eighth column? Y or N to be used in c. 8 to be consistent with rest of tables.• pg. 1, r. 1; c. 4: How are faults due to hydrocarbon exploration? Change wording. • pg. 1, r. 1; c. 5 and subsequent rows on page: What is OK aulacogen? Background? • pg. 1, r. 2; c. 1: Bold and italics• pg. 1, r. 3 & 4: Delete. These are data sets superseded by the EPRI data set.• pg. 2, r. 2: Delete this data set, superseded by the EPRI data set • pg. 3, r. 3; c. 7: Change to “within the Arbuckle”• pg. 4; r. 2; c. 2: 1990• pg. 4; r. 4; c. 2: What is BEG?• pg. 7; r. 1; c. 7; “fault slip” 

Revised as suggested 

Table C-6.1.5 • pg. 1; r. 2; c. 6: Change to ...are concentrated...; also ...projects to surface.. • pg. 1; r. 5; c. 6: Change to ...sequences provides...• pg. 4; r. 1; c. 3: Give map #• pg. 5; r. 5; c. 3: Is relatively short germane? Don’t know what short is. This is not used where abstracts are referenced. • pg. 6; r. 2; c. 4: Define abbreviations• pg. 6; r. 5; c. 6: Rationale or geophysical evidence?• pg. 8; r. 1; c. 7: What is significance of (“?”) 

Revised to address comments 
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Table C-6.1.6 • pg. 5; r. 2; c. 6: What is RP and ERM-SRP? ; need period after parenthesis • pg. 12; r. 1; c. 6: What is ERRM? ERM 

Revised to address comments: RP deleted. ERM-SRP Eastern Rift Margin-Seismic river picks; ERRM, which stands for Eastern Reelfoot rift 

margin, is an acronym used in a publication

Table C-6.1.7 • pg. 3; r. 5; c. 4; what is EMF_S? not in acronyms 

EMF_S has been changed to ERM_S 

Table C-6.1.8 • pg. 2; r. 1; c. 6: No CFZ in acronyms• pg. 3; r. 5; c. 6: Explain A and B; replace 

Revised to address comments. 

Table C-7.3.1 • pg. 2; r. 1; c. 6: Clarify the wording, “A general gradient in amplitude parallels” • pg. 4; r. 8; c. 6: Entries; period at end of sentence• pg. 5; r. 1; c. 6: Capitalize Mechanisms 

• Deleted statement. • Entry carries onto next page so no period was added • Entry not capitalized because sentence continues from the previous page.

Table C-7.3.3 • pg. 1: Shouldn’t the title be Northern Appalachian zone, without the “s”?• pg. 3; r. 2; c. 3: Parenthesis at end 

S deleted from header; Parenthesis added.

Table C-7.3.4 • pg. 1: In notes beneath title, need to identify the acronyms of the subdivisions of the

zone • pg. 2; r. 4 & 5; c. 3 & 6: What is CLFS? 

Clarified acronyms for source zone; Spelled out Clarendon-Linden fault system 

Table C-7.3.9 • pg. 1; r. 3 & 4; c. 7: If considered for defining boundaries, why 0 in column 6? 

A “0” was used when a data set was considered but not used 

Table C-7.3.12 • pg. 1; r. 5; c. 3: Do not capitalize intensity• pg. 2; r. 1; c. 6: Unfinished sentence• pg. 2; r. 2; c. 6: Belongs in column 6 of row 3; why 2 in column 5 for row 2 and 1 in column 5 for row 3?• pg. 5; r. 1; c. 6: Remove “yet” 

Revised to address comments. 

APPENDIX D—DATA SUMMARY TABLES General Comments G D-1. (NAR) The Data Summary tables of Appendix D contain a massive amount of information on references that include data considered by the TI Team in identifying, 

characterizing, and assessing the CEUS seismic sources. These data include all types of information that have a potential use in achieving these objectives. The tables provide a benchmark of germane data at the time of the Project, which gives transparency to the efforts of the TI Team and which future evaluations can augment with new sources of information. The tables include the citation, the title, and the data included in the 

reference that are relevant to seismic source identification and characterization. The tables are thorough and, in general, reasonably well prepared and presented. We proceed to point out minor problems needing attention before finalizing the appendix. 

No revision necessary. 
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Specific Comments S D-1. (CC) Difficulty in Relating the Appendix to the Main Body of the Report The labeling of the tables is not consistent with the titles and acronyms used in the main body of the report for the source zones, and source zone data summaries are grouped in 

a manner that makes it difficult to relate the tables to some of the specific zones. For example, the Gulf Highly Extended Crust zone is apparently included in Table D-7.3.9, 

Gulf Coast Data Summary. Similar situations occur in other tables of the appendix. This makes it very difficult to relate the tables to the source zones in the report and decreases the usefulness of the appendix. This inconsistency needs to be rectified. 

The list of tables on the cover sheet for Appendix D was expanded to indicate the applicable table for each RLME and Seismotectonic zone.Modifications have been made to the tables with an objective of achieving greater consistency. Explanation added in Section 7.1; a new Table 7.1-1 shows which Appendix C and D table numbers are associated with each of the seismotectonic zones. 

S D-2. (CC) Facilitating Use of the Data Summary Tables The Data Summary tables are explained in the text of the report (Section 4.2.2). However, consideration should be given to adding a short description of the objective, organization (including the keying of the table numbers to the main body of the report), preparation, and uses of the tables in an introductory paragraph to the appendix. This will facilitate the use of the tables. An explanation of the content of the columns used in the tables should be also included in this description for stand-alone reading. Also, all 

pages of Appendix D should be numbered consecutively, not separately for each table, to enable convenient reference—as opposed to having to point to a specific table and a 

page number within the table. 

Revisions made as suggested. 

S D-3. (CC) Inconsistencies in the Tables The Data Summary tables have numerous inconsistencies which should be eliminated because they diminish the quality and usefulness of the tables. We note the following: 1. The titles of the tables and the identified source in the notes at the top of each table should be consistent with the nomenclature of the text of the report, and tables should

be in the same sequence as the identified source is described in the text (or keyed to a table in the text).

2. The level of information given in the third column, Relevance to SSC, is variable.This may be due in part to the information available or it could be due to the detail that is 

provided by the individual preparing the table. Greater consistency in the level of information would be desirable.

3. Geographic (compass) directions are inconsistently given in abbreviated (e.g., NE) and spelled-out form. 4. Dates are presented in different formats.5. Some tables have the acronyms for the subdivisions of the seismic source zone identified in notes at the beginning of the tables, others do not.6. Column 3 descriptors are sometimes in sentences, while others are not. It may be useful to have both, but an effort to be consistent would be worthwhile.7. The use of blanks in the tables is inconsistent. Every cell needs to have something in it; if nothing else, N/A for not applicable or some other notation to indicate intention. Otherwise, the meaning of a blank cell will be unclear.8. Both the terms magnetic and aeromagnetic are used in the tables. The use of the term aeromagnetic should be changed to magnetic throughout. Aeromagnetic simplyrefers to the method of collecting the majority of the data in the file. Referring to “aeromagnetic” but only to “gravity” is inconsistent.9. The format of the references at the end of each table is inconsistent, and some 

1. Revisions made as suggested. 2. Modifications made with an objective of achieving greater consistency in the level of information.3. Modifications made to abbreviate compass directions in the tables. 4. Modifications made with an objective of achieving greater consistency. 5. Modifications made with an objective of achieving greater consistency. 6. Modifications made with an objective of achieving greater consistency in using non-sentence (or notes) form. 7. Modifications made with an objective of achieving greater consistency. 8. Revisions made as suggested.9. References have been deleted from the tables; all references are included in Chapter 10 References.10. Modifications made with an objective of achieving greater consistency. 11. Modifications made with an objective of achieving greater consistency. 
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references do not have complete information. 10. The ordering of the citations in the tables is not consistent. Some are listed chronologically, while others are listed alphabetically according to the first letter of the family name of the senior author.11. Use of bold letters for subtitles in several of the tables is inconsistent. 12. Capitalization of type of feature is inconsistent in the tables. It is suggested that the type of feature should not be capitalized, e.g., Commerce lineament, not CommerceLineament. 

12. Modifications made with an objective of achieving greater consistency. 

Comments by Table (for Clarity and Completeness) (Notation: pg. = page, c = column of table, r = row of table)Table D-5.4 • pg. 1, c. 1: Period after et al. on this page and throughout tables• pg. 4: Should Petersen et al. be included? 

Revised as suggested. Petersen et al. was not used to assess future earthquake characteristics. 

Table D-6.1.1 • pg. 1, c. 3: Spell aulacogens 

Revised as suggested. 

Table D-6.1.2 • pgs. 2 & 3, c. 3: No difference for Chapman and Beale, 2009 and 2010. Should there be a difference?• pg. 5, c.3, r.2: Should be Appalachian Mountains not Appalachians, similar comment for other geographic features throughout tables. • pg. 15, c.2, r.2: Why is journal listed? 

Revised as suggested. 

Table D-6.1.3 • pg. 1, c.3, r.2: The abbreviation for miles should be mi without a period (not mi.) — change throughout tables 

 Modifications were made to the tables to achieve consistency – English units are abbreviated and include a period at the end (e.g., mi. and ft.); metric units do not have a period at the end (e.g., km, cm) 

Table D-6.1.4 • pg. 3, c.3, r.1 & 2: Replace further with farther 

Replaced 

Table D-6.1.5 • pg. 40, c.3, r.2: Blank—similar blanks in other tables 

Revised to fill in blanks 

Table D-6.1.9 • pg. 4, c.3, r.4: Use of the casual Appalachians and Rockies should be avoided• pg. 12: Has horizontal line between rows missing—this occurs elsewhere in tables 

Revised as suggested. 

Table D-7.3.1 • pg. 4, c.2, r.2: Misspelled Quebec• pg. 5, c.3, r.2: Is it Sutton Mountain or Sutton Mountains? Both are used in this table. 

Revised as suggested. 

Table D-7.3.2 • pg. 10: Reference for N.H. Sleep; misspelled mantle 

Revised. 

Table D-7.3.4 • pg. 9, c.3: No references for two subheadings• pg. 15, r.: Geophysical Investigations should be bold; similar subheading concerns 

Entries added. Headings formatted.
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elsewhere in tables Table D-7.3.7 • pg. 1: Horizontal lines needed between citations • pg. 11: Misspelling of investigate 

Modifications made 

Table D-7.3.9 • pg. 1 and following: Why () around citations? 

Removed 

APPENDIX E—CEUS PALEOLIQUEFACTION DATABASE, UNCERTAINTIES ASSOCIATED WITH PALEOLIQUEFACTION DATA, AND GUIDANCE FOR SEISMIC SOURCE CHARACTERIZATION General Comments This appendix represents a thorough and well expressed compendium of methodology, data, and guidance related to paleoliquefaction studies in the CEUS. The written content and illustrations present the data and information clearly and with a high degree of technical quality. Generally the documentation of effort encompassed in this appendix supports the related assertions made in the CEUS SSC. This work is notable not only because it represents a new and productive field of study that was not included in the 

earlier EPRI-SOG and LLNL projects, but also because the effort has brought sets of 

information and data that were highly varied and inconsistent into a consistent and coherent framework. This appendix is likely to be used as a primer on the topic for future researchers in paleoliquefaction, and the fulfillment of the recommendations provided could significantly improve the understanding of RLMEs in areas of low to moderate seismicity areas in the U.S. and globally. 

No revisions required. 

Specific Comments for Clarity and Completeness S E-1. Incorporation of the Digital Database It is unclear how the digital database is going to be incorporated into the final report and how it will be accessed in the future. It would be useful to the reader if the location was noted after the sentence, “The database itself is available in digital format.” 

Text modified to indicate that the database will be available on the CEUS SSC project website.

S E-2. Recommendations for Clarification of the Digital Database Because Section 1.1 (Database Structure) uses many technical terms related to dating that are very well discussed later in the document, it may be useful for many readers who are not well versed on the techniques if a sentence were added at the end of the first paragraph of the section that says, “A discussion of the various dating methods and their uncertainties can be found in Section 2.1.3.”In relation to the description of the database on page 2, a simplified figure illustrating parameters such as SB_THICK, SB_WIDTH, SB_LENGTH, etc. may be helpful to the reader.Similarly, a simple figure illustrating the uncertainty estimates described in the last paragraph of Section 1.1 is not essential, but could be very useful for the reader. 

Text modified as recommended. Added two figures illustrating measured size parameters of liquefaction features and age data used to estimate ages and related uncertainty of liquefaction features.

S E-3. Clarification of Data Contributors At the beginning of each of the “Data Description” subsections in the discussions of regional datasets in Section 1.2, the authors note that “Paleoliquefaction data have been contributed by . . . .” It is unclear to the reader if the contributors listed represent a complete list of the researchers who have worked in the area or if it is a subset of 

Text revised for clarity as recommended. Clarified who contributed directly to the database and new maps produced for the report showing rivers searched. Changed Beta Analytic to Beta Analytic Radiocarbon Laboratory.
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researchers who have provided additional information specifically for this project (e.g. by providing 2-sigma data that were not otherwise published). Because this report is likely to be read by researchers not familiar with paleoliquefaction, it may be helpful to refer to Beta Analytic as “Beta Analytic Laboratories” or in similar terms. The way the text reads currently, those not familiar with the topic are likely to understand Beta Analytic to be a process or approach described in Talma and Vogel (1993) or Vogel et al. (1993). S E-4. Missing or Misnumbered Figures — There is a Figure 11a, followed by Figure 11. Presumably, the second should be Figure 11b.— Figure E28 is missing. — There is a Figure E-39 and a Figure E-39b. Only E-39 is noted in the text.— There is a Figure E-44 and an E-44b. Only E-44 is noted in the text. — On Figure E-50, it would be useful to note what the SL signifies in the description for 

those not familiar with that notation. 

— Figure E-51 is sideways. — Figures 53b and 55b are missing. S E-5. Additional Information and Clarification of Seismic Zones On page 8 in the first paragraph of Section 1.1.2, there is a discussion of a lineament throughout the paragraph. In the next paragraph there is reference to the “Daytona Beach” lineament at the end of the paragraph. It is unclear whether all the discussion relates to a single lineament called the Daytona Beach lineament. If so, perhaps the name should be noted at the start of the discussion. The discussion of the Wabash Valley Seismic Zone should be expanded to make the report more complete. Neither the text, nor the figures, provides any actual dates, with the figure instead indicating “Event A Dates,” “Event C Dates.” The description of the dataset in the report should discuss these events and their dates rather than expecting the reader to go to the original papers.On page 13, the report notes that “There is no evidence for repeated large earthquakes in the exposures.” This statement needs to be further explained. In what way do the data not meet the criteria established by the project? Because this is a hazard-significant finding for sites in the ALM region, the line of evidence that the features do NOT represent seismically-generated features should be made clear. Also, it is unclear how 

this bullet and the following bullet are different statements.

From discussion of the Charleston Seismic Zone, it is unclear from both the text and the figures what the number of events and the dates of those events are. One can only tell 

that there is a historic event, and at least one other event happened. Clarification as to what the outcomes are in the text would be helpful to the reader. 

Daytona lineament: The Daytona Beach lineament is named in the first paragraph of Section 1.1.2. Additional text added.Wabash Valley seismic zone: Text and figures describing the Wabash Valley seismic zone have been revised to provide additional detail. ALM: Text revised for clarity, including brief summary of how the ALM features do not meet the criteria for earthquake-induced liquefaction features.Charleston seismic zone: Text modified to provide cross-reference to Subsection 6.1.2 of the main report, which presents detailed discussions and figures for Charleston earthquake chronology. 

S E-6. Additional Guidance It would be appropriate to include a bullet point on considerations of completeness in Section 3 on guidance for the use of paleoliquefaction data in SSC. 

Text revised as suggested to include bullet about completeness in Section 3.

Minor Editorial Comments and Typographical Errors • TOC: The page number for 1.2.3 St. Louis Region is on the next line• p. 1: There is an EPRI logo embedded on the middle of page 

These and other minor editorial issues have been corrected. - Deleted EPRI logo - p. 1, sentence 3 edited. 
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• Several of the page numbers have “Cited” included before the number • p. 1: Consider changing sentence 3 as follows, “Under this task, a new paleoliquefaction database, including regional datasets, was created and this report was prepared, documentation and illustrating the databases, discussing . . .” • p. 6 and other similar sections: Some sections make reference to “Beta Analytic” and others to “Beta Analytic Beta Analytic”• p. 7, first paragraph: “...that may be capable of large earthquakes (e.g., EasternMargin and Commerce faults), and migration of seismicity from one part of the Reelfoot Rift...”• p. 5, Sand dikes, last bullet: Typo (“as well we as soft-sediment deformation”) • p. 19, second paragraph: “For the results of a paleoliquefaction study to be most useful in accessing assessing the long-term seismic hazards...” • p. 34, par. 1, line 3: Typo (change “earthquakes parameters” to “earthquakeparameters”)• p. 34, last paragraph: The text states that radiocarbon and OSL dating “provide age estimates with uncertainties of one hundred years in the best of circumstances. Dating  techniques that provide more precise results would help to improve age estimates of liquefaction features and their causative earthquakes.” In section 2.1.3.2 (p. 24, par. 2), examples are given of reported “precision” of ± 80 radiocarbon years, ± 20 radiocarbon 

years, and ± 40 radiocarbon years.

• The figures start on page E2. Presumably the page numbers will be changed for the final report. 

- Deleted “Cited” from footer. - Beta Analytic changed to Beta Analytic Radiocarbon Laboratory. - p. 7. Added references regarding the Commerce and Eastern Reelfoot Rift margin faults being earthquake sources. - p. 5. Changed to “as well as” - p. 19. Corrected typographical error. - p. 34, par.1. “s deleted from “earthquakes” - p. 34, last par. Explained the difference between sample dates and age estimates of liquefaction features and earthquakes responsible for their formation and referenced Figure E-3. 

APPENDIX F — WORKSHOP SUMMARIES General Comments The summaries of the workshop provided in Appendix F are well-written accounts of the 

presentations and subsequent discussions that transpired. The workshop summaries, coupled with the agendas, participant lists, and presentations, provide sufficient documentation regarding the content of the workshops. 

None required 

S F-1. Added Information for Each Workshop Information has been described as “what people need and want to know.” Inclusion of the agenda for each workshop would give the reader a useful “road map” for navigating through the dense narratives. Also, the list of attendees for each workshop should be included for complete documentation (Table 2-2, p. 2-47, provides a partial list). As an 

additional step to help those wishing to review the project in the future, we assume that copies of visual presentations made at the workshops will be included as part of the project report and will become available either as part of this Appendix or on a project Website or in some other conveniently accessible form. 

No change. The workshop agendas and lists of participants, as well as copies of all presentations, will be provided on the Project website.

APPENDIX G — BIOGRAPHIES OF PROJECT TEAM General Comments This appendix is a straightforward compilation of biographical sketches for members of the CEUS SSC Project. As part of this review, individual members of the PPRP were 

None required 
PPRP Comment Response Table 

I-85 

asked to carefully examine their own biosketches. Specific Comments for Clarity and Completeness S G-1. Correlation and Coordination of Appendix G with Figure 2.3-1 For stand-alone reading of Appendix G, it would be useful to give the reader an overview 

of the Project Team by either pointing the reader to the CEUS SSC Project Organization 

diagram (Figure 2.3-1), say by using a footnote on p. G-1, or by reproducing the diagram 

in this appendix. The inclusion of biographies for the Sponsor Reviewers in Appendix G, as part of the Project Team, implies that their names should also be included in the 

Project Organization diagram.The presentation of names in Appendix G is a mix of alphabetical and hierarchical ordering. If Figure 2.3-1 is to be a guide for the reader, consider ordering names in Appendix G as they appear in the various boxes on the figure.In both the Project Organization diagram and in Appendix G, the TI Team (and support staff) is arguably a more important component of the “Project Team” than the PPRP.Consider moving the PPRP box on Figure 2.3-1 to the right of the TI Team and, correspondingly, presenting the PPRP names last in Appendix G. A box for the Sponsor Reviewers could be added in the organizational chart to the right of the PPRP (and their biosketches could follow those for the PPRP as in the draft). 

New introduction added that points the reader to the CEUS Reference made to the SSC Project Organization diagram (Fig. 2.3-1) and discussion 

in Sec. 2.3.

Sponsor Reviewer box added to Fig. 2.3-1. Fig 2.3-1 names are in hierarchical order for Project management team. 

For all other boxes, order of names is alphabetical, except for TI and PPRP groups where the lead or chairman is first in box, followed by members of team in alphabetical order. Boxes for TI Team and PPRP 

rearranged. Appendix G bios reorganized consistent with order of names shown in Fig 2.3-1. 

Typographical Errors • p. G-7: Ending period missing in last line at the end of Mark Petersen’s biosketch. 

Change made 

APPENDIX H — EPRI/DOE/NRC CEUS SEISMIC SOURCE CHARACTERIZATION PROJECT: Draft Final Seismic Source Model Hazard Input Document (HID), Dated July 6, 2010General CommentsG H-1. (NAR) The intent of the HID is to give future users details on how to implement 

the CEUS SSC model. It contains the logic tree structure that defines the frequency, locations, and sizes of future earthquakes in this region. The appendix describes how the zones are characterized. A description of why the TI Team chose a particular equation, occurrence rate, magnitude, or source geometry, or references is not given in this section of the report. 

No revisions required. 

G H-2. (CC) The elements of the CEUS SSC model are clearly described in enough detail to support future users’ implementation of the model for PSHA at any site in the 

CEUS. Gaps not described in the July 6, 2010 draft should be described in the final revision of the appendix. 

Full model including seismicity inputs for distributed sources included 

G H-3. (CC) The PPRP’s review of the 11 chapters of the main report identified many opportunities to achieve greater clarity in the TI Team’s descriptions of the characterizations and assessments represented in the CEUS SSC model by proper and consistent use of terms. These comments apply as well to the descriptions contained in 

Appendix H. 

HID review for consistency with Chapters 4, 6, and 7 

Specific Comments S H-1. (CC) Title of Appendix H Consider changing the appendix title to: “CEUS SSC MODEL HAZARD INPUTDOCUMENT (HID).” 

Change made 

S H-2. (CC) Implementing the Variable a- and b-value Routines Calculation of the variable a and b values is not part the use of the CEUS 
PPRP Comment Response Table 

I-86 

To perform any hazard calculations using the HID, it would be difficult for most users to implement the variable a- and b-value routines described in Chapter 5. Therefore, the 

process is not open for most users to evaluate that methodology. It would be desirable that the computer codes be made available for these analyses. Alternatively, the TI Team could release the output gridded data. However, this is not the best alternative 

since most users would not understand how these numbers were generated. A third alternative is for the TI Team to revert to the smoothed seismicity kernel that is more intuitive to the user community. 

SSC model for application in PSHAs, the purpose of the HID, but rather is an issue for future updates to the model.

S H-3. (CC) Transparency of HID Tables for Recurrence The following excerpt is reproduced from PPRP Review Comment S 6-12: “The unalert reader (or analyst) examining the HID tables for computed annualfrequencies for the Charleston RLMEs may potentially be confused by: (1) the inverted order for the 5-point distributions compared to Table 5.3.3.-1, which was used to define 

the 5-point distribution; and (2) the need to refer to Tables 6.1.2-1 and 6.1.2-2 to discern 

the elapsed time since the oldest earthquake counted in the sequence. For example, examining “Table Charleston_HID-3,” it may escape the reader’s attention that the 5-

point distribution is not for four events in 5500 years, but rather four events in 1,524– 1,867 years (or possibly in 1,569–1,867 years). To reproduce the results in the table (and for virtually all the Poisson-model tables in the HID), there is no explicit information 

about the exact elapsed time that was used.”

Documentation of calculation process was expanded in Chapter 6, HID revised to be consistent with main chapters and to add pointers to specific sections of the main report

Comments for Clarity and Completeness Figures 8 and 9 appear to be identical figures with different figure captions.p. H-19, Degree of Smoothing: The text states that, “An “Objective” approach is used to 

select the degree of smoothing.” It would be very helpful to refer back in the text where this approach is described. 

References to main chapters added to HID as appropriate 

APPENDIX I — PPRP AND USGS REVIEW COMMENTS Specific Comments for Clarity and Completeness S I-1. Title of Appendix E Because this appendix contains both PPRP and USGS review comments, the title of the appendix should be changed. 

Title changed 

Specific Comments for Clarity and Completeness S I-2. Listing of Letters and Attachments In the summary of contents for the appendix, the separate listing of Attachments to PPRP Letter 1a as Items 1b and 1c poses a problem of consistency. PPRP Letter 2 (dated August 15, 2008) contains a substantive Attachment A (“Key Issues for CEUS SSC Relevant to Workshop #1) with three labeled enclosures. Also, USGS Letter 1 (dated April 8, 2010) contains five attachments. In the case of these three letters with attachments, one can either spell everything out or simply note that these letters have attachments (perhaps indicating their general nature). 

Descriptions of attachments added for PPRP Letters 1 and 2 and USGS Letter 1 

S I-3. Incorrect Date in Correspondence Contents p. I-2, TI Team Letter 1: Error in labeling the subject of the letter (change “dated August 

12, 2008” to “dated August 15, 2008”) 

Errors corrected (including a typo in the letter heading – 2010 date corrected to 2008)

APPENDIX J — MAGNITUDE RECURRENCE MAPS General Comments No revision necessary. 
PPRP Comment Response Table 

I-87 

Appendix J presents the recurrence maps developed for all of the alternative configurations of the distributed seismicity zones. A brief description of the organization of the maps within the Appendix is provided on the title page. Consistent with the care taken in the writing of Section 5.3.2 (Smoothing Approach), this appendix is well organized and explained—beginning with the text on the title page that provides helpful 

guidance to the reader. 

Comments for Clarity and Completeness • Page J-1: Consider adding additional reference to specific figures in Sections 6.4 and 

7.5; suggested wording: “Mean maps and magnitude-recurrence for each source zone 

are shown in Sections 6.4 (Figures 6.4-1 through 6.4-16) and 7.5 (Figures 7.5.2-1 

through 7.5.2-42).” • Check: Were rates indeed calculated for M > 5 or for M ≥ 5? If perchance they were 

calculated for the latter, then labels on the figures should be changed or an explanation can be added on the title page of the appendix.

• In figure caption for Figure J-1, need closing [“] for “no separation . . .” OR simply delete the [“], which doesn’t appear in the captions for the following figures.• On Figures J-17 through J-48, the header information incorrectly indicates “MES” vs. 

“MESE” (the correct acronym, according to the list of Acronyms) written in the figure captions. 

• On Figures J-49 through J-112, the acronym “RCG” is used for Rough Creek graben

vs. “RC” in the list of Acronyms.

• Page J-87: Realization 7 for the seismotectonic zone, wide interpretation, Rough Creek 

Graben in Mid-Continent, full magnitude weights is missing. 

Revisions made, as appropriate. 

APPENDIX K — SCR DATABASES USED TO DEVELOP MMAX PRIOR DISTRIBUTIONSGeneral Comments This appendix provides the database used to develop the Mmax prior distributions. The work done to update and refine data for the global Stable Continental Regions has great value and importance. However, there is no explanatory text provided beyond the Notes and the two tables. To help future users, as well as to enhance transparency, this Appendix could be improved by including additional information and a short description of the content being included in the appendix itself, or to a reference back to the relevant report text. It could also be noted whether or not the database is available in digital form elsewhere. 

Short description of process added. Data will be included on project web site.

Specific Comments for Clarity and Completeness K-1. Information that should be considered for Appendix K Appendix K would benefit from including additional information for the reader to better appreciate where the domains and super domains are, and to better integrate with the text.The TI Team should considering adding the following:• Maps showing domains and superdomains (useful files for the boundaries of these domains should also be included in the Project Database, with a pointer to those files) • Figures displaying the Mmax-obs statistics for each of the superdomains • Summary table of statistical analysis completed on the various superdomain classifications 

The digital data will be on project web site along with scanned images of the large plates from Johnston et al. (1994) 

K-2. Clarity of Documentation For clarity of documentation, attention should be paid to the following:8. Designation of time in an earthquake catalog should be explicit. Are the times/dates in 

Greater explanation added for entries to the tables. 
PPRP Comment Response Table 

I-88 

UTC? Local time? A mix? This is non-trivial if one tries to find the events in another catalog.9. How should the reader interpret the variable presentation of significant figures inTable K-1 for latitude, longitude, M, and sigM? 10. “Extensive stress” is an unorthodox descriptor for “extensional stress”. (Google the two terms to see how most readers would interpret the first term.)11. What are the units of “Area” in Table K-2? 12. Neither “Mx_obs” or “N > 4.5” is explicitly explained in Table K-2. 13. Check: Is N > 4.5 indeed the number of earthquakes greater than M 4.5? Or perchance is it M ≥ 4.5? 14. For the table to be self-contained, an explanation should be given for non-integer values of N > 4.5.15. The wording used to explain SDNT and SDNC in Table K-2 will trip up most readers. 

Just add a few words to make it plain English. The acronyms certainly aren’t intuitive, but given that they are what they are, suggestion: 

SDNT Indicates which Superdomain the domain is assigned to when TYPE is included in the classificationSDNC Indicates which Superdomain the domain is assigned to when TYPE is not included in the classification 
Technical Integration (TI) Team and

Project Manager (PM) Response to PPRP Letters 
September 16, 2008 

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801 581 7410 830 833 5446 

arabasz@seis.utah.edu cstepp@moment.net 

Subject: Response to Central and Eastern United States Seismic Source Characterization 

for Nuclear Facilities: Participatory Peer Review Report on Workshop No. 1, 

dated August 15, 2008. 

Dear Carl and Walter, 

Thank you for your letter summarizing the Participatory Peer Review Panel’s review of 

Workshop No. 1 for the CEUS SSC project. The letter reflects a clear understanding of the 

purposes of the workshop in the context of the SSHAC Level 3 process. In the spirit of a 

participatory peer review process, we welcome timely, insightful, and constructive reviews and 

suggestions that will assist the Project Manager and TI team in steering the project toward a 

successful conclusion. One mechanism for that interaction is this correspondence between the 

PPRP and the project management. 

To provide the PPRP with insights into our intentions relative to the specific recommendations 

made in the letter, we provide below a response to the recommendations that have been 

underlined in your letter to draw attention to their priority. We also value the perspectives 

provided in other parts of the letter and these will be given serious consideration during the 

course of the project activities leading up to and including Workshop No. 2. 

1. Basic goals of workshop 

While the resource experts did a high-quality job of describing data sets, the uncertainty in the 

data sets was not generally described. Uncertainty involving both quality and quantity of data—

including non-uniqueness of interpretation—is fundamentally important for assessing a SSC 

model, both for evaluating alternatives and for considering the longevity of the results of the 

study. Future improvements in the quantity and quality of the data being used in the analysis 

may have an important effect on uncertainty and thus the stability of seismic hazard assessment.

Evaluation and understanding of the present uncertainty in the data sets should be a key element 

of the assessment. In order to fully address this important need, we recommend that the TI Team 

continue to interact with the data resource experts to evaluate the uncertainty in their data. In 

this connection, we emphasize the importance of obtaining germane reference lists from the 

resource experts.

The TI team has established contact with a number of resource experts regarding their datasets, 

including the subset of experts who made presentations at the first workshop. We agree that a 

key consideration in the use of the various datasets is an evaluation of the quality of the data and 

the associated uncertainties. We will continue to interact with resource experts to evaluate the 

uncertainty in the various data that are compiled for the project. 

1
2. How will data sets be used? 

The schedule for the project specifies that a preliminary SSC model be completed over the period 

December 2008 to August 2009. However, the data sets, including the earthquake catalog, that 

will be used to evaluate and assess sources are not scheduled to be completed until June 2009. 

We recommend prioritizing this work element to ensure that the critical data sets are completed 

early so that the assessment is not left until the final two months of the assessment effort.

Although the schedule calls for carrying out the data compilation effort throughout the entire 

SSC model development period, most of the data compilation effort has already been completed. 

Work is proceeding on the seismicity catalog effort and priority will be given to completing it in 

a timeframe that makes it readily available during the SSC model development period. 

Interpretations of these data that are in the public domain are spread throughout the geosciences 

literature. In view of the potential significance of the information from the seismic reflection 

profiles, not only for identifying seismic source zones and their properties but also for evaluating 

competing tectonic models, we recommend that interpretations of relevant seismic reflection 

profiles over the CEUS that are in the public domain be compiled for use in the project.

A variety of geophysical datasets are being compiled and considered in the SSC model 

development process. Most of the datasets reside within the literature. Seismic reflection data 

are one of the datasets that are being compiled and the TI team will make every effort to identify 

and consider the data that are available. The team is open to suggestions for datasets that might 

be identified by members of the PPRP and this input would be appreciated. 

3. Identifying key SSC issues and alternative viewpoints 

The PPRP recognizes the difficulty of identifying the SSC issues and relevant alternative 

interpretations that will be central to achieving the goals of Workshop #2 (WS-2). We

recommend that the TI Team initiate identification and evaluation of these issues and 

interpretations as early as possible—to allow time for their full consideration prior to WS-2 and 

to ensure completeness vis-à-vis the diversity of views within the informed technical community. 

To this end, the PPRP has identified some key issues that should be considered when preparing 

for WS-2; these are listed below. 

The goal of the TI team, as evaluators responsible for capturing the range of views held by the 

larger informed technical community, will use a variety of methods to identify alternative 

technical viewpoints, including reviews of the literature, conversations with researchers, 

professional conferences and proceedings (e.g., the upcoming USGS Maximum Magnitude 

workshop), and discussions at the workshops. The purpose of Workshop #2 is to consider 

alternative interpretations of important technical issues. The TI team agrees that the early 

identification of issues and proponents to speak to those issues is important and every effort will 

be made to do so. It is also recognized that not all proponents of alternative viewpoints will be 

able to attend the workshop, but this will not prevent the TI team from communication with the 

individuals or from evaluating their points of view. 
Because of the key importance of WS-2, we recommend that the Project Team actively engage 

the PPRP in reviewing and commenting on the planning of WS-2 and in the development of the 

workshop agenda.

We welcome the assistance and perspectives that members of the PPRP can provide in the 

planning of WS -2. 

5. Six test sites for hazard calculations

Insofar as the planned test sites (a) have not yet been selected and (b) apparently will play an 

important role later in the SSC process, the criteria for site selection will be of great interest to 

the PPRP beyond the example given in the Project Plan. We note that in the discussion of the 

test site selection in the Project Plan (see p. 4-4) the provision is made that the sites should be 

“as generic as possible.” We recommend that the sites should be representative of the range of 

seismogenesis over the region of applicability of the CEUS SSC model.

We agree that the sites should be representative of the range of seismotectonic conditions that 

any site in the CEUS might entail. The notion of choosing “generic” sites was merely meant to 

imply that we are not planning to choose any particular named nuclear facility site. The TI Team 

and Project Manager will also provide the PPRP the criteria and timetable for identifying the 

demonstration sites. The TI Team and Project Manager will provide to the PPRP the preliminary 

demonstration sites for review and comment prior to their finalization for use in sensitivity 

analyses performed during Task 4. 

Thanks again for the excellent reviews, and we trust that this will set a positive tone for carrying 

out this important project. If you have any questions regarding this letter, please feel free to 

contact us. 

Sincerely,

Kevin Coppersmith 

TI Team Leader 

Coppersmith Consulting, Inc. 

2121 N. California Blvd., #290 

Walnut Creek, CA 94596 

Tel. 925 974-3335 

kcoppersmith@earthlink.net

Lawrence A. Salomone 

Project Manager 

Savannah River Nuclear Solutions, LLC 

Savannah River Site

Building 730-4B, Room 3125

Aiken, SC 29808 

Tel. 803 645-9195 

lawrence.salomone@srs.gov
	
		 


March 20, 2009 

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801 581 7410 830 833 5446 

arabasz@seis.utah.edu cstepp@moment.net 

Subject: Response to Central and Eastern United States Seismic Source Characterization 

for Nuclear Facilities: Participatory Peer Review Report on Workshop No. 2

dated March 10, 2009. 

Dear Carl and Walter, 

Thank you for your letter summarizing the Participatory Peer Review Panel’s review of 

Workshop No. 2 for the CEUS SSC project. The letter reflects a clear understanding of the 

purposes of the workshop in the context of the SSHAC Level 3 process. In the spirit of a 

participatory peer review process, we welcome timely, insightful, and constructive reviews and 

suggestions that will assist the Project Manager and TI team in steering the project toward a 

successful conclusion. One mechanism for that interaction is this correspondence between the 

PPRP and the project management. 

To provide the PPRP with insights into our intentions relative to the specific recommendations 

made in the letter, we provide below a response to the recommendations that have been 

underlined in your letter to draw attention to their priority. We also value the perspectives 

provided in other parts of the letter and these will be given serious consideration during the 

course of the project activities leading up to and including Workshop No. 3. 

1. Need for a Tectonic Framework: The range and complexity of alternative hypotheses and 

interpretations presented at WS-2 reinforce our previous recommendations concerning the need, 

first, to evaluate an overall tectonic framework for the study region and, second, to properly 

incorporate this evaluation into the CEUS seismic source model assessment. We consider a 

transparent evaluation of uncertainty to be a necessary element of the tectonic framework 

evaluation. The tectonic framework should have a universal role in the seismic source model 

assessment. This would establish the approach and scale for the seismic source model 

assessment, and it would provide a transparent, consistent assessment (weighting) of the 

complex alternative interpretations and hypotheses that constitute the current state of knowledge 

of the technical community.

We agree with the PPRP’s recommendation that a Tectonic Framework be developed for the 

CEUS SSC project and this topic has been the subject of considerable focus by the TI team and 

staff over the past several months. To avoid narrowing the concept to include only a 

consideration of tectonic features, the project has used the term “Conceptual SSC Framework” to 

describe the process that is being used to identify and characterize seismic sources for the 

project. Over the course of three working meetings, the TI team and staff have reviewed the 

criteria that will be used to identify seismic sources, the process that will be used to identify and 

2
	
		 


evaluate the data, the manner in which the criteria will be applied, and the means of documenting 

the evaluations in tables and text. These processes are being summarized in a document that will 

become a chapter in the project report. The concepts will be discussed at the PPRP meeting in 

May.

We observed that some proponent interpretations regarding seismic sources and the origin of the 

seismicity in the CEUS pointed to the significance of evaluating the geological and seismological 

characteristics of the entire lithosphere—including the upper brittle crust, the ductile lower 

crust, and the upper mantle. Geological and geophysical evidence indicates that these various 

zones of the lithosphere are laterally heterogeneous, which could have profound impact on the 

seismicity of the brittle upper crust. As a result, we recommend that the TI Team should include 

the attributes of the entire lithosphere in their evaluation of the tectonic framework and their 

seismic source model assessment.

As witnessed by the identification of resource experts with expertise in lithospheric modeling at 

WS2, the TI team and staff are aware of the potential importance of this type of data. Inasmuch 

as researchers have made assessments of the potential implications of their modeling of deeper 

mantle processes to seismicity within the seismogenic crust, the TI team and staff will make 

every effort to include this information in the considerations for identifying seismic sources. 

2. Approach to Seismic Source Assessment and Scale: 

a) “Granularity” of Seismic Source Model (i.e., the scale of uniform scrutiny): During the 

workshop, geological structures ranging in scale from very local to continental-scale were 

described and discussed. We recommend that the TI Team provide early assurance, through 

assessment criteria that are explained and justified, that a systematic approach and procedure 

are being used for defining and assessing seismic sources in terms of scale. These assessment 

criteria will facilitate subsequent use of the model for a site-specific PSHA at any site in the 

study region. The assessment criteria should be at a level of detail that appropriately 

incorporates the state of knowledge of the sources and the current understanding of their 

inherent complexity. Using the criteria, one should be able to distinguish specific sources that 

have significant, identifiable, and relatively consistent seismic hazard potential. This systematic 

approach should be applied consistently across the study region. 

It is agreed that the “granularity” of the seismic source model and characterization effort is 

important and needs to be defined on a consistent basis for the entire study region. The 

Conceptual SSC Framework being used on the project begins with identifying the criteria that 

call for identifying a unique seismic source: variations in maximum magnitude, variations in 

recurrence rate, variations in future earthquake characteristics (e.g., depth, style of faulting), and 

significant variations in tectonic feature characteristics. It is acknowledged that the product of 

the CEUS SSC project is a regional seismic source model that can be applied at any location 

within the CEUS. As such, it includes variations in seismic source criteria that would lead to 

hazard-significant variations across the study region. It is also recognized that the CEUS SSC 

product will not include the detail that would be required for a site-specific application, say for 

inclusion in a PSHA conducted for power plant licensing. Per regulatory guidance (e.g., 

Regulatory Guide 1.208), those site-specific applications would need to consider possible 

refinements that might be needed to the CEUS SSC seismic source model in light of local 
	
		 


geologic or seismologic investigations. It may be that a more refined model is possible at a few 

locations (e.g. New Madrid, Charleston) and we propose to use this refinement rather sacrificing 

the detail for the sake of a common level of “granularity.”

b) Approach to Smoothing: We observed that there was little discussion or consideration of 

uncertainty involved in smoothing recorded seismicity versus deductive seismic source 

assessment, and there was no evaluation of alternative smoothing parameters. We consider this 

to be an important part of the assessment for the CEUS seismic source model and we recommend 

greater attention to the issue of smoothing and corresponding documentation.

The focus of the workshop was on alternative interpretations of various datasets and conceptual 

models. The notion of smoothing has a conceptual basis as well (i.e., degree of spatial 

stationarity in rates), which was addressed by those talks related to stationarity (e.g., Kafka talk 

on statistical analysis of past and future patterns of seismicity; multiple talks related to possible 

spatial migration of seismicity in New Madrid area). The audience at the workshop was not 

familiar with the mechanics of smoothing, and the mechanics of smoothing (e.g., kernel types, 

smoothing distances, etc.) were not discussed at the workshop. These details are recognized by 

the TI to be important and are the focus of attention by the TI team. We anticipate that 

alternative approaches will be used and captured in the SSC model. 

3. Integrated Evaluation of Paleoliquefaction and Interpretations of Paleo-Fault

Displacements: 

a) Uncertainties in age dating: Multiple proponent experts discussed their interpretations 

of evidence for recent fault movement or the dating of geologic surfaces related to the formation 

of paleoliquefaction features. The proponents did not sufficiently describe the uncertainties in 

the age dating within their respective studies, and as such, the overall quality and reliability of 

this information is in question. The TI Team should strive to better understand the overall 

quality of these studies and develop a cohesive understanding of how the results can and cannot 

be used to establish recurrence information for various seismic sources. We recommend that the 

TI Team perform an integrated analysis of the body of paleoseismic investigation results in the 

vicinity of the New Madrid Seismic Zone using appropriate statistical methods. The study should 

incorporate uncertainty in the interpretations, to the extent that the uncertainty is described in or 

can be reasonably interpreted from the study results, in order to better correlate event times and 

rates of activity. 

It is agreed that the ongoing studies of paleoseismicity in the New Madrid region are important 

and uncertain. The presenters at the workshop were encouraged to discuss uncertainties in the 

ages, locations, and sizes of paleo-earthquakes; some experts were more adept than others at 

describing their uncertainties. One of the responsibilities of the TI team and staff is to develop 

seismic source models that consider the present level of knowledge and uncertainties in the 

larger technical community. It is recognized that the seismic source models will provide a 

snapshot in time in this regard and that new data and information will continue to be developed 

in the future. Our focus, then, will be to incorporate the center, body, and range of views in the 

technical community on the recurrence models and rates in the New Madrid region. Given the 
	
		 


present level of knowledge and uncertainties, it is likely that the “appropriate statistical methods” 

will be quite simple and will not entail unwarranted sophistication. 

b) Size of paleoearthquakes: Paleoliquefaction is widely accepted to be a useful basis for 

assessing a seismic source model for the CEUS region; it is likely to gain even more importance 

in the future. The new approaches presented at WS-2 for assessing uncertainty in the observed 

data and interpretations and for using the interpretations for estimating the size of causal 

earthquakes have great promise and should be pursued in the future. At present, the 

uncertainties resulting from both the current and the newly presented method are poorly 

constrained. We recommend that particular care be taken in estimating magnitude and in 

assigning corresponding uncertainties. We further recommend that the lack of evidence of 

paleoliquefaction not be used to determine maximum magnitude.

We agree that the methods for assessing the magnitudes of paleo-earthquakes are still under 

development and that limited data have been developed that allow more quantitative methods to 

be applied consistently throughout the CEUS. For example, the geotechnical characterization 

that would lead to more confident magnitude estimates, as discussed by Drs. Green and Olsen, is 

only available in a limited number of cases at the present time. Hence, the magnitude estimates 

for paleo-events reported in the literature will be reviewed with care. We plan to factor 

appropriate uncertainty estimates of the size of paleo-earthquakes into the assessment of 

maximum magnitudes. We agree that the lack of evidence of paleoliquefaction needs to be 

interpreted with considerable caution, and there are no plans to use that evidence to place limits 

on maximum magnitudes. 

c) Time-dependent models: Given the importance of paleoliquefaction studies for evaluating the 

New Madrid and Charleston seismic zones, the TI Team should make a fundamental decision 

whether the incorporation and use of time-dependent recurrence models should be pursued.

While this topic came up during the workshop, there was no discussion focused on what weight 

should be given to time-dependent recurrence models. It was not clear how the TI Team would 

assess the views of the technical community on this issue. 

The notion of time-dependent earthquake behavior in the New Madrid and Charleston seismic 

zones has been proposed by the technical community1

 and, therefore, must be seriously 

considered for inclusion by the TI team and staff. In addition, it has been used in several COLA 

applications. A variety of approaches exist for incorporating time-dependent behavior into a 

classical PSHA (i.e., one that is based on Poissonian temporal behavior), should we decide to do 

so. It is assumed that the CEUS SSC product will provide input to a PSHA that could be used to 

assess hazard for nuclear facilities having a design life of approximately 50 years. It would be in 

1

 Recent examples include: 

James S. Hebden, J. S. and Stein, S., 2009, Time-dependent seismic hazard maps for the New Madrid seismic zone 

and Charleston, South Carolina, areas: Seismological Research Letters, 80(1):12-20 

Li, Q., Liu, M., and Stein, S., 2009, Spatiotemporal Complexity of Continental Intraplate Seismicity: Insights from 

Geodynamic Modeling and Implications for Seismic Hazard Estimation: Bulletin of the Seismological Society of 

America; v. 99; no. 1; p. 52-60 

Calais, E. and Stein, S., 2009, Time-Variable Deformation in the New Madrid Seismic Zone

Science, March 13, 2009; 323(5920): 1442 - 1442. 
	
		 


this context that time-dependent recurrence models would be incorporated, should the TI team 

and staff judge this to be an important mechanism for capturing the views of the larger technical 

community.

4. Documentation of how alternative views are used: At WS-2 a wide range of proponent views 

within the scientific community were presented about a number of important seismic source 

related issues. It is clear that, when assessed in detail, most CEUS locations are complex, with 

heterogeneities playing an important role in creating the data observed in the field. The TI 

Team needs to document how alternative views are accounted for in the assessment of the 

seismic source model to be presented in May 2009. 

We agree that any given seismic source or region of interest within the CEUS will potentially 

have a number of datasets that pertain to the spatial and temporal aspects of the source 

characteristics. The TI team and staff are fully aware of the responsibility to document in the 

project report all of the data and information sources that were used in the assessment. Doing so 

will allow future readers to understand how the views of the larger technical community were 

considered in the evaluation process. 

5. The hypothesis of late aftershocks: During the workshop, a proponent, using chiefly 

qualitative evidence, offered the view that much of the contemporary seismicity observed in the 

CEUS represents late aftershock activity of prior moderate to large earthquakes. If this view is 

used by the TI Team as a working hypothesis, it should first be critically examined. Standard 

seismological and statistical tools exist for verifying whether observed contemporary seismicity 

can plausibly be related to prior earthquakes, consistent with aftershock decay models such as 

the modified Omori model or Ogata’s epidemic-type aftershock sequence (ETAS) model.

Modern aftershock sequences in the CEUS, for example, can provide Omori parameters that can 

be used to test the hypothesis of long-lived aftershock sequences in the region.

The term “aftershock” was used in a variety of ways at the workshop, including some ways that 

would imply very long-lived sequences of earthquakes that occur decades to centuries following 

the “main shock.” The TI team and staff agree that this issue must be viewed with caution and 

with care. Likewise, the treatment of the seismicity catalog for purposes of earthquake 

recurrence analysis (i.e., de-clustering) will also require that we consider the issue. 

6. Temporal Clustering: One uncertainty that was briefly discussed is whether the New 

Madrid seismic source zone is coming out of a cluster in terms of short repeat times for larger 

earthquakes. Some proponents cited GPS data that indicate little if any measurable strain in the 

New Madrid seismic zone region over the past 20 years, and one proponent presented geologic 

evidence that could be interpreted to indicate a history of clustering with very long geologic time 

intervals between clusters. The available data and overall lack of understanding of the 

mechanisms that may drive a clustering model for the New Madrid seismic source zone warrant 

caution about the supposition that a clustered sequence of higher recurrence behavior is ending.

As noted by several of the resource experts at the workshop, the notion of temporal clustering of 

earthquake behavior has been postulated based on geologic and seismic evidence at a number of 

localities within stable continental regions. It is true that the present state of knowledge does not 
	
		 


provide insights into the physical mechanisms for this phenomenon, although attempts have been 

made (e.g., migrating strain localization, evolution of zones of weakness). The lack of 

understanding of the causative mechanism for temporal clustering adds uncertainty. 

Nevertheless, temporally-clustered behavior continues to be reported and must be considered in 

our evaluations. Likewise, some members of the larger technical community favor a temporal 

model in which the 1811-1812 earthquakes marked the end of a temporal cluster and the absence 

of evidence for contemporary strain accumulation is cited as evidence for the model. We agree 

that this model warrants caution in considering the manner in which it will be evaluated for 

incorporation into the CEUS SSC model. 

7. SSHAC process issues: Under SSHAC guidelines, the makeup of the TI team has 

implications for ownership issues relating to the seismic source model and subsequent hazard 

results. As evident during the workshop, there are blurred boundaries between the TI Team 

specified in the CEUS SSC organization chart and the TI Staff. The working “TI Team” appears 

to consider itself a larger group than listed in the Project Plan. The makeup of the “TI Team” in 

terms of individuals who will be responsible for ownership of the SSC inputs should be clarified.

We also note that in the SSHAC framework there conventionally is a distinction between the TI 

(or TI Team) and the hazard analyst. In the CEUS SSC project this distinction is blurred with 

Robin McGuire having a dual role as a member of the TI Team and as one of the key analysts 

responsible for computing hazard at seven demonstration sites. This is not a conflicting role and 

indeed adds strength to the project. We suggest, however, that this circumstance be explained in 

the final project report.

During the course of discussions about the project activities, the term TI Team was used to 

indicate the working team that is evaluating the data and developing the seismic source model. 

This terminology is not consistent with the organization chart in the Project Plan. More 

accurately, the evaluations and development of the seismic source model is being conducted by 

the TI Team and the TI Staff. On the second point, the circumstance will be explained in the 

final project report. 

Thanks again for the insightful review comments, and we are convinced that they will assist us in 

developing a better product. If you have any questions regarding this letter, please feel free to 

contact us. 

Sincerely,

Kevin Coppersmith 

TI Team Leader 

Coppersmith Consulting, Inc. 

2121 N. California Blvd., #290 

Walnut Creek, CA 94596 

Tel. 925 974-3335 

kcoppersmith@earthlink.net

Lawrence A. Salomone 

Project Manager 

Savannah River Nuclear Solutions, LLC 

Savannah River Site

Building 730-4B, Room 3125

Aiken, SC 29808 

Tel. 803 645-9195 

lawrence.salomone@srs.gov

		 


September 25, 2009 

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801 581 7410 830 833 5446 

arabasz@seis.utah.edu cstepp@moment.net 

Subject: Response to Central and Eastern United States Seismic Source Characterization 

for Nuclear Facilities: Participatory Peer Review Report on Workshop No. 3.,

dated September 18, 2009. 

Dear Carl and Walter, 

Thank you for your letter summarizing the Participatory Peer Review Panel’s review of 

Workshop No. 3 for the CEUS SSC project. The letter reflects a clear understanding of the 

purposes of the workshop in the context of the SSHAC Level 3 process. In the spirit of a 

participatory peer review process, we welcome timely, insightful, and constructive reviews and 

suggestions that will assist the TI team in achieving a successful conclusion. One mechanism for 

that interaction is this correspondence between the PPRP and the project management. 

We appreciate the kind words given in the General Observations regarding the management and 

TI team preparations for and success of the workshop. It is heartening to know that the PPRP 

recognizes the considerable efforts made over the months leading up to the workshop to ensure 

its success. Further, the comments demonstrate that the PPRP understands the preliminary 

nature of the SSC sensitivity model and how WS-3 provides a starting point for the development 

of the SSC model. 

To provide the PPRP with insights into our intentions relative to the specific recommendations 

made in the letter, we provide below a response to the recommendations that have been 

underlined in your letter to draw attention to their priority. We also value the perspectives 

provided in other parts of the letter and these will be given serious consideration during the 

course of the project activities leading up to and including the development of the project report. 

1. The Principal SSHAC Goal for a PSHA: We appreciate Dr. Coppersmith’s informative 

presentation of the background and context of the principal SSHAC goal for a PSHA: “to

represent the center, the body, and the range of technical interpretations that the larger 

technical community would have if they were to conduct the study.” His description of the 

historical context of the treatment of uncertainties in seismic regulation practice illustrates 

the critical importance to safety decision making of proper treatment of uncertainty, which 

formed the basis for the SSHAC’s evolution of this important goal as well as the process that 

the SSHAC defined for achieving it. The SSHAC assessment process defines roles for 

participants as well as process activities that when properly implemented provide reasonable 

assurance that the goal for a PSHA established by the SSHAC is achieved. Based on Dr. 

Coppersmith’s presentation and the follow-on discussions during the workshop, we concur 

that the assessment process activities being implemented for the CEUS SSC Project satisfy 

3

		 


the SSHAC guidance. We recommend that this important presentation be developed in the 

form of a white paper suitable for inclusion as a section in the project final report and that the 

white paper be distributed among the project participants, including the PPRP and sponsor 

technical representatives, for early review.

Dr. Coppersmith’s presentation was developed in response to the PPRP’s previous suggestion 

that the conceptual framework for the SSC evaluation process be documented. As such, the TI 

team plans to include the discussion in the project report. The PPRP will have ample 

opportunity for review of the draft project report.

2. USGS Open-File Report on Maximum Magnitude: Although briefly mentioned during the 

workshop, it was not clear to us how the soon-to-be issued USGS Open-File Report on 

estimation of maximum magnitude for seismic sources in the CEUS will be considered by 

the TI Team. We recommend that the report be considered as part of the information base for 

assessment of the CEUS SSC model. 

Several members of the TI team were in attendance at the workshop and the report has been 

available in draft form—along with a transcript of the meeting—for the use of the TI team. The 

recommendation to include the report as part of the information base is accepted. 

3. CEUS Earthquake Catalog: The development and attendant analyses of the updated CEUS 

Earthquake Catalog are important contributions of the CEUS SSC Project that could 

potentially have high value for use in future PSHAs. The work summarized by Dr. Youngs 

on the catalog reflects a tremendous amount of work and represents a significant 

advancement in this important hazard data base. In order to be assured of the catalog’s 

continuing high value, arrangements should be made to continually maintain this consensus 

catalog, and the analyses should be periodically updated as warranted by the addition of new 

data. Because multiple agencies and organizations will use the SSC Model, we recommend 

that the Project suggest a plan for keeping the CEUS Earthquake Catalog current into the 

future as a companion product for use of the SSC Model.

We agree that the CEUS Earthquake Catalog will be a significant product developed as part of 

the CEUS SSC project. It is envisioned that the project report will include a section devoted to 

recommendations for the future implementation of the products of the study. This discussion 

will include recommendations regarding plans for keeping the catalog current into the future. 

4. Comments on Smoothing:

We consider the alternative procedures for smoothing seismicity that were presented and 

discussed during the workshop to be valuable tools for the TI Team to use to express 

uncertainty in its tectonic-based assessments of the spatial variation of seismicity. 

Accordingly, we recommend that the use of these tools (i.e., the choice of smoothing 

method, the use of anisotropic kernels, priors on parameters, and so on) be justified in 

terms of the Team’s evaluations of tectonic processes governing earthquake occurrence.

It is agreed that the justifications for the choice of smoothing tools should be made in terms of 

tectonic and other technical arguments. For example, if an adaptive kernel is used that varies the 

		 


smoothing distance as a function of data density, the technical basis for the use of such a kernel 

will be documented in terms of the expected future spatial distribution of seismicity. 

6. Data Summary Table and Data Evaluation Table: The Data Summary Table appears to be 

a highly valuable means of documenting the current range of the larger technical 

community’s technical interpretations. We believe that the Data Evaluation Table also is 

an important part of the documentation of the CEUS SSC assessment that can serve the 

important need for transparent documentation of the TI Team’s evaluations supporting its 

assessments of the center and body of uncertainty in the larger technical community’s 

technical interpretations. The Data Evaluation Table also is potentially useful as a record 

of lessons learned and as such will be valuable in considering the need for and planning 

future investigations of the CEUS. This includes not only the utility of the various data most 

important in the SSC assessment, but also the nature and quality of data which imposed 

limitations on their use in identification and characterization of the seismic source zones. A 

summary of the various documents, their contents, and relationships would likely prove 

helpful and increase clarity for future implementation of the SSC Model. We recommend 

that the Project and TI Teams give careful consideration to these important potential uses of 

the Data Evaluation Table as the assessment goes forward.

It is agreed that the data evaluation and data summary tables provide a valuable means of 

documenting the use and considerations of data made by the TI team. In the project report, the 

tables will supplement the detailed discussions of the technical bases for the SSC model (i.e., 

documentation of the bases for the branches and weights on the final logic trees). The TI team 

will give due consideration to the potential uses for the tables given in the PPRP comment. 

7. Sensitivity studies: We consider the sensitivity studies to be highly valuable for providing 

insights and gaining understanding of the sensitivity of PSHA at a specific site to various 

elements of the SSC model. Additional sensitivity studies at a range of distances from the 

sources of frequent large earthquakes could add value for future use of the SSC model. 

However, we recommend that the sensitivity studies not be used to justify devoting a 

reduced effort to assessing any fundamental element of the SSC model. (See also Comment 

11.)

See response to Comment 11. 

8. Lack of Consideration of Focal Depths: There was a lack of discussion of earthquake focal 

depths in the workshop presentation on the updated CEUS seismicity catalog. This omission 

should be rectified. Because focal depth is a potentially important contributor to our 

knowledge of seismic hazards, useful in characterizing and defining the limits of seismic 

source zones, and helpful in assessing potential ground motion, we recommend that greater 

consideration be made of this parameter in the CEUS SSC.

We agree that seismic sources are three-dimensional and the vertical dimension is to a large 

extent constrained by the depth of earthquake hypocenters. The accuracy of focal depths varies 

		 


considerably throughout the study region. The project report will include a discussion of 

earthquake focal depths and their use in characterizing seismic sources for the CEUS SSC 

project.

9. Plan for use of gravity and magnetic data. Gravity and magnetic anomaly data and a variety 

of maps processed from these data are important in mapping largely hidden geological 

structures of the CEUS that may be useful in identifying seismic source zones and their 

geographic boundaries. We note that the contract for preparing the gravity anomaly data and 

associated maps has been let to the University of Oklahoma, but the contract has not been 

executed for preparing and processing the magnetic anomaly data. Furthermore, the 

Expanded Schedule for the CEUS project (7/14/09) set the completion date for both of these 

contracts as October 30, 2009, which we learned at WS-3 has now been delayed until 

December 31, 2009. Despite the lack of the products from these contracts, the work of the 

TI team including the identification and delimiting of source zones must continue. As a 

result, we recommend that after December 31, 2009, once the new data sets and maps are 

available, a thorough review be conducted of decisions on identification and bounding of 

source zones that were reached prior to the availability of the gravity and magnetic anomaly 

data and related maps. This review may lead to modification of previous decisions.

The TI team will plan to carry out such a review once the gravity and magnetic data are 

available. 

10. Preliminary Seismic Source Zones: The seismic source zones used for the sensitivity 

evaluations and discussions during WS-3 are still tentative, but a cursory review of these 

zones raises several concerns: 

• Where the evidence for the identified seismic source zones and their geographic 

limits are not described in referenced publications, we recommend that a 

comprehensive description be provided for the basis underlying the assessments of 

the source zones and their boundaries.

Descriptions of the bases for all seismic sources will be provided in the project report. 

• It is unclear why certain regions were selected as “zones of elevated seismicity.” 

What is their role? Why was the Clarendon-Linden region identified but not 

southeastern New York, the Niagara Peninsula, and other CEUS regions of above 

normal seismicity in the historical record? We recommend that definitive criteria be 

cited for the selection of elevated seismicity zones.

Zones of elevated seismicity were identified as a means of organizing the data summary 

tables. That is, the historical literature refers to several seismicity zones (e.g., Central 

Virginia, eastern Tennessee, Charlevoix) and we use this terminology to assist the reader 

of the data summary tables in recognizing the geographic distribution used in the 

literature. In most cases, zones of elevated seismicity—without a clear RLME source—

are handled in the SSC model by the use of spatial smoothing. A complete discussion of 

the manner in which observed seismicity is used in the SSC model will be included in the 

project report. 

		 


• Earlier at Workshop No. 2, a scheduled presentation by Nano Seeber on seismicity 

and faulting in Ohio, Pennsylvania, New York State, and New York City was 

canceled and no similar presentation on this topic was made. Has anything been done 

to fill this void in the consideration and treatment of alternative interpretations? For 

example, a 2008 paper by Sykes and others4 suggests an alternative view of seismicity 

in the New York City area that has not been cited in the Data Summary Table. We 

recommend that the list of alternative interpretations be updated to include those 

pertaining to the region that was to be discussed by Dr. Seeber at WS-2.

We appreciate the PPRP providing recommended literature and databases that the TI 

team should include in its considerations; hence, we welcome the suggestions for 

inclusion of the cited paper. Despite Dr. Seeber’s cancelation of his participation at WS2 due to illness, the TI team is aware of his models and will ensure that his publications 

are included in the associated data tables. In addition, representatives from the TI team 

will be attending the upcoming Eastern Section of the Seismological Society of America 

and the associated field trip led by Dr. Seeber. 

• There may be an inconsistency in the way that “extended zones” are used in the 

identification of seismic source zones. The area of the extended zone with normal 

faulting associated with the Iapetan Rift Margin is moved hundreds of kilometers 

west into the stable craton from the mapped rift margin. However, the limits of the 

seismic source zone associated with Iapetan (Cambrian) rifting in the midcontinent, 

including the New Madrid Rift Zone and its extensions, appear to be limited to 

mapped grabens without consideration of a bordering extended zone. Of particular 

note is the lack of an extended zone associated with the Grayville graben in southern 

Indiana. The “wide” interpretation of the seismic source zones is a step in the correct 

direction, but without further documentation on the factors defining the boundaries of 

this interpretation, it is difficult to determine if the broader extended zone is being 

captured in this interpretation. We recommend that the TI Team consider the 

possibility of an “extended zone” marginal to midcontinent seismic source zones.

The TI team will reexamine the technical bases for defining the extended/non-extended 

boundary, relative to its potential influence on establishing a prior distribution on Mmax 

consistent with the way that extended/non-extended SCR crust has been subdivided 

elsewhere. Further, the technical bases for the alternative locations of the boundary will 

be documented in the project report as a means of expressing the epistemic uncertainty. 

11. Pruning the Logic Tree and Need for Complete, Clear Documentation. The use of an initial 

sensitivity model to inform evaluations to support the final model assessments is a sound 

and efficient approach. However, care must be taken to fully and clearly document the 

results of the sensitivity study, particularly as it impacts development of the final model and 

particularly in cases where alternative branches are removed. In a SSHAC level-3 study, the 

degree of credibility that the technical community grants the final model may be based 

heavily on the clarity and completeness of documentation and the ability of the technical 

community to understand the basis of assessments made by the TI team. In addition, robust 

		 


documentation can more easily allow for the incorporation of new data and site-specific 

information into the model. In fact, specific guidance on how new or site-specific data 

should be evaluated could prove very valuable to the practitioner.

The final model must represent the range of legitimate interpretations of the informed 

technical community in a scientifically defensible way. While some pruning of the tree based 

on the sensitivity study is desirable, we recommend that the sensitivity study not be used to 

trim branches that represented significant concepts or alternate hypotheses, even if the 

inclusion of alternate branches does not impact hazard. Some computational efficiencies 

could possibly be gained for the future hazard analyst if the study provides specific guidance 

as to the distance from the more significant sources at which the source no longer impacts 

hazard, and can be trimmed from the model. 

The TI team is aware of the need to show that all potentially significant hypotheses have been 

considered in the course of the evaluations. We are also aware that some hypotheses—although 

subject to debate within the technical community—may have relatively little significance to 

hazard at the annual frequencies of interest. Likewise, certain technical issues will have a 

profound effect on hazard (e.g., those related to rate) and should be given priority in the 

development of the preliminary SSC model. In this spirit, the feedback gained from the analyses 

conducted for WS-3 and the follow-on analyses that were identified during the workshop will 

serve as a means to prioritize the subsequent efforts by the TI team as we move forward. This 

certainly does not mean that “significant concepts or hypotheses” will be “trimmed from the 

tree.” However, first priority will be given to the concepts and hypotheses that matter most to 

hazard. Whether or not the concepts and hypotheses are actually included in the logic trees, 

evidence that they have been fully considered and evaluated will be included in the project 

documentation. In addition, consideration will be given to including specific guidance for sitespecific application of the SSC model relative to the distances and sources that may need to be 

included. This guidance would be part of the site-specific implementation guidance anticipated 

for inclusion in the project report. 

13. Sanity Check for Seismic Sources Defined by Paleoliquefaction: We recommend that the TI 

Team make a sanity check for those seismic sources defined by paleoliquefaction—that is, 

whether the source boundaries make sense, given the assumed magnitude versus area (or 

length) using relationships between magnitude and the maximum distance to liquefaction. 

For example, the magnitude-versus-area relationship for the CEUS results in an assumed 

rupture length of ~21 km for M = 6.7. For the currently defined Charleston source options, 

can ruptures at the far ends of the source (e.g., the southeastern or northwestern corners of 

the large zone shown on Figure 15 in the HID) explain the observed paleoliquefaction at the 

opposite end of the source? The TI Team may need to factor in how they are modeling the 

recurrence of the source relative to the paleoliquefaction—but they need to make sure that 

the sources for the paleoliquefaction regions do not become too large when considering how 

rupture length is being modeled relative to paleoliquefaction. 

The TI team will plan to conduct such sanity checks during the development of the preliminary 

SSC model. 

		 


15. Need for Uniform Rigor in Assessing Rate-Information Inputs. Examination of the SSC 

Sensitivity Model shows an apparent unevenness in rigor applied to assessing rateinformation inputs in terms of significant figures and assessed distributions. This stands in 

contrast to the systematic rigor applied, say, to recurrence modeling. Because of the 

fundamental importance of rate information to hazard, we recommend careful uniform 

attention to the assessment of rate inputs. Such assessments should meet the basic 

expectations of a normative expert in a PSHA if one were overseeing the assessments. 

The TI team agrees with the comment and will provide uniform attention to the assessment of 

rate inputs across the entire SSC model. 

16. PPRP Observers in Remaining Working Meetings. Under the CEUS SSC Project Expanded 

Schedule (dated July 14, 2009), the next face-to-face meeting of the PPRP with the TI Team 

will be in March 2010. Because this will be at a relatively late stage of shaping a near-final 

(albeit still “preliminary”) SSC model, we recommend that the Project Manager facilitate 

participation of at least two PPRP members as observers in the TI Team’s Working Meeting 

#6 (October 20–21, 2009) and Working Meeting #7 (January 12–13, 2010). 

We agree with the comment and encourage participation by members of the PPRP at the 

upcoming working meetings. 

Thanks again for your insightful review comments, and we are convinced that they will assist us 

in developing a better product. If you have any questions regarding this letter, please feel free to 

contact us. 

Sincerely,

Kevin Coppersmith 

TI Team Leader 

Coppersmith Consulting, Inc. 

2121 N. California Blvd., #290 

Walnut Creek, CA 94596 

Tel. 925 974-3335 

kcoppersmith@earthlink.net

Lawrence A. Salomone 

Project Manager 

Savannah River Nuclear Solutions, LLC 

Savannah River Site

Building 730-4B, Room 3125

Aiken, SC 29808 

Tel. 803 645-9195 

lawrence.salomone@srs.gov

		 


April 19, 2010 

Walter J. Arabasz J. Carl Stepp 

2460 Emerson Avenue 871 Chimney Valley Road 

Salt Lake City, UT 84108 Blanco, TX 78606-4643 

Tel: 801 581 7410 830 833 5446 

arabasz@seis.utah.edu cstepp@moment.net 

Subject: Central and Eastern United States Seismic Source Characterization for 

Nuclear Facilities: Feedback on CEUS SSC Preliminary Model dated April 7, 

2010.

Dear Carl and Walter, 

Thank you for your letter summarizing the Participatory Peer Review Panel’s review of the 

Preliminary SSC Model for the CEUS SSC project. The letter reflects the Panel’s continuing 

review of both the technical and process aspects of the project. In the spirit of a participatory 

peer review process, we welcome timely, insightful, and constructive reviews and suggestions 

that will assist the TI team in achieving a successful conclusion.

To provide the PPRP with insights into our intentions relative to the specific recommendations 

made in the letter, we provide below a response to the recommendations that have been 

underlined in your letter to draw attention to their priority. We also value the perspectives 

provided in other parts of the letter, and these will be given serious consideration during the 

course of the project activities leading up to and including the development of the project report. 

“General Observations 

We commend the Project Manager and TI Team leader for their continuing effective 

leadership of the Project. This leadership continues to stimulate and maintain productive 

interactions among TI Team members and between the Project Team and the Panel. 

Actions required to complete the Project identified in “Path Forward” discussed at the 

end of the meeting appear to be well formed and achievable. The Panel noted, however, 

that the actions do not include a feedback interaction following completion of the Panel’s 

review of the Draft Project Report to be delivered on September 1, 2010. We recommend 

that a process for resolving the Panel’s comments and recommendations aimed at 

completing the Final Project Report be identified and scheduled.”

We agree that a process for resolving the Panel’s comments and recommendations on the 

Draft Project Report should be identified and scheduled. The process will be developed in 

consultation with the PPRP. 

“Specific Comments and Recommendations 

2. Differences Between Seismic Source Zones: The TI Team stated that the conceptual 

approach used to define distributed seismic sources, specifically those defined on a 

seismotectonic basis, focused on four key factors: (1) earthquake recurrence rates; (2) 

maximum magnitude; (3) expected earthquake characteristics; and (4) tectonics. The 

4

		 


Data Evaluation Tables provide information on some of these factors indicating some 

differences between seismic source zones. However, because the TI Team had not 

completed development of the final earthquake catalog, implementation of the approach 

to defining maximum magnitude and spatial smoothing of earthquake recurrence rates for 

each of the distributed seismic sources had not been finalized. As a result it is difficult for 

the PPRP to have high confidence that the preliminary seismic source characterization 

model captures the center, body, and range of the ITC. While some significant 

differences between distributed seismic sources may be anticipated (e.g., Mmax 

differences between Non-Extended crust relative to differences between the Illinois Basin 

Extended Basement (IBEB) and Mid-continent Crust seismic sources), it is not intuitive 

that such differences will fully support the seismotectonic zones that subdivide the 

Mesozoic Extended crust, and as a result the conceptual approach used to define 

distributed seismic sources. The PPRP had expected that the Hazard Input Document 

would have included information to justify the approach being used. The PPRP 

recommends that the TI Team provide this information for PPRP review concurrent with 

providing hazard input to the project’s hazard analyst.

We recommend the following with respect to maximum magnitude: (1) The TI Team 

should describe how paleoliquefaction evidence was used to define seismic source 

likelihood functions. (2) The TI Team should provide specific likelihood functions and 

posterior distributions for each of the Hybrid and Seismotectonic source zones, for each 

of the prior assumption cases considered. 

With respect to the application of the smoothed seismicity approach, we recommend that 

the PPRP be provided with sufficient activity rate maps for each hybrid and 

seismotectonic source zone (such as for M = 5) to appreciate the significance of 

recurrence rate differences between seismic sources.”

The TI Team will provide the HID for the Final SSC Model to the PPRP at the time that it is 

provided to the hazard analyst for calculations. The HID will include the Mmax distributions 

for all sources as well as the earthquake recurrence rates that are derived from spatial 

smoothing. For each seismic source, the largest observed event that defines the likelihood 

function will be identified, including those derived from paleoseismic data and historical 

seismicity data. An appropriate display of earthquake recurrence rate spatial variation will 

also be provided. 

“3. Organization of the Logic Trees: We note that there are significant changes in the 

organization of the logic trees of the current CEUS SSC from previous PSHAs of the 

region. The Panel is generally supportive of these changes, but we recommend that the 

documentation of the design of the logic trees include a clear and detailed explanation of 

the reasoning involved in making the changes from previous studies. For example, the 

magnitude of the largest observed events (both historical and inferred from 

paleoliquefaction) is a major factor in isolating source zones for detailed characterization 

(the RLMEs), while regions of moderate to intense earthquake activity without moment 

magnitudes that exceed mid-5 values such as eastern Tennessee, northeastern Ohio, the 

		 


Humboldt fault zone (Nemaha Ridge), and the Ramapo fault that have been included in 

earlier studies are not called out as specific seismic zones. 

Furthermore, we have the sense that some lines of evidence used by the ITC in 

identifying and characterizing the seismic source zones of the CEUS have not received 

the attention in the current study that they have been given by some members of the ITC 

and in former PSHAs of the region. For example, contrary to the present study, some 

investigators place considerable emphasis on recent strain (GPS) measurements and 

others give considerable weight to tectonic features of the CEUS that have been mapped 

directly or indirectly in the identification and characterization of seismic source zones. 

The project would be well served by documented justification of the reasoning supporting 

minimization of these elements by the TI team in their decisions—and we recommend 

that the Draft Technical Report include such documentation.”

We agree that the project documentation must provide a detailed discussion of the criteria that 

were used to identify seismic sources and a justification for all logic tree branches and 

weights. To the extent that it helps the explanation, this discussion will be made in the context 

of previous seismic source characterizations for PSHA and the evolution of the technical 

community. Elements of emerging issues within the technical community that have not yet 

seen routine incorporation into SSC for PSHA, such as the use of geodetic strain data, will be 

discussed in the project report if they were evaluated for potential use by the TI Team in the 

SSC Model. It is important to note that the “informed technical community” that is being 

represented in the SSC Model is the hypothetical community of seismic source characterizers 

for purposes of PSHA, who are assumed to have been through the same interactive process 

that the TI Team has been through. As such, there is often a difference between the issues 

being considered by the larger research community and those that find their way into the SSC 

Model for a PSHA. 

“4. Clarity of terms in the Master Logic Tree: In labeling and discussing branches of the 

Master Logic Tree, clarity can be improved. The TI Team may want to consider another 

term for “hybrid” at the very front end of the tree. The term is a vestige from labeling a 

former three-branch node (now collapsed to two), and many readers would expect a 

hybrid branch to be a combination of two other branches. Referring to “zoneless” 

seismicity sources is confusing insofar as these sources lie within demarcated areas of 

differently affected Mesozoic crust. In general, we recommend that the TI Team examine 

jargon that has evolved in their internal discussions and evaluate whether terms used in 

their working discussions now help or hinder clear communication to others. Labeling of 

Iapetan Extended/Non-extended as a different case from Mesozoic Extended/Nonextended may be confusing to those unfamiliar with the arcane term “Iapetan.” Labeling 

of “Inter-event Times” as a Recurrence Method for the RLME logic tree branches is 

confusing because the method used in fact involves the use of both inter-event and eventinterval paleoearthquake data. In source geometry branches for RLME sources (e.g., 

Figures 15 and 17 in the HID), “extended trace” should be used instead of just 

“extended” to avoid confusion with crustal extension.” 

		 


The terminology used in the Master Logic Tree will be re-examined and revised to assist the 

reader. 

“5. Assigning Weights to the Logic Trees: As mentioned during the Briefing Meeting, we

recommend that TI Team describe the overall approach to assigning weights to the logic 

trees, and that this written description be included in the Draft Technical Report. In some 

cases these weights represent an explicit statistical assumption or distribution while in 

other cases these weights are the TI’s evaluated judgment of the informed technical 

community views. In these cases it would be useful to have an understanding of how the 

TI assigned weights from a generic perspective.” 

A description of the overall approach to assigning weights to the logic tree will be provided in 

the Draft Project Report. 

“6. Spatial Smoothing: Conceptually, the PPRP endorses the direction the TI team is 

taking with respect to spatial smoothing approach and implementation. However, thus far 

there has been no written documentation provided to us that: (1) describes the method in 

detail as it is being applied in this project, (2) describes the bases for choices of 

parameters of the model, or (3) justifies reliance entirely on the penalized likelihood 

method. We recommend that the eventual documentation not only describe the adopted 

technique in detail but also document any perceived advantages of this technique relative 

to simpler kernel techniques. Some discussion of “floor” values in regions of very low 

rates should also be included. It would benefit our review to receive this section for 

review as soon as is practicable.” 

A discussion of the spatial smoothing approach and its technical basis are planned for 

inclusion in the Draft Project Report. The discussion will include a comparison to kernel 

smoothing approaches as well as the issue of a “floor” on recurrence rates in regions lacking 

seismicity. Every effort will be made to provide the written discussion in advance of the 

delivery of the Draft Project Report. 

“7. ALM Area Characterization: The TI Team presented its independent evaluation of 

published field data, including original field copies of trench logs and field photographs 

of features that Randy Cox had described in WS #2 and interpreted as liquefaction 

features. “Project-specific Criteria for Identifying Earthquake-Induced Liquefaction 

Features Used in Development of Paleoearthquake Chronologies” were used to perform 

the evaluation. Discussions during the TI Team’s presentation identified that these 

criteria are current state of practice for determining whether observed features are 

earthquake-induced liquefaction features or properly explained as depositional or due to 

another geologic process. First, given that the criteria are identified as representing the 

state of practice of the informed technical community, the “project-specific” qualification 

is confusing and misleading. We recommend that these criteria be clarified or removed.

Second, the Team’s evaluation appears to reasonably support their conclusion that the 

features do not satisfy the informed community’s criteria for reasonably assessing that the 

features are earthquake-induced. However, this evaluation appears inconsistent with the 

		 


highly qualified ALM area model assessment conclusion: “the paleoliquefaction data 

from the ALM region are immature and highly uncertain and, at the present time, do not 

provide strong evidence for a source of RLME in the ALM area.” This highly qualified 

conclusion clearly conveys a level of uncertainty that would support giving some 

assessed weight to an interpretation that the ALM should be modeled as a RLME. 

Perhaps what is meant is that the information in the current dataset, when assessed using 

the criteria for determining whether features are indeed liquefaction features consistent 

with current state of practice, does not support the interpretation that these are 

paleoliquefaction features. We strongly support the TI Team’s decision, as stated during 

the discussion, to revisit and clarify this assessment—and we recommend that the TI 

Team do so.

To support this last point, it would be helpful if the discussion of the criteria include not 

only what the specific criteria are but the scientific and technical basis of each criterion. 

This would support not only this assessment, but would provide a valuable tool for 

projects in the future when datasets are not clear, or even as new information becomes 

available in the ALM area.” 

The criteria used to evaluate the paleoliquefaction in the CEUS, including the ALM area, will 

be clearly stated and defended technically in the Draft Project Report. Also, the terminology 

used in the evaluation of paleoliquefaction in the ALM area will be revised to more accurately 

reflect the assessment made. 

“8. Data Summary and Evaluation Tables: The Panel finds the Data Summary and Data 

Evaluation tables to be highly important in supporting and annotating the decisions 

regarding identification and characterization of the seismic source zones of the CEUS. 

Every effort should be made to include in these tables documentation for the current, 

complete center, body, and range of the ITC by seeking feedback from appropriate 

current investigators prior to finalizing the tables. A full description is warranted of the 

procedures used in selecting material for the Data Summary table. Additionally, both 

tables are essential in reviewing the basis for, and the assessments regarding, seismic 

source zones—but there remains the need for a full narrative that will allow the user of 

the CEUS SSC Model to completely understand the data evaluations that support the 

assessments made by the TI Team. We recommend that the Draft Technical Report

include such a full narrative for the Data Summary and Data Evaluation tables.”

The Draft Project Report will include a discussion of the purpose and content of the Data 

Summary and Data Evaluation tables. The tables are intended to support the discussions of 

the characterization of the seismic sources, which will also be included in the Draft Project 

Report.

“10. “Other” Reviews of the CEUS SSC Model: At the Briefing Meeting, the Project 

Manager showed tracking milestones including “Review of Draft [Technical] Report by 

PPRP, USGS, and Sponsor Reviewers—August 2, 2010 to September 1, 2010.” It seems 

appropriate to call attention to the following statement in Implementation of the SSHAC 

		 


Guidelines for Level 3 and 4 PSHAs—Experience Gained from Actual Applications 

(USGS Open-File Report 2009-1093, p. 35: 

The PPRP is the only legitimate review panel recognized by the SSHAC 

Guidelines; there is only one PPRP for a SSHAC Level 3 or 4 study, and its sole 

and unique obligation is to provide on-going commentary to TI/TFI as the project 

develops. All other “review panels” should be considered as observers, unless the 

project leadership agrees in advance to a different role/format for them. 

The Panel recognizes the prerogative of the Project Sponsors to request comments on the 

Draft Technical Report from other parties of its choosing for its own purposes. However, 

we recommend—and believe it is essential—that any comments on the CEUS SSC 

Model provided to the TI Team that result from a TI Team request be made available to 

the PPRP for its awareness and consideration.”

We agree that within the context of a SSHAC process, the PPRP is the only group with 

standing to review the technical and process aspects of the project. As noted, the Sponsors, as 

observers, may carry out their own reviews of the Draft Project Report and provide comments 

to the TI Team for consideration.

“11. Comments on Draft Report Outline: We recognize that the Draft Report Outline 

dated March 9, 2010, is preliminary (in its present form, the outline is a mix of topical 

phrases and explanations of what specific subsections will contain). As such, a detailed 

review is premature, and we only offer some general comments (not exhaustive). We

recommend that the PPRP have another opportunity to review the Draft Report Outline 

after the TI Team finalizes it. This could avoid some late-stage criticisms of the content 

of the Draft Technical Report during our August review.” 

We appreciate the comments made on the preliminary Draft Report Outline and, as requested, 

the final draft outline will be sent to the PPRP for their review. 

“Closing Comment 

The Panel is aware that, at the request of the Project, the USGS is preparing to deliver to 

the TI team independent feedback on the Project Earthquake Catalog and on the draft 

HID focusing on completeness of datasets, models, and tools being used in the CEUS 

SSC assessment. Based on telephone discussions between the PPRP and the Project 

Team on April 5, 2010, we understand that the TI Team will evaluate the USGS 

comments and will consider them in its final assessment and in its development of the 

final HID for the Project. We further understand that the TI Team’s evaluation of the 

USGS comments will be finalized as part of its final working meeting scheduled to be 

held on April 12-13, 2010, in which one or more PPRP members will participate as 

observers.”

As noted, the USGS was asked to provide their comments on two review products, and they 

responded in letters dated April 8, 2010 and April 9, 2010, which was provided to the PPRP on 

April 9, 2010. We have responded to the USGS letter in a letter dated April 9, 2010, which was 

		 


provided to the PPRP on April 9, 2010. Working Meeting #8 on April 12-13, 2010 provided 

the opportunity to ensure that all comments are addressed. 

Thanks again for your insightful review comments, and we are convinced that they will assist us 

in developing a better product. If you have any questions regarding this letter, please feel free to 

contact us. 

Sincerely,

Kevin Coppersmith 

TI Team Leader 

Coppersmith Consulting, Inc. 

2121 N. California Blvd., #290 

Walnut Creek, CA 94596 

Tel. 925 974-3335 

kcoppersmith@earthlink.net

Lawrence A. Salomone 

Project Manager 

Savannah River Nuclear Solutions, LLC 

Savannah River Site

Building 730-4B, Room 3125

Aiken, SC 29808 

Tel. 803 645-9195 

lawrence.salomone@srs.gov
NUREG-2115 DOE/NE-0140 EPRI 1021097

APPENDIX J 

Magnitude-Recurrence Maps for All Realizations and All Source-Zone 

Configurations 

J-1 

J 

APPENDIX 

MAGNITUDE-RECURRENCE MAPS FOR ALL 

REALIZATIONS AND ALL SOURCE-ZONE 

CONFIGURATIONS 

The figures in this appendix show the eight alternative realizations of the recurrence maps, as 

well as maps of the uncertainty in recurrence parameters, for all alternative source zone 

configurations in the master logic tree and for the three alternative magnitude weights (Cases A, 

B, and E). Figures J-1 through J-81 show the maps for the three alternative configurations of the 

Mmax source zones. Figures J-82 through J-189 show the maps for the four alternative 

configurations of the seismotectonic source zones. The methodology used to generate these maps 

is documented in Section 5.3.2. Mean maps and magnitude-recurrence comparisons for each 

source zone are shown in Chapter 6 on Figures 6.4.1-1 through 6.4.1-9 and Figures 6.4.2-1 

through 6.4.2-15, respectively; and in Chapter 7 on Figures 7.5.1-1 through 7.5.1-12 and Figures 

7.5.2-1 through 7.5.2-51, respectively. 
J-2 

Figure J-1 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 1 
J-3 

Figure J-2 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 2 
J-4 

Figure J-3 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 3 
J-5 

Figure J-4 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 4 
J-6 

Figure J-5 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 5 
J-7 

Figure J-6 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 6 
J-8 

Figure J-7 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 7 
J-9 

Figure J-8 

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 8 
J-10 

Figure J-9 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with no separation of Mesozoic extended and non-extended; Case A magnitude weights 
J-11 

Figure J-10

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 1 
J-12 

Figure J-11

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 2 
J-13 

Figure J-12

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 3 
J-14 

Figure J-13

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 4 
J-15 

Figure J-14

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 5 
J-16 

Figure J-15

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 6 
J-17 

Figure J-16

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 7 
J-18 

Figure J-17

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 8 
J-19 

Figure J-18

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with no separation of Mesozoic extended and non-extended; Case B magnitude weights 
J-20 

Figure J-19

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 1 
J-21 

Figure J-20

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 2 
J-22 

Figure J-21

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 3 
J-23 

Figure J-22

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 4 
J-24 

Figure J-23

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 5 
J-25 

Figure J-24

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 6 
J-26 

Figure J-25

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 7 
J-27 

Figure J-26

Map of the rate and b-value for the study region under the Mmax zonation, with no separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 8 
J-28 

Figure J-27

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with no separation of Mesozoic extended and non-extended; Case E magnitude weights 
J-29 

Figure J-28

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 1 
J-30 

Figure J-29

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 2 
J-31 

Figure J-30

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 3 
J-32 

Figure J-31

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 4 
J-33 

Figure J-32

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 5 
J-34 

Figure J-33

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 6 
J-35 

Figure J-34

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 7 
J-36 

Figure J-35

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 8 
J-37 

Figure J-36

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with separation of Mesozoic extended and non-extended; Case A magnitude weights 
J-38 

Figure J-37

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 1 
J-39 

Figure J-38

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 2 
J-40 

Figure J-39

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 3 
J-41 

Figure J-40

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 4 
J-42 

Figure J-41

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 5 
J-43 

Figure J-42

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 6 
J-44 

Figure J-43

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 7 
J-45 

Figure J-44

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 8 
J-46 

Figure J-45

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with separation of Mesozoic extended and non-extended; Case B magnitude weights 
J-47 

Figure J-46

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 1 
J-48 

Figure J-47

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 2 
J-49 

Figure J-48

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 3 
J-50 

Figure J-49

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 4 
J-51 

Figure J-50

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 5 
J-52 

Figure J-51

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 6 
J-53 

Figure J-52

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 7 
J-54 

Figure J-53

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 8 
J-55 

Figure J-54

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with separation of Mesozoic extended and non-extended; Case E magnitude weights 
J-56 

Figure J-55

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 1 
J-57 

Figure J-56

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 2 
J-58 

Figure J-57

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 3 
J-59 

Figure J-58

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 4 
J-60 

Figure J-59

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 5 
J-61 

Figure J-60

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 6 
J-62 

Figure J-61

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 7 
J-63 

Figure J-62

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case A magnitude weights: Realization 8 
J-64 

Figure J-63

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with separation of Mesozoic extended and non-extended; Case A magnitude weights 
J-65 

Figure J-64

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 1 
J-66 

Figure J-65

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 2 
J-67 

Figure J-66

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 3 
J-68 

Figure J-67

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 4 
J-69 

Figure J-68

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 5 
J-70 

Figure J-69

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 6 
J-71 

Figure J-70

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 7 
J-72 

Figure J-71

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case B magnitude weights: Realization 8 
J-73 

Figure J-72

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with separation of Mesozoic extended and non-extended; Case B magnitude weights 
J-74 

Figure J-73

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 1 
J-75 

Figure J-74

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 2 
J-76 

Figure J-75

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 3 
J-77 

Figure J-76

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 4 
J-78 

Figure J-77

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 5 
J-79 

Figure J-78

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 6 
J-80 

Figure J-79

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 7 
J-81 

Figure J-80

Map of the rate and b-value for the study region under the Mmax zonation, with separation of Mesozoic extended and nonextended; Case E magnitude weights: Realization 8 
J-82 

Figure J-81

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the Mmax 

zonation, with separation of Mesozoic extended and non-extended; Case E magnitude weights 
J-83 

Figure J-82

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 1 
J-84 

Figure J-83

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 2 
J-85 

Figure J-84

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 3 
J-86 

Figure J-85

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 4 
J-87 

Figure J-86

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 5 
J-88 

Figure J-87

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 6 
J-89 

Figure J-88

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 7 
J-90 

Figure J-89

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 8 
J-91 

Figure J-90

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with narrow interpretation of PEZ; Case A magnitude weights 
J-92 

Figure J-91

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 1 
J-93 

Figure J-92

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 2 
J-94 

Figure J-93

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 3 
J-95 

Figure J-94

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 4 
J-96 

Figure J-95

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 5 
J-97 

Figure J-96

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 6 
J-98 

Figure J-97

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 7 
J-99 

Figure J-98

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 8 
J-100 

Figure J-99

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with narrow interpretation of PEZ; Case B magnitude weights 
J-101 

Figure J-100 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 1 
J-102 

Figure J-101 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 2 
J-103 

Figure J-102 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 3 
J-104 

Figure J-103 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 4 
J-105 

Figure J-104 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 5 
J-106 

Figure J-105 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 6 
J-107 

Figure J-106 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 7 
J-108 

Figure J-107 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 8 
J-109 

Figure J-108 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with narrow interpretation of PEZ; Case E magnitude weights 
J-110 

Figure J-109 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 1 
J-111 

Figure J-110 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 2 
J-112 

Figure J-111 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 3 
J-113 

Figure J-112 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 4 
J-114 

Figure J-113 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 5 
J-115 

Figure J-114 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 6 
J-116 

Figure J-115 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 7 
J-117 

Figure J-116 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case A 

magnitude weights: Realization 8 
J-118 

Figure J-117 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with narrow interpretation of PEZ; Case A magnitude weights 
J-119 

Figure J-118 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 1 
J-120 

Figure J-119 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 2 
J-121 

Figure J-120 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 3 
J-122 

Figure J-121 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 4 
J-123 

Figure J-122 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 5 
J-124 

Figure J-123 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 6 
J-125 

Figure J-124 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 7 
J-126 

Figure J-125 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case B 

magnitude weights: Realization 8 
J-127 

Figure J-126 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with narrow interpretation of PEZ; Case B magnitude weights 
J-128 

Figure J-127 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 1 
J-129 

Figure J-128 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 2 
J-130 

Figure J-129 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 3 
J-131 

Figure J-130 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 4 
J-132 

Figure J-131 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 5 
J-133 

Figure J-132 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 6 
J-134 

Figure J-133 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 7 
J-135 

Figure J-134 

Map of the rate and b-value for the study region under the seismotectonic zonation, with narrow interpretation of PEZ; Case E 

magnitude weights: Realization 8 
J-136 

Figure J-135 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with narrow interpretation of PEZ; Case E magnitude weights 
J-137 

Figure J-136 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 1 
J-138 

Figure J-137 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 2 
J-139 

Figure J-138 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 3 
J-140 

Figure J-139 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 4 
J-141 

Figure J-140 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 5 
J-142 

Figure J-141 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 6 
J-143 

Figure J-142 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 7 
J-144 

Figure J-143 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 8 
J-145 

Figure J-144 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with wide interpretation of PEZ; Case A magnitude weights 
J-146 

Figure J-145 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 1 
J-147 

Figure J-146 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 2 
J-148 

Figure J-147 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 3 
J-149 

Figure J-148 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 4 
J-150 

Figure J-149 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 5 
J-151 

Figure J-150 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 6 
J-152 

Figure J-151 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 7 
J-153 

Figure J-152 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 8 
J-154 

Figure J-153 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with wide interpretation of PEZ; Case B magnitude weights 
J-155 

Figure J-154 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 1 
J-156 

Figure J-155 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 2 
J-157 

Figure J-156 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 3 
J-158 

Figure J-157 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 4 
J-159 

Figure J-158 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 5 
J-160 

Figure J-159 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 6 
J-161 

Figure J-160 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 7 
J-162 

Figure J-161 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 8 
J-163 

Figure J-162 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with wide interpretation of PEZ; Case E magnitude weights 
J-164 

Figure J-163 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 1 
J-165 

Figure J-164 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 2 
J-166 

Figure J-165 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 3 
J-167 

Figure J-166 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 4 
J-168 

Figure J-167 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 5 
J-169 

Figure J-168 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 6 
J-170 

Figure J-169 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 7 
J-171 

Figure J-170 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case A 

magnitude weights: Realization 8 
J-172 

Figure J-171 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with wide interpretation of PEZ; Case A magnitude weights 
J-173 

Figure J-172 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 1 
J-174 

Figure J-173 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 2 
J-175 

Figure J-174 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 3 
J-176 

Figure J-175 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 4 
J-177 

Figure J-176 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 5 
J-178 

Figure J-177 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 6 
J-179 

Figure J-178 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 7 
J-180 

Figure J-179 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case B 

magnitude weights: Realization 8 
J-181 

Figure J-180 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with wide interpretation of PEZ; Case B magnitude weights 
J-182 

Figure J-181 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 1 
J-183 

Figure J-182 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 2 
J-184 

Figure J-183 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 3 
J-185 

Figure J-184 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 4 
J-186 

Figure J-185 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 5 
J-187 

Figure J-186 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 6 
J-188 

Figure J-187 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 7 
J-189 

Figure J-188 

Map of the rate and b-value for the study region under the seismotectonic zonation, with wide interpretation of PEZ; Case E 

magnitude weights: Realization 8 
J-190 

Figure J-189 

Map of the coefficient of variation of the rate and the standard deviation of the b-value for the study region under the 

seismotectonic zonation, with wide interpretation of PEZ; Case E magnitude weights 
NUREG-2115 DOE/NE-0140 EPRI 1021097

APPENDIX K 

SCR Database Used To Develop MMAX Prior Distributions 

K

APPENDIX 

SCR DATABASE USED TO DEVELOP MMAX PRIOR 

DISTRIBUTIONS 

This appendix contains the Stable Continental Regions (SCR) database utilized in the CEUS 

SSC Project to develop prior distributions for Mmax. The database consists of two components: 

the catalog of SCR earthquakes and the catalog of SCR crustal domains. The use of these data to 

develop the Mmax prior distributions is described in Section 5.2.1.1. The databases are based 

primarily on the work presented in Johnston et al. (1994) updated as described below for the 

CEUS SSC Project. 

K.1 SCR Earthquake Catalog 

Johnston et al. (1994) developed a catalog of SCR earthquakes. An important part of that catalog 

was the development of moment magnitude, M, estimates for all of the SCR earthquakes 

contained in the catalog. For the most part, the assessment of moment magnitude was based on 

correlations with other size measures. These included correlations with other magnitude scales 

for instrumentally recorded earthquakes and correlations with shaking intensity measures for preinstrumental earthquakes. 

Schulte and Mooney (2005) extended the SCR earthquake catalog of Johnston et al. (1994) to 

include earthquakes in the time period 1991 through 2003 as well as additional earthquakes 

identified from the literature that occurred in the time period covered by Johnston et al. (1994). 

The Schulte and Mooney (2005) update of the Johnston et al. (1994) SCR earthquake catalog 

was used as the basis for the SCR earthquake catalog used in the CEUS SSC Project. The SCR 

catalog was extended to cover the time period ending 12/31/2008 utilizing moment magnitudes 

from the Harvard Central Moment Tensor (CMT) catalog for earthquakes that occurred in the 

SCR regions described in Section K.2. Table K-1 lists the resulting updated SCR earthquake 

catalog developed for the CEUS SSC Project. The dates, times, and locations were taken directly 

from the catalog sources Johnston et al. (1994), Schulte and Mooney (2005), and Harvard CMT. 

The magnitudes utilized in the CEUS SSC catalog of SCR earthquakes are values of E[M], the 

expected value of moment magnitude given the uncertainty in its estimate. The value of E[M] 

also incorporates the effect of the general exponential distribution of earthquake magnitudes. 

Section 3.3.1 discusses the estimation of E[M] from observations and the relationships presented 

in that section are utilized to produce values of E[M] for the SCR earthquakes. The two general 

cases are when M is based on direct observations of moment magnitude computed from wave 

form inversions (e.g. Harvard CMT value) and when M is estimated from other size measures. 

For the case when M is obtained directly from observations of moment magnitude, its value is 

designated 

M

ˆ

to indicate that it is observed with some level of uncertainty. As described in 

K-1
Appendix K 

Section 3.3.1, in this case E[M] is obtained by the relationship given in Equation 3.3-5 utilizing 

the uncertainty in the measurement of M defined by 

]

ˆ

[ MM

. For those earthquakes in Table K1 whose moment magnitudes were directly estimated, the values of E[M] were computed from 

the reported values of 

M

ˆ

utilizing Equation 3.3-5 and the reported values of 

]

ˆ

[ MM

. The 

adjustments to E[M] were made using a b-value of 0.95, an average value found for earthquakes 

in the SCR domains. The second case is when M is estimated from other size measures. As 

discussed in Section 3.3.1, estimation of M from regression relationships with other size 

measures directly produces values of E[M]. In this case, the reported values of M are used 

directly as E[M]. However, an adjustment to the value of the standard error of the estimate of M

is needed to account for the inflation of the standard error obtained from regression due to the 

uncertainty in the values of 

M

ˆ

used in the regressions (see Equation 3.3-8 and related text). 

The magnitudes and magnitude uncertainties listed in Schulte and Mooney (2005) were updated 

as follows. Johnston (1996a, 1996b) provides updates to the magnitude conversion relationships 

presented in Johnston et al. (1994) as well as updated moment magnitude and magnitude 

uncertainty estimates for many of the SCR earthquakes. These updated magnitudes were used in 

updating the SCR earthquake catalog for the CEUS SSC Project. Reported values of standard 

error given by the relationships in Johnston (1996a, 1996b) were reduced using the average value 

of 

]

ˆ

[ MM

equal to 0.16 reported in Johnston (1996b). The magnitude and uncertainty estimates 

for those SCR earthquakes that are in the CEUS SSC Project catalog were taken directly from 

Appendix B. 

Updates to the magnitude and uncertainty values reported in Schulte and Mooney (2005) and 

Johnston et al. (1994) were made for earthquake magnitudes based on maximum intensity, I0. 

These earthquake magnitudes were designated type X in Johnston et al. (1994, Appendix C). The 

Johnston et al. (1994) type X magnitudes were converted back into I0 using the relationship 

given in Johnston et al. (1994) and then new estimates of E[M] and standard error were obtained 

using Johnston (1996b). The following table summarizes the adjustments. 

Update of Johnston et al. (1994) Type X 

EPRI (1994) M I0 Johnston (1996b) 

E[M]

Johnston (1996b) 

σP

]I[  M 0

4.20 V 4.22 0.522 0.50

V-VI 4.46 0.522 0.50

4.39 VI 4.72 0.522 0.50

4.62 VI-VII 4.98 0.522 0.50

4.85 VII 5.25 0.522 0.50

5.16 VII-VIII 5.53 0.522 0.50

5.46, 5.47 VIII 5.81 0.524 0.50

5.85, 5.86 VIII-IX 6.11 0.527 0.50

6.24 IX 6.41 0.534 0.51

6.67 IX-X 6.72 0.545 0.52

6.94 X 7.04 0.563 0.54

Johnston et al. (1994) designated type Z as earthquakes of type X with additional uncertainty in 

the estimates of I0. Following Johnston (1996b, Equation 18) the uncertainty in these earthquakes 

K-2
Appendix K 

was set at the nominal standard error for type X, 0.5, times the square root of 2, or a nominal 

value of 0.7. 

Johnston et al. (1994) reports magnitude estimates based on the number of stations reporting the 

earthquake. These are designated magnitude type D1 in Johnston et al. (1994, Appendix C). 

Figure K-1 compares the relationships between number of reporting stations, NR, normalized by 

the maximum number of stations available, NM and moment magnitude developed by Johnston et 

al. (1994) with the updated relationship presented in Johnston (1996b). Significant differences in 

the estimated values of moment magnitude are indicated on the figure. Therefore, the type D1 

magnitudes reported in Johnston et al. (1994) were updated using the relationship presented in 

Johnston (1996b). The values of NR/NM were estimated from the moment magnitudes listed in 

Johnston et al. (1994) and then used to compute E[M] using the relationship in Johnston (1996b). 

The value of standard error was reduced from 0.48 reported in Johnston (1996b) to a value of 

0.45 representing the uncertainty in the true moment magnitude using Equation 3.3-8 and the 

average value of 

]

ˆ

[ MM

equal to 0.16 reported in Johnston (1996b). 

Many of the moment magnitudes reported in Johnston et al. (1994) were based on correlations 

between M and various isoseismal areas. Figure K-2 compares these relationships with the 

updated relationships presented in Johnston (1996b). For the most part, the updated relationships 

are similar to those published in Johnston et al. (1994) and no update to the magnitude estimates 

of this type was considered necessary. 

K.2 SCR Crustal Domains 

Johnston et al. (1994) divided the SCR portions of the earth into 255 domains based on 

differences in their geology and tectonic history. These domains were used in the CEUS SSC 

Project without modification to their boundaries. Table K-2 lists the 255 domains. Scanned 

images of the plates from Johnston et al. (1994) that outline the domains as well as digital 

listings of the domain boundaries are contained on the CEUS SSC Project web site. 

Table K-2 lists the attributes assigned to the domains used in the development of the prior 

distributions for Mmax. The AGE attribute has two entries. The first is the age assigned in 

Johnston et al. (1994). The second is the age of most recent extension (MRE Age) which was 

found to provide a better means of discriminating between domains in assessing Mmax priors 

(see Section 5.2.1.1). 

The maximum observed magnitude in each domain is based on the SCR earthquake catalog 

listed in Table K-1. The number of earthquakes of magnitude equal to or larger than M 4.5 

includes the adjustment for the effect of magnitude completeness defined by Equation 5.2.1-3. 

As described in Section 5.2.1.1, the domains were grouped into superdomains using the 

attributes listed in Table K-2. The last two columns of Table K-2 indicate the superdomain 

number each domain was assigned to. The designation SDNT indicates the superdomain number 

for the case when the superdomains are separated into two groups by the attribute TYPE. In this 

case the extension attribute and the MRE Age attribute are used to group the domains into 

extended superdomains, indicated by the characters SE in the superdomain number, and nonextended superdomains, indicated by the characters SN in the superdomain number. The 

K-3
Appendix K 

designation SDNC indicates the superdomain number for the case when the superdomains are 

not separated into two groups by the attribute TYPE. 

K-4
Appendix K 

Table K-1 

SCR Earthquake Catalog 

Notes: 

Year, Month, Day Earthquake Date 

Hour, Minute, Second Earthquake Time. The time is based on values reported in 

the primary sources and is assumed to be UTC time. 

However, these times were not verified as UTC and may 

contain a mixture time zone values. 

Latitude, Longitude Earthquake Location. The precision of the location values 

were taken directly from the catalog source. 

E[M] Expected value of Moment Magnitude 

sigM Standard deviation of moment magnitude estimate 

DN SCR Domain Number (see Table K-2)

K-5
Appendix K 

Table K-1 

SCR Earthquake Catalog 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

495 3 31 0 0 0 37.5 121.5 5.22 0.44 133

827 0 0 0 0 0 51.1 12.8 5.25 0.50 192

973 9 0 0 0 0 32.2 46.3 5.53 0.50 81

999 10 0 0 0 0 31.8 119.9 5.25 0.50 132

1058 12 8 0 0 0 34.3 44.7 5.62 0.47 81

1062 2 8 0 0 0 49 12 5.81 0.50 192

1067 11 0 0 0 0 23.6 116.5 6.12 0.32 125

1068 3 18 0 0 0 28.7 36.75 6.9 0.47 81

1088 5 12 0 0 0 51.1 13.1 5.25 0.50 192

1112 0 0 0 0 0 48.417 8.833 5.81 0.50 195

1128 0 0 0 0 0 47.483 7.567 5.81 0.50 195

1130 2 27 0 0 0 33.6 45.7 6.09 0.47 81

1185 4 15 0 0 0 53.22 -0.5 5.53 0.50 187

1194 3 0 0 0 0 32 44.3 4.67 0.44 81

1247 2 20 0 0 0 52 -6 5.28 0.32 197

1275 9 11 0 0 0 51 -2.5 5.49 0.44 196

1279 9 2 0 0 0 49 8 5.81 0.50 195

1344 0 0 0 0 0 38.9 -8.85 5.96 0.50 199

1346 0 0 0 0 0 50.8 12.2 5.39 0.50 192

1366 5 24 0 0 0 50.8 12.2 5.25 0.50 192

1382 5 21 0 0 0 51.5 2.5 5.41 0.44 187

1407 11 0 0 0 0 31.2 112.6 5.25 0.50 130

1430 0 0 0 0 0 32.2 46.4 5.48 0.47 81

1445 2 14 0 0 0 50 6.3 5.81 0.50 196

1445 12 12 0 0 0 24.5 117.6 5.65 0.44 125

1457 0 0 0 0 0 31.9 46.9 5.7 0.47 81

1477 8 6 0 0 0 45.8 3 5.51 0.32 195

1490 3 1 0 0 0 45.85 3.1 5.85 0.32 195

1523 8 14 0 0 0 29.9 121.7 5.25 0.50 125

1528 3 12 0 0 0 39.7 -8.9 5.25 0.50 199

1531 1 26 0 0 0 38.95 -9 7.04 0.54 199

1548 9 13 0 0 0 38 121 6.1 0.32 133

1553 8 17 0 0 0 51.583 13 5.39 0.50 192

1556 1 0 0 0 0 29.4 113.1 5.15 0.32 130

1558 6 0 0 0 0 23.4 111.5 4.81 0.32 129

1568 0 0 0 0 0 41.5 -72.5 5.25 0.50 218

1574 0 0 0 0 0 27.6 119.1 5.25 0.50 125

1574 0 0 0 0 0 41.5 -72.5 5.25 0.50 218

1574 8 19 0 0 0 26.1 119.3 5.83 0.32 125

1575 2 26 0 0 0 53 -1.5 4.9 0.44 187

1580 4 6 0 0 0 50.9 1.7 6.67 0.32 187

1584 0 0 0 0 0 41.5 -72.5 5.25 0.50 218

1585 3 6 0 0 0 31.2 117.7 5.28 0.32 130

1592 0 0 0 0 0 41.5 -72.6 5.25 0.50 222

1600 9 29 0 0 0 23.5 117 6.84 0.32 125

K-6
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1604 12 29 0 0 0 25 119.5 7.65 0.32 127

1605 7 13 0 0 0 19.9 110.5 7.47 0.32 126

1611 9 9 0 0 0 21.5 111.3 5.25 0.50 129

1615 0 0 0 0 0 5.1 -1.3 5.81 0.50 100

1618 2 18 0 0 0 16.7 -3.2 5.37 0.44 99

1618 5 26 0 0 0 18.9 72.9 6.41 0.51 106

1624 2 10 0 0 0 32.4 119.5 5.73 0.32 132

1624 9 1 0 0 0 31.2 121.4 4.65 0.32 132

1624 10 0 0 0 0 33.2 107.5 5.25 0.50 131

1626 5 14 0 0 0 66 35.5 5.27 0.44 173

1631 8 14 0 0 0 29.3 111.7 6.38 0.32 130

1635 10 26 0 0 0 33.2 107.5 5.25 0.50 131

1636 0 0 0 0 0 33.1 107 5.25 0.50 131

1636 12 18 0 0 0 5.1 -2.2 6.19 0.32 100

1638 6 11 0 0 0 42.5 -69 5.81 0.50 218

1641 11 26 0 0 0 23.6 116.5 5.47 0.44 125

1651 2 15 0 0 0 26.2 116.6 5.16 0.32 125

1655 3 29 0 0 0 48.5 9.067 5.25 0.50 195

1657 2 15 0 0 0 47.1 0.6 5.53 0.50 196

1661 2 10 0 0 0 45.5 -73 5.25 0.50 227

1663 2 5 0 0 0 47.6 -70.1 6.72 0.52 227

1668 7 25 0 0 0 34.3 118.5 7.87 0.32 132

1679 12 16 0 0 0 31.4 119.5 4.98 0.50 132

1682 5 12 0 0 0 47.9 6.5 6.55 0.32 195

1690 10 7 0 0 0 53 -3 4.77 0.44 185

1692 9 18 0 0 0 50.7 4.333 5.08 0.32 187

1710 4 16 0 0 0 27.8 111.3 5.25 0.50 129

1711 10 6 0 0 0 47.06 0.03 5.93 0.32 196

1720 7 15 0 0 0 28.53 77.2 6.11 0.50 113

1727 7 19 0 0 0 51.5 -3.5 5.09 0.32 196

1727 11 10 0 0 0 42.8 -70.8 4.77 0.32 218

1728 8 3 0 0 0 48.3 7.8 5.55 0.32 195

1732 9 16 0 0 0 45.5 -73.6 6.25 0.32 227

1736 4 30 0 0 0 56.18 -3.77 4.98 0.50 186

1737 12 19 0 0 0 40.8 -74 5.25 0.50 218

1743 6 29 0 0 0 30.7 118.4 4.76 0.32 130

1751 12 19 0 0 0 41 -7 5.53 0.50 200

1752 3 27 0 0 0 40.65 -8.55 5.53 0.50 199

1755 11 18 0 0 0 42.7 -70.3 6.1 0.26 218

1755 12 26 0 0 0 50.8 6.333 5.5 0.32 195

1759 12 22 0 0 0 57.7 11.1 5.1 0.32 177

1764 6 4 0 0 0 24 88 5.81 0.50 118

1764 8 17 0 0 0 17.9 73.7 4.65 0.44 106

1769 11 14 0 0 0 57.46 -4.22 4.69 0.44 185

1772 2 18 0 0 0 68.7 33.3 4.66 0.44 171

1772 6 0 0 0 0 44.37 4.82 5.35 0.32 195

1775 9 8 0 0 0 51.6 -4 5.01 0.32 196

K-7
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1775 12 30 0 0 0 49.17 -0.4 5.28 0.32 196

1780 0 0 0 0 0 58.5 121 5.08 0.44 147

1782 4 30 0 0 0 26.2 111.7 4.91 0.32 129

1785 1 2 0 0 0 42.3 -71.1 5.25 0.50 218

1786 8 11 0 0 0 54.53 -3.68 4.98 0.50 185

1788 0 0 0 0 0 7.6 1.7 5.74 0.44 92

1791 4 8 0 0 0 24.5 117.7 5.25 0.50 125

1791 12 6 0 0 0 47.4 -70.5 5.5 0.48 226

1795 5 20 0 0 0 9.3 -13.4 4.78 0.32 105

1798 5 23 0 0 0 57.9 56.8 4.76 0.44 166

1799 1 25 0 0 0 46.95 -2 5.91 0.32 196

1803 9 1 0 0 0 27.5 77.7 6.65 0.44 113

1804 5 5 0 0 0 53.3 104 5.41 0.44 149

1806 1 11 0 0 0 25.3 115.7 5.71 0.44 125

1808 8 8 0 0 0 -5.7 -37.7 4.58 0.32 56

1809 12 4 0 0 0 -34 18.4 5.53 0.50 59

1811 6 2 0 0 0 -34 18.4 5.25 0.50 59

1812 2 7 0 0 0 36.5 -89.6 7.8 0.17 228

1816 8 13 0 0 0 57.45 -4.17 4.71 0.32 185

1816 9 9 0 0 0 45.5 -73.6 5.25 0.50 227

1817 3 18 0 0 0 42.25 -2.1 5.24 0.32 201

1817 5 22 0 0 0 44.72 -67.5 4.69 0.32 222

1818 1 0 0 0 0 12.1 -12.4 5.85 0.32 100

1819 6 16 0 0 0 23.6 69.6 7.79 0.32 114

1819 8 31 0 0 0 66.7 15.5 6.38 0.32 179

1819 9 14 0 0 0 26.5 107.2 5.25 0.32 130

1820 0 0 0 0 0 -4.5 11.6 6.35 0.44 74

1822 4 3 0 0 0 24 89 5.25 0.50 118

1823 2 9 0 0 0 7 80 5.25 0.50 107

1824 0 0 0 0 0 -8 -39 5.81 0.50 56

1827 5 0 0 0 0 57.9 108.8 6.4 0.44 149

1827 9 24 0 0 0 31.57 74.35 6.11 0.50 113

1828 7 8 0 0 0 22.6 88.4 5.25 0.50 118

1828 8 22 0 0 0 13 75 5.25 0.50 106

1829 12 1 0 0 0 53.8 82.4 4.95 0.44 156

1831 5 8 0 0 0 47.3 -70.5 5.25 0.50 227

1833 10 4 0 0 0 27 85 6.41 0.51 112

1833 10 18 0 0 0 27 84 5.81 0.50 112

1834 9 3 0 0 0 61 6 5.15 0.32 179

1838 6 9 0 0 0 38.5 -89 5.12 0.48 230

1841 4 3 0 0 0 56.9 8 4.64 0.32 190

1842 5 21 0 0 0 25 87 5.25 0.50 111

1843 1 5 0 0 0 35.5 -90.5 6 0.17 228

1843 3 31 0 0 0 15.2 76.9 5.29 0.32 106

1845 6 19 0 0 0 23.78 68.83 5.53 0.50 114

1845 8 6 0 0 0 22.7 88.4 5.25 0.50 118

1846 0 0 0 0 0 31.6 106 5.22 0.44 131

K-8
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1846 5 27 0 0 0 23 80 5.25 0.50 111

1846 7 29 0 0 0 50.2 7.7 4.55 0.32 195

1848 4 26 0 0 0 24.4 72.7 5.48 0.44 113

1850 1 18 0 0 0 58.5 121 5.55 0.44 147

1852 4 29 0 0 0 36.7 -82 5.21 0.26 224

1852 11 9 0 0 0 53.23 -4.12 4.99 0.32 185

1853 4 1 0 0 0 49.27 -1.82 4.72 0.32 196

1854 11 24 0 0 0 29.1 107.1 5.25 0.50 131

1855 2 8 0 0 0 46 -64.5 4.9 0.32 221

1855 12 11 0 0 0 39.1 121.6 5.25 0.50 133

1856 6 10 0 0 0 29.7 108.8 4.79 0.32 130

1856 12 25 0 0 0 21.15 72.9 5.12 0.50 115

1857 10 8 0 0 0 38.7 -89.2 5.13 0.32 230

1858 11 11 0 0 0 38.2 -9 7.09 0.32 199

1859 11 21 0 0 0 -40.7 145.2 4.73 0.32 26

1860 0 0 0 0 0 45.97 -94.82 4.98 0.50 236

1860 10 17 0 0 0 47.5 -70.1 6.08 0.48 227

1861 2 16 0 0 0 22.6 88.4 5.25 0.50 118

1861 7 13 0 0 0 45.4 -75.4 4.71 0.48 227

1861 7 19 0 0 0 39.1 121.7 5.81 0.50 133

1861 8 31 0 0 0 36.2 -81.2 5.63 0.26 223

1862 7 10 0 0 0 7 0.4 6.75 0.32 92

1863 10 6 0 0 0 51.97 -2.88 4.89 0.32 187

1863 11 18 0 0 0 21.8 75.3 5.53 0.50 120

1864 4 29 0 0 0 22.3 72.8 4.98 0.50 115

1864 12 7 0 0 0 33.3 45.9 5.91 0.47 81

1865 5 7 0 0 0 59.5 4.8 4.92 0.32 179

1865 8 17 0 0 0 36 -89.5 5.21 0.32 228

1866 3 9 0 0 0 63.3 6.7 5.75 0.32 183

1866 5 23 0 0 0 25 87 5.67 0.50 111

1866 9 14 0 0 0 46.8 1.2 4.98 0.32 196

1867 4 24 0 0 0 39.17 -96.3 5.08 0.15 235

1867 12 18 0 0 0 44.7 -75.2 4.4 0.15 226

1868 6 18 0 0 0 -32.8 151.6 4.64 0.32 27

1868 9 30 0 0 0 24 85 5.25 0.50 111

1869 10 22 0 0 0 45 -67.5 5.47 0.32 222

1870 10 20 0 0 0 47.4 -70.5 6.55 0.48 226

1872 3 6 0 0 0 50.86 12.28 4.9 0.32 192

1872 4 14 0 0 0 5.5 -0.4 5.06 0.44 92

1873 7 19 0 0 0 44.48 4.72 5.2 0.32 195

1873 12 15 0 0 0 -26.8 127.2 6.04 0.70 9

1875 6 18 0 0 0 40.2 -84 4.6 0.32 235

1875 8 17 0 0 0 50.3 24.2 4.86 0.44 167

1875 12 12 0 0 0 31.57 74.35 5.53 0.50 113

1875 12 23 0 0 0 37.8 -78 4.77 0.32 218

1877 11 4 0 0 0 44.5 -74 4.71 0.32 226

1877 11 15 0 0 0 41 -97 5.05 0.32 255

K-9
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1878 1 28 0 0 0 49.8 -0.3 4.78 0.32 196

1878 8 26 0 0 0 50.9 6.4 4.94 0.32 195

1879 2 11 0 0 0 6.5 -3.3 5.56 0.32 100

1880 2 3 0 0 0 -43 146.4 4.62 0.32 26

1880 11 28 0 0 0 56.4 -7.3 4.88 0.32 184

1882 1 0 0 0 0 8.6 81.2 5.81 0.50 107

1882 3 15 0 0 0 54.7 83.2 5.24 0.44 156

1882 10 22 0 0 0 35.9 -95.1 5.58 0.32 231

1883 8 0 0 0 0 30 9.5 4.93 0.44 89

1883 8 28 0 0 0 -25.5 151.7 5.12 0.32 28

1884 4 22 0 0 0 51.83 0.92 4.8 0.32 187

1884 7 13 0 0 0 -40.5 148.5 5.66 0.32 26

1884 8 10 0 0 0 40.6 -74 4.79 0.32 218

1885 1 5 0 0 0 -26.5 116.3 6.5 0.70 7

1885 5 12 0 0 0 -39.9 148.9 5.96 0.32 26

1885 7 2 0 0 0 -39 146 4.92 0.44 26

1885 7 14 0 0 0 24 90 5.25 0.50 118

1886 9 1 0 0 0 32.9 -80 6.9 0.17 218

1886 10 25 0 0 0 61.6 5.9 5.01 0.32 179

1886 11 29 0 0 0 -34.75 148.8 4.79 0.32 27

1888 8 23 0 0 0 50 134 5.53 0.50 139

1889 0 0 0 0 0 6.8 -6.7 5.09 0.44 100

1889 5 30 0 0 0 49.5 -0.5 4.77 0.32 196

1891 9 27 0 0 0 38.25 -88.5 5.52 0.32 230

1892 1 26 0 0 0 -40.4 149.5 6.35 0.32 26

1892 5 15 0 0 0 60.6 4.4 5.4 0.32 194

1892 8 18 0 0 0 51.6 -5.2 4.77 0.32 196

1893 11 2 0 0 0 51.6 -4.6 4.58 0.32 196

1893 11 27 0 0 0 45.5 -73.3 5.12 0.48 227

1894 7 23 0 0 0 68.5 13 5.84 0.32 183

1895 2 5 0 0 0 63.5 5 5.47 0.32 183

1895 8 8 0 0 0 57 133 6.19 0.44 147

1895 8 30 0 0 0 23.5 116.3 5.67 0.50 125

1895 10 31 0 0 0 37 -89.4 6 0.17 230

1896 9 2 0 0 0 50.3 2.88 4.87 0.32 196

1896 12 17 0 0 0 52.02 -2.69 4.75 0.32 187

1897 3 23 0 0 0 45.5 -73.6 4.59 0.48 227

1897 5 10 0 0 0 -37.33 139.75 6.16 0.32 23

1897 5 31 0 0 0 37.3 -80.7 5.91 0.32 224

1897 6 22 0 0 0 19.4 84.9 5.12 0.50 108

1897 8 25 0 0 0 62.5 55 4.86 0.44 168

1900 2 8 0 0 0 10.75 76.75 5.66 0.32 106

1901 1 10 0 0 0 50.5 16.1 4.67 0.32 192

1902 4 10 0 0 0 64.3 27.6 4.81 0.44 173

1902 9 19 0 0 0 -35 137.4 5.38 0.32 19

1902 11 4 0 0 0 38.9 -5.6 5.43 0.44 200

1903 1 14 0 0 0 24 70 5.53 0.50 114

K-10
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1903 4 6 0 0 0 -38.43 142.53 4.5 0.37 23

1903 6 4 0 0 0 0 26 6.3 0.37 78

1903 6 19 0 0 0 53.05 -4.38 4.58 0.32 185

1903 7 14 0 0 0 -38.43 142.53 4.58 0.32 23

1903 8 9 0 0 0 38.3 -9 6 0.32 199

1903 11 4 0 0 0 36.9 -89.3 4.97 0.32 228

1904 2 13 0 0 0 56.4 73 5.26 0.44 158

1904 3 21 0 0 0 45 -67.2 5.73 0.32 222

1904 4 9 0 0 0 -37 147.1 4.5 0.44 27

1904 10 23 0 0 0 59 10.5 5.87 0.37 177

1905 7 18 0 0 0 -10.2 -40.4 4.67 0.32 47

1905 8 22 0 0 0 36.8 -89.6 4.95 0.32 228

1906 1 8 0 0 0 39.2 -96.5 4.91 0.32 235

1906 3 27 0 0 0 24.5 118.5 6.04 0.37 125

1906 6 27 0 0 0 52.64 -4 4.87 0.32 185

1906 11 19 0 0 0 -19.1 111.8 7.2 0.19 2

1906 11 20 0 0 0 6.5 0.3 5.09 0.32 92

1907 1 14 0 0 0 65.5 11 5.32 0.37 183

1908 0 0 0 0 0 7.7 -7.8 5.8 0.32 100

1908 4 2 0 0 0 3 25.5 6.3 0.37 73

1909 4 23 0 0 0 38.95 -8.82 6.4 0.37 199

1909 5 16 0 0 0 50 -104 5.72 0.32 237

1909 5 26 0 0 0 41.75 -88.3 5.15 0.48 230

1909 8 5 0 0 0 -22.2 29 5.01 0.32 66

1909 9 27 0 0 0 39.5 -87.4 4.73 0.32 230

1910 1 8 0 0 0 35 122 6.5 0.19 132

1910 5 30 0 0 0 10 27 5.8 0.37 84

1910 10 21 0 0 0 -30.5 24.7 5.26 0.32 63

1910 12 4 0 0 0 -10 140 6.8 0.25 13

1911 3 26 0 0 0 3.1 11 5.79 0.37 73

1911 8 6 0 0 0 53.5 127.1 4.92 0.44 136

1911 11 16 0 0 0 48.22 9.05 6.17 0.25 192

1912 2 20 0 0 0 -29.45 25.06 6.04 0.25 63

1912 4 13 0 0 0 78.9 108 5.12 0.37 170

1912 6 12 0 0 0 32.9 -80 4.5 0.48 218

1912 11 6 0 0 0 42.9 -2.7 5.25 0.50 198

1913 1 1 0 0 0 34.7 -81.7 4.54 0.32 218

1913 4 3 0 0 0 32.2 119.5 5.22 0.37 132

1913 7 19 0 0 0 64 8 5.15 0.37 183

1913 8 4 0 0 0 61.3 5.2 4.95 0.37 179

1913 10 9 0 0 0 3.8 12.3 4.9 0.32 84

1913 10 27 0 0 0 41.67 -8.72 4.7 0.32 199

1913 12 18 0 0 0 -20 147 5.12 0.37 27

1914 2 10 0 0 0 46 -75 5.1 0.48 226

1914 4 13 0 0 0 53.8 81.5 5.06 0.37 156

1914 5 18 0 0 0 31.35 15.25 5.35 0.37 90

1914 5 24 0 0 0 -10 15 6.15 0.25 72

K-11
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1914 6 7 0 0 0 73 119 5.37 0.37 146

1914 8 17 0 0 0 57 59.4 5.24 0.44 159

1914 9 25 0 0 0 39 -8.82 4.91 0.32 199

1915 6 2 0 0 0 48.9 11.4 4.68 0.32 192

1915 10 10 0 0 0 48.8 11.6 4.84 0.32 192

1916 2 21 0 0 0 35.5 -82.5 5.13 0.32 223

1916 10 18 0 0 0 33.5 -86.2 4.98 0.32 224

1916 12 3 0 0 0 43.7 -7.5 5.25 0.50 198

1917 1 21 0 0 0 -3 10 5.63 0.37 76

1917 4 9 0 0 0 38.1 -90.2 4.86 0.32 229

1917 4 17 0 0 0 18 84 4.66 0.45 117

1917 7 30 0 0 0 28 104 6.5 0.25 131

1918 2 13 0 0 0 23.54 117.243 7.42 0.19 125

1918 6 6 0 0 0 -23.5 152.5 5.8 0.25 32

1919 4 21 0 0 0 22 72 5.25 0.50 113

1919 6 1 0 0 0 27.074 123.315 7.5 0.25 127

1919 6 1 0 0 0 -18 -56 4.75 0.44 49

1919 10 31 0 0 0 -27 31.5 6.5 0.47 64

1919 10 31 0 0 0 24 116.5 5.33 0.45 125

1920 2 8 0 0 0 -35 111 6.15 0.25 6

1920 5 29 0 0 0 25.1 120.5 5.13 0.47 127

1920 11 26 0 0 0 42.4 -8.6 4.97 0.37 199

1921 5 30 0 0 0 -35 145 4.95 0.37 27

1921 9 16 0 0 0 3.8 16.3 4.84 0.32 84

1921 12 1 0 0 0 33.7 122 6.4 0.37 132

1922 1 19 0 0 0 -7 143 7.29 0.37 16

1922 1 27 0 0 0 -22.17 -47.04 4.78 0.32 49

1922 4 7 0 0 0 23.5 119 5.71 0.37 127

1922 4 10 0 0 0 -39.14 144.85 5.11 0.37 26

1922 4 13 0 0 0 60 -110 5.11 0.37 239

1922 5 20 0 0 0 24.7 116.5 4.79 0.44 125

1922 7 26 0 0 0 70 -70 5.12 0.37 248

1922 8 14 0 0 0 52.069 130.539 6.72 0.52 139

1923 10 15 0 0 0 48.5 122.5 4.98 0.50 135

1923 12 8 0 0 0 32 127.5 5.71 0.37 127

1924 3 1 0 0 0 -41.6 145 4.52 0.32 26

1924 5 27 0 0 0 62 135.5 5.34 0.37 147

1924 7 25 0 0 0 72.5 16 5.09 0.37 183

1924 9 30 0 0 0 47.6 -69.7 4.69 0.16 222

1924 10 17 0 0 0 60 -118 5.08 0.37 241

1925 2 1 0 0 0 49.16 -5.22 5.04 0.32 197

1925 2 7 0 0 0 48 105 5.3 0.37 136

1925 2 18 0 0 0 69 145 4.97 0.37 141

1925 3 1 0 0 0 47.76 -69.84 6.18 0.29 227

1925 4 27 0 0 0 38.3 -87.6 4.87 0.32 229

1925 7 30 0 0 0 35.4 -101.3 5.24 0.32 231

1925 9 24 0 0 0 25.51 55.38 5.88 0.37 81

K-12
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1925 11 6 0 0 0 26.5 81.5 4.52 0.45 112

1925 12 18 0 0 0 -33 151.6 4.56 0.32 27

1926 2 28 0 0 0 38.58 -7.9 5.28 0.32 200

1926 3 10 0 0 0 66.5 -130 4.55 0.45 241

1926 6 13 0 0 0 20 116.5 4.78 0.45 127

1926 6 29 0 0 0 27 121 5.06 0.44 127

1926 7 30 0 0 0 49.22 -1.82 4.98 0.32 196

1926 8 18 0 0 0 65.8 28.5 4.76 0.44 173

1926 9 19 0 0 0 57.3 67 5.3 0.44 158

1926 9 29 0 0 0 48 122.7 4.98 0.50 135

1926 12 14 0 0 0 -12 121 6.26 0.25 1

1926 12 31 0 0 0 25 77.5 4.47 0.45 112

1927 1 24 0 0 0 59.9 1.8 5.57 0.32 188

1927 2 3 0 0 0 33.5 121 6.6 0.25 132

1927 5 7 0 0 0 35.7 -90.6 4.84 0.32 228

1927 6 2 0 0 0 23.5 81 6.4 0.25 119

1928 4 5 0 0 0 9.8 -13.3 4.51 0.32 105

1929 2 8 0 0 0 24.9 119.9 4.47 0.45 127

1929 4 11 0 0 0 25 77.5 5.39 0.50 112

1929 7 26 0 0 0 -2.5 24.5 5.5 0.37 73

1929 8 12 0 0 0 42.91 -78.402 4.72 0.20 226

1929 8 16 0 0 0 -16.99 120.66 6.26 0.25 1

1929 10 24 0 0 0 22 118 6.57 0.25 127

1929 11 18 0 0 0 44.691 -56.006 6.97 0.31 218

1929 12 28 0 0 0 -39.69 149.45 5.42 0.37 26

1930 1 3 0 0 0 32.2 119.4 5.04 0.44 132

1930 1 9 0 0 0 47.62 -2.88 5.1 0.37 196

1930 4 3 0 0 0 32.5 43.7 5.2 0.37 81

1930 6 25 0 0 0 25 77.5 4.45 0.45 112

1930 7 5 0 0 0 37.6 -4.6 5.21 0.37 200

1930 9 23 0 0 0 27.5 106 5.15 0.37 130

1931 1 8 0 0 0 47.63 -70.17 4.89 0.37 226

1931 4 20 0 0 0 43.4 -73.7 4.58 0.32 224

1931 5 1 0 0 0 3 27 5.21 0.37 73

1931 6 7 0 0 0 54.1 1.5 5.7 0.32 194

1931 6 29 0 0 0 48.5 123.5 4.98 0.37 135

1931 7 1 0 0 0 30 109 4.44 0.45 130

1931 9 17 0 0 0 50.1 127 5 0.44 138

1931 9 20 0 0 0 40.4 -84.21 4.58 0.48 235

1931 9 21 0 0 0 19.421 113.158 6.73 0.25 127

1931 12 17 0 0 0 34.1 -89.9 4.71 0.32 225

1932 6 21 0 0 0 16.7 111.8 5.31 0.37 127

1932 8 14 0 0 0 62.8 154.6 4.97 0.37 140

1932 8 22 0 0 0 36.1 121.6 6.26 0.25 132

1932 11 20 0 0 0 51.71 5.61 4.97 0.37 195

1932 12 31 0 0 0 -28.5 32.75 6.61 0.25 63

1933 2 8 0 0 0 48.8 8.2 4.71 0.37 195

K-13
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1933 7 14 0 0 0 42.9 56.5 5.33 0.37 160

1933 12 2 0 0 0 -51.5 -44 6.49 0.25 35

1934 5 12 0 0 0 44.43 4.82 4.75 0.32 195

1934 5 21 0 0 0 25 118.2 5.47 0.37 125

1934 11 12 0 0 0 38 -8.5 5.15 0.37 199

1934 11 18 0 0 0 -34.8 149.2 4.99 0.32 27

1935 3 1 0 0 0 40.35 -96.15 4.5 0.32 235

1935 3 21 0 0 0 24.2 89.5 6.08 0.25 118

1935 4 12 0 0 0 -25.5 151.67 5.14 0.37 28

1935 4 18 0 0 0 70.5 -73 5.38 0.37 248

1935 4 19 0 0 0 31.243 15.3 6.62 0.31 90

1935 6 27 0 0 0 48.1 9.5 5.44 0.32 192

1935 7 17 0 0 0 66.05 8.1 5.26 0.37 183

1935 7 20 0 0 0 21 72.4 4.98 0.50 115

1935 11 1 0 0 0 46.885 -79.004 6.06 0.20 226

1935 12 30 0 0 0 48.6 8.2 4.91 0.37 195

1936 1 12 0 0 0 -27 31 4.82 0.32 64

1936 1 16 0 0 0 -29.8 25.3 5.3 0.32 63

1936 4 1 0 0 0 22.5 109.4 6.24 0.32 129

1936 4 26 0 0 0 28.733 103.497 6.72 0.52 131

1936 6 13 0 0 0 32.75 22.5 5.79 0.37 90

1936 6 20 0 0 0 42.4 -9.8 5.56 0.37 199

1937 1 24 0 0 0 56 130 4.76 0.58 147

1937 3 9 0 0 0 40.47 -84.28 5.11 0.32 235

1937 10 28 0 0 0 -26.1 136.5 5.35 0.37 12

1937 12 20 0 0 0 -25.4 136.5 5.55 0.37 12

1938 1 26 0 0 0 33.12 45.87 5.63 0.37 81

1938 3 11 0 0 0 61.7 4.2 4.75 0.37 183

1938 3 14 0 0 0 21.68 75.2 6.26 0.25 106

1938 3 24 0 0 0 -35.5 146 4.97 0.37 27

1938 4 17 0 0 0 -25.5 137.2 5.84 0.25 5

1938 6 11 0 0 0 50.78 3.58 5.28 0.37 187

1938 7 23 0 0 0 22.4 71.8 4.93 0.37 113

1938 9 10 0 0 0 7.7 79.2 5.56 0.37 117

1938 10 16 0 0 0 43.25 -3.62 5.3 0.25 198

1939 1 20 0 0 0 31.03 15.84 5.7 0.37 90

1939 1 23 0 0 0 31.69 16.06 5.95 0.37 90

1939 2 2 0 0 0 31.8 16.8 5.21 0.37 90

1939 3 26 0 0 0 -32 138 5.79 0.37 21

1939 6 22 0 0 0 5.18 -0.13 6.35 0.24 91

1939 6 28 0 0 0 -29 -49 6.08 0.32 46

1939 8 18 0 0 0 6.2 -0.3 5.25 0.37 100

1939 10 19 0 0 0 48.016 -69.734 5.02 0.36 227

1940 1 19 0 0 0 42.7 121.3 5.89 0.37 137

1940 2 27 0 0 0 8.3 -60.8 5.78 0.25 52

1940 5 24 0 0 0 51.467 11.792 4.85 0.37 192

1940 5 29 0 0 0 67 -135 6.21 0.25 241

K-14
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1940 6 23 0 0 0 74.7 -14 5.7 0.37 254

1940 10 31 0 0 0 22.5 70.4 5.71 0.37 113

1940 11 10 0 0 0 -24 30.2 5.16 0.32 65

1940 12 24 0 0 0 43.908 -71.283 5.13 0.47 222

1941 3 4 0 0 0 30.75 15.75 5.17 0.37 90

1941 4 29 0 0 0 -26.791 116.197 6.78 0.25 7

1941 5 4 0 0 0 -26.3 136.9 5.9 0.37 12

1941 5 5 0 0 0 46.5 126.9 6.22 0.25 137

1941 6 27 0 0 0 -25.95 137.34 6.49 0.25 12

1941 9 21 0 0 0 25.1 115.6 5.02 0.32 125

1942 2 14 0 0 0 -29.5 136 4.97 0.37 19

1942 7 8 0 0 0 43.5 121.9 5.71 0.37 137

1943 5 28 0 0 0 48.2 9 5.2 0.37 192

1943 7 16 0 0 0 33 21.5 5.28 0.37 90

1943 11 7 0 0 0 21.6 119.3 4.72 0.45 127

1944 4 9 0 0 0 49.92 -67.43 4.44 0.13 226

1944 6 23 0 0 0 49.42 -67.75 4.79 0.37 226

1944 7 17 0 0 0 35.91 42.55 6.21 0.58 81

1944 9 5 0 0 0 44.958 -74.723 5.71 0.19 226

1944 12 19 0 0 0 39.7 124.3 6.73 0.25 133

1945 9 12 0 0 0 2.5 15.6 5.92 0.27 84

1945 11 8 0 0 0 83 -15 6.16 0.25 251

1946 4 19 0 0 0 -33.5 114.5 4.5 0.70 6

1946 9 14 0 0 0 -40.2 149 5.56 0.37 26

1948 1 21 0 0 0 -31.11 -57.27 4.87 0.32 42

1948 5 23 0 0 0 37.2 121.8 5.71 0.37 133

1948 8 6 0 0 0 -37.36 139.68 5.24 0.37 23

1948 9 26 0 0 0 80.7 99.6 4.97 0.37 170

1949 1 14 0 0 0 33.2 121 5.39 0.37 132

1949 3 10 0 0 0 -34.74 149.2 5.04 0.37 27

1949 5 2 0 0 0 -30.9 116.4 4.6 0.37 7

1949 9 17 0 0 0 3.83 -51.84 5.11 0.32 52

1950 4 14 0 0 0 48 -75.7 4.59 0.37 226

1950 9 30 0 0 0 -30.5 18 4.36 0.45 60

1950 10 28 0 0 0 52.3 79.3 4.56 0.37 157

1951 1 1 0 0 0 47.7 109.9 5.69 0.37 136

1951 3 10 0 0 0 38.18 -3.82 5.47 0.32 200

1951 3 14 0 0 0 50.633 6.717 5.49 0.37 195

1951 4 8 0 0 0 18.5 70.8 4.69 0.45 116

1951 4 19 0 0 0 -19.2 28.8 4.41 0.45 67

1951 4 22 0 0 0 76 -73 5.32 0.37 248

1951 5 28 0 0 0 31.8 27 5.18 0.37 90

1951 6 27 0 0 0 45 -57 4.59 0.37 218

1951 9 17 0 0 0 -18.5 23 5.12 0.50 61

1952 1 28 0 0 0 -32.9 20.5 4.98 0.50 58

1952 3 19 0 0 0 39 125.5 6.2 0.37 133

1952 4 9 0 0 0 35.525 -97.85 5.29 0.12 231

K-15
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1952 4 20 0 0 0 -69.9 157.7 4.60 0.45 208

1952 5 10 0 0 0 -18 22.5 5.25 0.50 61

1952 6 9 0 0 0 -27.5 18.6 5.25 0.50 60

1952 6 24 0 0 0 -25.5 152.8 4.81 0.37 32

1952 9 7 0 0 0 -34.8 149.3 4.66 0.37 27

1952 10 11 0 0 0 -19.3 23.4 5.02 0.45 61

1952 10 14 0 0 0 48.02 -69.78 4.54 0.32 227

1953 2 22 0 0 0 50.917 10 5.09 0.37 192

1953 4 2 0 0 0 -18 27 5.53 0.50 67

1953 5 1 0 0 0 -29 17 5.53 0.50 61

1953 9 28 0 0 0 41.13 -1.58 5.09 0.37 201

1954 2 28 0 0 0 -34.93 138.69 5.09 0.32 21

1954 7 7 0 0 0 59.8 4.8 4.64 0.37 179

1954 8 18 0 0 0 -19.5 23.5 5.25 0.50 61

1954 8 28 0 0 0 45.17 -56.87 4.79 0.37 218

1954 9 19 0 0 0 -28.5 148.6 4.74 0.37 27

1954 10 16 0 0 0 44.83 -56.8 4.86 0.37 218

1954 11 26 0 0 0 -18 13 4.98 0.50 61

1955 1 31 0 0 0 -12.42 -57.3 6.12 0.37 52

1955 3 30 0 0 0 22.4 118.7 4.78 0.37 127

1955 5 26 0 0 0 25.5 105 4.56 0.37 130

1955 6 3 0 0 0 61.9 4.15 5.12 0.37 183

1955 8 23 0 0 0 31.31 71.38 5.56 0.37 113

1955 11 27 0 0 0 -18 25 5.25 0.50 61

1956 1 29 0 0 0 61.5 131.4 4.72 0.37 147

1956 4 9 0 0 0 49 130.5 4.88 0.37 139

1956 6 3 0 0 0 79.5 -118.5 5.77 0.37 250

1956 6 5 0 0 0 56.8 -58.9 4.67 0.37 247

1956 6 29 0 0 0 -5 22 5.02 0.37 73

1956 7 21 0 0 0 23.3 70 5.96 0.17 114

1956 10 10 0 0 0 28.2 77.7 6.05 0.37 113

1956 10 13 0 0 0 48.5 122 4.98 0.44 135

1957 1 4 0 0 0 7.42 -12.52 5.2 0.44 105

1957 2 11 0 0 0 52.86 -1.15 4.66 0.37 187

1957 4 13 0 0 0 -30.18 26.91 5.56 0.37 60

1957 4 16 0 0 0 -9.5 -67 4.92 0.44 51

1957 8 9 0 0 0 62.3 132 4.59 0.37 147

1957 8 25 0 0 0 22 80 4.9 0.37 111

1958 1 1 0 0 0 -42.2 146.1 4.79 0.37 26

1958 1 23 0 0 0 65.19 6.91 5.42 0.37 183

1958 3 2 0 0 0 67 144 4.69 0.37 141

1958 5 14 0 0 0 47.092 -76.818 4.17 0.16 226

1958 5 17 0 0 0 31.81 11.28 5.25 0.37 89

1958 7 8 0 0 0 50.833 10.117 5.15 0.37 192

1958 8 6 0 0 0 59.61 5.94 4.78 0.37 179

1958 9 25 0 0 0 22.5 109.5 4.7 0.32 129

1959 1 2 0 0 0 47.99 -3.99 5.35 0.37 196

K-16
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1959 1 30 0 0 0 61 -78.5 4.46 0.25 237

1959 3 10 0 0 0 -15.31 30.16 5.31 0.37 68

1959 4 14 0 0 0 -14.55 22.11 5.16 0.37 61

1959 5 18 0 0 0 -36.218 148.64 4.61 0.37 27

1959 5 21 0 0 0 -31.4 139 4.64 0.37 21

1959 8 12 0 0 0 -14.96 26.54 5.86 0.37 70

1959 10 12 0 0 0 15.68 80.07 5.15 0.37 117

1959 10 21 0 0 0 65 -87 4.84 0.37 239

1959 11 2 0 0 0 -33.36 135.98 4.64 0.37 19

1959 12 31 0 0 0 43.5 111 4.73 0.37 135

1960 5 12 0 0 0 -9 -72.5 4.92 0.47 51

1960 7 15 0 0 0 -14.15 21.85 4.91 0.37 72

1960 8 26 0 0 0 -11 123.9 5.4 0.37 1

1960 8 27 0 0 0 28.59 76.72 4.7 0.32 113

1960 9 6 0 0 0 64.7 -86.4 4.98 0.37 239

1960 10 19 0 0 0 -21 149.3 4.49 0.32 32

1960 11 5 0 0 0 24 108.5 4.87 0.32 129

1960 12 24 0 0 0 -38.88 143.59 4.79 0.37 23

1961 3 7 0 0 0 30.28 111.2 4.75 0.32 130

1961 5 16 0 0 0 -30.85 147.27 4.61 0.37 27

1961 5 21 0 0 0 -34.547 150.503 5.08 0.37 27

1961 6 12 0 0 0 21.6 106.02 5.53 0.32 130

1961 6 18 0 0 0 -20.1 119.3 4.88 0.37 9

1961 8 23 0 0 0 -18.5 119 4.79 0.37 2

1961 12 28 0 0 0 -28.12 141.57 4.5 0.37 27

1962 3 8 0 0 0 3.73 28.99 5.67 0.37 83

1962 3 18 0 0 0 23.72 114.67 6.00 0.14 125

1962 4 20 0 0 0 24.3 106 4.65 0.32 130

1962 12 15 0 0 0 67.36 13.9 4.73 0.37 179

1962 12 26 0 0 0 39.3 -10.6 5.33 0.32 199

1963 1 18 0 0 0 -32.25 117.17 4.64 0.32 7

1963 2 21 0 0 0 32.6 21 5.71 0.37 90

1963 3 3 0 0 0 36.7 -90 4.62 0.14 230

1963 3 8 0 0 0 76.6 -94.33 5.18 0.37 248

1963 3 14 0 0 0 -25.7 137.4 4.75 0.37 5

1963 4 9 0 0 0 22.5 85.8 4.8 0.70 109

1963 5 8 0 0 0 21.7 84.9 5.1 0.37 109

1963 6 21 0 0 0 47.91 130.61 5.62 0.37 139

1963 6 22 0 0 0 53.1 121.4 5.27 0.37 136

1963 7 13 0 0 0 24.77 70.26 5.61 0.37 113

1963 8 15 0 0 0 56 134.5 4.59 0.37 147

1963 9 4 0 0 0 71.234 -72.998 6.14 0.05 248

1963 9 6 0 0 0 36.47 130.76 5.80 0.05 127

1963 9 23 0 0 0 -16.58 28.46 5.65 0.17 67

1963 10 7 0 0 0 42.9 110.5 5.35 0.37 135

1963 12 14 0 0 0 -2.3 -61.01 5.21 0.20 53

1963 12 26 0 0 0 76.53 23.46 4.62 0.45 169

K-17
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1964 1 8 0 0 0 46.23 -77.53 3.74 0.12 226

1964 2 13 0 0 0 -18.06 -56.69 5.3 0.25 49

1964 3 23 0 0 0 -17.71 123.16 5.26 0.37 11

1964 3 28 0 0 0 42.997 -101.798 4.84 0.32 255

1964 4 15 0 0 0 21.6 88.07 5.25 0.25 118

1964 5 12 0 0 0 -11 126 4.83 0.25 1

1964 6 19 0 0 0 2.55 -59.3 4.56 0.25 52

1964 7 12 0 0 0 53.8 81.4 4.79 0.25 156

1964 7 14 0 0 0 57.03 7.2 4.71 0.25 189

1964 8 10 0 0 0 9.15 -62.02 5.35 0.25 52

1964 9 23 0 0 0 23.73 114.68 4.74 0.32 125

1965 1 25 0 0 0 -31.93 138.49 4.73 0.25 21

1965 2 15 0 0 0 53.65 81.53 5.2 0.25 156

1965 3 2 0 0 0 -30.52 138.22 5.2 0.25 21

1965 3 14 0 0 0 -31.95 138.57 4.93 0.37 21

1965 3 18 0 0 0 -40.29 149.59 4.5 0.37 26

1965 3 26 0 0 0 24.18 69.56 4.75 0.25 114

1965 5 18 0 0 0 -17.6 49.91 5.38 0.14 71

1965 5 19 0 0 0 -25 112.5 5.09 0.25 4

1965 6 3 0 0 0 -28.084 150.217 4.49 0.32 28

1965 8 15 0 0 0 2.71 -60.24 4.96 0.25 52

1965 8 28 0 0 0 -32.23 138.1 4.69 0.25 21

1965 9 10 0 0 0 -18.1 122.2 4.6 0.37 11

1965 9 14 0 0 0 -38.68 144.24 4.94 0.25 23

1965 10 13 0 0 0 71.1 -20 4.83 0.25 254

1965 10 21 0 0 0 37.5 -91 4.61 0.08 230

1966 1 1 0 0 0 42.8 -78.2 4.26 0.08 226

1966 3 22 0 0 0 64.75 -88 4.69 0.37 239

1966 3 26 0 0 0 -18.54 26.39 5.06 0.25 67

1966 4 5 0 0 0 -16.45 28.68 4.71 0.25 67

1966 5 3 0 0 0 -37.042 147.168 4.40 0.17 27

1966 5 27 0 0 0 24.46 68.69 4.96 0.25 113

1966 6 18 0 0 0 -29.52 29.37 4.92 0.25 60

1966 6 23 0 0 0 -14.17 22.03 4.96 0.25 61

1966 8 15 0 0 0 28.67 78.93 5.51 0.25 113

1966 9 26 0 0 0 22.3 117.9 4.88 0.25 127

1966 10 2 0 0 0 43.83 125.12 4.6 0.25 137

1966 10 9 0 0 0 12.63 30.75 5.64 0.37 82

1966 10 12 0 0 0 -11.94 121.77 5.58 0.25 1

1966 11 13 0 0 0 -23.97 111.67 5.1 0.25 4

1966 12 3 0 0 0 -8.8 135.5 4.55 0.25 13

1967 3 20 0 0 0 35.89 44.08 5.01 0.25 81

1967 3 27 0 0 0 15.6 80.1 5.2 0.25 117

1967 4 20 0 0 0 -16.64 28.26 5.14 0.37 67

1967 4 25 0 0 0 18.26 73.3 4.31 0.45 106

1967 6 4 0 0 0 33.6 -90.9 4.29 0.08 225

1967 6 13 0 0 0 42.9 -78.2 4.07 0.08 226

K-18
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1967 6 21 0 0 0 48.7 122 4.63 0.25 135

1967 8 9 0 0 0 39.9 -104.7 4.79 0.15 255

1967 8 21 0 0 0 57.06 4.92 4.67 0.25 194

1967 10 14 0 0 0 -3.32 38.19 5.16 0.14 79

1967 12 10 0 0 0 17.39 73.774 6.27 0.14 106

1967 12 30 0 0 0 20.4 118.2 4.92 0.25 127

1968 1 12 0 0 0 -33.7 25.2 5.01 0.25 59

1968 4 1 0 0 0 25.1 117.6 4.89 0.32 125

1968 5 15 0 0 0 -15.92 26.099 5.70 0.25 61

1968 6 13 0 0 0 23.2 105.2 4.5 0.70 130

1968 7 6 0 0 0 -6.351 133.831 5.64 0.25 16

1968 10 14 0 0 0 -31.522 116.978 6.57 0.08 7

1968 11 9 0 0 0 37.96 -88.46 5.32 0.06 230

1968 12 2 0 0 0 -14.104 23.779 5.47 0.27 61

1968 12 15 0 0 0 -13.47 26.6 4.83 0.25 61

1968 12 31 0 0 0 -31.04 149.26 4.67 0.37 27

1969 4 13 0 0 0 17.838 80.68 5.72 0.10 110

1969 6 17 0 0 0 -25.26 116.73 5.25 0.37 7

1969 6 20 0 0 0 -38.47 146.3 4.79 0.37 26

1969 7 25 0 0 0 21.611 111.803 5.71 0.17 129

1969 8 30 0 0 0 -26.77 26.8 4.9 0.25 63

1969 9 9 0 0 0 -2.602 24.744 5.1 0.25 73

1969 9 11 0 0 0 -33.41 21.8 4.89 0.37 58

1969 9 29 0 0 0 -33.191 19.335 6.38 0.10 58

1969 9 29 0 0 0 65.1 6.5 4.75 0.25 183

1969 10 24 0 0 0 24.76 72.54 5.01 0.25 113

1969 11 20 0 0 0 37.4 -81 4.5 0.14 224

1969 12 17 0 0 0 18.11 110.55 4.79 0.25 127

1970 1 22 0 0 0 48.328 9.094 4.52 0.25 192

1970 2 8 0 0 0 -27.4 125.073 4.33 0.45 3

1970 2 13 0 0 0 24.603 68.617 4.88 0.25 113

1970 3 8 0 0 0 55 -116.6 4.75 0.25 242

1970 3 10 0 0 0 -31.093 116.513 5.46 0.25 7

1970 3 23 0 0 0 21.7 73 5.37 0.10 115

1970 3 24 0 0 0 -22.053 126.666 6.03 0.08 9

1970 4 14 0 0 0 -33.17 19.47 5.69 0.20 58

1970 6 15 0 0 0 -25.97 28.18 4.55 0.37 63

1970 7 25 0 0 0 25.711 88.496 5.06 0.25 112

1970 8 22 0 0 0 -26.36 27.38 4.52 0.37 63

1970 8 29 0 0 0 51.1 135.1 5.3 0.25 139

1970 10 14 0 0 0 31.226 74.34 5.1 0.25 113

1970 10 31 0 0 0 -26.78 26.85 4.62 0.37 63

1970 11 19 0 0 0 -22.19 30.73 4.78 0.37 66

1970 12 2 0 0 0 68.5 -67.55 5.06 0.15 248

1971 2 22 0 0 0 -18.425 26.474 4.87 0.25 67

1971 7 6 0 0 0 -38.423 145.113 4.45 0.32 26

1971 7 26 0 0 0 -31.37 138.76 4.5 0.37 21

K-19
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1971 8 16 0 0 0 28.879 103.673 5.4 0.25 131

1971 10 2 0 0 0 64.4 -86.5 4.68 0.05 239

1971 11 26 0 0 0 79.438 -17.766 5.06 0.25 253

1971 12 7 0 0 0 55.082 -54.352 5.52 0.15 247

1972 1 15 0 0 0 57.5 121.1 4.63 0.25 147

1972 1 21 0 0 0 71.84 -74.96 4.56 0.15 248

1972 2 3 0 0 0 33.31 -80.58 4.31 0.15 218

1972 2 25 0 0 0 -34.22 147.47 4.5 0.37 27

1972 4 5 0 0 0 23 118.3 4.85 0.37 127

1972 4 14 0 0 0 40.1 122.5 4.45 0.25 133

1972 4 18 0 0 0 -31.58 138.62 4.87 0.32 21

1972 8 9 0 0 0 56.9 127.7 5.15 0.19 147

1972 8 28 0 0 0 -24.992 136.326 5.28 0.10 5

1972 9 2 0 0 0 31.39 16.09 5.53 0.19 90

1972 9 7 0 0 0 45.99 -1.5 5.01 0.25 196

1972 9 30 0 0 0 79.88 -107.72 4.49 0.25 250

1972 10 21 0 0 0 -24.88 115.55 4.71 0.37 3

1972 10 24 0 0 0 -21.8 -40.5 4.83 0.25 46

1972 12 18 0 0 0 -16.7 28.1 5.57 0.17 67

1972 12 27 0 0 0 76.759 -107.093 6.10 0.30 249

1973 3 9 0 0 0 -34.14 150.29 5.06 0.19 27

1973 3 11 0 0 0 -21.96 127.44 4.34 0.45 13

1973 6 15 0 0 0 45.3 -70.9 4.48 0.08 222

1973 12 15 0 0 0 74.2 147.1 4.86 0.25 144

1974 2 1 0 0 0 -17.882 26.05 4.65 0.37 61

1974 3 17 0 0 0 13.32 30.88 4.8 0.25 82

1974 4 3 0 0 0 38.6 -88.1 4.29 0.15 230

1974 4 22 0 0 0 31.6 119.1 5.31 0.10 132

1974 5 10 0 0 0 28.181 103.994 6.8 0.25 131

1974 8 1 0 0 0 -16.652 28.004 4.96 0.25 67

1974 9 4 0 0 0 33.103 13.411 5.68 0.10 90

1974 9 23 0 0 0 -0.296 12.758 5.98 0.05 73

1974 9 27 0 0 0 2.646 -71.355 5.9 0.19 52

1974 10 8 0 0 0 60.6 118.5 4.75 0.25 148

1974 10 15 0 0 0 -70.55 161.3 4.75 0.25 208

1974 11 17 0 0 0 -22 126.53 4.94 0.25 9

1974 12 24 0 0 0 -21.81 153.21 4.59 0.37 32

1975 3 6 0 0 0 -17.08 126.38 4.91 0.32 14

1975 3 8 0 0 0 79.82 -94.07 5.03 0.19 249

1975 4 15 0 0 0 9.42 -61.47 5.27 0.19 52

1975 6 23 0 0 0 50.592 9.859 4.57 0.32 195

1975 6 30 0 0 0 71.44 -71.19 4.75 0.25 248

1975 7 24 0 0 0 -21.09 120.47 4.49 0.37 10

1975 9 2 0 0 0 32.83 121.83 4.93 0.19 132

1975 10 3 0 0 0 -22.21 126.58 4.95 0.25 9

1975 10 6 0 0 0 44.71 -57.07 5.06 0.14 218

1976 1 18 0 0 0 77.816 18.466 5.98 0.19 181

K-20
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1976 1 22 0 0 0 8.8 -60.3 4.32 0.45 52

1976 2 19 0 0 0 66.41 -135.28 4.94 0.19 241

1976 3 12 0 0 0 -0.487 12.624 5.06 0.25 73

1976 3 25 0 0 0 35.59 -90.48 4.62 0.08 228

1976 5 15 0 0 0 4.461 19.348 5.43 0.14 84

1976 6 4 0 0 0 24.575 68.41 5.23 0.19 113

1976 6 23 0 0 0 21.415 88.79 5.06 0.25 118

1976 7 1 0 0 0 -29.559 25.112 5.74 0.10 63

1976 8 28 0 0 0 43.88 114.17 4.45 0.25 135

1976 10 6 0 0 0 35.296 124.297 5.32 0.19 132

1976 12 8 0 0 0 -27.91 26.71 5.1 0.25 63

1977 3 24 0 0 0 51.48 16.05 4.64 0.19 192

1977 4 6 0 0 0 61.605 2.466 4.67 0.25 188

1977 8 2 0 0 0 -0.1 -50 4.67 0.25 54

1977 10 19 0 0 0 23.229 107.594 5.06 0.19 130

1978 1 10 0 0 0 3.51 -73.64 4.88 0.25 51

1978 2 5 0 0 0 78.24 -107.33 5.08 0.14 249

1978 5 1 0 0 0 -23.64 115.59 4.76 0.32 3

1978 5 6 0 0 0 -19.55 126.56 4.89 0.37 11

1978 6 16 0 0 0 33.01 -100.72 4.49 0.10 231

1978 9 3 0 0 0 48.283 9.033 5.04 0.17 192

1978 11 28 0 0 0 -23.34 152.52 4.94 0.25 32

1978 12 9 0 0 0 23.951 26.353 5.11 0.19 82

1979 2 6 0 0 0 48.9 116.8 5.02 0.19 136

1979 2 12 0 0 0 -17.34 -63.63 4.92 0.25 51

1979 4 23 0 0 0 -16.616 120.163 6.12 0.08 1

1979 5 21 0 0 0 31.08 110.5 4.92 0.25 130

1979 6 2 0 0 0 -30.818 117.105 6.08 0.05 7

1979 6 27 0 0 0 70.03 -96.48 4.96 0.14 239

1979 7 9 0 0 0 31.45 119.25 5.44 0.08 132

1979 7 14 0 0 0 -18.42 122.82 5.03 0.14 9

1979 8 19 0 0 0 47.672 -69.901 4.72 0.12 227

1979 12 26 0 0 0 54.903 -2.683 4.5 0.25 185

1980 1 7 0 0 0 40.26 125.11 5.09 0.17 133

1980 2 10 0 0 0 48.9 122.02 5.04 0.17 135

1980 3 6 0 0 0 -6.17 -71.16 4.83 0.25 51

1980 7 27 0 0 0 38.18 -83.94 5.01 0.13 226

1980 9 2 0 0 0 17.179 73.707 5.49 0.19 106

1980 11 12 0 0 0 -8.04 -50.14 4.79 0.25 52

1980 11 20 0 0 0 -4.3 -38.4 5.19 0.08 56

1981 3 3 0 0 0 31.39 73.216 4.98 0.19 113

1981 4 25 0 0 0 48.93 121.952 5.02 0.19 135

1981 6 16 0 0 0 -38.913 144.262 4.81 0.37 23

1981 6 18 0 0 0 -10.328 135.476 4.94 0.25 13

1981 8 18 0 0 0 65.67 -90.5 4.6 0.25 239

1981 9 3 0 0 0 69.62 13.68 4.75 0.25 183

1981 11 18 0 0 0 -2.282 22.813 5.53 0.14 73

K-21
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1981 11 21 0 0 0 79.52 -108.11 4.7 0.19 249

1981 12 15 0 0 0 -65.74 133.6 4.75 0.25 213

1982 1 9 0 0 0 46.98 -66.66 5.47 0.05 222

1982 2 13 0 0 0 -22.096 126.643 4.74 0.25 9

1982 2 14 0 0 0 38.27 125.68 5.17 0.15 132

1982 2 28 0 0 0 37.04 129.6 4.83 0.25 127

1982 4 8 0 0 0 -24.8 -58.1 4.96 0.19 41

1982 4 13 0 0 0 -27.926 26.783 4.88 0.25 63

1982 5 1 0 0 0 31.583 71.41 5.31 0.19 113

1982 6 28 0 0 0 50.733 7.804 4.51 0.37 195

1982 7 29 0 0 0 60.118 2.151 4.79 0.25 188

1982 10 27 0 0 0 23.951 106.049 5.19 0.14 130

1982 11 3 0 0 0 -20.53 120.48 4.69 0.37 9

1982 11 4 0 0 0 -80.79 36.9 4.52 0.25 202

1982 11 21 0 0 0 -37.205 146.956 4.60 0.15 27

1983 1 26 0 0 0 -30.73 117.13 4.96 0.25 7

1983 2 8 0 0 0 -26.26 -59.89 4.88 0.25 41

1983 3 8 0 0 0 59.74 5.38 3.28 0.32 179

1983 8 5 0 0 0 -3.59 -62.17 5.39 0.19 52

1983 9 20 0 0 0 -68.87 122.1 4.45 0.25 202

1983 10 7 0 0 0 43.938 -74.258 4.84 0.05 226

1983 11 8 0 0 0 50.63 5.5 4.68 0.20 187

1983 12 22 0 0 0 11.863 -13.512 6.21 0.12 105

1983 12 25 0 0 0 -5.09 -73.42 5.1 0.19 51

1983 12 29 0 0 0 -30.79 138.4 4.62 0.37 21

1984 3 16 0 0 0 -14.95 123.38 4.64 0.25 14

1984 5 19 0 0 0 -67.43 113 4.91 0.17 202

1984 5 21 0 0 0 32.694 121.513 6.06 0.10 132

1984 7 19 0 0 0 52.958 -4.398 4.95 0.19 185

1984 8 31 0 0 0 -10.698 126.349 4.5 0.70 1

1984 9 8 0 0 0 44.24 -106.019 4.90 0.14 238

1984 10 26 0 0 0 -16.465 28.667 5.29 0.14 67

1984 11 29 0 0 0 -11.614 123.952 4.84 0.25 1

1985 3 13 0 0 0 -15.45 121.853 4.83 0.37 1

1985 4 12 0 0 0 -23.94 -60.55 5.09 0.14 41

1985 4 19 0 0 0 -10.552 124.403 5.05 0.25 1

1985 5 26 0 0 0 37.84 -4.69 4.96 0.19 200

1985 7 23 0 0 0 -19.14 126.77 4.64 0.25 13

1985 7 28 0 0 0 -32.51 122.22 5.13 0.19 8

1985 10 4 0 0 0 -18.304 48.433 5.53 0.14 71

1985 10 23 0 0 0 -11.109 125.159 5.77 0.10 1

1985 12 21 0 0 0 50.14 12.44 4.65 0.32 193

1986 1 2 0 0 0 -34.484 112.098 5.56 0.19 6

1986 1 31 0 0 0 41.65 -81.162 4.65 0.20 226

1986 2 5 0 0 0 62.68 5.05 4.69 0.10 183

1986 2 10 0 0 0 -27.944 26.735 4.88 0.25 63

1986 3 30 0 0 0 -26.31 132.741 5.76 0.05 9

K-22
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1986 4 20 0 0 0 57.4 -59.6 5.07 0.20 247

1986 7 18 0 0 0 -16.356 28.502 5.19 0.14 67

1986 8 1 0 0 0 73.031 56.726 4.68 0.19 156

1986 8 15 0 0 0 48.638 126.621 4.95 0.14 137

1986 10 5 0 0 0 -30.546 28.737 5.33 0.14 60

1986 10 22 0 0 0 22.42 118.79 5.01 0.19 127

1986 11 30 0 0 0 -5.5 -35.75 5.08 0.14 56

1987 1 9 0 0 0 -20.11 133.636 5.40 0.14 13

1987 1 26 0 0 0 6.373 12.453 4.89 0.14 85

1987 2 17 0 0 0 33.69 120.66 5.1 0.19 132

1987 3 5 0 0 0 52.48 132.64 5.04 0.19 136

1987 4 18 0 0 0 22.346 79.259 4.79 0.25 111

1987 6 10 0 0 0 38.713 -87.954 4.95 0.08 230

1987 8 2 0 0 0 24.924 115.608 4.99 0.10 125

1987 9 5 0 0 0 22.5 118.73 4.98 0.19 127

1987 12 13 0 0 0 74.46 -93.71 5.35 0.14 248

1987 12 22 0 0 0 -36.11 141.54 4.75 0.19 31

1988 1 3 0 0 0 -14.31 25.4 4.52 0.25 61

1988 1 5 0 0 0 -26.807 26.64 4.92 0.25 63

1988 1 7 0 0 0 0.56 18.43 4.71 0.25 73

1988 1 22 0 0 0 -19.896 133.856 6.56 0.05 13

1988 1 28 0 0 0 32.33 21.2 5.3 0.25 90

1988 1 28 0 0 0 48 -65.58 3.55 0.06 222

1988 1 31 0 0 0 67.81 10.2 4.67 0.25 183

1988 2 6 0 0 0 -16.679 124.663 5.09 0.14 13

1988 3 10 0 0 0 -17.2 13.4 4.52 0.25 61

1988 3 26 0 0 0 33.2 13.34 5.2 0.37 90

1988 6 15 0 0 0 -31.51 126.51 4.88 0.25 19

1988 6 26 0 0 0 -36.27 -52.73 5 0.19 46

1988 8 8 0 0 0 63.673 2.397 5.53 0.17 183

1988 9 6 0 0 0 61.33 47.98 4.85 0.25 167

1988 9 12 0 0 0 -26.89 26.65 4.6 0.25 63

1988 9 30 0 0 0 -20.08 133.84 5.25 0.25 13

1988 11 10 0 0 0 21.2 108.57 4.6 0.25 129

1988 11 25 0 0 0 48.056 -71.28 5.84 0.08 226

1988 12 31 0 0 0 -26.88 26.64 4.8 0.25 63

1989 1 4 0 0 0 -7.486 133.25 4.67 0.25 1

1989 1 12 0 0 0 40.42 122.66 4.83 0.25 133

1989 1 23 0 0 0 61.949 4.504 5.12 0.10 183

1989 1 25 0 0 0 -27.96 26.72 5.14 0.19 63

1989 1 29 0 0 0 59.45 5.9 4.75 0.25 179

1989 3 10 0 0 0 -5.81 -35.56 5.17 0.19 56

1989 3 13 0 0 0 50.72 9.91 5.22 0.19 195

1989 3 16 0 0 0 -16.927 -65.005 5.22 0.14 51

1989 3 16 0 0 0 59.93 -69.66 4.97 0.17 239

1989 3 23 0 0 0 -11.148 123.737 4.75 0.25 1

1989 3 26 0 0 0 -5.05 -37.6 4.7 0.25 56

K-23
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1989 4 7 0 0 0 -12.516 122.161 5.1 0.25 1

1989 4 8 0 0 0 39.45 -8.92 4.89 0.19 199

1989 5 14 0 0 0 50.87 51.4 4.52 0.25 161

1989 5 28 0 0 0 -25.07 130.78 5.57 0.19 12

1989 6 5 0 0 0 -11.97 14.59 4.96 0.25 72

1989 6 12 0 0 0 21.829 89.754 5.76 0.08 118

1989 6 18 0 0 0 -12.449 121.52 5.20 0.14 1

1989 6 29 0 0 0 51.44 16.07 4.55 0.25 192

1989 7 18 0 0 0 76.865 12.972 4.88 0.19 182

1989 9 29 0 0 0 -30.6 28.7 4.82 0.19 60

1989 10 13 0 0 0 -17.59 122.4 5.47 0.14 11

1989 10 25 0 0 0 57.519 118.811 5.38 0.16 147

1989 10 28 0 0 0 51.6 16.01 4.67 0.25 192

1989 11 20 0 0 0 29.882 106.804 5.14 0.19 131

1989 11 25 0 0 0 23.72 114.52 5.40 0.27 125

1989 12 10 0 0 0 24.81 70.89 4.67 0.25 113

1989 12 25 0 0 0 60.045 -73.538 6.03 0.08 236

1989 12 27 0 0 0 -32.94 151.56 5.28 0.27 27

1990 1 17 0 0 0 -31.68 116.99 5.1 0.25 7

1990 2 7 0 0 0 -26.8301 26.6818 4.5 0.37 63

1990 2 9 0 0 0 31.72 121.03 4.92 0.19 132

1990 2 12 0 0 0 -31.22 -48.9 5.15 0.19 46

1990 2 14 0 0 0 -26.29 27.43 4.5 0.25 63

1990 2 20 0 0 0 32.5564 44.2181 4.6 0.25 81

1990 3 3 0 0 0 -26.9543 26.72 4.9 0.37 63

1990 3 13 0 0 0 -4.03 39.93 5.49 0.14 80

1990 4 2 0 0 0 52.32 -3 4.65 0.25 185

1990 5 20 0 0 0 5.121 32.145 7.22 0.15 82

1990 5 25 0 0 0 8.259 32.9262 4.7 0.25 82

1990 5 28 0 0 0 55.15 58.63 4.6 0.25 159

1990 6 9 0 0 0 75.12 113.1 4.75 0.25 152

1990 6 24 0 0 0 -17.6407 27.7695 4.5 0.25 67

1990 7 18 0 0 0 -26.8569 26.6248 4.6 0.25 63

1990 7 28 0 0 0 74.8794 -79.9866 4.5 0.37 248

1990 9 20 0 0 0 4.2221 9.0551 4.5 0.37 85

1990 9 26 0 0 0 -28.014 26.727 4.97 0.14 63

1990 10 19 0 0 0 46.4373 -75.5759 4.53 0.20 226

1990 10 24 0 0 0 73.3597 54.6741 5.1 0.47 156

1990 11 11 0 0 0 33.94 12.04 5.15 0.14 90

1990 11 29 0 0 0 78.4481 -108.4902 4.7 0.25 249

1990 12 6 0 0 0 -26.35 27.31 4.5 0.25 63

1990 12 31 0 0 0 47.7018 -72.6666 4.16 0.15 226

1991 1 13 0 0 0 65.628 -37.5123 4.6 0.25 239

1991 1 24 0 0 0 -13.1283 23.1763 4.8 0.25 61

1991 2 4 0 0 0 60.9412 -43.3441 4.9 0.25 244

1991 2 12 0 0 0 71.4432 -75.0874 5 0.37 248

1991 2 27 0 0 0 25.6762 103.9086 4.8 0.25 130

K-24
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1991 4 19 0 0 0 -4.006 -39.7315 4.7 0.25 56

1991 4 26 0 0 0 20.8118 89.6729 4.7 0.25 118

1991 5 10 0 0 0 -17.3484 24.982 4.7 0.25 61

1991 6 10 0 0 0 -26.8689 26.7138 4.7 0.25 63

1991 6 19 0 0 0 -20.0685 133.9655 5.1 0.25 13

1991 9 10 0 0 0 24.1675 68.6842 4.9 0.25 114

1991 9 30 0 0 0 43.0932 112.5325 4.8 0.25 134

1991 11 3 0 0 0 -26.8912 26.6395 4.9 0.37 63

1991 11 3 0 0 0 28.3437 104.0239 4.5 0.37 131

1991 11 8 0 0 0 26.28 70.58 5.36 0.14 113

1992 1 2 0 0 0 32.3641 -102.9665 4.66 0.16 231

1992 1 4 0 0 0 66.84 -94.46 5.37 0.17 239

1992 1 22 0 0 0 35.3276 121.09 5.02 0.10 132

1992 3 7 0 0 0 -26.4414 27.3387 4.9 0.25 63

1992 4 13 0 0 0 51.16 5.82 5.31 0.10 195

1992 4 17 0 0 0 -20.0236 133.7528 4.6 0.25 13

1992 6 6 0 0 0 -27.9762 26.7805 5 0.37 63

1992 6 12 0 0 0 44.2414 116.2393 4.6 0.37 135

1992 6 13 0 0 0 -23.8616 130.0962 5 0.25 12

1992 7 1 0 0 0 -19.0302 111.8556 4.5 0.25 2

1992 7 9 0 0 0 20.98 89.96 5.3 0.25 118

1992 7 9 0 0 0 -5.5221 137.9927 4.7 0.25 16

1992 7 15 0 0 0 -22.4264 126.5028 4.9 0.25 9

1992 8 31 0 0 0 43.93 106.92 5.33 0.14 135

1992 9 2 0 0 0 45.5822 117.9208 4.7 0.25 135

1992 9 18 0 0 0 21.286 117.6981 5.1 0.47 127

1992 9 29 0 0 0 34.501 14.4913 5.1 0.37 90

1992 9 30 0 0 0 -11.349 134.5335 5.26 0.17 17

1992 10 23 0 0 0 31.35 -4.33 5.55 0.04 95

1992 11 3 0 0 0 35.3446 123.2905 4.57 0.10 132

1992 11 8 0 0 0 61.9791 2.6797 4.5 0.37 183

1992 11 28 0 0 0 -26.9957 26.5164 4.6 0.37 63

1992 12 23 0 0 0 -23.8258 17.3111 4.8 0.25 61

1993 2 4 0 0 0 -7.9448 134.1146 4.8 0.37 13

1993 2 8 0 0 0 -8.8653 133.8904 4.8 0.37 13

1993 2 20 0 0 0 -7.7297 22.3845 4.6 0.25 73

1993 2 21 0 0 0 -20.1311 133.733 5 0.37 13

1993 2 23 0 0 0 -26.3566 27.3881 4.5 0.37 63

1993 3 13 0 0 0 71.211 -71.8438 4.9 0.25 248

1993 3 28 0 0 0 32.9404 123.7381 5 0.25 128

1993 5 5 0 0 0 30.0425 108.2326 4.5 0.37 131

1993 5 16 0 0 0 23.1388 86.8324 4.5 0.25 111

1993 6 2 0 0 0 28.91 47.5708 4.6 0.37 81

1993 6 15 0 0 0 79.7807 -16.6234 4.5 0.25 253

1993 6 30 0 0 0 51.4914 16.0949 4.5 0.25 192

1993 7 18 0 0 0 17.9312 -93.1846 4.5 0.25 215

1993 8 1 0 0 0 15.4 31.67 5.49 0.13 82

K-25
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1993 8 10 0 0 0 83.03 -27.92 5.56 0.14 251

1993 8 18 0 0 0 -26.9049 26.6872 4.6 0.25 63

1993 8 24 0 0 0 20.6973 71.4408 5.1 0.37 116

1993 8 28 0 0 0 17.2402 73.7331 5.1 0.25 106

1993 8 29 0 0 0 -26.3489 27.3139 5.2 0.47 63

1993 9 3 0 0 0 19.8473 -13.0178 4.6 0.25 98

1993 9 9 0 0 0 32.2394 20.3859 4.8 0.25 90

1993 9 13 0 0 0 66.3237 5.8379 4.8 0.47 183

1993 9 29 0 0 0 18.077 76.486 6.2 0.37 106

1993 10 13 0 0 0 28.6253 103.3757 4.8 0.25 131

1993 11 1 0 0 0 51.625 16.0294 4.6 0.37 192

1993 12 6 0 0 0 6.8278 78.3202 5.3 0.25 117

1993 12 18 0 0 0 -11.8274 133.8567 4.8 0.37 13

1993 12 20 0 0 0 -26.9098 26.7103 4.7 0.25 63

1993 12 30 0 0 0 38.1635 122.7901 4.6 0.25 133

1994 2 6 0 0 0 3.5021 27.5524 5 0.37 73

1994 2 8 0 0 0 -19.9992 133.5254 5.1 0.25 13

1994 2 11 0 0 0 64.9006 -52.0772 4.6 0.37 246

1994 3 2 0 0 0 26.32 118.64 4.8 0.25 125

1994 5 5 0 0 0 51.648 133.3765 4.9 0.25 139

1994 5 10 0 0 0 -26.8869 26.7634 4.7 0.25 63

1994 6 4 0 0 0 49.0688 129.811 4.5 0.37 139

1994 7 25 0 0 0 34.97 124.43 5.14 0.16 132

1994 8 1 0 0 0 47.994 67.5271 5 0.25 158

1994 8 6 0 0 0 -32.9377 151.1628 5 0.25 27

1994 8 31 0 0 0 25.8963 78.6269 4.8 0.25 112

1994 10 2 0 0 0 -26.4123 27.4682 4.7 0.25 63

1994 10 30 0 0 0 -28.0213 26.7184 5.3 0.25 63

1994 11 30 0 0 0 -30.6245 137.608 4.9 0.25 21

1994 12 29 0 0 0 29.09 103.85 5.12 0.12 131

1995 1 5 0 0 0 59.6137 56.6197 4.9 0.25 166

1995 1 10 0 0 0 20.4195 109.4385 5.53 0.04 126

1995 1 15 0 0 0 20.69 109.8 5 0.25 126

1995 2 10 0 0 0 -26.8338 26.669 4.8 0.37 63

1995 2 25 0 0 0 24.3716 118.6643 5 0.25 127

1995 2 27 0 0 0 -2.9306 39.9749 4.8 0.25 80

1995 3 8 0 0 0 82.3577 -71.7175 5 0.25 249

1995 3 12 0 0 0 17.3784 73.9096 4.6 0.25 106

1995 4 14 0 0 0 30.2885 -103.3188 5.64 0.05 226

1995 4 28 0 0 0 -6.2142 -73.2034 4.6 0.25 51

1995 6 3 0 0 0 47.138 -76.2833 3.28 0.17 226

1995 6 14 0 0 0 -20.149 133.7148 4.8 0.37 13

1995 6 21 0 0 0 21.7637 85.286 4.5 0.47 109

1995 7 4 0 0 0 79.9971 94.8377 5 0.37 154

1995 7 24 0 0 0 38.0329 124.285 5.1 0.25 133

1995 8 25 0 0 0 -23.7538 112.1831 4.6 0.25 4

1995 9 22 0 0 0 1.0903 19.3548 5.24 0.22 73

K-26
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1995 10 20 0 0 0 61.5656 116.4441 4.8 0.25 149

1995 10 28 0 0 0 -26.3378 27.5454 4.7 0.25 63

1995 10 30 0 0 0 -49.6603 -42.775 4.6 0.25 35

1995 11 14 0 0 0 68.41 51.61 4.8 0.25 168

1995 11 25 0 0 0 -26.9224 26.6805 4.8 0.37 63

1995 11 29 0 0 0 42.9189 -7.2295 5 0.25 200

1995 12 5 0 0 0 57.6977 107.0928 4.7 0.25 149

1995 12 17 0 0 0 -27.9673 26.6594 4.5 0.25 63

1996 1 14 0 0 0 51.5986 16.1205 4.5 0.37 192

1996 1 15 0 0 0 52.9635 83.7387 4.5 0.25 156

1996 2 7 0 0 0 27.4584 106.5679 4.7 0.25 130

1996 2 28 0 0 0 29.0782 104.7045 5.2 0.25 131

1996 3 29 0 0 0 82.8988 -43.6804 5 0.25 251

1996 6 9 0 0 0 -34.1658 135.8155 4.5 0.25 19

1996 6 15 0 0 0 51.5675 16.2235 5.2 0.37 192

1996 6 26 0 0 0 -18.3579 48.4751 4.98 0.50 71

1996 7 22 0 0 0 44.2 -105.68 4.6 0.37 238

1996 8 13 0 0 0 -30.0363 143.5507 4.9 0.25 27

1996 9 8 0 0 0 -4.4521 -76.7274 4.6 0.37 51

1996 9 11 0 0 0 51.4666 11.7071 4.8 0.37 192

1996 9 16 0 0 0 -26.857 26.7031 4.5 0.25 63

1996 9 25 0 0 0 -37.7783 146.258 4.7 0.25 27

1996 10 30 0 0 0 32.4343 20.5326 4.7 0.25 90

1996 11 9 0 0 0 31.6311 123.3463 5.59 0.03 128

1996 12 11 0 0 0 -27.8959 26.729 4.7 0.25 63

1996 12 13 0 0 0 37.1873 128.7499 5 0.25 128

1997 1 23 0 0 0 17.1421 76.6916 4.7 0.25 106

1997 2 10 0 0 0 -26.933 26.7087 5 0.37 63

1997 3 5 0 0 0 -33.7067 138.9698 4.8 0.25 21

1997 5 2 0 0 0 28.94 122.77 4.5 0.25 125

1997 5 21 0 0 0 23.062 80.088 5.81 0.02 111

1997 5 21 0 0 0 42.85 -7.1535 5.33 0.15 200

1997 6 15 0 0 0 23.98 89.91 4.6 0.37 118

1997 7 21 0 0 0 -26.8706 26.7773 4.7 0.25 63

1997 7 27 0 0 0 33.5481 122.2349 5.1 0.68 132

1997 7 29 0 0 0 -27.9521 26.6442 5.1 0.37 63

1997 8 10 0 0 0 -16.154 124.338 6.24 0.02 14

1997 8 13 0 0 0 29.4139 105.6148 4.9 0.25 131

1997 9 11 0 0 0 -3.6376 -76.9265 4.9 0.37 51

1997 9 11 0 0 0 -31.4593 117.5452 4.6 0.37 7

1997 9 22 0 0 0 54.7642 19.6155 4.7 0.37 175

1997 9 25 0 0 0 -26.372 27.3481 4.7 0.25 63

1997 10 3 0 0 0 -22.7886 147.1643 4.6 0.37 27

1997 10 11 0 0 0 -10.6132 24.6701 4.8 0.25 77

1997 10 24 0 0 0 31.1933 -87.1997 4.88 0.10 217

1997 11 6 0 0 0 46.7275 -71.3546 4.41 0.12 222

1997 12 6 0 0 0 64.904 -88.0878 5.2 0.25 239

K-27
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

1997 12 11 0 0 0 -26.8974 26.6575 4.5 0.25 63

1998 3 3 0 0 0 -3.7548 -77.322 4.6 0.37 51

1998 3 5 0 0 0 0.8049 17.3948 4.98 0.21 73

1998 3 10 0 0 0 -11.745 -56.9634 5.2 0.25 52

1998 3 29 0 0 0 -12.3957 139.2206 5.1 0.25 13

1998 4 12 0 0 0 -12.4435 25.5442 4.8 0.37 61

1998 4 16 0 0 0 25.0379 107.9586 4.7 0.25 129

1998 4 16 0 0 0 25.2458 108.2534 4.5 0.25 129

1998 5 11 0 0 0 27.0812 71.7594 4.8 0.25 113

1998 5 28 0 0 0 31.4459 27.6426 5.50 0.03 90

1998 6 3 0 0 0 29.15 103.19 4.6 0.25 131

1998 7 13 0 0 0 -27.9098 26.8024 4.5 0.25 63

1998 8 29 0 0 0 43.445 109.0753 4.8 0.25 135

1998 9 24 0 0 0 46.3059 106.3265 5.56 0.03 136

1998 9 25 0 0 0 41.4444 -80.3388 4.55 0.17 226

1998 10 14 0 0 0 60.6616 -44.0581 4.99 0.15 244

1998 11 2 0 0 0 -19.8618 113.8855 4.5 0.37 2

1998 11 5 0 0 0 27.0812 71.7594 4.8 0.25 113

1998 11 17 0 0 0 -26.8668 26.6823 4.5 0.25 63

1998 12 1 0 0 0 26.385 103.938 4.9 0.37 130

1998 12 5 0 0 0 -26.2962 27.5215 4.6 0.25 63

1998 12 22 0 0 0 79.9756 -90.6722 4.8 0.25 249

1999 1 1 0 0 0 80.003 -111.51 5.00 0.24 250

1999 1 5 0 0 0 4.239 44.062 5.6 0.37 79

1999 1 18 0 0 0 33.408 -87.258 4.7 0.25 224

1999 1 25 0 0 0 43.67 -105.094 4.5 0.37 238

1999 1 27 0 0 0 -22.221 16.291 5.1 0.37 61

1999 1 29 0 0 0 2.12 45.721 5.4 0.25 80

1999 1 29 0 0 0 44.648 115.721 5 0.25 135

1999 2 10 0 0 0 32.944 15.277 4.7 0.25 90

1999 2 14 0 0 0 -19.27 21.256 4.6 0.37 61

1999 3 9 0 0 0 -10.8895 128.7734 5.5 0.25 1

1999 4 15 0 0 0 -20.124 134.061 4.7 0.25 13

1999 4 22 0 0 0 -27.939 26.675 5.3 0.25 63

1999 7 18 0 0 0 -6.3221 141.8213 4.8 0.37 16

1999 8 6 0 0 0 -8.543 21.517 4.5 0.25 72

1999 8 17 0 0 0 29.406 105.607 4.8 0.47 131

1999 8 17 0 0 0 67.813 34.498 4.5 0.47 171

1999 8 28 0 0 0 22.915 89.795 4.8 0.25 118

1999 12 7 0 0 0 75.588 -121.197 4.9 0.25 249

1999 12 30 0 0 0 43.735 -105.137 4.9 0.37 238

2000 1 1 0 0 0 46.875 -78.756 4.62 0.11 226

2000 2 8 0 0 0 -26.438 27.474 4.5 0.25 63

2000 3 12 0 0 0 17.244 73.707 4.87 0.28 106

2000 4 11 0 0 0 51.418 16.043 4.7 0.25 192

2000 7 13 0 0 0 -26.383 27.537 4.7 0.25 63

2000 8 13 0 0 0 21.212 71.105 4.7 0.25 113

K-28
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

2000 9 5 0 0 0 17.332 73.79 5.17 0.15 106

2000 9 5 0 0 0 1.029 25.835 4.5 0.2 78

2000 10 11 0 0 0 -20.065 112.905 4.93 0.27 2

2000 11 8 0 0 0 77.042 -77.829 6 0.25 248

2000 12 8 0 0 0 59.749 1.924 4.9 0.25 188

2000 12 23 0 0 0 -7.832 135.889 6 0.47 13

2001 1 22 0 0 0 65.879 -52.497 4.7 0.25 246

2001 1 24 0 0 0 -26.742 26.844 4.8 0.37 63

2001 1 26 0 0 0 23.442 70.31 7.6 0.25 114

2001 2 3 0 0 0 -16.906 28.542 4.9 0.25 67

2001 2 28 0 0 0 18.1 -87.9 5.4 0.25 214

2001 3 18 0 0 0 -14.4643 137.0496 5.6 0.37 13

2001 4 5 0 0 0 -15.5248 122.6804 5.3 0.37 13

2001 4 9 0 0 0 43.783 -105.109 4.8 0.37 238

2001 4 12 0 0 0 60.3706 64.5696 5.7 0.37 159

2001 4 14 0 0 0 56.04 -119.583 5.27 0.04 242

2001 4 17 0 0 0 -6.196 22.71 4.7 0.25 73

2001 4 21 0 0 0 46.2 -105.4 5.3 0.25 238

2001 5 2 0 0 0 49.91 130.15 5 0.37 139

2001 5 5 0 0 0 18 -90.6 5.3 0.25 214

2001 5 20 0 0 0 42.806 -7.612 4.7 0.37 200

2001 6 12 0 0 0 22.24 83.918 4.8 0.25 110

2001 6 23 0 0 0 29.325 105.563 4.8 0.25 131

2001 6 25 0 0 0 35.1035 43.4952 5.6 0.25 81

2001 6 26 0 0 0 -26.34 27.487 4.5 0.25 63

2001 6 27 0 0 0 -12.1 -63.7 5.2 0.25 51

2001 7 12 0 0 0 21.2717 70.8706 4.6 0.25 113

2001 7 13 0 0 0 18.1502 78.8564 5.1 0.37 106

2001 7 16 0 0 0 75.5434 -23.5549 5.5 0.25 253

2001 7 25 0 0 0 33.4073 118.8967 4.5 0.25 132

2001 7 25 0 0 0 -12.663 -59.8357 4.5 0.25 52

2001 7 26 0 0 0 30.6635 21.6633 4.8 0.25 90

2001 7 26 0 0 0 48.5692 0.6203 4.8 0.25 196

2001 7 31 0 0 0 80.6 -80.3 5.4 0.25 249

2001 7 31 0 0 0 -9.2026 -70.0348 5.1 0.25 51

2001 7 31 0 0 0 -26.896 26.737 4.8 0.25 63

2001 8 5 0 0 0 -9.2812 137.2033 5 0.25 13

2001 8 5 0 0 0 -6.3181 137.017 4.8 0.25 13

2001 8 9 0 0 0 -26.543 150.3748 4.9 0.25 28

2001 8 13 0 0 0 -8.4663 138.0104 5.2 0.37 13

2001 8 14 0 0 0 76.658 -107.228 5.2 0.25 249

2001 8 16 0 0 0 12.4503 107.3692 4.6 0.25 123

2001 8 18 0 0 0 63.3427 -106.1729 5 0.25 239

2001 8 19 0 0 0 -13.365 119.5607 4.8 0.25 1

2001 8 20 0 0 0 -25.585 133.2451 4.9 0.25 9

2001 8 20 0 0 0 -17.426 129.9737 4.8 0.25 13

2001 8 23 0 0 0 -17.344 140.6926 5.6 0.25 18

K-29
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

2001 8 25 0 0 0 36.2641 125.3343 5 0.25 132

2001 8 26 0 0 0 76.3339 -20.322 6.1 0.25 253

2001 8 26 0 0 0 -14.256 123.8186 5 0.25 1

2001 8 30 0 0 0 28.274 19.4471 5 0.25 90

2001 8 30 0 0 0 19.0558 31.2686 4.9 0.25 82

2001 9 2 0 0 0 -6.7649 10.4997 5.1 0.25 76

2001 9 2 0 0 0 37.673 129.78 4.9 0.25 127

2001 9 5 0 0 0 75.1661 -106.1823 5.1 0.25 249

2001 9 5 0 0 0 77.984 -114.673 4.7 0.25 249

2001 9 5 0 0 0 37.109 -104.528 4.42 0.10 255

2001 9 7 0 0 0 28.1113 15.1375 4.9 0.25 89

2001 9 7 0 0 0 29.7381 123.8315 4.6 0.25 127

2001 9 10 0 0 0 29.8725 104.5288 4.8 0.25 131

2001 9 11 0 0 0 18.5 -92.2 5.7 0.25 215

2001 9 13 0 0 0 27.9811 20.8813 5.7 0.25 90

2001 9 14 0 0 0 -40.278 149.7071 5.2 0.25 26

2001 9 14 0 0 0 -20.019 133.804 5 0.25 13

2001 9 15 0 0 0 19.7238 -91.9038 4.7 0.25 214

2001 9 16 0 0 0 32.6497 19.2837 5.5 0.25 90

2001 9 17 0 0 0 23.0733 117.7519 5 0.25 127

2001 9 17 0 0 0 45.3943 113.7827 4.7 0.25 135

2001 9 21 0 0 0 51.508 15.924 4.6 0.25 192

2001 9 22 0 0 0 34.3917 6.15 4.8 0.25 93

2001 9 22 0 0 0 -14.177 124.448 4.5 0.25 14

2001 9 23 0 0 0 18.3224 32.8639 4.9 0.25 82

2001 9 25 0 0 0 11.984 80.225 5.2 0.25 117

2001 9 25 0 0 0 31.7297 29.0631 5.1 0.25 90

2001 9 26 0 0 0 -13.243 147.2773 5.2 0.25 34

2001 9 26 0 0 0 -34.763 151.8227 5.1 0.25 30

2001 9 26 0 0 0 25.8207 22.8831 5 0.25 89

2001 9 28 0 0 0 -32.995 120.9596 5.2 0.25 8

2001 9 28 0 0 0 -30.399 117.319 4.9 0.25 8

2001 9 28 0 0 0 38.0842 126.5439 4.5 0.25 132

2001 9 30 0 0 0 -12.991 126.7785 5.1 0.25 15

2001 10 1 0 0 0 68.8555 -127.6986 4.8 0.25 241

2001 10 2 0 0 0 -16.542 129.5569 4.9 0.25 13

2001 10 2 0 0 0 27.5382 118.6441 4.8 0.25 125

2001 10 3 0 0 0 -6.9671 137.0515 6.2 0.25 13

2001 10 8 0 0 0 34.8007 121.2051 5 0.25 132

2001 10 8 0 0 0 -6.2523 137.4915 4.8 0.25 13

2001 10 9 0 0 0 21.7104 -92.8017 5.1 0.25 214

2001 10 16 0 0 0 47.4945 112.7612 5 0.25 136

2001 10 16 0 0 0 26.8645 49.1077 4.8 0.25 81

2001 10 17 0 0 0 -10.052 133.2564 4.6 0.25 17

2001 10 19 0 0 0 -7.941 12.104 5.3 0.25 76

2001 10 19 0 0 0 -33.712 120.628 5.1 0.25 8

2001 10 20 0 0 0 -31.605 147.4204 4.8 0.25 27

K-30
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

2001 10 21 0 0 0 -13.734 122.9126 4.5 0.25 1

2001 10 23 0 0 0 27.8303 18.7848 4.7 0.25 89

2001 10 24 0 0 0 -9.0099 133.5067 4.5 0.25 13

2001 10 25 0 0 0 29.1506 122.51 4.7 0.25 125

2001 10 28 0 0 0 27.2492 70.5076 4.8 0.25 113

2001 10 29 0 0 0 -19.293 115.2423 4.8 0.25 2

2001 10 30 0 0 0 19.1093 19.1265 4.7 0.25 89

2001 11 1 0 0 0 23.513 55.6403 4.6 0.25 81

2001 11 2 0 0 0 23.7152 49.4 5.2 0.25 81

2001 11 2 0 0 0 27.658 19.7634 4.8 0.25 90

2001 11 2 0 0 0 -16.8054 134.754 4.5 0.25 13

2001 11 4 0 0 0 26.8836 21.4003 5.3 0.25 89

2001 11 4 0 0 0 25.3812 47.0527 4.9 0.25 81

2001 11 4 0 0 0 9.4009 4.7531 4.7 0.25 89

2001 11 5 0 0 0 -15.767 126.3471 5.1 0.25 14

2001 11 7 0 0 0 20.8091 74.3352 4.8 0.37 106

2001 11 7 0 0 0 43.775 -105.215 4.7 0.37 238

2001 11 7 0 0 0 24.3326 70.5843 4.6 0.37 113

2001 11 10 0 0 0 -12.809 12.6848 5 0.25 75

2001 11 14 0 0 0 7.8137 105.9438 6.5 0.25 122

2001 11 14 0 0 0 -22.876 151.377 4.8 0.25 32

2001 11 16 0 0 0 31.84 43.2838 4.7 0.25 81

2001 11 17 0 0 0 27.5644 49.4508 4.7 0.25 81

2001 11 18 0 0 0 32.7764 42.6509 4.5 0.25 81

2001 11 19 0 0 0 23.0845 72.7343 4.9 0.25 115

2001 11 19 0 0 0 -26.675 150.897 4.7 0.25 28

2001 11 20 0 0 0 26.1886 19.0605 4.8 0.25 89

2001 11 20 0 0 0 -19.373 128.96 4.8 0.25 13

2001 11 20 0 0 0 -17.96 135.7664 4.8 0.25 13

2001 11 21 0 0 0 -16.784 152.113 4.9 0.25 34

2001 11 21 0 0 0 33.1923 123.9614 4.5 0.25 132

2001 11 23 0 0 0 -16.497 121.1809 4.8 0.25 1

2001 11 23 0 0 0 24.5701 71.1103 4.6 0.25 113

2001 11 25 0 0 0 22.594 52.9846 5 0.25 81

2001 11 26 0 0 0 30.993 18.9136 5.6 0.25 90

2001 11 26 0 0 0 50.1921 16.3672 5 0.25 192

2001 11 26 0 0 0 28.8118 20.472 4.9 0.25 90

2001 12 13 0 0 0 31.157 110.781 4.8 0.25 130

2002 1 7 0 0 0 69.11 -95.87 4.7 0.25 239

2002 1 8 0 0 0 -29.268 24.112 4.7 0.37 63

2002 2 20 0 0 0 51.561 16.082 4.8 0.25 192

2002 2 28 0 0 0 -27.982 26.789 4.8 0.25 63

2002 3 5 0 0 0 -11.779 24.762 5.1 0.25 61

2002 3 5 0 0 0 -30.52 117.18 4.8 0.25 7

2002 3 21 0 0 0 -26.496 27.346 4.6 0.25 63

2002 3 23 0 0 0 -26.877 26.574 4.8 0.25 63

2002 4 16 0 0 0 40.705 128.67 4.6 0.37 133

K-31
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

2002 4 19 0 0 0 -23.306 26.115 4.5 0.25 66

2002 4 20 0 0 0 44.513 -73.699 4.91 0.18 227

2002 4 30 0 0 0 29.459 105.647 4.8 0.37 131

2002 5 31 0 0 0 30.293 104.219 4.6 0.25 131

2002 6 13 0 0 0 -20.76 113.752 4.5 0.37 2

2002 6 15 0 0 0 -42.223 147.37 4.7 0.25 26

2002 6 18 0 0 0 38.069 -87.68 4.48 0.10 230

2002 7 12 0 0 0 -26.412 29.015 4.7 0.25 63

2002 7 22 0 0 0 50.889 6.103 4.8 0.25 195

2002 7 23 0 0 0 35.571 122.181 4.9 0.25 132

2002 8 10 0 0 0 35.353 123.252 4.5 0.25 132

2002 9 22 0 0 0 52.52 -2.15 4.8 0.25 187

2002 10 3 0 0 0 31.695 73.704 4.6 0.25 113

2002 10 8 0 0 0 -25.409 115.888 4.6 0.37 3

2002 10 20 0 0 0 44.621 117.371 4.6 0.25 135

2002 12 8 0 0 0 50.91 124.726 4.5 0.25 135

2003 1 23 0 0 0 41.541 -6.005 4.5 0.37 200

2003 2 22 0 0 0 48.342 6.57 4.78 0.31 195

2003 3 22 0 0 0 35.056 124.411 5.1 0.37 132

2003 3 22 0 0 0 48.21 9 4.7 0.37 192

2003 3 23 0 0 0 -13.763 14.273 4.8 0.25 72

2003 3 30 0 0 0 37.573 123.821 4.7 0.25 132

2003 4 29 0 0 0 34.494 -85.629 4.57 0.10 224

2003 5 24 0 0 0 6.498 -65.147 4.5 0.25 52

2003 6 4 0 0 0 75.154 16.726 4.8 0.25 181

2003 6 18 0 0 0 72.07 15.525 4.5 0.25 183

2003 7 4 0 0 0 76.372 23.282 5.4 0.25 169

2003 7 19 0 0 0 -26.425 27.333 4.6 0.25 63

2003 8 4 0 0 0 65.989 5.477 4.8 0.25 183

2003 8 10 0 0 0 27.216 75.739 4.5 0.37 113

2003 8 11 0 0 0 -18.436 147.114 4.8 0.25 33

2003 8 16 0 0 0 43.77 119.643 5.42 0.04 137

2003 10 5 0 0 0 51.517 16.201 4.8 0.25 192

2004 2 6 21 29 21.4 -4.5 137.31 4.87 0.08 16

2004 2 11 9 30 39 -22.51 130.17 4.85 0.13 5

2004 3 24 1 53 49.4 45.38 118.15 5.37 0.02 135

2004 5 29 10 14 28.4 36.66 129.95 5.10 0.03 127

2004 7 10 8 56 20.5 -8.72 130.57 4.81 0.08 1

2004 8 10 10 26 14.7 27.16 103.78 5.35 0.02 130

2004 9 21 13 32 30.8 54.79 20.11 4.74 0.09 175

2004 10 16 10 4 38 33.56 45.63 4.79 0.18 81

2004 12 5 1 52 37.2 48.03 8.04 4.73 0.15 195

2005 1 22 10 48 45.7 -10.76 124.19 5.15 0.07 1

2005 2 22 23 14 17.8 -65.64 133.54 5.46 0.02 213

2005 3 14 9 43 49.1 17.1 73.79 4.91 0.07 106

2005 7 18 2 6 53.8 -10.33 124.72 5.47 0.05 1

2005 7 20 21 54 5.7 43.04 109.04 5.21 0.02 135

K-32
Appendix K 

Year Month Day Hour Minute Second Latitude Longitude E[M] sigma M DN

2005 7 25 15 43 41.1 46.86 124.88 5.01 0.03 137

2005 8 5 14 14 48 26.46 103.19 5.26 0.03 130

2005 8 10 22 8 22.6 36.9 -104.79 4.93 0.07 255

2005 9 19 3 27 53.2 49.72 120.93 4.46 0.24 135

2005 11 8 7 54 39 10.12 108.26 5.33 0.03 122

2005 11 10 19 29 54.1 57.48 120.63 5.86 0.01 147

2005 11 26 0 49 37.7 29.66 115.71 5.20 0.03 130

2006 2 15 1 46 4.1 -9.63 126.57 4.74 0.18 1

2006 3 7 18 20 46.1 23.72 70.77 5.48 0.01 114

2006 3 10 7 50 14.4 32.62 73.51 4.96 0.08 113

2006 3 31 12 23 17.9 44.65 124.08 4.76 0.06 137

2006 4 6 17 59 16.4 23.25 70.35 5.56 0.02 114

2006 6 8 16 29 13.3 4.88 -51.96 5.07 0.03 52

2006 8 25 5 51 44.4 28 104.31 5.04 0.08 131

2006 11 17 9 25 21.4 -4.7 138.27 5.08 0.09 16

2007 1 7 1 50 53.8 62.08 1.22 4.85 0.07 184

2007 1 20 11 56 53.7 37.65 128.43 4.76 0.06 132

2007 7 9 15 58 22.3 34.1 6.89 4.85 0.05 93

2007 11 4 20 35 37.3 -67.27 111.53 5.72 0.01 202

2007 11 6 9 38 5.8 21.04 70.49 5.13 0.04 113

2007 11 28 15 16 8.5 10.02 108.28 5.20 0.03 122

2007 12 23 12 56 13 -4.08 39.45 4.90 0.05 80

2008 2 21 2 46 17.9 77.02 19.28 6.10 0.01 181

2008 3 6 12 19 16.4 -24.92 -64.29 4.97 0.05 41

2008 4 18 9 36 59.1 38.49 -87.86 5.3 0.09 229

2008 4 20 7 30 44.3 -3.66 25.97 5.27 0.03 72

2008 4 26 13 14 52.2 50.71 51.8 5.13 0.04 161

2008 6 10 6 5 4.7 49.07 122.47 4.96 0.06 135

2008 8 15 15 52 50.8 82.23 -18.58 4.78 0.05 239

2008 10 7 10 0 48.1 79.77 -116.02 5.77 0.01 250

2008 12 16 5 20 1.5 55.55 13.76 4.30 0.11 177

K-33
Appendix K 

Table K-2 

SCR Domains Updated from Johnston et al. (1994) 

Notes: 

DN Domain Number 

Type Domain type 

E – Extended crust 

NE – Non-extended crust (crustal age domain) 

Age Domain age assigned in Johnston et al. (1994) 

CZ – Cenozoic 

MZ – Mesozoic 

PZ – Paleozoic 

PC – PreCambrian 

MRE Age Age of most recent extension. For Type NE domains, this equals Age 

CZ – Cenozoic 

MZ – Mesozoic 

PZ – Paleozoic 

PC – PreCambrian 

Stress Crustal Stress State in Domain 

C – Compressive 

E – Extensive 

U – Unknown 

SS_Ang Classification of angle between maximum horizontal stress vector and 

strike of major domain structures with respect to reactivation 

F – Favorable orientation 

NF – Unfavorable orientation 

UK – Unknown 

Area Area of domain in km2

Mmax_obs Largest observed magnitude in domain 

N ≥ 4.5 Number of earthquakes in domain with magnitudes ≥ M, adjusted for 

completeness 

SDNT Indicates which Superdomain the domain is assigned to when TYPE is 

included in the classification 

SDNC Indicates which Superdomain the domain is assigned to when Type is not 

included in the classification 

K-34
Appendix K 

Table K-2 

SCR Domains Updated from Johnston et al. (1994) 

DN Type Age MRE Age Stress SS_Ang Area Mmax_obs N ≥ 4.5 SDNT SDNC

1 E MZ CZ C F 542655 6.3 35.4 SE01 SD01

2 E MZ CZ C NF 383752 7.2 29.4 SE02 SD02

3 NE PC PC C UK 369232 4.8 4 SN07 SD15

4 E MZ MZ C UK 420994 5.1 4 SE08 SD08

5 NE PC PC C NF 279587 5.8 4 SN06 SD14

6 E MZ MZ C UK 115589 6.2 3.3 SE08 SD08

7 NE PC PC C NF 237858 6.7 20.3 SN06 SD14

8 NE PC PC C NF 501577 5.2 4.6 SN06 SD14

9 NE PC PC C UK 853794 6 12.5 SN07 SD15

10 NE PC PC C UK 192642 4.5 1 SN07 SD15

11 E MZ CZ C F 118809 5.5 4 SE01 SD01

12 E PC PZ C NF 200768 6.5 7.2 SE18 SD21

13 NE PC PC C UK 2010402 6.8 81.2 SN07 SD15

14 NE PC PC C UK 197610 6.2 6.8 SN07 SD15

15 E PZ MZ C UK 140443 5.1 1 SE08 SD08

16 E MZ CZ C UK 310194 7.3 23.3 SE03 SD03

17 E PZ PZ C UK 27315 5.3 3 SE19 SD22

18 NE PC PC C NF 645753 5.6 1 SN06 SD14

19 NE PC PC C UK 838499 5.4 5.2 SN07 SD15

20 E MZ MZ C UK 430647 0 0 SE08 SD08

21 E PC CZ C NF 109798 5.8 21.6 SE02 SD02

22 E PC PC C F 31132 0 0 SE13 SD13

23 E MZ MZ C F 91577 6.2 7.1 SE06 SD06

24 E MZ CZ C UK 21214 0 0 SE03 SD03

25 E MZ CZ C NF 38206 0 0 SE02 SD02

26 E MZ CZ C NF 578458 6.4 16.9 SE02 SD02

27 NE PZ PZ C UK 1732818 5.4 26.2 SN14 SD22

28 NE PZ PZ C F 320334 5.1 6.2 SN12 SD20

29 NE MZ MZ C F 33900 0 0 SN01 SD06

30 E MZ MZ C NF 64704 5.1 1 SE07 SD07

31 NE PZ PZ C UK 203355 4.7 1 SN14 SD22

32 E MZ MZ C UK 465267 5.8 6 SE08 SD08

33 E MZ CZ C UK 130520 4.8 1 SE03 SD03

34 E CZ CZ C UK 330468 5.2 2.6 SE03 SD03

35 E MZ MZ C UK 1174158 6.5 4.3 SE08 SD08

36 NE PC PC C UK 88752 0 0 SN07 SD15

37 NE PZ PZ C UK 854067 0 0 SN14 SD22

38 NE PZ PZ C UK 136385 0 0 SN14 SD22

39 E MZ MZ C F 90689 0 0 SE06 SD06

40 NE PZ PZ C UK 239608 0 0 SN14 SD22

41 NE PC PC C UK 923063 5.1 4 SN07 SD15

42 NE PC PC C F 509261 4.9 1 SN05 SD13

43 E MZ MZ C NF 73005 0 0 SE07 SD07

44 NE PC PC C NF 286827 0 0 SN06 SD14

45 NE PC PC C NF 718524 0 0 SN06 SD14

K-35
Appendix K 

DN Type Age MRE Age Stress SS_Ang Area Mmax_obs N ≥ 4.5 SDNT SDNC

46 E MZ MZ C F 784433 6.1 4.2 SE06 SD06

47 NE PC PC C UK 941052 4.7 1 SN07 SD15

48 NE PC PC C UK 324268 0 0 SN07 SD15

49 NE PC PC C UK 860086 5.3 3 SN07 SD15

50 NE PC PC C UK 229524 0 0 SN07 SD15

51 NE PC PC C NF 2130122 5.3 15.1 SN06 SD14

52 NE PC PC C UK 4715337 6.3 22.2 SN07 SD15

53 E PZ CZ C NF 281647 5.3 1 SE02 SD02

54 E MZ MZ C NF 680267 4.7 1 SE07 SD07

55 NE PC PC C UK 90225 0 0 SN07 SD15

56 NE PC PC C F 1052751 5.4 8.4 SN05 SD13

57 E MZ MZ C NF 17869 0 0 SE07 SD07

58 NE PZ PZ C F 141370 6.4 10.2 SN12 SD20

59 E MZ MZ C UK 392983 5.2 3.3 SE08 SD08

60 NE PC PC E UK 577400 5.6 7.5 SN10 SD18

61 NE PC PC E NF 1197397 5.8 33.2 SN09 SD17

62 E MZ MZ C F 527118 0 0 SE06 SD06

63 NE PC PC E NF 480297 6.6 368 SN09 SD17

64 E PC PC E UK 22629 6.5 2 SE15 SD18

65 E PC MZ E UK 46793 5.2 1 SE11 SD11

66 NE PC PC E UK 295236 5 3.9 SN10 SD18

67 NE PC PC E F 655453 5.7 19 SN08 SD16

68 NE PC PC E F 60012 5.3 1 SN08 SD16

69 NE PC PC E NF 11451 0 0 SN09 SD17

70 E MZ MZ E NF 28193 5.9 1 SE10 SD10

71 E MZ MZ E NF 701414 5.6 4.1 SE10 SD10

72 NE PC PC C F 1004603 6.2 13.6 SN05 SD13

73 NE PC PC C UK 1985264 6.3 28.7 SN07 SD15

74 NE PC PC C NF 132886 6.4 1 SN06 SD14

75 E MZ MZ U UK 80902 5 1 SE12 SD12

76 E MZ MZ U UK 372829 5.6 3 SE12 SD12

77 NE PC PC U UK 49528 4.8 1 SN11 SD19

78 NE PC PC U UK 45208 6.3 4.8 SN11 SD19

79 NE PC PC E F 803876 5.6 2 SN08 SD16

80 E MZ MZ E NF 492873 5.5 4.9 SE10 SD10

81 NE PC PC C NF 2971006 6.9 55.2 SN06 SD14

82 NE PC PC C NF 2034295 7.3 18.7 SN06 SD14

83 NE PC PC C UK 244105 5.7 1 SN07 SD15

84 NE PC PC C NF 2323466 6.1 6 SN06 SD14

85 E CZ CZ C NF 355539 4.9 2.9 SE02 SD02

86 E MZ MZ U UK 187366 0 0 SE12 SD12

87 E MZ MZ U UK 81856 0 0 SE12 SD12

88 E MZ MZ U UK 57545 0 0 SE12 SD12

89 NE PC PC C NF 3890522 5.3 9.3 SN06 SD14

90 E MZ MZ C NF 960298 6.8 86.9 SE07 SD07

91 E MZ MZ C NF 175410 6.5 1 SE07 SD07

92 NE PC PC C UK 689805 6.8 4 SN07 SD15

K-36
Appendix K 

DN Type Age MRE Age Stress SS_Ang Area Mmax_obs N ≥ 4.5 SDNT SDNC

93 NE PC PC C UK 421251 4.9 2 SN07 SD15

94 NE PC PC U UK 176032 0 0 SN11 SD19

95 NE PZ PZ C UK 164906 5.5 1 SN14 SD22

96 NE PC PC U UK 306656 0 0 SN11 SD19

97 NE PC PC U UK 396208 0 0 SN11 SD19

98 NE PC PC U UK 1128104 4.6 1 SN11 SD19

99 E PC PC U UK 429359 5.4 1 SE16 SD19

100 NE PC PC C UK 1374935 6.2 7 SN07 SD15

101 E MZ MZ U UK 188729 0 0 SE12 SD12

102 NE PZ PZ U UK 14966 0 0 SN15 SD23

103 NE PZ PZ C UK 19779 0 0 SN14 SD22

104 NE PZ PZ U UK 150047 0 0 SN15 SD23

105 E MZ MZ E F 1272700 6.2 4 SE09 SD09

106 NE PC PC C NF 781860 6.3 26.3 SN06 SD14

107 NE PC PC C UK 79382 5.5 2 SN07 SD15

108 NE PC PC C NF 155035 4.7 1 SN06 SD14

109 NE PC PC C UK 41141 5.1 3.9 SN07 SD15

110 NE PC PC C UK 142062 5.7 2.3 SN07 SD15

111 NE PC PC C NF 178946 5.8 11.8 SN06 SD14

112 NE PC PC C UK 504375 6.2 9 SN07 SD15

113 NE PC PC C F 810970 6.7 71.7 SN05 SD13

114 E MZ MZ C NF 76406 7.8 31 SE07 SD07

115 E MZ CZ C NF 39598 5.4 5 SE02 SD02

116 E MZ CZ C UK 248085 5.4 2 SE03 SD03

117 E MZ MZ C F 326551 5.6 6 SE06 SD06

118 E MZ CZ C F 243283 6.1 20.9 SE01 SD01

119 E PZ MZ C NF 65847 6.4 1 SE07 SD07

120 E MZ CZ C NF 55041 5.2 1 SE02 SD02

121 E PZ MZ C NF 61324 0 0 SE07 SD07

122 NE PZ PZ C UK 310144 6.5 5.1 SN14 SD22

123 NE PC PC C UK 377393 4.6 1 SN07 SD15

124 NE PZ PZ C UK 178223 0 0 SN14 SD22

125 E MZ MZ C NF 383113 7.3 307.5 SE07 SD07

126 E CZ CZ C NF 64880 7.5 12.1 SE02 SD02

127 E CZ CZ C NF 1258535 7.7 124.2 SE02 SD02

128 NE MZ MZ C NF 201788 5.6 4.5 SN02 SD07

129 NE MZ MZ C NF 603996 6.2 42 SN02 SD07

130 NE MZ MZ C UK 682979 6.4 91.6 SN03 SD08

131 NE PC PC C UK 261381 6.8 454.8 SN07 SD15

132 E CZ CZ C NF 495752 7.9 501.6 SE02 SD02

133 NE PC PC C F 312369 6.7 107.7 SN05 SD13

134 NE PZ PZ C F 127045 4.8 1 SN12 SD20

135 NE PZ PZ C F 712893 5.4 26 SN12 SD20

136 NE PZ PZ C F 641577 5.7 11.8 SN12 SD20

137 E MZ MZ C NF 333684 6.2 15.7 SE07 SD07

138 NE MZ MZ C UK 152897 5 1 SN03 SD08

139 NE PZ PZ C UK 173986 6.8 20.4 SN14 SD22

K-37
Appendix K 

DN Type Age MRE Age Stress SS_Ang Area Mmax_obs N ≥ 4.5 SDNT SDNC

140 NE PC PC U UK 229180 5 1 SN11 SD19

141 NE MZ MZ U UK 204323 5 2 SN04 SD12

142 NE MZ MZ U UK 234618 0 0 SN04 SD12

143 NE MZ MZ U UK 160531 0 0 SN04 SD12

144 E MZ MZ U UK 499042 4.9 1 SE12 SD12

145 E CZ CZ U UK 151400 0 0 SE05 SD05

146 NE PC PC U UK 296773 5.4 1 SN11 SD19

147 NE PC PC U UK 750750 6.2 14.5 SN11 SD19

148 E PC MZ U UK 200729 4.8 1 SE12 SD12

149 NE PC PC U UK 2249521 6.4 10.8 SN11 SD19

150 E PC PC U UK 72411 0 0 SE16 SD19

151 NE PC PC U UK 202499 0 0 SN11 SD19

152 NE PZ PZ U UK 436997 5.2 1 SN15 SD23

153 NE PC PC U UK 312722 0 0 SN11 SD19

154 NE PZ PZ U UK 155264 5 1 SN15 SD23

155 E MZ MZ U UK 1083894 0 0 SE12 SD12

156 NE PZ PZ C UK 1206616 5.2 9.8 SN14 SD22

157 NE PZ PZ U UK 178540 4.6 1 SN15 SD23

158 NE PZ PZ U UK 1145766 5.3 3.4 SN15 SD23

159 NE PZ PZ U UK 1334133 5.7 5.3 SN15 SD23

160 NE PC PC U UK 209438 5.3 1 SN11 SD19

161 E PZ PZ U UK 561624 5.1 2.9 SE20 SD23

162 E PZ PZ C NF 276360 0 0 SE18 SD21

163 NE PC PC U UK 561495 0 0 SN11 SD19

164 NE PC PC C F 371000 0 0 SN05 SD13

165 E PC PC U UK 54556 0 0 SE16 SD19

166 NE PC PC U UK 1276933 4.9 2 SN11 SD19

167 E PC PC C NF 182051 4.9 2 SE14 SD14

168 E PC PZ U UK 525509 4.9 2 SE20 SD23

169 NE PC PC E UK 1166510 5.4 2 SN10 SD18

170 E CZ CZ U UK 141010 5.1 2 SE05 SD05

171 NE PC PC C F 241485 4.7 2 SN05 SD13

172 NE PC PC C UK 96452 0 0 SN07 SD15

173 NE PC PC C F 821894 5.3 3 SN05 SD13

174 NE PC PC C F 76920 0 0 SN05 SD13

175 NE PC PC C F 1056504 4.8 2 SN05 SD13

176 NE PC PC C F 76985 0 0 SN05 SD13

177 NE PC PC C F 174915 5.9 2 SN05 SD13

178 E PZ MZ C NF 26218 0 0 SE07 SD07

179 NE PZ PZ C NF 342539 6.4 26.6 SN13 SD21

180 E MZ MZ C NF 274830 0 0 SE07 SD07

181 NE PZ PZ C UK 109385 6.1 4.4 SN14 SD22

182 NE PZ PZ U UK 35620 4.9 1 SN15 SD23

183 E MZ CZ C NF 411360 5.8 33.5 SE02 SD02

184 E MZ CZ C UK 734600 4.9 2 SE03 SD03

185 NE PZ PZ C NF 399518 5.1 10 SN13 SD21

186 E PZ PZ C NF 66123 4.6 1 SE18 SD21

K-38
Appendix K 

DN Type Age MRE Age Stress SS_Ang Area Mmax_obs N ≥ 4.5 SDNT SDNC

187 NE PC PC C UK 123709 6.7 31.9 SN07 SD15

188 E MZ MZ C NF 150936 5.6 6 SE07 SD07

189 E MZ MZ C NF 15655 4.7 1 SE07 SD07

190 NE PZ PZ C UK 186309 4.6 1 SN14 SD22

191 E PZ CZ C F 101917 0 0 SE01 SD01

192 NE PZ PZ C F 360973 6.2 223.4 SN12 SD20

193 E CZ CZ C NF 11175 4.7 1 SE02 SD02

194 E MZ CZ C F 163623 5.7 3.5 SE01 SD01

195 E CZ CZ C NF 265266 6.6 104 SE02 SD02

196 NE PZ PZ C UK 540395 5.9 34.5 SN14 SD22

197 E MZ MZ C F 423541 5.3 2 SE06 SD06

198 E MZ MZ E NF 57097 5.3 3 SE10 SD10

199 E MZ MZ C NF 180858 7.1 45 SE07 SD07

200 NE PZ PZ C F 288764 5.5 15.8 SN12 SD20

201 E MZ CZ C F 156373 5.2 2 SE01 SD01

202 NE PC PC C UK 7263353 5.7 3.1 SN07 SD15

203 NE PC PC U UK 1028169 0 0 SN11 SD19

204 NE PC PC U UK 79414 0 0 SN11 SD19

205 NE PC PC U UK 152545 0 0 SN11 SD19

206 NE PC PC U UK 4175 0 0 SN11 SD19

207 E MZ CZ U UK 1250511 0 0 SE05 SD05

208 E CZ CZ U UK 606087 5.2 2 SE05 SD05

209 E MZ MZ U UK 14821 0 0 SE12 SD12

210 E MZ MZ U UK 122104 0 0 SE12 SD12

211 E MZ MZ U UK 346880 0 0 SE12 SD12

212 E MZ MZ U UK 177314 0 0 SE12 SD12

213 E MZ MZ U UK 900281 5.5 2 SE12 SD12

214 E MZ MZ C F 523819 5.4 4.9 SE06 SD06

215 E MZ MZ C F 89292 5.7 2.9 SE06 SD06

216 E MZ MZ E UK 1150114 0 0 SE11 SD11

217 E MZ MZ C NF 501647 4.9 1 SE07 SD07

218 E MZ MZ C F 1023295 7.3 35.1 SE06 SD06

219 E MZ MZ C UK 498363 0 0 SE08 SD08

220 NE PZ PZ C NF 339302 0 0 SN13 SD21

221 E PZ MZ C F 176827 4.9 1 SE06 SD06

222 NE PZ PZ C NF 395328 5.7 19.4 SN13 SD21

223 NE PZ PZ C NF 141177 5.2 2 SN13 SD21

224 NE PZ PZ C NF 252674 5.9 17.9 SN13 SD21

225 NE PZ PZ C UK 272762 4.7 2 SN14 SD22

226 NE PC PC C NF 1297437 6.6 96.5 SN06 SD14

227 E PZ MZ C NF 136629 6.9 27 SE07 SD07

228 E MZ CZ C NF 20987 7.8 17.5 SE02 SD02

229 E PZ PZ C F 82782 5.5 4.1 SE17 SD20

230 NE PC PC C UK 498443 6.8 30.2 SN07 SD15

231 NE PC PC C UK 540467 5.7 7.7 SN07 SD15

232 E PZ PZ C NF 27481 0 0 SE18 SD21

233 NE PC PC C UK 272794 0 0 SN07 SD15

K-39
Appendix K 

DN Type Age MRE Age Stress SS_Ang Area Mmax_obs N ≥ 4.5 SDNT SDNC

234 NE PC PC C F 130527 0 0 SN05 SD13

235 E PC PC C NF 325388 5.5 6.5 SE14 SD14

236 NE PC PC C F 2195241 6 2 SN05 SD13

237 NE PC PC C UK 1344617 5.7 5.3 SN07 SD15

238 NE PC PC C F 373331 5.3 9.3 SN05 SD13

239 NE PC PC C UK 3882973 5.4 20.6 SN07 SD15

240 NE PC PC C UK 483039 0 0 SN07 SD15

241 NE PC PC C NF 1067319 6.2 7 SN06 SD14

242 NE PC PC C F 550542 5.2 2.5 SN05 SD13

243 NE PC PC C UK 73011 0 0 SN07 SD15

244 NE PC PC C UK 96381 5 2.3 SN07 SD15

245 NE PC PC U UK 18765 0 0 SN11 SD19

246 NE PC PC C UK 296714 4.7 2 SN07 SD15

247 E MZ MZ C NF 235667 5.6 7.2 SE07 SD07

248 E CZ CZ E NF 1651160 6.2 16.1 SE04 SD04

249 E MZ MZ C NF 649859 6.3 20.6 SE07 SD07

250 E MZ MZ C NF 259139 5.8 4.3 SE07 SD07

251 NE PZ PZ C UK 189322 6.2 5 SN14 SD22

252 NE PZ PZ U UK 194188 0 0 SN15 SD23

253 E PZ PZ U UK 170849 6.1 6.4 SE20 SD23

254 E MZ CZ C UK 350276 5.7 2 SE03 SD03

255 NE PC PC C UK 601885 5.1 5.9 SN07 SD15

K-40
4

4.5

5

5.5

6

6.5

7

7.5

8

-2 -1.5 -1 -0.5 0

Moment Magnitude

Log(NR/NM)

Johnston et al. (1994)

Johnston (1996b)

Figure K-1 

Comparison of relationships between number of reporting stations and moment 

magnitude presented in Johnston et al. (1994) and Johnston (1996b). 

K-41
3

4

5

6

7

8

4 4.5 5 5.5 6 6.5 7 Moment Magnitude

Log(FA in sq km)

Felt, Johnston et al. (1994)

MMI IV, Johnston et al. (1994)

MMI V, Johnston et al. (1994)

MMI VI, Johnston et al. (1994)

Felt, Johnston (1996b)

MMI IV, Johnston (1996b)

MMI V, Johnston (1996b)

MMI VI, Johnston (1996b)

Figure K-2 

Comparison of relationships between isoseismal areas and moment magnitude presented 

in Johnston et al. (1994) and Johnston (1996b). 

K-42
NUREG-2115 DOE/NE-0140 EPRI 1021097

APPENDIX L 

Quality Assurance

L

APPENDIX

QUALITY ASSURANCE

L.1 BACKGROUND 

Embedded in the SSHAC PSHA process described in NUREG/CR-6372 (Recommendations for 

Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts) and 

ANSI/ANS-2.29-2008 (Probabilistic Seismic Hazard Analysis) is “participatory peer review,” 

defined as both process and technical review of the PSHA starting at an early stage and 

continuing through the life of a project. Participatory peer review is a fundamental element of 

ensuring the quality of the resulting PSHA product. Both ANSI/ANS-2.29-2008 and ANSI/ANS2.27-2008 (Criteria for Investigation of Nuclear Facility Sites for Seismic Hazard Assessments) 

were developed to be consistent with ANSI/ASME NQA-1-2008 (Quality Assurance 

Requirements for Nuclear Facility Applications). Hence, for a regional study such as the Central 

and Eastern United States (CEUS) Seismic Source Characterization (SSC) for Nuclear Facilities 

Project, following the guidance contained in NUREG/CR-6372, ANSI/ANS-2.29-2008, and 

ANSI/ANS-2.27-2008 will result in adequate products and output. Site-specific assessments that 

start with a Level 3 or 4 regional model and perform a Level 2 refinement for site-specific 

applications will also need to comply with specific requirements in ASME NQA-1-2008 Parts I 

and II. 

Within the SSHAC hazard assessment framework, a traditional verification and validation 

(V&V) program is limited to specific numerical tools, such as the software used to perform the 

PSHA calculations. A quality or “cross-check” protocol may also be used to ensure the accuracy 

of compiled tables, data sets, and other project products. However, it is not possible to apply a 

V&V program to the SSHAC process itself. Similarly, it does not make sense to impose a 

restriction on the use of data for cases where a formal quality assurance program for the 

collection of field data outside of the project cannot be verified (e.g., if a quality control program 

cannot be verified for a USGS or university data set). The rejection of data sets in these cases 

could seriously diminish, instead of enhance, the process. This is because a key part of a SSHAC 

Level 3 or 4 process is the evaluation of data by the evaluator experts. Therefore, the evaluator 

experts are able to make an informed assessment of the quality of various data sets, whether or 

not those data were gathered within a formal quality program. This does not mean, however, that 

nonqualified data used in a SSHAC process can be considered qualified after their use in the 

process.

L-1
Appendix L

Within the SSHAC hazard assessment framework, the collection and evaluation of existing 

scientific information is performed with the aim of ascertaining the current state of knowledge 

regarding a specific issue. The majority of existing information that may be used in a SSHAC 

Level 3 or 4 PSHA will have been published in some fashion previously. Moreover, the data, 

methods, and models considered and used will also undergo what effectively constitutes peer 

review by the TI Team, which is likely to be at least as rigorous as that conducted for journal 

publication. Thus, that information has been reviewed and “vetted” by the broad technical 

community. The systematic compilation of all pertinent information from the scientific literature 

(including specialized journals, technical reports, conference proceedings) or other relevant 

sources of information (e.g., databases of scientific data, historical or archival documents) is a 

vital element in a SSHAC PSHA study. In addition, in some cases, nontraditional types of data 

that may be beneficial to the project may be available. It is important that data not be dismissed 

without appropriate consideration, particularly in regions where data may be scarce.

Beyond the assurance of quality arising from that external scientific review process, a 

fundamental component of the SSHAC process is the evaluation of the data, models, and 

methods by the evaluator experts as a means of establishing the quality, relevance, technical 

basis, and uncertainties. Further, in the integration stage of the SSHAC assessment process, the 

TI team or evaluator experts build models and apply weights to elements of the model based on 

due consideration of the technical support for various models and methods proposed by the 

technical community. Therefore, it is the collective, informed judgment of the TI Team (via the 

process of data evaluation and model integration) and the concurrence of the PPRP (via the 

process of participatory peer review), as well as adherence to the national standards described 

above, that ultimately lead to the assurance of quality in the process followed and in the products 

resulting from the SSHAC hazard assessment framework. 

L.2 CEUS SSC PROJECT 

L.2.1 Introduction

The TI Team, Project Manager, and Sponsors determined the approach for quality control for the 

CEUS SSC Project in 2008, taking into account the SSHAC assessment process and national 

standards described above. The approach was documented in the CEUS SSC Project Plan, dated 

June 2008. The technical assessments made as part of the CEUS SSC entailed the use of a wide 

range of databases, including those that have been subject to peer review in the professional 

literature, those that have been gathered for scholarly research, and those that have been 

developed for site-specific commercial application. In creating the CEUS SSC model, the TI 

Team had extensive interactions with the technical community about identifying data, evaluating

alternative hypotheses, and collecting feedback regarding all assessments. These interactions 

helped ensure a high level of review for the TI Team’s technical assessments. 

A participatory peer review process was used for both the technical and process elements of the 

project. This process provides high confidence that the project assessments and results will be

accepted by the technical community. The level of assurance exceeds that associated with 

publication in a peer-reviewed technical journal. In addition to the peer review process that is 

L-2
afforded by the SSHAC Level 3 process, certain other activities were conducted as best business 

practices. These activities are described below. 

L.3 BEST BUSINESS PRACTICES 

L.3.1 General

A hazard input document (HID) was developed that documents and summarizes the key 

elements of the SSC model, including logic trees, parameter distributions, and derived Mmax 

and recurrence parameters. The HID specifies the exact inputs provided by the SSC model to the 

hazard calculations and thus provides a clear record of how the SSC model is translated into 

hazard calculations. As discussed in Task 2 of the CEUS SSC Project Plan, “Develop a 

Database,” the management and documentation of the data were done in accordance with a data 

management procedure developed specifically for this project. As part of Task 7 of the Project 

Plan, “Construct a Preliminary SSC Model,” new computer codes were developed for estimating

seismicity rates and b-values. These computer codes were documented and are available as part 

of project documentation on the CEUS SSC Project website. All hazard calculations were 

conducted using software that had been previously qualified in accordance with 10 CFR 50, 

Appendix B (Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing 

Plants) requirements. Also, an internal documentation package was prepared to archive the 

hazard calculations. The results for seven test sites were documented as example calculations in 

Chapter 8 of the main project report. 

L.4 CEUS SSC EARTHQUAKE CATALOG DEVELOPMENT 

L.4.1 External Review of Earthquake Catalog

The initial earthquake catalog assembled for the project was submitted for external review by 

seismologists familiar with compiling and analyzing earthquake data in the CEUS. The 

reviewers are listed as follows: 

• Charles Mueller and Margaret Hopper (U.S. Geological Survey) 

• John Ebel (Boston College) 

• Martin Chapman (Virginia Tech) 

• Pradeep Talwani (University of South Carolina) 

• Don Stevenson (Savannah River Nuclear Solutions, LLC) 

• James Marrone (Bechtel)

These reviewers provided recommendations for additional sources of data and for treatment of 

the data from various catalog sources; they also provided specific recommendations on 

individual earthquakes. These recommendations were considered in developing the final project 

catalog.

L-3
Appendix L

L.4.2 Simulation Testing

A series of simulation tests were performed to verify a number of processes used in the 

development of the earthquake catalog, including the following: 

• Verifying no adverse effect from rounding magnitudes reported in various catalogs to one 

decimal place when testing for differences in magnitudes from separate sources.

• Verifying the relationships developed by EPRI (1988) for developing uniform magnitude 

estimates, adjusting for bias in earthquake recurrence parameters due to magnitude 

uncertainty.

• Assessing the impact of catalog incompleteness on estimating earthquake recurrence 

parameters from uncertain magnitudes. 

• Developing an improved method of correcting for bias in earthquake recurrence parameters 

from uncertain magnitudes and partially complete earthquake catalogs.

L.4.3 Checks for Consistency in Magnitude Conversion from Intensity

Because a large part of the earthquake catalog contains pre-instrumental earthquakes, 

relationships are needed to estimate earthquake magnitude from the reported level of shaking 

intensity. In past studies, the body-wave-magnitude scale has been used, and relationships have 

been developed to estimate body-wave magnitude from maximum shaking intensity in order to 

use the pre-instrumental earthquake data. However, the CEUS SSC Project earthquake catalog 

uses the moment magnitude scale as the uniform measure of earthquake size. As part of the 

catalog development, assessments were performed to ensure consistency between conversions 

from intensity to moment magnitude and conversions from intensity to body-wave magnitude, 

and consistency between body-wave magnitude and moment magnitude. 

L.4.4 Use of Verified Computer Programs

Two principal computer programs were used in the development of the earthquake catalog: 

EQCLUST, which was used to identify dependent earthquakes, and EQPARAM, which was 

used to estimate earthquake catalog completeness. Both programs were checked as part of the 

verification process of the EPRI-SOG set of computer programs (EPRI, 1988). 

L.5 RECURRENCE ANALYSIS AND SPATIAL SMOOTHING 

L.5.1 Introduction

The recurrence parameters (i.e., rate and b-value) were calculated using penalized-likelihood 

formulation that allows for spatial variation in the rate and b-value and also quantifies the 

uncertainty in these parameters. The methodology divides the source zones into cells of 

dimensions a quarter- or half-degree and then calculates the rate and b-value in each cell using 

the likelihood function of the data in that cell, together with penalty functions that tend to smooth 

L-4
the cell-to-cell variation in the rate or the b-value. In addition, this procedure characterizes 

epistemic uncertainty in the recurrence parameters by generating eight alternative maps of the 

recurrence parameters. The following is a partial list of the tests and confirmation steps that were 

performed to ensure that the methodology was adequate for the desired purpose and that it was 

properly implemented in the software. 

L.5.2 Recurrence Comparisons at the Source-Zone Level

The recurrence comparisons presented in Sections 6.4.2 and 7.5.2 compare the cumulative 

earthquake counts over an entire source zone, as predicted by the methodology, to the 

corresponding counts as observed in the catalog. These comparisons provide a consistency check 

for the methodology and its implementation in the software because the penalized-likelihood 

formulation operates at the level of each individual cell without explicitly considering the total 

rates. These comparisons indicate a good match to the catalog, after taking into account the error 

bars introduced by the size of the catalog.

L.5.3 Recurrence Comparisons for Portions of a Source Zone

Similar comparisons were performed for interesting portions of certain source zones, as 

presented in Section 5.3.2.3. These comparisons also indicate a good match to the catalog at 

these smaller spatial scales, after taking into account the error bars introduced by the size of the 

catalog.

L.5.4 Examination of Recurrence Maps

Maps were generated for the mean rates and b-values and associated uncertainties, as well as for 

the eight realizations of the recurrence parameters for each zone. These maps are presented in 

Sections 6.4.2 and 7.5.2 and Appendix J. All maps were examined to verify that the recurrence 

parameters were reasonable.

L.5.5 Test with a Synthetic Catalog Homogeneous Seismicity

The purpose of this test was to confirm that the methodology does not interpret chance variations 

in activity as spatial variations in rate and/or b-value. A synthetic catalog was generated, under 

the assumption of a spatially homogeneous rate, a b-value of 1, Poisson occurrences, and 

independent earthquake locations. The rate and duration were selected so that the mean number 

of earthquakes per cell was comparable to that of the Midcontinent source zone (approximately 

one event for every three cells). Calculations were performed for one rectangular source zone of 

dimensions 5 degrees by 5 degrees (containing 100 half-degree cells), using objective smoothing 

and unit weights for all magnitude bins. The methodology produced homogeneous rates and bvalues, and these values were consistent with those used to generate the synthetic catalog. This 

confirms that the spatial variations detected by the program are not due to chance variations 

resulting from the limited duration of the catalog.

L-5
Appendix L

L.5.6 Test for the Adequacy of Eight Maps to Represent Epistemic Uncertainty

The purpose of this test was to verify that the eight alternative maps provide an adequate 

representation of the epistemic uncertainty in recurrence parameters. Two separate sets of eight 

alternative maps were generated for the Northern Appalachian source zone using different values 

of the seed for the Latin hypercube randomization algorithm, and then hazard calculations were 

performed. The two sets of hazard calculations produced consistent results, demonstrating that 

the eight alternative maps provide an adequate representation of epistemic uncertainty in hazard.

L.6 HAZARD CALCULATION SOFTWARE 

L.6.1 Introduction

Modifications were required to the software that had been previously qualified in accordance 

with Appendix B of 10 CFR 50; these modifications were necessary to accommodate new 

elements in the source characterization. The modifications were checked by performing a 

number of tests that exercise the modified features of the software. This was done by comparing 

the results obtained with the new feature to either the equivalent results obtained with the 

qualified features of the software or the results from independent calculations. A brief summary 

of these tests is provided below. 

L.6.2 Test for the Treatment of Variable b

Calculations were performed for a source zone with variable b and for an equivalent problem 

where each cell is modeled as a separate source zone with constant rate and b. This test showed 

consistent results.

L.6.3 Test for the Treatment of Dipping Ruptures Within a Source Zone

Calculations were performed for a number of options regarding dip, orientation, and behavior at 

boundaries. These tests showed consistent results. 

L.6.4 Tests for Treatment of Epistemic Uncertainty from Sources that Make Small 

Contribution to Hazard

For the sake of efficiency, a new approach was developed to introduce “pinch points” in the 

portion of the logic tree associated with sources that make small contributions to total hazard.

This approach was tested by comparing fractiles hazard curves with and without this pinch point, 

showing consistent results.

L-6
BIBLIOGRAPHIC DATA SHEET

(See instructions on the reverse)

NRC FORM 335

(12-2010)

NRCMD 3.7

U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

 (Assigned by NRC, Add Vol., Supp., Rev.,

 and Addendum Numbers, if any.)

NUREG-2115

Vol. 6

3. DATE REPORT PUBLISHED

MONTH

January

YEAR

2012

4. FIN OR GRANT NUMBER

K6877

2. TITLE AND SUBTITLE

Central and Eastern United States Seismic Source Characterization for Nuclear Facilities

Volume 6: Appendices G to L

5. AUTHOR(S)

G. Stirewalt (NRC), L. Salomone (Savannah River Nuclear Solutions, LLC), S. McDuffie (DOE),

K. Coppersmith (Coppersmith Consulting, Inc), Fugro William Lettis & Associates, Inc.: C. Fuller,

R. Hartleb, W. Lettis, S. Lindvall, R. McGuire, G. Toro, D. Slayter, R. Cumbest, A. Shumway, F.

Syms, AMEC Geomatrix, Inc: L. Glaser, K. Hanson, R. Youngs, S. Bozkurt, V. Montaldo Falero,

R. Perman, R. McGuire (Risk Engineering), M. Tuttle (M. Tuttle & Associates)

6. TYPE OF REPORT

Technical

7. PERIOD COVERED (Inclusive Dates)

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor,

U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Washington DC 20555

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (If NRC, type "Same as above"; if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission, 

U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Washington DC 20555

provide name and mailing address.)

and mailing address.)

10. SUPPLEMENTARY NOTES

11. ABSTRACT (200 words or less)

This report describes a new seismic source characterization (SSC) model for the Central and Eastern United States (CEUS). It

will replace the Seismic Hazard Methodology for the Central and Eastern United States, EPRI Report NP-4726 (July 1986) and

the Seismic Hazard Characterization of 69 Nuclear Plant Sites East of the Rocky Mountains, Lawrence Livermore National

Laboratory Model, (Bernreuter et al., 1989). The objective of the CEUS SSC Project is to develop a new seismic source model

for the CEUS using a Senior Seismic Hazard Analysis Committee (SSHAC) Level 3 assessment process. The goal of the

SSHAC process is to represent the center, body, and range of technically defensible interpretations of the available data,

models, and methods. Input to a probabilistic seismic hazard analysis (PSHA) consists of both seismic source characterization

and ground motion characterization. These two components are used to calculate probabilistic hazard results (or seismic hazard

curves) at a particular site. This report provides a new seismic source model.

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating the report.)

Probabilistic seismic hazard analysis (PSHA)

Seismic source characterization (SSC)

Seismic source characterization model

Central and Eastern United States (CEUS)

14. SECURITY CLASSIFICATION

13. AVAILABILITY STATEMENT

unlimited

(This Page)

unclassified

(This Report)

unclassified

15. NUMBER OF PAGES

16. PRICE

NRC FORM 335 (12-2010)

U.S. Department of Energy, 1000 Independence Avenue SW, Washington DC 20585

Electric Power Research Institute, 3420 Hillview Avenue, Palo Alto, CA 94304

U.S. Department of Energy, 1000 Independence Avenue SW, Washington DC 20585

Electric Power Research Institute, 3420 Hillview Avenue, Palo Alto, CA 94304