National Landslide Hazards 

Mitigation Strategy—

A Framework for Loss Reduction

Circular 1244

U.S. Department of the Interior

U.S. Geological Survey
Landslide overview map of the conterminous United States. Different colors denote areas of varying landslide occurrence. From

U.S. Geological Survey, 1997, Digital compilation of landslide overview map of the conterminous United States: U.S. Geological

Survey Open-File Report 97–0289, digital compilation by Jonathan W. Godt, available on the web at

http://greenwood.cr.usgs.gov/pub/open-file-reports/ofr-97-0289/.

Front cover. Massive landslide at La Conchita, California, a small seaside community along Highway 101 north of Santa Barbara.

This landslide and debris flow occurred in the spring of 1995. Many people were evacuated because of the slide, and the houses

nearest the slide were completely destroyed. Fortunately, no one was killed or injured. Photograph by R.L. Schuster, U.S.

Geological Survey.
National Landslide Hazards 

Mitigation Strategy—

A Framework for Loss Reduction

By Elliott C. Spiker and Paula L. Gori

Circular 1244

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2003

Free on application to

U.S. Geological Survey

Information Services

Box 25286, Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1–888–ASK–USGS

World Wide Web: http://www.usgs.gov

Any use of trade, product, or firm names in this publication is for

descriptive purposes only and does not imply endorsement by

the U.S. Government.

Library of Congress Cataloging in Publications Data

Spiker, Elliott C.

National landslide hazards mitigation strategy : a framework for loss reduction / by

Elliott C. Spiker and Paula Gori.

p. cm.-- (Circular ; 1244)

Includes bibliographical references.

1. Landslide hazard analysis--United States. I. Gori, Paula. II. Title. III. U.S.

Geological Survey circular ; 1244.

QE599.U5S65 2003.

363.34’9--dc21 2002044779
Preface

House Report 106–222 accompanying the Interior Appropriations Bill for fiscal

year 2000 (as incorporated in Public Law 106–113) states, "The committee is

concerned over the lack of attention given to the Survey’s landslide program.

Because of this concern, the Survey is directed to develop by September 15,

2000, a comprehensive strategy, including the estimated costs associated with

addressing the widespread landslide hazards facing the Nation. The preparation

of this strategy should include the involvement of all parties having responsibility for dealing with the problems associated with landslides."

In fulfillment of the requirements of Public Law 106–113, the United States Geological Survey submits this circular, which describes a national strategy to

reduce losses from landslides. The circular includes a summary of the Nation’s

needs for research, monitoring, mapping, and assessment of landslide hazards

nationwide.

iii
v

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Losses from Landslide Hazards in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

A National Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

The National Landslide Hazard Mitigation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Reaching the Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Major Elements and Strategic Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Element 1. Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Element 2. Hazard Mapping and Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Element 3. Real-Time Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Element 4. Loss Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Element 5. Information Collection, Interpretation, Dissemination, and Archiving . . . . 20

Element 6. Guidelines and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Element 7. Public Awareness and Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Element 8. Implementation of Loss Reduction Measures . . . . . . . . . . . . . . . . . . . . . . . 24

Element 9. Emergency Preparedness, Response, and Recovery . . . . . . . . . . . . . . . . . 26

Action Items for a National Strategy for Reducing Losses from Landslides . . . . . . . . . . . . . . . . 28

Key Steps for Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Management Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

New and Enhanced Roles and Partnerships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Funding for the USGS to Implement a National Strategy for Reducing Losses

from Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Expansion of the Work Performed by Scientists in the Landslide Hazards Program . . . 31

Establishment of a New Cooperative Landslide Hazard Assessment and

Mapping Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Establishment of a New Cooperative Federal Land Management

Landslide Hazards Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Establishment of New Partnerships for Landslide Hazard Loss

Reduction Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Funding Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Major Accomplishments and Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Appendix 1. Previous Reports and Sources of Landslide Hazards Information . . . . . . . . . . . . . 35

Appendix 2. Meetings with Stakeholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Appendix 3. Landslide Hazards and Other Ground Failures—Causes and Types . . . . . . . . . . . . 39

Appendix 4. Landslide Hazards Mitigation Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Appendix 5. Landslide Hazards Maps and Risk Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Appendix 6. Current Landslide Research and Mitigation Activities and Responsibilities

in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Appendix 7. Federal Agency Landslide Hazard Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
vi

Highlights

1. Massive Landslide at Thistle, Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. Wildfires and Debris Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3. Building Disaster-Resistant Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4. Debris-Flow Flume—Understanding Landslide Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5. Mapping Debris-Flow Hazards in Madison County, Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6. Real-Time Monitoring of Active Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

7. Inventory of Slope Failures in Oregon for Three 1996–97 Storm Events . . . . . . . . . . . . . . . . 19

8. Warning of Potential Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. Alerting the Public to the Hazards of Mount Rainier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

10. Cincinnati, Ohio—A Leader in Landslide Loss Reduction Measures . . . . . . . . . . . . . . . . . . . 25

11. Daly City—The Human Cost of Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figures

1–4. Photographs showing—

1. Massive landslide at Thistle, Utah, 1983 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. Debris flow near Glenwood Springs, Colorado, 1994 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3. Landslide in northwest Seattle, Washington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4. Debris-flow flume, 45 miles east of Eugene, Oregon, constructed to conduct

controlled experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5. Portion of debris-flow hazard map, Madison County, Virginia . . . . . . . . . . . . . . . . . . . . . . . 15

6. Diagram showing network for transmission of real-time landslide data . . . . . . . . . . . . . . . 17

7. Photograph showing scientist measuring landslide movement . . . . . . . . . . . . . . . . . . . . . . 17

8. Photograph showing scientists testing a solar-powered radio telemetry system for

remote transmission of real-time landslide data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

9. Landslide-inventory map for three 1996–97 storm events in Oregon . . . . . . . . . . . . . . . . . . 19

10. Photographs showing debris flow in Pacifica, California, and house (inset) at

edge of debris flow, 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

11. Map showing hazard zones from lahars, lava flows, and pyroclastic flows

from Mount Rainier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

12. Photograph showing earthflow in Cincinnati, Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

13. Photograph showing gully retreat threatening evacuated houses in

Daly City, California, 1998 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5–1. Maps of part of Seattle, Washington, showing (A) landslide inventory, (B) landslide

susceptibility, (C), Probability of landslide occurrence, (D) Probability of landslide

damage, and (E) Risk of loss due to landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Table

1. New roles and partnership opportunities under the National Landslide Hazards

Mitigation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
This circular outlines the key elements of a comprehensive and effective

national strategy for reducing losses from landslides nationwide and provides

an assessment of the status, needs, and associated costs of this strategy. The circular is submitted in compliance with a directive of Public Law 106–113 (see

preface). A broad spectrum of expert opinion was sought in developing this

strategy report, as requested by the U.S. Congress in House Report 106–222.

The strategy was developed in response to the rising costs resulting from

landslide hazards in the United States and includes activities at the National,

State, and local levels, in both the public and private sectors. The strategy

gives the Federal Government a prominent role in efforts to reduce losses due

to landslide hazards, in partnership with State and local governments. The

U.S. Geological Survey (USGS) has taken the lead in developing the strategy

on behalf of the large multisector, multiagency stakeholder group involved in

landslide hazards mitigation. The USGS derives its leadership role in landslide

hazard-related work from the Disaster Relief Act of 1974 (Stafford Act). For

example, the Director of the USGS has been delegated the responsibility to

issue disaster warnings for an earthquake, volcanic eruption, landslide, or

other geologic catastrophe (1974 Disaster Relief Act 42 U.S.C. 5201 et seq).

The National Landslide Hazards Mitigation Strategy includes developing

new partnerships among government at all levels, academia, and the private

sector and expanding landslide research, mapping, assessment, real-time monitoring, forecasting, information management and dissemination, mitigation

tools, and emergency preparedness and response. Such a strategy uses new

technological advances, enlists the expertise associated with other related hazards such as floods, earthquakes and volcanic activity, and utilizes incentives

for the adoption of loss reduction measures nationwide.

Executive Summary

1

National Landslide Hazards 

Mitigation Strategy—

A Framework for Loss Reduction

By Elliott C. Spiker and Paula L. Gori

"Science by itself will not protect us. Federal, State, and local governments, the private sector, volunteer

and charitable organizations and individual citizens must work together in applying the science to make

our communities safer." 

—Charles Groat, Director of the U.S. Geological Survey
The strategy envisions a society that is fully aware of landslide hazards

and routinely takes action to reduce both the risks and costs associated with

those hazards. The long-term mission of a comprehensive landslide hazard

mitigation strategy is to provide and encourage the use of scientific information, maps, methodology, and guidance for emergency management, land-use

planning, and development and implementation of public and private policy

to reduce losses from landslides and other ground-failure hazards nationwide.

The 10-year goal is to substantially reduce the risk of loss of life, injuries,

economic costs, and destruction of natural and cultural resources that result

from landslides and other ground-failure hazards.

This comprehensive National Landslide Hazards Mitigation Strategy

employs a wide range of scientific, planning, and policy tools to address various aspects of the problem to effectively reduce losses from landslides and

other ground failures. It has the following nine major elements, spanning a

continuum from research to the formulation and implementation of policy

and mitigation:

• Research.—Developing a predictive understanding of landslide 

processes and triggering mechanism

• Hazard mapping and assessments.—Delineating susceptible areas and

different types of landslide hazards at a scale useful for planning and

decisionmaking

• Real-time monitoring.—Monitoring active landslides that pose substantial risk

• Loss assessment.—Compiling and evaluating information on the economic impacts of landslide hazards

• Information collection, interpretation, and dissemination.—

Establishing an effective system for information transfer

• Guidelines and training.—Developing guidelines and training for scientists, engineers, and decisionmakers

• Public awareness and education.—Developing information and education for the user community

• Implementation of loss reduction measures.—Encouraging mitigation

action

• Emergency preparedness, response, and recovery.—Building resilient

communities

In each of the above nine elements above, the USGS has a significant role;

however, the USGS is not the lead for all elements. 

2
Landslide hazards mitigation requires collaboration among academia, government, and the private sector. Aggressive implementation of a comprehensive and effective national landslide hazards mitigation strategy requires

increased investment in landslide hazard research, mapping and monitoring,

and mitigation activities. Reducing losses from landslide hazards can be

accomplished in part by expanding the existing USGS Landslide Hazard

Program, as follows:

• Expansion of research, assessment, monitoring, public information,

and response efforts by USGS scientists ($8 million annually)

• Establishment of a Cooperative Landslide Hazard Assessment and

Mapping Program to increase the efforts of State and local governments to map and assess landslide hazards within their jurisdictions

through competitive grants ($8 million annually, to be augmented

with 30 percent matching funds by the States and local jurisdictions)

• Establishment of a Cooperative Federal Land Management Landslide

Hazard Program to increase the capability of the National Park 

Service, U.S. Forest Service, Bureau of Land Management, and

other such organizations to address landslide hazards under their

jurisdictions ($2 million annually for work performed by USGS scientists on public lands)

• Establishment of a Partnerships for Landslide Hazard Loss Reduction

Program to support research and implementation efforts by universities, local governments, and the private sector through competitive

grants ($2 million annually)

Total new funding required for full implementation of the National Landslide

Hazards Mitigation Strategy within the USGS is estimated to be approximately $20 million annually.

An effective National Landslide Hazards Mitigation Strategy also depends

on stronger partnerships among Federal, State, and local governments and the

private sector in the areas of hazard assessments, monitoring, and emergency

response and recovery. The strategy recommended in this circular advocates

enhanced coordination among Federal, State, and local agencies to partner

effectively with the academic and the private sectors and to leverage shared

resources under the leadership of the USGS.

3
Landslides and other forms of ground failure affect communities all across

the Nation. Despite advances in science and technology, these events continue

to result in human suffering, billions of dollars in property losses, and environmental degradation. As our population increases and our society becomes ever

more complex, the economic and societal costs of landslides and other ground

failures will continue to rise.

We have the capability as a Nation to understand and identify these hazards and to implement mitigation measures. For many years, the U.S. 

Geological Survey (USGS), the States, numerous universities, and the private

sector have been grappling with understanding and reducing landslide hazards,

and they have developed an extensive body of knowledge (see appendix 1 for

sources of information). However, to achieve the goal of significantly reducing

losses from landslide hazards, we need a much more comprehensive scientific

understanding of landslide processes and occurrence, a robust monitoring program to warn of impending danger from active landslides, a much greater public awareness and understanding of the threat and the options for reducing the

risk, and action at the local level.

A significant, sustained, long-term effort to reduce losses from landslides

and other ground failures in the United States will require a national commitment among all levels of government and the private sector. The Federal

Government, in partnership with State and local governments, must provide

leadership, coordination, research support, incentives, and resources to encourage communities, businesses, and individuals to undertake mitigation to minimize potential losses and to employ mitigation in the recovery following landslides and other natural hazard events.

The USGS is the recognized authority for understanding landslide hazards

in the United States and the long-time leader in this area. The USGS derives

its leadership role in landslide-hazard-related work from the Disaster Relief

Act of 1974 (Stafford Act). The Director of the USGS has been delegated the

responsibility to issue disaster warnings for an earthquake, volcanic eruption,

landslide, or other geologic catastrophe consistent with the 1974 Disaster

Relief Act 42 U.S.C. 5201 et seq.

As requested by the U.S. Congress in House Report 106–222, the USGS

has prepared this National Landslide Hazards Mitigation Strategy on behalf of

the large multisector, multiagency stakeholder group involved in landslide

research and mitigation nationwide. A number of stakeholder workshops were

held during 1999 and 2000 with representatives of government and private

organizations, academicians, and private citizens to seek their opinion and

input (see appendix 2 for more information about the stakeholder workshops).

Introduction

4
The 1983 Thistle landslide began

moving in the spring of 1983 in

response to ground-water buildup

from heavy rains the previous

September and melting snowpack

from the winter of 1983. Within a few

weeks, the landslide dammed the

Spanish Fork River, consequently

obliterating U.S. Highway 6 and the

main line of the Denver and Rio

Grande Western Railroad (fig. 1).

The town of Thistle was inundated by the floodwaters rising behind

the landslide dam. Eventually a drain

system was engineered to drain the

lake and avert a potential disaster.

The landslide reached a state of equilibrium across the valley, but fears of

reactivation caused the railway to

construct a tunnel through bedrock

around the slide zone at a cost of millions of dollars. The highway likewise

was realigned around the landslide.

When the lake was drained, residual

muck partially buried the town, and virtually no one returned to Thistle. Total

costs (direct and indirect) incurred by

this landslide exceeded $400 million,

making this the most costly single

landslide event in U.S. history.

Figure 1. The 1983 Thistle landslide,

central Utah. Thistle Lake, which

resulted from damming of the Spanish

Fork River, was later drained as a precautionary measure. This view, taken

about 6 months after the slide

occurred, shows the realignment of the

Denver and Rio Grande Western

Railroad lines in the lower center and

the large cut for rerouting U.S.

Highway 6/50 on the extreme left side

of the photograph. 

Photograph by R.L. Schuster, U.S.

Geological Survey.

Highlight 1—

Massive Landslide at

Thistle, Utah

5
The National Landslide Hazards Mitigation Strategy provides a framework for reducing losses from landslides and other ground failures.

Although the strategy is national in scope, it is not exclusively Federal or

even exclusively governmental. Mitigation, defined as any sustained

action taken to reduce and eliminate long-term risk to life and property,

generally occurs at the State and local levels, and the strategy is based on

partnerships with stakeholders at all levels of government and in the

private sector.

The National Landslide Hazards Mitigation Strategy described here

incorporates many ideas and recommendations of previous studies and

reports that expressed the need for a national strategy to address natural

hazards, including landslides and other ground failures (see appendix 1).

These earlier studies and reports should be referred to for more in-depth

discussions of and insights into landslide hazard mitigation and research

needs. The National Landslide Hazards Mitigation Strategy builds on the

principles, goals, and objectives of the National Mitigation Strategy—

Partnerships for Building Safer Communities, developed in 1996 by the

Federal Emergency Management Agency (FEMA) to encourage mitigation

of all forms of natural hazards in the United States.

The term "landslide" describes many types of downhill earth movements, ranging from rapidly moving catastrophic rock avalanches and

debris flows in mountainous regions to more slowly moving earth slides

and other ground failures. In addition to the different types of landslides,

the broader scope of ground failure includes subsidence, permafrost, and

shrinking soils. This report focuses on landslides, the most critical groundfailure problem facing most regions of the Nation. However, the National

Landslide Hazards Mitigation Strategy provides a framework that can be

applied to other ground-failure hazards (see appendix 3 for more information about different types of landslide hazards and other forms of ground

failure).

6
Landslides are among the most widespread geologic hazards on Earth.

Landslides cause billions of dollars in damages and thousands of deaths and

injuries each year around the world. Landslides threaten lives and property in

every State in the Nation, resulting in an estimated 25 to 50 deaths and damage exceeding $2 billion annually. Although most landslides in the United

States occur as separate, widely distributed events, thousands of landslides can

be triggered by a single severe storm and earthquake, causing spectacular

damage in a short time over a wide area.

The United States has experienced several catastrophic landslide disasters

in recent years. In 1985, a massive slide in southern Puerto Rico killed 129

people, the greatest loss of life from a single landslide in U.S. history. The

1982–83 and 1983–84 El Niño seasons triggered landslide events that affected

the entire Western United States, including California, Washington, Utah,

Nevada, and Idaho. The Thistle, Utah, landslide of 1983 caused $400 million

in losses, the most expensive single landslide in U.S. history, and the 1997–98

El Niño rainstorms in the San Francisco Bay area produced thousands of landslides, causing over $150 million in direct public and private costs.

Landslides are a significant component of many major natural disasters

and are responsible for greater losses than is generally recognized. Landslide

damage is often reported as a result of a triggering event—floods, earthquakes,

or volcanic eruptions—even though the losses from landsliding may exceed all

other losses from the overall disaster. For example, flash floods in mountainous areas often have devastating debris flows. Also, most of the losses due to

the 1964 Alaska earthquake resulted from ground failure rather than from

shaking of structures, and landslides associated with a major earthquake in

Afghanistan and with Hurricane Mitch in Central America in 1998 caused the

majority of fatalities in these disasters.

All 50 States and the U.S. Territories experience landslides and other

ground-failure problems; 36 States have moderate to highly severe landslide

hazards. The greatest landslide damage occurs in the Appalachian, Rocky

Mountain, and Pacific Coast regions and Puerto Rico. Seismically active

mountainous regions, such as those in Alaska, Hawaii, and the West Coast are

especially at risk. Extremely vulnerable are areas where wildfires have

destroyed vegetation, exposing barren ground to heavy rainfall.

Landslide losses are increasing in the United States and worldwide as

development expands under pressures of increasing populations. The resulting

encroachment of developments into hazardous areas, expansion of transportation infrastructure, deforestation of landslide-prone areas, and changing climate patterns may lead to continually increasing landslide losses. However, an

increase in the cost of landslide hazards can be curbed through better understanding and mapping of the hazards and improved capabilities to mitigate and

respond to the hazards.

Losses from Landslide

Hazards in the United

States

7
Colorado River (fig. 2). A 3-mile length

of the highway was buried under tons

of rock, mud, and burned trees. The

closure of Interstate 70 imposed costly delays on this major transcontinental highway. The USGS assisted in

analyzing the debris-flow threat and

installing monitoring and warning systems to alert local safety officials

when high-intensity rainfall occurred

or debris flows passed through a susceptible canyon. Similar debris flows

threaten other transportation corridors and other development in and

near fire-ravaged hillsides.

From Highland, L.M., Ellen, S.D.,

Christian, S.B., and Brown, W.M., III,

1997, Debris-flow hazards in the

United States: U.S. Geological Survey

Fact Sheet FS–176–97, available on

the web at

http://geohazards.cr.usgs.gov/

factsheets/debrisflowfs.pdf.

During the summer of 2000,

numerous wildfires burned droughtparched areas of the Western United

States. U.S. Geological Survey (USGS)

scientists were enlisted to advise

Federal and State emergency

response teams on the potential for

future debris flows in burned areas,

such as the Cerro Grande fire (Los

Alamos, New Mexico) and the HiMeadow and Bobcat fires (Colorado).

Debris flows often occur during

the fall and winter following major

summer fires. One such combination

of fires and debris flows occurred in

July 1994, when a severe wildfire

swept Storm King Mountain west of

Glenwood Springs, Colorado, denuding the slopes of vegetation. Heavy

rains on the mountain the following

September caused numerous debris

flows, one of which blocked Interstate

70 and threatened to dam the

Highlight 2—

Wildfires and Debris Flows

8

Figure 2. Debris flows like this one near

Glenwood Springs, Colorado, in 1994

are a consequence of heavy rainfall on

previously burned hillsides. In addition

to personal injuries and damage to 30

vehicles engulfed by these flows, transportation along the Interstate 70 corridor was brought to a standstill for a day,

and business and emergency operations in the Glenwood Springs area

were seriously impeded. Photograph by

Jim Scheidt, U.S. Bureau of Land

Management.
Landslides and other ground failures impose many direct and indirect

costs on society. Direct costs include the actual damage sustained by buildings

and property, ranging from the expense of cleanup and repair to replacement.

Indirect costs are harder to measure and include business disruption, loss of

tax revenues, reduced property values, loss of productivity, losses in tourism,

and losses from litigation. The indirect costs often exceed the direct costs.

Much of the economic loss is borne by Federal, State, and local agencies that

are responsible for disaster assistance and highway maintenance and repair.

Landslides have a significant adverse effect on infrastructure and threaten

transportation corridors, fuel and energy conduits, and communications linkages. Ground-failure events have devastating economic effects on Federal,

State, local, and private roads, bridges, and tunnels every year. Railroads,

pipelines, electric and telecommunication lines, dams, offshore oil and gas

production facilities, port facilities, and waste repositories continually are

affected by land movement. Road building and construction often exacerbate

the landslide problem in hilly areas by altering the landscape, slopes, and

drainages and by changing and channeling runoff, thereby increasing the

potential for landslides. Landslides and others forms of ground failure also

have adverse environmental consequences, such as dramatically increased soil

erosion, siltation of streams and reservoirs, blockage of stream drainages, and

loss of valuable watershed, grazing, and timber lands.

9
ard map. This map includes Seattle's

detailed topographic database and

related geographic data, detailed precipitation data collected by the

National Weather Service, geographic

information system support for completing the maps, and a landslide

database from city records that date

back to the late 1800s. USGS scientists are analyzing city data along with

other information to determine the

degree of landslide hazard throughout

the city. The scientists are also conducting studies to determine the probability that landslides will result from

storms of different magnitudes.

The Disaster-Resistant

Communities project has resulted in

unprecedented awareness of landslide hazards by the private sector.

For example, major mortgage bankers

have realized that they hold mortgages on many properties in areas of

significant landslide hazard in Seattle

and elsewhere in the United States

and are beginning to take steps to

encourage homeowners to mitigate

the hazards.

An outstanding example of public-private partnerships is the Federal

Emergency Management Agency’s

(FEMA) Disaster-Resistant Communities

project (formerly called Project

Impact). Nearly 200 communities and

more than 1,100 business partners

have embraced this project since its

inception in 1997. Rather than waiting

for disasters to occur, communities

take action to reduce potentially devastating disasters. Seattle Washington,

a city that is exposed to significant

landslide hazards, was one of the first

communities in the United States to

join.

In conjunction with FEMA, the

city of Seattle collaborated with the

U.S. Geological Survey (USGS) to

develop landslide hazard maps that

will enable the city to be better prepared for landslide emergencies and

to reduce losses resulting from landslide disasters (fig. 3). The city made

available information needed by USGS

scientists to accurately assess landslide hazards in the area and to produce a computer-based landslide hazHighlight 3—

Building Disaster-Resistant

Communities

Figure 3. Landslide in northwest Seattle,

Washington. Foundation of the house on

the right edge of the photograph and

the decks of neighboring houses have

been undermined. Photograph by Alan 

F. Chleborad, U.S. Geological Survey.

10
Society is far from helpless in the face of these prospects.

Improvements in our scientific understanding of landslides and other

ground-failure hazards can provide more accurate delineation of hazardous

areas and assessments of their hazard potential. This information can be

developed in a form and at a scale meaningful and useful for decisionmaking. Cost-effective actions can be taken to reduce the loss of lives and property, damage to the environment, and economic and social disruption

caused by landslides and other ground failures (see appendix 4 for more

information about mitigation techniques).

Government at all levels plays critical roles in advancing landslide

hazard mitigation and developing programs and incentives that encourage

and support community-based implementation. A national strategy to

reduce losses from landslides and other ground failures must have both

research and implementation components to increase understanding of

landslides and other ground failures and put existing knowledge to use to

reduce losses. Developing durable and comprehensive solutions to landslides

and other ground-failure hazards will require a continuing dialog among

and concerted action by all sectors of our society.

A new public-private partnership is needed at the Federal, State, and

local levels to foster continuing cooperation among geologists, engineers,

hydrologists, planners, and decisionmakers regarding landslides and other

natural hazards. This ongoing effort will, over time, help to ensure that the

needed scientific and engineering information is developed in a form useful

for planning and decisionmaking and that such information is applied to

mitigate these hazards.

A National Strategy

11
of the flume permit measurements of

forces due to particles sliding and

colliding at the based of flows.

Additional insight can be gained by

using ultrasound imaging to "see"

into the interior of flows and by

deploying "smart rocks" containing

miniature computers that record the

rocks’ accelerations as they move

down the flume.

To create a debris flow, 20 cubic

meters (about 40 tons) of saturated

sediment are placed behind a steel

gate at the head of the flume and then

released. Alternatively, a sloping

mass of sediment can be placed

behind a retaining wall at the flume

head and watered until slope failure

occurs. The ensuing debris flow

descends the flume and forms a

deposit at the flume base. The flume

design thus accommodates research

on all stages of the debris-flow

process, from initiation through

deposition.

From Iverson, R.M., Costa, J.E., and

LaHusen, R.G., 1982, Debris flow

flume at H.J. Andrews Experimental 

Forest, Oregon: U.S.Geological Survey 

Open-File Report 92–483, 2 p.

U.S. Geological Survey (USGS)

and U.S. Forest Service (USFS) scientists recreate debris flows in a flume

that has been constructed to conduct

controlled experiments (fig. 4).

Located about 45 miles east of

Eugene, Oregon, this unique facility

provides research opportunities available nowhere else in the United

States. USGS and USFS scientists

conduct experiments to improve the

understanding of ground vibrations

caused by debris flows and to refine

automated debris-flow detection systems. The flume also provides an

ideal environment for testing landslide

controls that deflect, trap, or channelize debris flows. Experiments that

assess how debris flows react to and

act upon such controls can be used

to guide and evaluate engineering

designs.

The debris-flow flume is a reinforced concrete channel 310 feet

long, 6.6 feet wide, and 4 feet deep

that slopes 31 degrees, an angle typical of terrain where natural debris

flows originate. Removable glass windows built into the side of the flume

allow flows to be observed and photographed as they sweep past. A total

of 18 data-collection ports in the floor

Highlight 4—

Debris-Flow Flume—

Understanding Landslide

Processes

Figure 4. The U.S. Geological Survey

(USGS) debris-flow flume is located in

H.J. Andrews Experimental Forest,

Oregon. The flume was constructed to

conduct controlled debris-flow experiments. Photograph courtesy of the

USGS, taken September 13, 2001.

12
The National Landslide Hazards Mitigation Strategy described herein

envisions a society that is fully aware of landslide hazards and routinely takes

action to reduce both the risks and costs associated with those hazards. The

strategy envisions bringing together relevant scientific, engineering, construction, planning, and policy capabilities of the Nation to eliminate losses from

landslides and other ground-failure hazards nationwide.

The long-term mission of such a strategy is to provide and encourage the

use of scientific information, maps, methodology, and guidance for emergency

management, land-use planning, and development and implementation of public and private policy to reduce losses from landslides and other ground-failure

hazards nationwide.

The strategic plan described in this report has nine major elements, spanning a continuum from research to the formulation and implementation of policy and mitigation objectives. Implementation of such a strategy will demand a

multiyear coordinated public and private effort. All levels of government and

the private sector share responsibility for addressing these priorities and

accomplishing the objectives. Some of the objectives consist of a single, discrete action; others encompass a series of interdependent actions to be taken

over the first 10 years of implementation. Although the primary focus is on

landslide hazards, the national strategy provides a framework for addressing

other forms of ground failure as well.

The USGS has a role in each of the nine elements as a provider of landslide hazard information; however, the lead and participants in each element

differ with the nature of the element.

The National

Landslide Hazards

Mitigation Strategy 

13

Reaching the Goal
Research to develop a predictive understanding of landslide processes and

triggering mechanisms will be led by the USGS. Hazard identification is a

cornerstone of landslide hazard mitigation. Although many aspects of landslide hazards are well understood, a much more comprehensive understanding

of landslide processes and mechanisms is required to truly advance our ability

to predict the behavior of differing types of landslides. The following actions

will increase the Nation’s capability to forecast landslide hazards through

enhanced research, the application of new technology, and an increased understanding of landslide processes, thresholds, and triggering mechanisms:

• Develop a national research agenda and a multiyear implementation

plan based on the current state of scientific knowledge concerning

landslide hazard processes, thresholds, and triggers and on the ability to predict landslide hazard behavior

• Develop improved, more realistic scientific models of ground deformation and slope failure processes and implement their use in predicting

landslide hazards nationwide

• Develop dynamic landslide prediction systems capable of interactively

displaying changing landslide hazards in both space and time in areas

prone to different types of landslide hazards (for example, shallow

debris flows during intense rain, deep-seated slides during months of

wet weather, and rock avalanches during an earthquake)

Efforts to delineate susceptible areas and different types of landslide hazards at a scale useful for planning and decisionmaking will be led by the

USGS and State Geological Surveys. Landslide inventory and landslide susceptibility maps are critically needed in landslide-prone regions of the Nation.

These maps must be sufficiently detailed to support mitigation action at the

local level. To cope with the many uncertainties involved in landslide hazards,

probabilistic methods are being developed to map and assess landslide hazards

(see appendix 5 for more information about mapping and assessing landslide

hazards). Risk assessments estimate the potential economic impact of landslide hazard events. Landslide inventory and susceptibility maps and other

data are a critical first step and are prerequisite to producing probabilistic hazard maps and risk assessments, but these maps and data are not yet available

for most areas of the United States. The following actions will provide the

necessary maps and assessments and other information to officials and

planners to reduce risk and losses:

• Develop and implement a plan for mapping and assessing landslide

and other ground-failure hazards nationwide

• Develop an inventory of known landslide and other ground-failure

hazards nationwide

• Develop and encourage the use of standards and guidelines for landslide hazard maps and assessments

Major Elements and

Strategic Objectives

Element 1. Research

Element 2. Hazard

Mapping and

Assessments

14
Figure 5. Portion of debris-flow hazard

map, Madison County, Virginia. From

Morgan, B.A., Wieczorek, G.F., and

Campbell, R.H., 1999, Historical and

potential debris-flow and flood hazard

map of the area affected by the June

27, 1995, storm in Madison County,

Virginia: U.S. Geological Survey

Geologic Investigations Series Map

I–2623–B, 1 sheet.

Highlight 5—

Mapping Debris-Flow Hazards

in Madison County, Virginia

15

A major landslide event occurred

in Madison County, Virginia, in the

summer of 1995. During an intense

storm on June 27th, 30 inches of rain

fell in 16 hours. In mountainous areas,

rain-saturated landslides known as

debris flows were triggered by the

hundreds, causing extensive devastation and one fatality.

Historical records tell us that

destructive landslides and debris

flows in the Appalachian Mountains

occur when unusually heavy rain from

hurricanes and intense storms soaks

the ground, reducing the ability of

steep slopes to resist the downslope

pull of gravity. For example, during

Hurricane Camille in 1969, such conditions generated debris flows in

Nelson County, Virginia, 90 miles

south of Madison County. The storm

caused 150 deaths, mostly attributed

to debris flows, and more than $100

million in property damage. Likewise,

72 hours of storms in Virginia and

West Virginia during early November

1985 caused debris flows and flooding

in the Potomac and Cheat River

basins that were responsible for 70

deaths and $1.3 billion in damage to

homes, businesses, roads, and farmlands.

Scientists from the U.S.

Geological Survey have developed an

inventory of landslides, debris flows,

and flooding from the storm of June

27, 1995, by using aerial photography,

field investigations, rainfall measurements from rain gages, and National

Weather Service radar observations.

This inventory and a new debris-flow

hazard map (fig. 5) are being used to

help understand the conditions that

led to the floods and debris flows

caused by the 1995 summer storms in

Virginia and to suggest methods of

mitigating the effects of such events

in the future.

From Gori, P.L., and Burton, W.C., 1996,

Debris-flow hazards in the Blue Ridge

of Virginia: U.S. Geological Survey

Fact Sheet FS–159–96, 4 p.
Studies to monitor active landslides that pose substantial risk will be led

by the USGS. Monitoring active landslides serves the dual purpose of providing hazard warning in time to avoid or lessen losses, as well as supporting

landslide research by providing new insights into landslide processes and triggering mechanisms. Collection of rare dynamic movement behavior data

enables the testing of landslide velocity models and the development of

improved predictive tools applicable to other slides. Development and application of real-time monitoring of active landslides using state-of-the-art research

and telecommunications technologies are critically needed nationwide in cases

of imminent risk. The following actions will provide the necessary warning

and other information to officials and communities to avoid or reduce losses:

• Develop and implement a national landslide hazard monitoring and

prediction capability

• Develop real-time monitoring and prediction capabilities on both site

specific and regional scales, to assist Federal, State, and local emergency managers determine the nature of landslide hazards and the

extent of ongoing risks

• Apply remote-sensing technologies such as Synthetic Aperture radar

and laser altimetry for monitoring landslide movement nationwide

• Incorporate state-of-the-art techniques such as microseismicity and

rainfall and pore-pressure monitoring with hydrologically based models

of slope stability and global positioning systems (GPS)

• Integrate real-time monitoring capabilities with the National Weather

Service’s NEXRAD capabilities in selected locations nationwide

Element 3. Real-Time

Monitoring

16
Highlight 6—

Real-Time Monitoring of

Active Landslides

Five landslides that threaten U.S.

Highway 50 and nearby homes in

Sierra Nevada, California, are being

monitored by the U.S. Geological Survey (USGS) after heavy rains in

January 1997 generated debris flows

that blocked Highway 50. The cost of

reopening the highway was $4.5 million, with indirect economic losses

from closure of the highway amounting to an additional $50 million. To

monitor the risk posed by landslides

in this area, the USGS, in cooperation

with local, State, and other Federal

Agencies, provides continuous realtime monitoring of landslide activity

using a system developed by the

USGS for monitoring active volcanoes

in remote areas (fig. 6).

This system measures ground

movement and ground-water pressures every second. Slope movement

is recorded by instruments that detect

stretching and shortening of the

ground (fig. 7). Ground vibrations

caused by slide movement are monitored by geophones buried within the

slide. Ground-water conditions within

the slides are monitored by sensors,

and rain gauges record precipitation.

Under normal conditions, data are

transmitted to USGS computers every

10 minutes, but if strong ground vibrations caused by massive landslide

movement are detected, data are

transmitted immediately (fig. 8).

The USGS operates other remote

real-time landslide monitoring sites.

Near Seattle, Washington, a real-time

system monitors a slide threatening a

major railway, and in Rio Nido,

California, another system monitors a

large landslide threatening more than

140 homes. Remote monitoring also

can record the effects of wildfire in

destabilizing slopes.

From Reid, M.E., LaHusen, R.G., and

Ellis, W.L., 1999, Real-time monitoring

of active landslides: U.S. Geological

Survey Fact Sheet FS–91–99, 2 p.

17

Figure 8. Testing a solar-powered radio

telemetry system for remote transmission

of real-time landslide data. Photograph by

Mark Reid, U.S. Geological Survey.

Figure 7. Measuring landslide movement.

Photograph by Richard LaHusen, U.S.

Geological Survey.

Figure 6. Network for transmission of

real-time landslide data.
A project compiling and evaluating information on the economic impacts

of landslide hazards will be led by FEMA and the insurance industry.

Although losses from landslides and other natural hazards are frequent and

widespread, these losses are not consistently compiled and tracked in the

United States. Following a landslide or other natural hazard event, a variety of

different agencies and organizations may provide damage estimates, but these

estimates usually vary widely, cover a range of different costs, and change

through time. The National Research Council concluded in their 1999 report

"The Impact of Natural Disasters—A Framework for Loss Estimation" that

there is no widely accepted framework for estimating the losses from natural

disasters, including landslide and other ground-failure hazards. This lack of

information makes it difficult to set policies for coping with these hazards and

difficult to gage the cost-effectiveness of policy decisions and effectiveness of

mitigation measures. Loss data are critically needed to help government agencies identify trends and track progress in reducing losses from landslides. The

following actions will provide a framework for compiling and assessing a

comprehensive data base of losses from landslides and other ground -failure

hazards, which will help guide research, mapping, and mitigation activities

nationwide:

• Assess the current status of data on losses from landslides and other

ground failures nationwide, including the types and extent of losses to

public and private property, infrastructure, and natural and cultural

resources

• Establish and implement a national strategy for compilation, maintenance, and evaluation of data on the economic and environmental

impacts of landslide and other ground-failure hazards nationwide to

help guide mitigation activities and track progress

Element 4. Loss

Assessment

18
Three significant Pacific

Northwest storm events in February

1996, November 1996, and late

December 1996 and early January

1997 initiated widespread slope failures throughout Oregon. Each of

these storms was declared a "Major

Presidential Disaster Declaration,"

and damages to natural resources

and infrastructure were extreme. In

the Portland metropolitan region,

Oregon’s largest city, more than 700

slope failures were associated with

the heavy rains in 1996, with 17

houses completely destroyed and 64

partially condemned. An estimate of

statewide public and private damages

incurred from the February 1996 event

alone is $280 million.

To better characterize the distribution and magnitude of the slope

failures associated with the three

storms, the Federal Emergency

Management Agency provided funding for the consolidation of a landslide

inventory (fig. 9). The Oregon

Department of Geology and Mineral

Industries led the consolidation effort

and utilized various methods to contact potential data sources, inform

them of the existence of the study,

and request their participation. This

inventory will help lead to a greater

understanding of regional landslide

issues and assist government and

community agencies in devising

means to minimize the threat to public

health and property that landslides

pose.

Over 9,000 landslide locations

were incorporated into the inventory,

with varying amounts of information

reported for each. Many other slides

were not observed or recorded, and it

is estimated that two to three times

this many landslides occurred during

the time period. As shown on the

landslide inventory map, the vast

majority (98 percent) of the entries

are in the western portion of the

State. Most of these slides occurred

Highlight 7—

Inventory of Slope Failures in

Oregon for Three 1996–97

Storm Events

19

Figure 9. Landslide inventory for three

1996–97 storm events in Oregon.

in the Oregon Coast Range and Cascade province, with fewer in the

Willamette Valley and Klamath Mountains.

From Hofmeister, R.J., 2000, Database

of slope failures in Oregon for three

1996/97 storm events: Oregon

Department of Geology and Mineral

Industries.
The effort to establish an effective system for information transfer will

be led by the USGS and State Geological Surveys. Collecting and disseminating landslide hazards information to Federal, State, and local government

agencies; nongovernmental organizations; planners; policymakers; and private citizens in a form useful for planning and decisionmaking are critically

important to an effective mitigation program. Although landslide hazards

have been studied for decades, a systematic effort to collect and distribute

scientific and technical information is in its relative infancy. The USGS

National Landslide Information Center is a prototype system that can be

enhanced and extended into a robust nationwide system for the collection,

interpretation, and dissemination of landslide hazard maps, assessments, and

other scientific and landslide hazard technical information. The following

objectives will make landslide hazard information accessible to scientists,

officials, decisionmakers, and the public to assist research, planning, policy,

and mitigation activities:

• Evaluate and use state-of-the-art technologies and methodologies for

the dissemination of technical information, research results, maps, and

real-time warnings of potential landslide activity

• Develop and implement a national strategy for the systematic collection, interpretation, archiving, and distribution of this information

Element 5. Information

Collection, Interpretation,

Dissemination, and

Archiving

20
An experimental monitoring and

warning system was developed and

operated jointly by the U.S. Geological

Survey (USGS) and the National

Weather Service (NWS) from the

1980s to 1995 in the San Francisco

Bay region (fig. 10). The system used

(1) NWS protocols and outlets for

issuing warnings and (2) regional networks of NWS and USGS rain gages

and soil-moisture instruments to track

rainfall and soil-moisture conditions.

Rainfall thresholds for triggering landslides were determined on the basis

of observed relationships between

rainfall intensity and duration and the

occurrence of landslides. When realtime data and high precision forecasting by the NWS indicated that the

rainfall threshold for landslides had or

would soon be reached, USGS scientists informed the NWS to issue a

warning through normal media channels. The media, government officials,

Highlight 8—

Warning of Potential

Landslides

21

and the general public in the bay area

came to rely on these warnings and

took specific actions such as evacuating neighborhoods at particular risk.

Under the National Landslide

Hazards Mitigation Strategy, next-generation landslide warning systems will

be implemented in landslide-prone

regions nationwide. Precipitation, soil

moisture, and pore-pressure data will

telemetered in real time to network

centers for processing and analysis.

These measurements will help define

the precipitation thresholds and supplement the NWS NEXRAD (Next

Generation Radar) network and other

precipitation data and forecasts provided by the NWS or local agencies.

Warnings of potential landslide activity that might be triggered by storms or

extended rainy periods will be issued

in cooperation with the NWS and

Federal and State emergency management agencies.

Figure 10. Debris flow from a steep hillslope in Pacifica, California, about 10 miles south

of San Francisco, where three children were killed and two homes destroyed on January

4, 1982. Inset, View of destroyed homes from the street. Photograph by Gerald Wieczorek,

U.S. Geological Survey. From U.S. Geological Survey, 1995, Debris-flow hazards in the

San Francisco Bay region: U.S. Geological Survey Fact Sheet FS–112–95, 2 p. Available

on the web at http://greenwood.cr.usgs.gov/pub/fact-sheets/fs-0112-95/.
Efforts to develop guidelines and training for scientists, engineers, and decisionmakers will be led by the USGS and professional societies. The study of

landslide hazards is an area of active research and technological application, and

there is a critical need for guidelines and training for scientists and engineers in the

development of landslide maps and assessments. Hazard assessments involve

assumptions and calculations about the magnitude and return frequency in specific

geographic settings. Risk assessments involve assumptions about the potential

physical and economic impacts of landslide hazard events. The development and

presentation of the results in terms that are useful to citizens and decisionmakers

are critically important to effective mitigation. Likewise, development of guidelines

and training for planners and other decisionmakers in the use of these maps and

assessments are important to encouraging its appropriate use by the user community.

The following are high priority objectives related to guidelines and training:

• Develop and implement guidelines and training for scientists and geotechnical engineers in the use of landslide hazard and other technical

information for mapping and assessing landslide hazards

• Develop and implement guidelines and training for scientists and geotechnical engineers for responding to landslide disasters and providing

needed scientific and technical information for response and recovery

efforts

• Develop and implement guidelines and training for planners and decisionmakers in the use of landslide hazard maps, assessments, and other

technical information for planning, preparedness, and mitigation

Efforts to develop information and education programs for the user community will be led by FEMA and the USGS. Before individuals and communities can reduce their risk from landslide hazards, they need to know the nature

of the threat, its potential impact on them and their community, their options

for reducing the risk or impact, and methods for carrying out specific mitigation measures. Achieving widespread public awareness of landslide hazards

will enable communities and individuals to make informed decisions on where

to live, purchase property, or locate a business. Local decisionmakers will

know where to permit construction of residences, business, and critical facilities to reduce potential damage from landslide hazards. The following actions

will raise public awareness of landslide hazards and encourage landslide hazard

preparedness and mitigation activities nationwide, tailored to local needs:

• Develop public awareness, training, and education programs involving

land-use planning, design, landslide hazard curriculums, landslide hazard safety programs, and community risk reduction

• Evaluate the effectiveness of different methods, messages, and curriculums in the context of local needs

• Disseminate landslide-hazard-related curriculums and training modules

to community organizations, universities, and professional societies

and associations

Element 6. Guidelines and

Training

Element 7. Public

Awareness and

Education

22
Mount Rainier in Washington

State is an active volcano that is currently at rest between eruptions. Its

next eruption may produce volcanic

ash, lava flows, or pyroclastic flows

(fig. 11). Pyroclastic flows are hot

avalanches of lava fragments and gas

formed by volcanic eruptions.

Pyroclastic flows can rapidly melt

snow and ice, and the resulting meltwater torrent may produce lahars (the

widely used Indonesian word for volcanic mudflows and debris flows) that

travel down valleys beyond the base

of the volcano. Lahars may also occur

during noneruptive times when a section of the volcano collapses.

Lahars look and behave like

rapidly flowing concrete, and their

impact can destroy most manmade

structures. Historically at Mount

Rainier, they have traveled 45–50

miles per hour in thicknesses of 100

feet or more in confined valleys, slowing and thinning as they flowed into

wider valleys, most of which are populated. At Mount Rainier, lahars pose

a greater risk than other volcanic

hazards, such as lava and poisonous

gases.

The likely courses of lahars are

the river valleys that drain Mount

Rainier. Four of the five major river

systems flow westward into suburban

areas of Pierce County. The U.S.

Geological Survey mapped the likely

flow pathways and has joined with

local, county, and State agencies to

develop a Mount Rainier hazards plan

that will address such issues as

emergency response operations and

strategies for expanded public

awareness and mitigation.

From Scott, K.M., Wolfe, E.W., and

Driedger, C.L., 1998, Mount Rainier;

living with perilous beauty: U.S.

Geological Survey Fact Sheet

FS–065–97, 4 p. and Hoblitt, R.P.,

Walder, J.S., Driedger, C.L., Scott,

K.M., Pringle, P.T., and Vallance, J.W.,

1998 (rev.), Volcano hazards from

Mount Rainier, Washington: U.S.

Geological Survey Open-File Report

98–428, 11 p., 2 oversize sheets.

23

Highlight 9—

Alerting the Public to the

Hazards of Mount Rainier

Figure 11. Hazard zones from lahars, lava flows, and pyroclastic flows from Mount

Rainier. From Scott, K.M., Wolfe, E.W., and Driedger, C.L., 1998, Mount Rainier; living

with perilous beauty: U.S. Geological Survey Fact Sheet FS–065–97, 4 p. 
Efforts to encourage mitigation action will be led by FEMA, State

departments of emergency services, and professional societies. A successful

strategy for reducing landslide losses must also include a mitigation component. Mitigation actions generally fall to State and local governments, businesses, and individuals. As a result, societal attitudes and perceptions can

present formidable obstacles to landslide hazards reduction. Few communities have considered the full range of mitigation options despite their feasibility and cost effectiveness. Mitigation measures at the local level include

a range of tools and techniques, such as land-use planning, regulation of

development, engineering controls, building codes, assessment districts,

emergency planning and warning, and private financial and insurance incentives and disincentives. The following actions will facilitate and encourage

implementation of appropriate and effective mitigation measures that are

tailored to local needs:

• Evaluate impediments to effective planning and controls on development and identify approaches for removing those impediments.

• Develop an education program for State and local elected and appointed officials that sensitizes them to the risk and costs of landslide hazards and encourages them to develop legislation and policies that support effective landslide hazard mitigation

• Develop and disseminate prototype incentives and disincentives for

encouraging landslide mitigation to government agencies, the private

sector, and academia

• Evaluate engineering and construction approaches to mitigate landslide

hazards and develop a national plan for research to improve these techniques

• Encourage implementation of successful landslide mitigation

technologies

Element 8.

Implementation of Loss

Reduction Measures

24
Landslides are a significant problem in several areas of Ohio, and

Cincinnati has one of the highest per

capita costs due to landslide damage

of any city in the United States.

Landslides have been known to occur

in the Cincinnati area in southwestern

Ohio and the adjoining States of

Kentucky and Indiana since before

the 1850s, but the damage caused by

landslides has become increasingly

expensive as urban development

encroaches more and more on the

area’s hillsides. The city of Cincinnati

spent an average of $550,000 per year

on emergency street repairs for damage due to landslides between 1983

and 1987 (fig. 12).

In 1974, the Cincinnati City

Council passed an excavation and fill

ordinance to help reduce landslide

damage in areas of new construction.

In 1989, Cincinnati created a geotechnical office within its Department

of Public Works. The office, which is

staffed by a geotechnical engineer, an

engineering geologist, and two technicians, carries out a mitigation program. Since 1989, members of the

geotechnical staff have worked in

several ways to reduce landslide

damage in the city; their work

includes engineering geologic mapping of selected parts of the city,

inspecting retaining walls that affect

public right-of-way, reviewing proposed construction in hillside areas,

inspecting and arranging for repair of

landslide areas that affect city property, and compiling geologic and

geotechnical data on landslide areas

within the city. In 1990, Hamilton

County also adopted an excavation

and fill ordinance to help reduce the

damage due to landslides in areas of

new construction.

From Hansen, M.C., 1995, Geofacts:

Ohio Department of Natural

Resources, no. 8 and Baum, R.L., and

Johnson, A.M., 1996, Overview of

landslide problems, research, and

mitigation, Cincinnati, Ohio, area: U.S.

Geological Survey Bulletin 2059–A,

p. A1–A33.

Highlight 10—

Cincinnati, Ohio—A Leader

in Landslide Loss Reduction

Measures

25

Figure 12. Earthflow material being

removed by a highway crew along the

Columbia Parkway, Cincinnati, Ohio. Hamilton County, in the metropolitan Cincinnati

area, experienced an average annual economic loss of $5.80 per person (1975 dollars)

between 1973 and 1978, the highest calculated per capita loss of any municipality in the

United States. Photograph courtesy of the

U.S. Geological Survey.
Efforts to develop resilient communities will be led by FEMA and State

departments of emergency services. Despite improved landslide hazard mitigation, disasters will occur. For this reason, governments at all levels, the private

sector, and the public will need to be able to adequately prepare for, respond

to, and recover from disasters involving landslides. Governments will need to

better plan for landslide emergencies. Scientists, engineers, and emergency

response professionals will need to be trained in the best practices to employ

during a response, and public officials responsible for recovery from disasters

will need to be informed of options that will reduce future landslide losses.

Incorporating the following actions in a national landslide mitigation strategy

will improve the Nation’s ability to respond to and recover from landslide disasters:

• Provide training for Federal, State, and local emergency managers on

landslide hazards preparedness, response, and recovery

• Develop a coordinated landslide rapid response capability to assist

local, State, and Federal emergency managers in determining the

nature of landslide hazards and the extent of ongoing risks

• Provide dedicated landslide expertise and equipment required for rapid

emergency deployment of real-time data to emergency managers, as

well as the ability to successfully transfer monitoring technology to

other agencies

Element 9. Emergency

Preparedness,

Response, and

Recovery

26
Active landslides pose an increasing problem to older communities. An

example of this dilemma came to a

head in April 2000, when 21 late-1950s

era homes in Daly City, California,

were condemned because of continued landsliding along Westline Drive.

The homes were deemed permanently

uninhabitable, and the city had no

choice but to remove their inhabitants

from imminent danger. By May, all residents had moved.

The Westline Drive landslide first

came to the attention of Daly City residents in 1966, when sliding forced

the removal of homes from a subdivision developed just 7 years earlier.

One more home was removed in 1980.

The movement lessened until the El

Niño winter of 1997–98, one of the

wettest rainy seasons on record,

caused the landslide to reactivate

(fig. 13). As a result, Westline Drive

dropped as much as 4 feet in some

areas.

The decision by the city to condemn the houses was in reaction to

the local gas utility’s decision to shut

off gas service in February to the

affected area of Westline drive after

finding numerous irreparable leaks.

The utility feared that pipe ruptures

would cause an explosion. In addition, the city closed off the street to

traffic, including garbage and emergency vehicles, after discovering a

10-foot-square cavity beneath the

pavement.

Assisting the homeowners was a

challenge because no insurance was

available. The Federal Emergency

Management Agency offered to buy

the homes, but funds covered only

part of the previous value of the

homes. The Federal Small Business

Administration offered mortgage

loans at 4 percent, but only for a

reduced value of the homes, and the

homeowners had to pay off their

existing mortgages. Daly City and San

Mateo County planned to supplement

the Federal Government’s $6.5 million

offer of assistance with housing

funds totaling $1 million. Daly City

planned to take over the deeds from

the homeowners and turn the land

into open space.

From San Francisco Chronicle,

March 30 and May 2, 2000, Angelica

Pence, staff writer, and Russell

Graymer, U.S. Geological Survey.

Highlight 11—

Daly City—The Human Cost

of Landslides

27

Figure 13. Gully retreat threatening evacuated houses in Daly City, a suburb of San

Francisco, California, following the storm of

February 2–3, 1998. Landslide and mudslide

activity was extensively reported in the news

media following heavy rains on February 2–3,

1998. A number of scattered, slow-moving

landslides had been active over the weeks

prior to the storm in San Francisco, Oakland,

and elsewhere in the San Francisco Bay

region. As most of the area experienced

about 200 percent of normal rainfall in the

winter of 1998, these landslides were probably related more to the wet winter and less to

the effects of this particular storm. However,

based on limited ground reconnaissance,

scattered slope movements directly related

to the storm did occur. Debris flows directly

triggered by the storm affected a number of

homes and properties. From U.S. Geological

Survey web site http://landslides.usgs.gov/

html_files/landslides/reconrpt.html, 1998,

accessed July 29, 2002. Photograph by

Steve Ellen, U.S. Geological Survey.
Landslide hazard mitigation necessitates interactive collaboration among

academia, industry, government, and the private sector. The following key

aspects of a National Landslide Mitigation Strategy will allow for rapid and

significant progress toward a sustained mitigation of landslide hazards nationwide:

• Conduct Federal-State and public-private forums to establish regional

priorities for research, mapping, monitoring, forecasting, and mitigating landslide hazards

• Establish new and enhance existing programs to fund research, mapping, monitoring, and mitigation activities nationwide

• Develop Federal-State and public-private programs to delineate landslide prone areas, to forecast the potential for landslides, and to mitigate losses

• Establish and enhance Federal-State and public-private partnerships to

leverage and maximize relevant resources and expertise

Durable and effective solutions to the Nation’s ground-failure-hazard

problems will require a continuing dialog among and concerted action by all

sectors of our society. An effective National Landslide Hazards Mitigation

Strategy will require a combination of purposeful management to ensure

coordination and consortium-type decisionmaking to accommodate the multijurisdictional, cooperative nature of the program. An effective management

plan will include the following:

• Establish coordination of the National Landslide Hazards Mitigation

Strategy under the leadership of the USGS, using the bureau’s expertise and experience in landslide hazards research, monitoring, mapping

and data collection, analysis, archiving, and dissemination

• Establish working groups with representatives of Federal, State, and

local governments, academia, and private industry to help coordinate

and guide the National Landslide Hazards Mitigation Strategy

• Establish Federal-State public-private cooperative programs to fund

and encourage landslide hazard research, mapping, assessment, and

mitigation efforts nationwide

Many Federal, State, and local agencies; academia; and private companies

are involved in landslide research and mitigation in the United States (see

appendixes 6 and 7 for more information about Federal, State, and local programs). A National Landslide Hazards Mitigation Strategy offers new opportunities for mutually advantageous partnerships relating to hazard assessments,

monitoring, and emergency response and recovery.

The national strategy enhances the ability of Federal, State and local

agencies to partner effectively with the academic and the private sectors and to

leverage shared resources. Table 1 outlines the complementary and supportive

roles and opportunities for new partnerships for each participant in the

National Landslide Hazards Mitigation Strategy.

Action Items for a

National Strategy

for Reducing

Losses from

Landslides

Key Steps for

Implementation

Management Plan

New and Enhanced

Roles and Partnerships

28
Table 1. New roles and partnership opportunities under the National Landslide Hazards Mitigation Strategy.

Element Current New roles and partnership opportunities status Federal State Local Private Academic1. Research.— A much more comprehensive Coordinate research prioritiesDeveloping a predictive understanding of landslideunderstanding of processes and mechanisms is Conduct researchlandslide processes and required to advance our abilitytriggering mechanisms to predict the behavior of Use results of research in policy, planning, and mitigation decisions different types of landslides.2. Hazard Mapping and Landslide inventory and Map landslides Assessments.— landslide susceptibility maps on Federal landsDelineating susceptible are critically needed in many Establish mapping and areas and different types landslide-prone regions of the assessment standards of landslide hazards at Nation. In general, there are -

Map and assess landslide hazards a scale useful for planning no standards for mapping and

Use landslide hazard maps and assessments in planning, preparedness, and mitigation and decisionmaking assessments.

3. Real-Time Real-time monitoring of Improve real-time monitoring capabilitiesMonitoring.— active landslides is criticallyMonitoring active needed nationwide.landslides that pose Monitor landslides and establish landslide warning systemssubstantial risk 4. Loss Assessment.— Losses are not consistently Establish and implementCompiling and evaluating compiled and tracked in the a national strategyinformation on the United States. for compilation,economic and environ- maintenance, andmental impacts of land- evaluation of data

slide hazards. Compile and share records of losses

5. Information There is no systematic Develop robust landslide hazards Collect and distribute needed Develop and shareCollection, nationwide collection or information clearinghouse system information to decisionmakers informationInterpretation, distribution of landslide for the systematic collection,Dissemination, and hazards information. interpretation, archiving, andArchiving.— distribution of scientific andEstablishing an technical information, data bases,effective system and mapsfor information transfer

29
Table 1. New roles and partnership opportunities under the National Landslide Hazards Mitigation Strategy.—Continued

Element Current New roles and partnership opportunities status Federal State Local Private Academic6. Guidelines and There is a critical need for Develop and implement guidelines and training curriculumsTraining.— guidelines and training forDeveloping guidelines scientists, engineers, planners,

Participate in training programs and training for and decisionmakers. scientists, engineers,

and decisionmakers 7. Public Awareness There is little public awarenessand Education.— and understanding of landslide Develop and implement public awareness and education programs, involving land-use Developing information hazards, impacts on communities, planning, design, and landslide hazard curriculums; landslide hazard safety and education programs or options for reducing risk. and community risk reductionfor the user community 8. Implementation of Mitigation necessarily occurs Develop and encourage policies Adopt and implement policies Loss Reduction at the local level; therefore, that support landslide hazard and practices that supportMeasures.— implementation of loss mitigation landslide hazardsEncouraging mitigation reduction measures varies Develop financial incentives mitigationaction from community to community. and disincentives that

support landslide hazardmitigation

Serve as consultants and advisors Develop and encourage engineering and construction

approaches to mitigatelandslide hazards

9. Emergency Federal, State, and local Provide training for Federal, Participate Provide expertise during emergencies Preparedness, Response, governments; the State, and local emergency in trainingand Recovery.— private sector; and managersDeveloping resilient the public need to be able to Develop a coordinated landslide Effectively respond to landslide communities adequately prepare, respond to, rapid response capability, emergencies

and recover from landslide including landslide hazardsemergencies. expertise and equipment Implement policies

required for rapid emergency that reduce futuredeployment of real-time data landslide lossesto emergency managers

30
Implementation of the National Landslide Hazards Mitigation Strategy

within the USGS Landslide Hazards Program (LHP) will involve four

principal tasks—

• Expansion of work performed by scientists in the Landslide Hazards

Program

• Establishment of new Cooperative Landslide Hazard Assessment and

Mapping Program

• Establishment of a new Cooperative Federal Land Management

Landslide Hazards Program

• Establishment of new partnerships for the Landslide Hazard Loss

Reduction Program

The USGS Landslide Hazard Program is currently funded for $2.26 million in FY 2002. The changes above will require expansion of and additional

funding for the LHP.

Expanding efforts by USGS scientists in the areas of research, hazard

assessment, monitoring, public information, and response will be necessary

to meet the challenges of the national strategy. The Landslide Hazards

Program will also require additional funding to meet new responsibilities to

coordinate activities within the Federal Government to fully implement the

strategy. Approximately $8 million in new funding will be required to support

the following:

• Additional research on landslide processes and triggering mechanisms

(element 1) ($1.5 million)

• Additional hazard maps and assessments of landslide-susceptible areas,

including developing standards and guidelines (element 2) ($2 million)

• Additional monitoring of active landslides and improvement of stateof-the-art research and telecommunications technology (element 3)

($2 million)

• Improved information collection, interpretation, dissemination, and

technology transfer, including public awareness programs and education (elements 5 and 7) ($1 million)

• Expanded emergency response and recovery capability and activities

(element 9) ($1 million)

• Coordination of National Landslide Hazard Mitigation Strategy ($0.5

million)

A new cooperative program will be established to encourage the understanding and mitigation of landslide and other ground-failure hazards by

States, Territories, counties, and other local jurisdictions. The program will be

administered by the USGS Landslide Hazards Program. The primary goal of

this cooperative program will be to reduce hazard losses by increasing the

availability of assessments and maps of landslide- and other ground-failureprone areas in the United States. This program will address all elements of the

Funding for the

USGS to Implement

a National Strategy

for Reducing

Losses from

Landslides

Expansion of the Work

Performed by Scientists

in the Landslide

Hazards Program

Establishment of a New

Cooperative Landslide

Hazard Assessment and

Mapping Program

31
national strategy, with a primary focus on element 2, landslide hazard mapping

and assessments. The USGS will provide guidance to encourage standardized

assessment and map products that will be available digitally.

Priorities will be determined annually in consultation with State and

Territory representatives. Grants to States and Territories will be awarded

competitively. States and Territories will determine priorities and the size of

grants to be distributed to their local jurisdictions in consultation with

Statewide and Territorywide advisory committees.

Approximately $8.0 million will be required to support competitive grants

to the States, Territories, and local jurisdictions each year. Each grant will be

matched by a 30 percent State or Territory contribution to encourage the

development and use of landslide information in planning and mitigation

actions at the State and local levels. It is anticipated that all States and

Territories will participate in such a program and that grants will average

$150,000 per State or Territory.

A new program, administered by the USGS Landslide Hazards Program,

will be established to increase and encourage the understanding and mitigation

of landslide hazards on Federal lands, including assessment and mapping of

landslides, land-use planning and facility siting, emergency management, and

public education.

The goal of such a program will be to reduce losses from landslide and

other ground-failure hazards through more informed and, therefore, better

stewardship of Federal lands under the jurisdiction of the National Park

Service, the Bureau of Land Management, the Bureau of Reclamation, the

Bureau of Indian Affairs, and the U.S. Forest Service. The new program will

address all elements of the national strategy, with a primary focus on landslide

hazard mapping, assessments, and monitoring (elements 2 and 3).

Priorities for scientific and technical assistance for Federal land management agencies will be determined annually in consultation with representatives

of Federal land management agencies. Approximately $2.0 million will be

required for scientific and technical assistance for Federal land management

agencies. It is anticipated that the program will support approximately 20

agreements, averaging $100,000 each. Most of these funds will be used to

support hazard assessments and procure monitoring equipment, with USGS

staff providing technical assistance

Establishment of a New

Cooperative Federal

Land Management

Landslide Hazards

Program

32
A new competitive external grants program, administered by the USGS

Landslide Hazards Program, will be established for research and implementation efforts. The program will foster partnerships with universities, private

consulting firms, professional associations, Federally recognized Indian Tribal

Governments, States and Territories, and local agencies. This program will

address all elements of the strategy, with a primary focus on landslide hazard

research and development and application of mitigation measures (elements 1,

2, and 8).

Priorities for research and application of research will be determined

annually in consultation with Federal, State, Territory, local, and private

representatives. Approximately $2.0 million will be required for cooperative

agreements with universities, private consulting firms, professional associations,

Federally recognized Indian Tribal Governments, States and Territories, and

local agencies to support research and innovative application of research. It

is anticipated that the program will support approximately 25 agreements,

averaging $80,000 each.

Total new funding to support implementation of a National Landslide

Hazard Mitigation Strategy is estimated to be $20 million annually, as

follows:

• Expansion of the research, assessment, monitoring, public information,

and response efforts by USGS scientists ($8 million annually)

• Establishment of a Cooperative Landslide Hazard Assessment and

Mapping Program to increase the efforts of State and local governments to map and assess landslide hazards within their jurisdictions

through competitive grants ($8 million annually, to be augmented with

30 percent matching funds by States and local jurisdictions)

• Establishment of a Cooperative Federal Land Management Landslide

Hazard Program to increase the capability of the National Park

Service, U.S. Forest Service, Bureau of Land Management, and

other such organizations to address landslide hazards under their jurisdictions ($2 million annually for work performed by USGS scientists

on public lands)

• Establishment of a Partnerships for Landslide Hazard Loss Reduction

Program to support research and implementation efforts by universities,

local governments, and the private sector through competitive grants

($2 million annually)

Establishment of New

Partnerships for

Landslide Hazard Loss

Reduction Program

Funding Summary

33
Full implementation of the National Landslide Hazards Mitigation

Strategy will result in a number of major accomplishments and products

over the first 10 years of the program, including the following:

• Reduced losses from landslides

• Reduced risk from future landslides

• Greater public awareness of landslide hazards and options for mitigating losses

• Improved technology for landslide mitigation

• Assessments and maps of landslide susceptibility in landslide-prone

areas

• Assessments and maps of other ground-failure hazards in susceptible

areas

• Assessments and maps of landslide and ground-failure susceptibility

on Federal Lands

• Policies to encourage landslide mitigation by government, communities, and the private sector

• Robust national landslide hazards information clearinghouse system

• Data bases of economic and environmental losses from landslides and

other forms of ground failures nationwide

• Guidelines and training materials for scientists, engineers, planners,

decisionmakers

• Curriculums and training materials for public awareness of landslide

hazards

• Real-time monitoring of critically hazardous active landslides nationwide

• Coordinated landslide emergency response capability nationwide

Progress in implementing the National Landslides Hazards Mitigation

Strategy will be monitored by working groups established to coordinate and

guide the strategy. These groups will include representatives of Federal, State,

and local governments and the private sector. Specific performance goals for

the strategy, including accomplishments and products, will come from a comprehensive review of national needs and priorities and will result in specific

plans and schedules. In addition, progress in reducing losses will be monitored

as part of element 4— compilation and evaluation of losses from landslide

hazards.

This report is based on an early draft by Randall Updike of the USGS and

on the ideas and suggestions from landslide hazard experts and others who

attended five stakeholder meetings. The report benefited from contributions

from and reviews by numerous USGS scientists and other Federal and State

agency representatives. The authors would especially like to thank the

American Association of State Geologists for their thoughtful input and

review of the report.

Major

Accomplishments

and Products

Acknowledgments

34
Appendix 1. Previous Reports and Sources of

Landslide Hazards Information

The proposed National Landslide Hazards Mitigation Strategy incorporates

many ideas and recommendations of previous studies and reports. The following

studies and reports should be referred to for more in-depth discussions of and

insights into landslide hazard mitigation and research needs.

U.S. Geological Survey Open-File Report 81–987, Goals, Strategies, Priorities and Tasks of a National Landslide Hazard Loss Reduction Program (USGS, 1981),

sets forth goals and tasks for landslide studies, evaluating and mapping a

hazard, disseminating information, and evaluating the use of the information. 

U.S. Geological Survey Circular 880, Goals and Tasks of the Landslide Part of a

Ground-Failure Hazards Reduction Program (USGS, 1982), describes a

national program. 

U.S. Geological Survey Open-File Report 85–276, Feasibility of a Nationwide

Program for the Identification and Delineation of Hazards from Mud Flows

and Other Landslides (Campbell and others, 1985), identifies the need for a

national program.

Reducing Losses from Landsliding in the United States (Committee on Ground Failure Hazards, National Research Council, 1985, National Academy Press)

recommends development of a national program and summarizes the roles of

government and the private sector in landslide mitigation nationwide.

U.S. Geological Survey Open File-Report 85–276–A, Landslide Classification

for Identification of Mud Flows and other Landslides (Campbell and others,

1985), resulted from a joint study by the USGS and FEMA to evaluate the

feasibility of delineating landslide hazards nationwide.

Landslides Investigation and Mitigation, Special Report 247 (Transportation

Research Board, National Research Council, 1996, National Academy

Press), provides a summary of the state-of-the-science of landslide hazard

research, mapping, and assessment in the United States.

National Mitigation Strategy—Partnerships for Building Safer Communities

(Federal Emergency Management Agency, 1996) provides a framework for

mitigation of all natural hazards in the United States. 

The Impacts of Natural Disasters—A Framework for Loss Estimation (Board on

Natural Disasters, National Research Council, 1999, National Academy

Press) recommends compilation of a comprehensive data base on losses from

natural disasters.

U.S. Geological Survey Circular 1182, Land Subsidence in the United States

(Galloway, Jones, and Ingebritsen, eds., 1999), explores the role of underground water in human-induced land subsidence through case histories.

Disasters by Design—A Reassessment of Natural Hazards in the United States

(Mileti, 1999, Joseph Henry Press) provides an overview of what is known

about managing natural hazard disasters, recovery, and mitigation.

35
Appendix 2. Meetings with Stakeholders

In 1999 and 2000, meetings among various stakeholder organizations were held to obtain input into a

national strategy to mitigate landslide hazards. Attendees included State geologists, private consultants

and university professors concerned with landslide hazards, and Federal, State and local government officials whose responsibilities include landslide hazard loss reduction. Many of their recommendations have

been incorporated into the strategy either through input at meetings or subsequent reviews of this report.

The meetings and participants are listed below.

Landslide Hazards Mitigation Stakeholders Meeting 

State Geologists meeting

Philadelphia, Pennsylvania 

January 16–17, 1999

Attendee Title Organization

Lee Allison State Geologist Kansas Geological Survey

John Beaulieu State Geologist Oregon Department of Geology

and Mineral Industries

Tom Berg State Geologist Ohio Geological Survey

Vicki Cowart State Geologist Colorado Geological Survey

Jim Davis State Geologist California Department of 

Mines and Geology

Charles Gardner State Geologist North Carolina Geological 

Survey

Don Hoskins State Geologist Pennsylvania Geological 

Survey

John Kiefer Assistant State Geologist Kentucky Geological Survey

William Shilts State Geologist Illinois Geological Survey

Randy Updike U.S. Geological Survey

Lynn Highland U.S. Geological Survey

John Filson U.S. Geological Survey

Landslide Hazards Mitigation Stakeholders Meeting

Private sector meeting 

Albuquerque, New Mexico 

February 23–24, 1999

Attendee Title/Company Location

Don Banks Consultant Vicksburg, Mississippi

Bill Cotton Cotton, Shires & Associates, Inc. Los Gatos, California

Bruce Clark Leighton & Associates, Inc. Irvine, California

Lloyd Cluff Pacific Gas & Electric San Francisco, California

Richard Gray GAI Consultants, Inc. Monroeville, Pennsylvania

Jim Hamel Hamel Geotechnical Consultants Monroeville, Pennsylvania

36
G.P. Jayaprakash NRC Transportation Research Board Washington, D.C.

Jeff Keaton AGRA Earth and Environmental, Inc. Phoenix, Arizona

George Kiersch Kiersch Associates Tucson, Arizona

George Mader Spangle Associates Portola Valley, California

Ralph Peck Consultant Albuquerque, New Mexico

Bill Roberds Golder Associates Redmond, Washington

Roy Shelmon Consultant Newport Beach, California

Rex Baum U.S. Geological Survey Golden, Colorado

Randy Updike U.S. Geological Survey Golden, Colorado

Landslide Hazards Mitigation Stakeholders Meeting 

Academic sector meeting 

Albuquerque, New Mexico 

February 26–27, 1999

Attendee University/Organization

Ed Cording University of Illinois

Herbert Einstein Massachusetts Institute of Technology

Arvid Johnson Purdue University

Howard Kunreuther Wharton School, University of Pennsylvania

David Montgomery University of Washington

Rob Olshansky University of Illinois

Nick Sitar University of California

Keith Turner Colorado School of Mines

Erik VanMarcke Princeton University

Bob Watters MacKay School of Mines, University of Nevada

Bob Fleming U.S. Geological Survey, Golden, Colorado

Randy Updike U.S. Geological Survey, Golden, Colorado

Landslide Hazards Mitigation Strategy Summit Meeting

San Antonio, Texas

August 31–September 1, 1999

Attendee Organization

David Applegate American Geological Institute

Rex Baum U.S. Geological Survey, Golden, Colorado

Steven R. Bohlen U.S. Geological Survey, Reston, Virginia

Bruce Clark Leighton & Associates

Timothy Coh U.S. Geological Survey, Reston, Virginia

Derek Cornforth Landslide Technology, Portland, Oregon

Vicki Cowart Colorado Geological Survey

Kim Davis California Department of Conservation

Anthony de Souza National Research Council

Robert Fakundiny New York Geological Survey

John Filson U.S. Geological Survey, Reston, Virginia

John Grant National Aeronautics and Space Administration

Robert Hamilton National Research Council

37
Lynn Highland U.S. Geological Survey, Golden, Colorado

G.P. Jayaprakash NRC Transportation Research Board

Arvid Johnson Purdue University

Jeff Keaton AGRA Earth & Environmental, Inc., Phoenix, Arizona

Pat Leahy U.S. Geological Survey, Reston, Virginia

Lindsay McClelland National Park Service

Doug Morton U.S. Geological Survey, Riverside, California

Robert Olshansky University of Illinois, Urbana/Champaign

John Pallister U.S. Geological Survey, Reston, Virginia

William Roberds Golder Associates, Redmond, Washington

William Shilts Illinois State Geological Survey

Elliott Spiker U.S. Geological Survey, Reston, Virginia

Randy Updike U.S. Geological Survey, Golden, Colorado

Erik Van Marcke Princeton University

Tom Yorke U.S. Geological Survey, Reston, Virginia

Landslide Hazards Mitigation Stakeholders Meeting

Land-use planners meeting

Chicago, Illinois

February 17–18, 2000

Attendee Organization

Steven Briggs Cincinnati Planning Department

Paula Gori U.S. Geological Survey, Reston, Virginia

James A. Hecimovich American Planning Association

Lynn Highland U.S. Geological Survey, Golden, Colorado

Sanjay Jeer American Planning Association

George Mader Spangle Associates, Portola Valley, California

Robert B. Olshansky University of Illinois – Urbana-Champaign

Jane Preuss, AICP GeoEngineers, Seattle, Washington

Daniel Sentz Pittsburgh Department of City Planning

Elliott Spiker U.S. Geological Survey, Reston, Virginia

38
Causes of Landslides

Landslide is a general term for a wide variety of

downslope movements of earth materials that result

in the perceptible downward and outward movement

of soil, rock, and vegetation under the influence of

gravity. The materials may move by falling, toppling,

sliding, spreading, or flowing. Some landslides are

rapid, occurring in seconds, whereas others may take

hours, weeks, or even longer to develop.

Although landslides usually occur on steep

slopes, they also can occur in areas of low relief.

Landslides can occur as ground failure of river bluffs,

cut and-fill failures that may accompany highway

and building excavations, collapse of mine-waste

piles, and slope failures associated with quarries and

open-pit mines. Underwater landslides usually

involve areas of low relief and small slope gradients

in lakes and reservoirs or in offshore marine settings.

Landslides can be triggered by both natural

changes in the environment and human activities.

Inherent weaknesses in the rock or soil often combine with one or more triggering events, such as

heavy rain, snowmelt, changes in ground water level,

or seismic or volcanic activity. Long-term climate

change may result in an increase in precipitation and

ground saturation and a rise in ground-water level,

reducing the shear strength and increasing the weight

of the soil. Erosion can remove the toe and lateral

slope support of potential landslides. Storms and sealevel rise often exacerbate coastal erosion and landslides. Earthquakes and volcanoes often trigger landslides.

Human activities triggering landslides are usually

associated with construction and changes in slope and

surface-water and ground-water levels. Changes in

irrigation, runoff, and drainage can increase erosion

and change ground-water levels and ground saturation.

Types of Landslides

The common types of landslides are described

below. These definitions are based mainly on the

work of Varnes (Varnes, D.J., 1978, Slope movement

types and processes, in Schuster and Krizek, eds.,

Special Report 176, Landslides—Analysis and control: Transportation Research Board, National

Research Council, Washington, D.C., p. 12–13).

39

Appendix 3. Landslide Hazards and Other Ground Failures—Causes and Types

falls Abrupt movements of materials that become

detached from steep slopes or cliffs, moving by

free-fall, bouncing, and rolling.

flows General term including many types of mass

movement, such as creep, debris flow, debris

avalanche, lahar, and mudflow.

creep Slow, steady downslope movement 

of soil or rock, often indicated by curved 

tree trunks, bent fences or retaining walls, 

tilted poles or fences.

debris flow Rapid mass movement in 

which loose soils, rocks, and organic matter

combine with entrained air and water to 

form a slurry that then flows downslope, 

usually associated with steep gullies.

flows—Continued

debris avalanche A variety of very rapid 

to extremely rapid debris flow.

lahar Mudflow or debris flow that originates on the slope of a volcano, usually triggered by heavy rainfall eroding volcanic 

deposits, sudden melting of snow and ice 

due to heat from volcanic vents, or the 

breakout of water from glaciers, crater lakes,

or lakes dammed by volcanic eruptions.

mudflow Rapidly flowing mass of wet 

material that contains at least 50 percent 

sand-, silt-, and clay-sized particles.
lateral spreads Often occur on very gentle slopes

and result in nearly horizontal movement of earth

materials. Lateral spreads usually are caused by

liquefaction, where saturated sediments (usually

sands and silts) are transformed from a solid into a

liquefied state, usually triggered by an earthquake.

slides Many types of mass movement are included in the general term "landslide.” The two major

types of landslides are rotational slides and translational landslides.

rotational landslide The surface of rupture

is curved concavely upward (spoonshaped), and the slide movement is more or

less rotational. A slump is an example of a 

small rotational landslide.

translational landslide The mass of soil 

and rock moves out or down and outward 

with little rotational movement or backward 

tilting. Translational landslide material may 

range from loose, unconsolidated soils to 

extensive slabs of rock and may progress 

over great distances under certain conditions.

40

submarine and subaqueous landslides Include

rotational and translational landslide, debris flows

and mudflows, and sand and silt liquefaction flows

that occur principally or totally underwater in lakes

and reservoirs or in coastal and offshore marine

areas. The failure of underwater slopes can result

from rapid sedimentation, methane gas in sediments, storm waves, current scour, or earthquake

stresses. Subaqueous landslides pose problems for

offshore and river engineering, jetties, piers, levees,

offshore platforms and facilities, and pipelines and

telecommunications cables.

topple A block of rock that tilts or rotates forward

and falls, bounces, or rolls down the slope.
Over the past few decades, an array of techniques and practices has evolved to reduce and

cope with losses from landslide hazards. Careful

land development can reduce losses by avoiding

the hazards or by reducing the damage potential.

Landslide risk can be reduced by the following five

approaches used individually or in combination to

reduce or eliminate losses.

Restricting development in landslide-prone

areas.—Land-use planning is one of the most

effective and economical ways to reduce landslide

losses by avoiding the hazard and minimizing the

risk. This minimization is accomplished by

removing or converting existing development or

discouraging or regulating new development in

unstable areas. In the United States, restrictions on

land use generally are imposed and enforced by

local governments by land-use zoning districts and

regulations. Implementation of avoidance procedures has met with mixed success. In California,

extensive restriction of development in landslideprone areas has been effective in reducing landslide losses. For example, in San Mateo County,

California, since 1975 the density of development

has been limited in landslide-susceptible areas.

However, in many other States, there are no widely accepted procedures or regulations for avoiding

or minimizing landslides.

Standardizing codes for excavation, construction, and grading.—Excavation, construction, and

grading codes have been developed for construction in landslide-prone areas; however, there is no

nationwide standardization. Instead, State and local

government agencies apply design and construction criteria that fit their specific needs. The city of

Los Angeles has been effective in using excavation

and grading codes as deterrents to landslide activity and damage on hillside area. The Federal

Government has developed codes for use on

Federal projects. Federal standards for excavation

and grading often are used by other organizations

in both the public and private sectors.

Protecting existing development.—Control of

surface-water and ground water drainage is the

most widely used and generally the most successful

slope-stabilization method. Stability of a slope can

be increased by removing all or part of a landslide

mass or by adding earth buttresses placed at the

toes of potential slope failures. Restraining walls,

piles, caissons, or rock anchors are commonly used

to prevent or control slope movement. In most

cases, combinations of these measures are used.

Utilizing monitoring and warning systems.—

Monitoring and warning systems are utilized to

protect lives and property, not to prevent landslides.

However, these systems often provide warning of

slope movement in time to allow the construction

of physical measures that will reduce the immediate or long-term hazard. Site-specific monitoring

techniques include field observation and the use of

various ground motion instruments, trip wires,

radar, laser beams, and vibration meters. Data from

these devices can be telemetered for real-time

warning.

Development of regional real-time landslide

warning systems is one of the more significant

areas of landslide research. One such system was

successfully developed for the San Francisco Bay

region, California, by the USGS in cooperation

with National Oceanic and Atmospheric

Administration and the National Weather Service.

The system is based on relations between rainfall

intensity and duration and thresholds for landslide

initiation, geologic determination of areas susceptible to landslides, real-time monitoring of a regional

network of rain gages, and National Weather

Service precipitation forecasts.

41

Appendix 4. Landslide Hazards Mitigation Strategies
private landslide insurance. This limited customer

base would lead to very high premiums, perhaps

nearly equal to the value of the property. An alternative to private sector insurance is a public insurance program, possibly modeled after the National

Flood Insurance Program. Incentives to mitigate

landslide hazards must also accompany insurance

coverage, much like fire preventive incentives

appear on current homeowners insurance polices.

A major obstacle to implementing some form

of landslide insurance is the lack of technical information, maps, and assessments of landslide hazards. A joint study in 1985 by the USGS and the

Federal Emergency Management Agency examined

the feasibility of a nationwide program for identification and delineation of hazards from mudflows

and other landslides. That study concluded that

landslide hazards can be evaluated and mapped

nationwide through a systematic sequence of studies, ranging from regional to local in progressively

more detail. The comprehensiveness and accuracy

with which landslide hazards would be delineated

could be balanced against the costs of the program.

Providing landslide insurance and compensation for losses.—Landslide insurance is a logical

means to provide compensation and incentive to

avoid or mitigate the hazard. Landslide insurance

coverage could be made a requirement for mortgage loans. Controls on building, development, and

property maintenance would need to accompany

the mandatory insurance. Insurance and appropriate government intervention can work together,

each complementing the other in reducing losses

and compensating victims. However, landslide

insurance is essentially absent across the Nation,

except for mine subsidence coverage in eight States

and some coverage for landslides due to earthquakes, if earthquake insurance is purchased, and

minimal coverage for mudslides by the National

Flood Insurance Program (Federal Emergency

Management Agency).

The primary reason that insurance companies

do not offer landslide insurance is the potential for

adverse selection by the insured population. In

addition, if available, it is likely that only those

individuals in the most hazardous areas would buy

42
Public and private organizations need sound

economic and scientific bases for making decisions

about reducing landslide-related losses. Quantitative risk assessment is a widely used tool for

making such decisions because it provides estimates of the probable costs of losses and various

options for reducing the losses. Such assessments can be either site specific or regional.

A risk assessment is based on the probability of

the hazard and on an analysis of all possible consequences (property damage, casualties, and loss of

service). Typically, private consultants with expertise in risk assessment, in cooperation with other

partners or landowners, conduct risk assessments

based on the results of the landslide susceptibility

and probability studies. In many cases, private users

such as insurance companies perform their own risk

assessments from the probability data.

Regional landslide risk assessments can be

accomplished through public and private partnerships involving the USGS, State Geological

Surveys, local governments, and private consultants. In such a partnership (1) the USGS and the

State Geological Surveys would cooperate to collect the basic geologic map data and landslide

inventory data, (2) local governments would provide access to their detailed topographic data bases

and records of landslide occurrence, and (3) the

USGS would analyze the geologic, topographic,

landslide, and other data to determine landslide

susceptibility and probability.

Federal, State, and local government agencies,

banks, and private landowners can use probability

estimates and risk assessments to help identify

areas where expected landslide losses are costly

enough to justify remedial efforts or avoidance.

More detailed studies can then be conducted in

these areas to determine the optimal strategy for

reducing landslide-related losses.

There are four types of landslide hazards

maps—

• A landslide inventory map (fig. 5–1A)

shows the locations and outlines of landslides. A landslide inventory is a data set

that may represent a single event or multiple events. Small-scale maps may show

only landslide locations, whereas largescale maps may distinguish landslide

sources from deposits and classify different

kinds of landslides and show other pertinent

data.

• A landslide susceptibility map (fig. 5–1B)

ranks slope stability of an area into categories that range from stable to unstable.

Susceptibility maps show where landslides

may form. Many susceptibility maps use a

color scheme that relates warm colors (red,

orange, and yellow) to unstable and marginally unstable areas and cool colors (blue

and green) to more stable areas.

• A landslide hazard map (fig. 5–1C, D) indicates the annual probability (likelihood) of

landslides occurring throughout an area. An

ideal landslide hazard map shows not only

the chances that a landslide may form at a

particular place but also the chances that a

landslide from farther upslope may strike

that place.

• A landslide risk map (fig. 5–1E) shows the

expected annual cost of landslide damage

throughout an area. Risk maps combine the

probability information from a landslide

hazard map with an analysis of all possible

consequences (property damage, casualties,

and loss of service).

43

Appendix 5. Landslide Hazards Maps and Risk Assessments
A, Inventory of landslides triggered by

storms during the winter of 1996-97 overlain on a shaded-relief topographic base

map (U.S. Geological Survey and Shannon

and Wilson, Inc.).

B, Landslide susceptibility (U.S. Geological

Survey). 

44

C, Probability of landslide occurrence

given the event depicted in map A (U.S.

Geological Survey and Shannon and Wilson, Inc.).

Figure 5–1. Maps showing some of the steps of a regional landslide risk assessment for part of Seattle, Washington. Names in

parentheses indicate major contributors of data or analysis. From Baum, R.L., Harp, E.L., Michael, J.A., and Roberds, W.A., 2001,

Regional landslide hazard assessment, an example from Seattle, Washington, in Zoghi, M., ed., Contemporary solutions to land mass

stabilization: Proceedings of the 9th annual Great Lakes Geotechnical and Geoenvironmental Conference.
45

D, Landslide hazard map, which combines

the results of map C with an assessment

of landslide travel distance to show the

probability of landslide damage (U.S.

Geological Survey and Golder Associates).

Figure 5–1.—Continued

E, Risk of loss due to landslides (U.S.

Geological Survey and Golder Associates).

Estimated cost of landslide-related losses

in U.S. dollars.
community. Personnel of the National Oceanic and

Atmospheric Administration—National Weather

Service (NWS) provide weather forecasts and

assist in emergency response activities. Other

Federal agencies, including the U.S. Army Corps

of Engineers, Bureau of Land Management, Forest

Service, National Park Service, Office of Surface

Mining Reclamation and Enforcement, and

Department of Transportation (especially the

Federal Highway Administration) have landslide

hazard experts and activities relating to lands and

infrastructure under their jurisdiction.

The Federal Emergency Management Agency

(FEMA) is responsible for emergency management

and long-term mitigation of natural hazards including landslides. FEMA is the Federal coordinating

agency for emergency response, disaster relief

funding, and hazard mitigation efforts. The Federal

Insurance and Mitigation Administration, a part of

FEMA, provides insurance coverage for flood

damages, including "mudslides." However, implementation has been difficult because of the absence

of an accepted technical definition of a mudslide

and an accepted methodology for delineating mudslide-hazard areas. Landslides other than mudslides

are not insured under this program.

State and Local Government Agencies

While the Federal Government plays a lead

role in funding and conducting landslide research,

in developing landslide mapping and monitoring

techniques, and in landslide hazard management

on Federal lands, the reduction of landslide losses

on other lands is primarily a State and local

responsibility. A number of State agencies, commissions, and councils have responsibility for landslide hazards, including those with oversight of

natural resources, transportation, geology, hazards,

emergency services, and land-use issues.

Many Federal, State, and local agencies; academia; and private companies are involved in landslide

research and mitigation in the United States; however, there is little coordination of landslide hazard mitigation activities. The need for information and cooperation spans the interests of many public and private

organizations. The National Landslide Hazards

Mitigation Strategy offers new opportunities for

mutually advantageous partnerships related to hazard

assessments, monitoring, and emergency response

and recovery. Under the strategy, each level of government (Federal, State, and local), nongovernmental

organizations, businesses, and individuals have some

responsibility for mitigating, responding to, and

recovering from landslide hazards.

Federal Agencies

The Federal role in hazard reduction has its

origin in the Organic Act of 1879, which created

the USGS. More recent legislation addressing the

Federal role in landslide hazards includes the Dam

Inspection Act of 1972, which stipulated responsibilities for landslide hazards affecting the safety of

dams and reservoirs, and the 1974 Disaster Relief

Act and subsequent reauthorizations, which gave

the USGS responsibility to issue timely disaster

warning of potential landslides.

The USGS Landslide Hazard Program is the

only Congressionally authorized program dedicated

to landslide hazards. The USGS National Landslide

Information Center is a prototype clearinghouse for

issuing advisories, press statements, and other information about landslides. The USGS has developed

expertise in research, assessment, and mapping of

landslide hazards and provides technical assistance

during disaster response.

The National Science Foundation and the

National Aeronautics and Space Administration

fund landslide hazard research in the academic

46

Appendix 6. Current Landslide Research, Mitigation Activities, and

Responsibilities in the United States
States vary in their approaches to landslide

hazards. Some States produce inventories of landslides and maps of landslide-prone areas for use by

local government, business, and the public.

However, landslide mapping has been done without

widely accepted standards of accuracy, scale, and

format. Some States monitor landslide-prone areas

and provide expertise for response and recovery

activities. Several States conduct research on landslide problems in their State, and a few States have

regulatory authority.

The reduction of landslide losses through landuse planning and application of building and grading codes is the function of local government.

Localities throughout the Nation differ in their regulatory authority and approach to reducing losses

from landslide hazards. Local governments have

the responsibility of issuing warnings of imminent

landslides and managing emergency operations

after a landslide. FEMA may become involved

after a Presidentially declared disaster.

Landslide hazards have traditionally occupied a

relatively modest place in public policy, embodied

in zoning, legal liability, insurance, building codes,

land use practices, and environmental quality.

Maps showing historic landslides and areas susceptible to landslides have been used only sporadically

for zoning and for purposes of real-estate disclosure. Building codes have been drafted for some

localities to set minimum standards for construction on unstable slopes. Federal and State forestry

practices in many localities include attention to

landslide hazards. Building setbacks from coastal

or riverine bluffs have been established in some

areas on the basis of projected failure by landsliding. However, broad systematic policy approaches

to landslide and other ground-failure hazards are

rare, and most areas of the Nation lack the most

fundamental technical information or policies to

cope with their hazards.

Private and Academic Sectors

Private sector geologists, engineers, and building professionals are often involved in the identification and implementation of landslide reduction

measures in building design and planning.

University researchers study landslide processes

and the development of monitoring and mitigation

technologies and methods. These professionals

provide advice to business and industry for loan,

insurance, and investment decisions. Professional

societies such as the American Society of Civil

Engineers, the Association of Engineering

Geologists, and the American Planning Association

serve as conduits of information from researchers

to practitioners and practitioners to researchers.

Professional societies are generally the source of

model codes, handbooks, and professional training

for their membership, who in turn use the information to improve the state-of-knowledge of landslide

loss reduction in the private and public sectors.

47
forestry project proponents. Environmental or engineering geologists, as one of their primary duties,

minerals geologists, as a related duty, or other earth

scientists, where geologists are unavailable, carry

out these evaluations. Engineering geologists and

geotechnical engineers carry out environmental

assessments and participate in designs to address

landslide hazard to system roads.

Another activity is assessing damage from

landslides following major natural disasters. The

most formalized of these assessments is the Burned

Area Emergency Rehabilitation procedure instituted

during major wildfires. This activity also includes

participating in development of stabilization and

restoration projects to counter wildfire damage.

A national geographic information system

(GIS) network of national forest lands and a data

base that includes landslide information is under

development. The landslide hazard information for

this GIS is generated from USGS and State

Geological Survey information and mapping by

Forest Service geologists. The Research Branch of

the Forest Service has contributed many studies

that improve the understanding of landslide hazards

relative to specific forest management activities.

—By Jerome DeGraff

Forest Service

Department of Commerce—National

Oceanic and Atmospheric Administration

The National Oceanic and Atmospheric

Administration (NOAA)—National Weather

Service (NWS) is involved in landslide mitigation

through its role in the Federal Response Plan and

its mission of providing services for the protection

of life and property. The National Weather Service

works with other Federal, State, and local agencies

Department of Agriculture—

Forest Service

The U.S. Department of Agriculture Forest

Service is a land-management agency with responsibility for natural resources on national forests.

Most of the national forest lands are located in the

mountainous areas of the Western United States,

including large parts of Alaska. The road system in

national forests is comparable in size to many State

road systems. Consequently, designing low volume

roads to avoid landslide problems and repairing the

damage to them from landslides are major tasks.

Additionally, interstate and major State highways,

railroad lines, oil and gas pipelines, and electric

transmission corridors pass through the national

forests. Assessing landslide hazards along such projects is increasingly important.

National forests generally occupy the headwaters

of major rivers, increasing the importance of watershed management, especially for those watersheds

where anadromous fisheries and significant inland

fisheries are present. Increased landslide activity can

produce sediment loads that degrade water quality and

adversely affect fisheries habitat. Landslide hazard can

be a more localized, but equally important, problem

on national forests where development of large ski

resorts, mines, or hydroelectric facilities takes place.

Major wildfires can denude watersheds and lead to

short-term landslide activity. The potential for loss of

life and damage from debris flows initiated by precipitation events on burned watersheds must be considered

in national forests, especially those having developed,

private in-holdings and adjacent urban areas.

A primary landslide hazard activity conducted

by Forest Service personnel is evaluating landslide

hazard potential in environmental assessments or in

reviewing environmental assessments prepared by

48

Appendix 7. Federal Agency Landslide Hazard Activities

The Federal role in landslide-hazard reduction involves numerous Federal agencies. The following

Federal agencies provided descriptions of their landslide-hazard reduction activities. Contacts for various

Federal agencies involved in landslide-hazard reduction are listed at the end of this appendix.
by providing forecasts of hydrologic and meteorological conditions for landslide forecasts and mitigation efforts. This assistance may include onscene meteorological personnel to assist in emergency response activities at landslides. The NOAA

Weather Radio and other NWS dissemination systems broadcast "Civil Emergency Messages" concerning landslide warnings and response and

recovery efforts at the request of local, State, and

Federal emergency management officials.

—By Robert Livezey

National Oceanic and Atmospheric 

Administration

Department of Defense—

U.S. Army Corps of Engineers

As the premier, full-spectrum engineering organization of the United States military, the mission of

the Corps of Engineers includes planning, design,

building, and operating water resources and civil

projects in the areas of flood control, navigation,

environmental quality, coastal protection, and disaster response, as well as the design and construction

of facilities for the Army, the Air Force, and other

Federal agencies. In performing this broad mission,

the Corps has addressed a full range of technical

challenges associated with landslides and ground

failure. Corps engineering geologists, geotechnical

engineers, and geophysicists have been involved in

the assessment, monitoring and analysis, and mitigation of landslides in a wide range of settings at locations around the world, as well as basic and applied

research on topics directly related to the analysis and

mitigation of landslides and ground failures.

Landslide assessment activities by Corps scientists and engineers have included investigations of

landslides of various mechanisms and scales along

navigable waterways such as the Mississippi and

Ohio Rivers and that result in serious navigation hazards and threats to or loss of flood protection works.

Landslides also play an important role in the erosion

of the Nation’s shoreline; the protection of shoreline

is a major responsibility of the Corps. Many Corps

dam-site investigations have involved the identification and assessment of past and potential landslides.

Corps engineering geologists, geotechnical engineers, and geophysicists have been involved in monitoring active landslides and ground failure in both natural and engineered soils and earth materials. These

tasks have focused on identifying the temporal and

spatial variability of earth movements and identifying

causal factors. Monitoring data have been used along

with detailed site information to analyze the stability

of a landslide in terms of initial movements, present

conditions, and conditions after mitigation actions.

As an engineering agency, the Corps has a significant role in the planning, design, and construction of landslide mitigation measures associated

with the protection of its civil and military projects.

Specific methods for reducing landslide hazards and

increasing slope stability have been developed and

implemented by Corps engineers at sites around the

world. The Corps’ role in initial engineering geological investigation, engineering analysis, remedial

design, implementation, construction, and postproject monitoring is of particular value to the Nation

and the international community.

The Corps has an important national mission in

disaster response. This mission has involved the

Corps in responding to landslides, especially those

resulting from floods, hurricanes, volcanic eruptions,

and earthquakes. In assistance to FEMA, Corps personnel have provided emergency assessments and

immediate mitigation of past and potential landslides. The Corps’ role in international disaster

response has become a major focus in landslide

engineering. Recent landslide assessments, analysis,

and mitigation efforts have been conducted in

Venezuela, Honduras, Nicaragua, Colombia, Peru,

Haiti, Puerto Rico, South Korea, and the Philippines.

Research at the Corps’ Engineering Research

and Development Center includes the development

and testing of analytical tools and assessment methods and approaches for landslide mitigation. Basic

research in soil and rock mechanics, geomorphology, hydrogeology, remote sensing, geophysics, and

engineering geology has resulted in advancements

in the understanding of the causative factors and

mechanics of landslides and ground failures.

—By Lawson Smith (deceased)

U.S. Army Corps of Engineers

49
Department of the Interior—

National Park Service

Many national parks are geologically active,

exposing park visitors, staff, and infrastructure to

geologic hazards. Landslides, including slope failures, mudflows, and rockfalls, adversely affect

parks, causing deaths and injuries, closing roads and

trails, and damaging park infastructure. Recent

examples include several rockfalls in Yosemite

Valley, each with one fatality; damaging landslides

in Shenandoah National Park triggered by torrential

rains; repeated slope failures fed by artificial

aquifers at Hagerman Fossil Beds National

Monument; landslides that closed roads in Zion and

Yellowstone National Parks; and the threat of large

debris flows at Mt. Rainier. USGS scientists have

provided insights essential to effective response to

landslides hazards at these and other national parks.

Because it is a natural process, landslide activity is generally allowed to proceed unimpeded in

national parks unless safety is a concern. However,

where people have destabilized the landscape (for

example, by logging, mining, and road building),

disturbed lands are restored where practical to their

pre disturbance condition.

To reduce risk from landslides and other geologic hazards, park planners must incorporate information from hazard assessments and maps into decisions about appropriate sites for facilities such as

campgrounds, visitor centers, and concession areas.

Planners face difficult choices as they attempt to balance risks from different hazards, such as floods and

rockfalls in confined valleys, and at the same time

provide public access to popular but potentially hazardous areas. When a landslide or other hazard

occurs, park personnel must quickly rescue people,

stabilize structures, and clear debris from roads and

other public areas. Then park personnel must work

with experts to assess the nature and extent of the

event and the risk of recurrence. Short-term studies

are required to help managers decide whether and

when to reopen affected areas; then more detailed

research is often needed to make informed decisions

about future use of the immediately affected area

and other areas that may face similar hazards.

Department of the Interior—

Bureau of Land Management

The Bureau of Land Management is a Federal

Agency that manages multiple uses of approximately 264 million surface acres of Federal land located

primarily in 12 Western States. A relatively small

portion of this land is located in steep mountainous

terrain with geologic and climatic conditions resulting in high landslide hazards, such as in western

Oregon, northern California, and northern Idaho.

Many landslides on public land are the result of

natural disturbance events, but land-management

activities, including road building, timber harvest,

historic mining, and water impoundments, can contribute to their occurrence. The Bureau of Land

Management does not have an agencywide landslide hazards program or specialized personnel. The

bureau’s local field office landslide hazards prevention activities include identification of unstable

slopes by using aerial photograph interpretation,

landslide hazards guides, on-site indicators, predictive models, and limited inventory and monitoring

of landslides.

Prevention and mitigation of landslides are

accomplished by using a variety of methods.

Existing roads may be closed and obliterated,

rerouted, or kept open and stabilized with additional

runoff control structures, subsurface drainage control, or other techniques. Routine road maintenance is an important factor in helping to reduce

landslide hazards. Prudent route analysis and

design to minimize landslide hazard are employed

for new roads in landslide prone areas. Hazardousfuels management can reduce the risk of catastrophic wildfires that could increase landslide

hazards. Timber management silvicultural practices are employed to maintain root strength where

needed for slope stability. Sites that are a threat to

human health and safety, roads and recreational

facilities, water quality, fisheries and aquatic habitat, and other resource values are stabilized, and

sediment is controlled with revegetation and

structural controls.

—By William Ypsilantis

Bureau of Land Management

50
Park interpretive programs inform visitors

about key resources and issues, enabling the

public to better understand geologic hazards.

Interpreters communicate directly with visitors

through programs such as nature walks and campfire presentations, as well as through exhibits in

visitor centers and, in some cases, books and

videos sold by cooperating associations and concessionaires. The National Park Service is

increasingly reaching out to a broader audience,

many of whom may not have the opportunity to

visit parks, through innovative methods such as

school programs and Web sites. Interpreters work

in partnership with the scientific community to

ensure that complex information can be conveyed

accurately and in a form that is comprehensible

and relevant to nonspecialists.

These and other park programs welcome additional help to assess landslide hazards in parks,

provide input to park planning so that infrastructure can be located away from zones of greatest

landslide risk, respond quickly after significant

landslide events, and improve communication with

the public.

—By Lindsay McLelland

National Park Service

Department of the Interior—

Office of Surface Mining Reclamation 

and Enforcement

The Office of Surface Mining’s (OSM) role in

landslide mitigation is confined to those landslides

that are related to past coal mining activity, as

authorized by the Surface Mining Control and

Reclamation Act. A coal mining technique in the

Appalachians involving mountaintop removal and

valley filling is monitored by OSM to prevent serious landslides. Most abandoned mine land landslide areas are reclaimed through State or Indian

Tribe abandoned mine land programs, funded with

OSM grants. The Office of Surface Mining,

through its Federal Reclamation Program, has

responsibility for those States and Tribes that do

not have approved programs.

When there is an immediate danger to the

occupants of dwellings caused by a landslide,

abatement actions are taken immediately through

OSM or State emergency programs. Otherwise,

landslide problem areas that endanger human

health, safety, and general welfare are assigned priorities, and mitigation actions are taken based on

the highest priority.

Reclamation records, maintained in OSM’s

Abandoned Mine Land Inventory System, indicate

that OSM and the States and Tribes have completed reclamation on 3,367 acres of dangerous slides

at a cost of $125.25 million. Also, 651 acres are

designated as high priority and have been funded,

but not yet reported as completed, at $30.69 million. An additional 2,276 acres, with an estimated

cost of $73.77 million, are unfunded.

—By Gene Krueger

Office of Surface Mining Reclamation and

Enforcement

Department of the Interior—

U.S. Geological Survey

The U.S. Geological Survey (USGS) directly

or indirectly funds and maintains landslide hazard

expertise in several of its programs. The following

programs direct research and assessment of landslides, debris flows, and lahars caused by storms,

earthquakes and volcanoes, submarine landslides,

and riverine and coastal erosion.

USGS Landslide Hazards Program.—The

USGS Landslide Hazards Program supports hazard investigations and assessments, research on

monitoring and forecasting landslides, landslide

emergency response, operation of the National

Landslide Information Center in Golden,

Colorado, and research and assessment for the

implementation of mitigation strategies for

Federal, State, and local land-management and

emergency-response agencies. The information

generated also provides a basis for land-use planning, emergency planning, and private decisionmaking, including insurance and financial incentives. Much of the current work is being conducted

51
Department of Transportation—

Federal Highway Administration

The Federal Highway Administration (FHWA)

is a part of the Department of Transportation, with

field offices across the United States. The FHWA

performs its mission primarily through the following

two programs:

• The Federal-Aid Highway Program provides

Federal financial assistance to the State

Departments of Transportation to construct

and improve the National Highway System,

urban and rural roads, and bridges. The program provides funds for general improvements

and development of safe highways and roads.

• The Federal Lands Highway Program provides access to and within national forests,

national parks, Indian reservations, and other

public lands by preparing plans, letting contracts, supervising construction facilities, and

conducting bridge inspections and surveys.

In support these program areas, the FHWA conducts

and manages a comprehensive research, development,

and technology program.

The FHWA has recognized a need for consistent

understanding and application of soil and rock slope

stability analysis and mitigation for highway projects

across the United States. These analyses generally are

carried out throughout the life of most highway projects; that is, during planning, design, construction,

improvement, rehabilitation, and maintenance. Planners, engineers, geologists, contractors, technicians, and

maintenance workers are involved in the process.

To this end, the FHWA geotechnical engineering

program continues to develop and support the development of training courses, design manuals, demonstration projects, and geotechnical software. The

FHWA geotechnical engineering program maintains

an ongoing dialogue and exchange of information

with and among State Departments of Transportation

through annual Regional Geotechnical Meetings,

training courses, and technical assistance provided

through the FHWA Resource Centers.

—By Barry D. Siel

Federal Highway Administration

in the Pacific Northwest, California, and the Blue

Ridge Mountains in the Eastern United States;

most real-time monitoring activities are taking

place in Washington, California, New Mexico,

and Colorado.

Earthquake Hazards Program.—The USGS

National Earthquake Hazards Reduction Program

supports USGS studies and external, cooperative

studies of landslides caused by earthquakes,

including liquefaction investigations in California.

It also supports seismic instrumentation of landslide sites.

Volcano Hazards Program.—The Volcano

Hazards Program funds debris-flow research at the

Cascades Volcano Observatory. The research

includes field investigations at Mount St. Helens

and Mount Rainier, Washington, and an experimental debris-flow flume in the Willamette

National Forest, Oregon. The Volcano Disaster

Assessment Program conducts lahar investigations

internationally.

Coastal and Marine Geology Program.—

The Coastal and Marine Geology Program focuses

on coastal and submarine landslide studies. The

areas of investigations include California,

Washington, Alaska, Hawaii, and Lake Michigan.

The program also conducts subsidence studies in

Louisiana.

National Geologic Cooperative Mapping

Program.—The National Geologic Cooperative

Mapping Program supports comprehensive geologic

mapping as a basis for landslide hazard assessment

through the matching-fund STATEMAP grants

program.

Earth Surface Dynamics Program.—The Earth

Surface Dynamics Program supports research on

landslide processes and climate history in the Blue

Ridge in the Eastern United States.

Water Resource Programs.—Water Resource

programs conduct research on landslides, debris

flows, subsidence, and riverine and coastal erosion.

Research is also supported through USGS District

Offices in Hawaii, Puerto Rico, and other States as

landslides occur.

—By Paula L. Gori

U.S. Geological Survey

52
Department of Transportation—

Federal Railroad Administration

The Federal Railroad Administration's (FRA)

primary mission is to promote and regulate railroad

safety. To support its mission, the FRA sponsors

research projects to develop and demonstrate techniques for advancing railroad safety and for improving railroad operating and maintenance practices.

As with any surface transportation, landslides

can threaten the safety of railroad operations, but

landslide mitigation planning and implementation

for railroads must consider the following characteristics of railroad operations and of the U.S.

railroad network. First, warnings must allow for

trains to safely stop in advance of a hazard. For

heavy freight trains or faster passenger trains on

descending grades, stopping distances are often 1

to 2 miles. Second, trains cannot steer around

even the smallest slides or obstructions. And

third, especially in the Western United States,

there are relatively few alternative railroad routes,

and the detour distances for accessing these may

be hundreds of miles long.

Landslide mitigation methods on railroads are

similar to those used for highway transport, mainly

slide fences, rock or slide sheds (in areas of frequent,

heavy slides), and anchoring or stabilization of

unstable rock or soil slopes. Slide fences are often

tied into the signal systems, so that any slide of

sufficient intensity to break wires in the fence will

cause the signals protecting the nearby section of

track to show a stop indication; the train dispatcher

may also receive an indication. Because of the mitigation efforts that the railroad industry has taken,

serious accidents, injuries, and fatalities due to slides

are relatively few, but there are still a considerable

number of disruptions and delays due to slide

events.

Recent FRA landslide mitigation activities

include sponsoring the demonstration of two techniques in the Northwest Corridor (between Vancouver, British Columbia, and Eugene, Oregon) – 

• A cellular confinement method for stabilizing slopes subject to failure by weathering

and erosion of the surface layer and

• A method to install liquid level sensors

for indicating slope movement

In addition, the FRA, along with the Association

of American Railroads (AAR) and the National

Center for Atmospheric Research (NCAR), sponsored a symposium in 2001 on Enhanced Weather

Information for Railroad Productivity and Safety. A

major focus of this symposium was weather and

weather events as causes or triggers of natural hazards, including landslides. The FRA also participated in the May 2002 Canadian workshop on Natural

Hazard Mitigation on Railroads. This workshop

focused on addressing research needs for hazard risk

management, hazard characterization (prediction of

frequency and magnitude), and monitoring and

detection technology. 

Railroad landslide mitigation needs and ideas

resulting from the 2001 FRA/AAR/NCAR symposium and the 2002 Natural Hazard workshop were

consistent with the objectives of the National

Landslide Hazards Mitigation Strategy, particularly

with respect to the need for improved understanding of slide triggers, better monitoring and detection technology, and the potential benefits of sharing information among different transportation and

communications organizations with facilities and

operations close to active slide areas. The FRA will

continue to support work in these areas in partnership with the railroad and research communities.

—By Donald Plotkin

Federal Railroad Administration

Federal Emergency Management Agency

The Federal Emergency Management Agency

(FEMA) has many roles in landslide hazard loss

reduction. FEMA has responsibilities in emergency

response, disaster recovery assistance, and promotion

of landslide hazard mitigation. FEMA coordinates

the Federal Government’s response to disasters such

as earthquakes, hurricanes, and volcanic eruptions

that include landslides through the Federal Response

Plan. The agency provides financial assistance to

State and local governments for repair of public

facilities damaged during these disasters, including

replacement of lost fill and construction of fill53
In the Directorate for Engineering, funding

mechanisms include peer reviewed unsolicited proposals, support for workshops, Small Grants for

Exploratory Research, and the CAREER Program

(http://www.nsf.gov/pubsys/ods/getpub.cfm?gp). The

GHS Program does not have solicitations directed

specifically toward landslide and slope stability

research; all current research in this area is the result

of unsolicited proposals. Historically, GHS has supported development of numerical analysis techniques for slope stability, landslide mitigation techniques, investigations of seismic slope stability and

earthquake induced submarine landslides, constitutive and rheological model development related to

slope stability and mud and debris flows, and postlandslide reconnaissance. Current GHS-funded

research includes development of probabilistic methods of stability analysis, analysis of the role of strain

localization and dilatancy on slope stability, development of Time Domain Reflectometry sensors for

early warning of slope movement, using geographic

information systems to evaluate the factors controlling seismic slope stability, and stabilization of

slopes by using in-situ reinforcement.

In the Directorate for Geosciences, the

Hydrologic Sciences Program supports work on

landslide triggering caused by high water contents in

soils and lubricating slip planes between strata; the

Geology and Paleontology Program focuses on the

role of landslides in reshaping the Earth's surface.

Both programs interact with other NSF earth science

programs to study landslide triggering by earthquakes or volcanic events. Projects include studies

on diffusive soil transport as a process in hillslope

evolution and studies on reconstructing landslide

history. The NFS is also starting a Science and

Technology Center at the University of Minnesota;

here new analytical tools will be refined and developed to study the various processes that sculpt the

Earth's surface. A major focus will be the study of

the patterns in which landslide materials accumulate

over sequential events. The simulation of this

process is receiving growing attention as a tool in

mapping aquifer properties.

—By Richard J. Fragaszy

National Science Foundation

retaining devices such as gabions and rock toes. Following disasters, the agency also supports installation

of mitigation measures, such as installing drainage

ditches to direct flow away from the landslide areas.

FEMA provides relief to individuals who have

sustained losses due to mudslides and who are

insured under the National Flood Insurance program.

However, the distinctions that the agency makes

between landslides and mudslides have been a source

of controversy, as the agency provides only limited

damage coverage. Also encouraging mitigation measures in tandem with insurance coverage, which is a

cornerstone of the flood insurance program, has been

impossible because, to date, there are no maps that

delineate mudslide zones and no standards governing

development in mudslide-prone areas.

FEMA promotes landslide-hazard mitigation by

developing State and national guidebooks for landslide loss reduction, including a prototype mitigation plan that can be incorporated into existing hazard mitigation plans. Through its Disaster-Resistant

Communities project, FEMA is encouraging local

jurisdictions to implement mitigation programs that

reduce, among other hazards, landslides.

—By Ed Pasterick

Federal Insurance Administration

National Science Foundation

According to the National Science Foundation

Act of 1950, the mission of the National Science

Foundation (NSF) is to promote the progress of

science; to advance the national health, prosperity,

and welfare; and to secure the national defense.

The NSF provides funding for landslide and slope

stability research through several programs—

• The Geotechnical and GeoHazards Systems

(GHS) Program (http://www.eng.nsf.gov/

cms/ghs.htm), under the Division of Civil 

 and Mechanical Systems in the Directorate 

 for Engineering (CMS/ENG)

 • The Hydrologic Sciences Program and the

 Geology and Paleontology Program, under

 the Division of Earth Sciences in the Direc-

 torate for Geosciences (EAR/GEO)
Contacts

Jerome DeGraff

Department of Agriculture

Forest Service

Sierra National Forest

1600 Tollhouse Road

Clovis, CA 93611

E-mail: Fishlake@worldnet.att.net

Telephone: 209-297-0706, X4932

Fax: 209-222-4122

Jerry DiMaggio

Department of Transportation

Federal Highway Administration 

400 7th Street, SW., HNG-31

Washington, DC 20590

E-mail: Jerry.Dimaggio@fhwa.dot.gov

Telephone: 202-366-1569

Fax: 202-366-3378

Richard J. Fragaszy

Geomechanics and Geotechnical Systems

Civil & Mechanical Systems Division

National Science Foundation

4201 Wilson Blvd., Room 545

Arlington, VA 22230

E-mail: rfragasz@nsf.gov

Telephone: 703-292-7011

Paula L. Gori

Department of the Interior

U.S. Geological Survey

904 National Center

Reston, VA 20192

E-mail: pgori@usgs.gov

Robert Higgins

Department of the Interior

National Park Service

Geologic Resources Division

P.O. Box 25287

Denver, CO 80225

E-mail: Robert-Higgins@nps.gov>

Telephone: 303-969-2018

Fax: 303-987-6792

Michael J. Klosterman

Department of Defense

U.S. Army Corps of Engineers

441 G Street, NW.

Washington, DC 20314

E-mail: michael.klosterman@usace.army.mil

Telephone: 202-761-5887

Fax: 202-761-0633

Gene Krueger

Department of the Interior

Office of Surface Mining Reclamation

and Enforcement

1951 Constitution Ave., NW.

Washington, DC 20240

E-mail: GKRUEGER@OSMRE.GOV

Telephone: 202-208-2937

Robert Livezey

Department of Commerce

National Oceanic and Atmospheric Administration

Climate Prediction Center

N/NP51 NOAA Science Center

Camp Springs, MD 20746

E-mail: Robert.E.Livezey@noaa.gov

Telephone: 301-763-8155

Fax: 301-763-8395

Lindsay McLelland

Department of the Interior

National Park Service

908 National Center

Reston, VA 20192

E-mail: Lindsay-Mclland@NPS.gov

Telephone: 202-208-4958, X6610

Fax: 202-208-4620

Ed Pasterick

Federal Insurance Administration 

Federal Emergency Management Agency

500 C Street, SW.

Washington, DC 20472

E-mail: Edward.pasterick@fema.gov

Telephone: 202-646-3443

55
William Ypsilantis

Department of the Interior

Bureau of Land Management

P.O. Box 25047

Denver Federal Center, Building 50

Denver, CO 80225–0047

E-mail: bill_ypsilantis@blm.gov

Donald Plotkin

Research Program Manager

Department of Transportation

Federal Railroad Administration

Office of Research and Development

1120 Vermont Avenue - Mail Stop 20

Washington, DC 20590

E-mail: Donald.Plotkin@fra.dot.gov

Telephone: 202-493-6334

Fax: 202-493-6333

Barry D. Siel

Department of Transportation

Federal Highway Administration

Western Resource Center

555 Zang Street, No. 400

Lakewood, CO 80228

E-mail: barry.siel@fhwa.dot.gov

Telephone: 303-716-2294

Fax: 303-969-6727

56
Published in the Eastern Region, Reston, Va.

Manuscript approved for publication October 28, 2002