Seismic Hazard Assessment in Japan

Hiroyuki Fujiwara

National Research Institute for Earth Science and Disaster Prevention

National seismic hazard maps for JapanLong term evaluation

Strong-motion evaluation

Probability of occurrence, magnitude, location

Strong-motion, underground structure

Probabilistic Seismic Hazard Maps

Scenario Earthquake Shaking Maps

・Showing the strong-motion
intensity with a given
probability, or the probability
with a given intensity.
・Considering all possible
earthquakes.

・Showing the strong-motion
intensity around the fault
for a specified earthquake.

Background of the Project The Great Hanshin-Awaji Earthquake Disaster on January

17, 1995 killed 6,434 people and destroyed over 100,000
buildings, and brought to light a number of problems in our
national earthquake disaster prevention measures.
 Following on the lessons learned from this disaster, theSpecial Measure Law on Earthquake Disaster Prevention
was enacted in July 1995 to promote a comprehensive
national policy on earthquake disaster prevention.
 Headquarters for Earthquake Research Promotion wasestablished in accordance with the Special Measure Law on
Earthquake Disaster Prevention (1995).

Background of the Project Promotion of Earthquake Research -（April 23, 1999）－Comprehensive and Fundamental Measures for Promotion of
Observation, Measurement and Research on Earthquakes(The 1st stage : 1999-2008)
Major subjects of Earthquake researches immediately
１．Preparation of seismic hazard maps based on surveys of active
faults, long-term evaluations of the probability of earthquake
occurrence, and evaluations of strong ground motion
２．Promotion of real-time transmission of earthquake information
３．Improvement of observation system for earthquake disasterprevention
４．Promotion of observation and research for earthquake
prediction

Background of the Project The next Promotion of Earthquake Research -（April 21, 2009）－Comprehensive and Fundamental Measures for Promotion of
Observation, Measurement and Research on Earthquakes(The 2nd stage : 2009-2018)
The objectives of the earthquake research which should be promoted in the
coming 10 years are as follows.
(1) Improving the accuracy of the prediction of earthquake occurrence, strong
ground motion and tsunami based on the observation and research for the
subduction-zone earthquake(2) Systematic accumulation and maintenance of the information for the
research related to active faults and advanced evaluation(3) Strengthening of mediation function to promote the study on engineeringand social science for disaster prevention and disaster reduction

Probabilistic Seismic Hazard Map
Predicting possibility that a certain area is attacked
by strong ground motion in a given years.
PSHM Feature・Showing the strong-motion intensity witha given probability, or the probability witha given intensity.
・Considering all possible earthquakes.
・Showing comprehensive ground motions
caused by independent earthquakes
Example of probabilistic map

Evaluation of occurrence probability of earthquakes
by ERCJFlowchart of PSHA
Modeling of seismic activity

Evaluation of an EQ occurrence probability P(Ei)Probabilistic evaluation of an intensity level P(Yi > y|Ei)

Evaluation of probabilistic seismic hazard
for each earthquake P(Yi > y)= P(Ei) P(Yi > y|Ei)
Evaluation of probabilistic seismic hazard
for all earthquakes P(Y > y)=1-Π[1- P(Yi > y)]Probabilistic Seismic Hazard Maps

Probability in 30 years.
(≧JMA Seismic Intensity 6-）

Seismic Intensity with 3% probability ofexceedance in 30 year.

Probabilistic Seismic Hazard Maps

≧JMA SI 5-≧JMA SI 5+

These maps show the
probability in 30 years
with the JMA seismic
intensity more than orequal 5-, 5+, 6-, 6+,
respectively.
≧JMA SI 6-≧JMA SI 6+

Classification into Earthquake category
Earthquake
category 1

Earthquake
category 2

Earthquake
category 3

Characteristic Subductionzone Earthquakes

Fused Subduction-zone
Earthquakes

Crustal Earthquakes

Hazard Map for each earthquake category

Probability in 30 years. (≧JMA Seismic Intensity 6-）

1/4

2/4

3/4

1/4

2/4

3/4

interquartle

1/4

2/4

3/4

The 2011 Tohoku-oki earthquake

Comparison between the hazard maps and observed strong motions

Seismic Intensity with 2% probabilityof exceedance in 50 year.

Seismic Intensity with 5% probabilityof exceedance in 50 year.

Modeling of seismic activity in the Pacific plate

M=8.0

M=7.5

Mu=7.0?

Mu=7.0Mu=7.2
Mu=7.5

M=7.7

Mu=7.1

M=7.4

Mu=7.5

M=8.2
Mt=8.2

M=7.0?
M for characteristic earthquakes

Mu=7.3

Mu=7.0Max M for background earthquakes

Issues to be solved for improvement ofseismic hazard assessment for Japan
1) Modeling of seismic activity with no oversight to
low-probability earthquakes.
2) Preparation of strong ground motion maps
considering low-probability earthquakes.
3) Development of methodology for selecting
appropriate scenario earthquakes from probabilistic
seismicity model.
4) Development of methodology for prediction ofstrong ground motions for mega-thrust earthquakes.

Scenario Earthquake Shaking Maps
The shaking maps are evaluated for 490 scenario earthquakesof almost all of major faults in Japan.

Selection of a specified scenario is essential to make a shaking map. The basic policy of the selection of a
scenario earthquake is that we choose the most probable case.
For treatment of uncertainties, we assume several cases of source model and compare the results of them toshow deviation of strong-motion evaluation due to uncertainties.

Theoretical approach for evaluationof strong-motion
Amplification due to soft soil near surface

Complicatedsource process

Wave propagation in aheterogeneous medium

Amplification due tothick sedimentHybrid method for evaluation of strong-motion
Low frequency range

Matching filterLowfrequency
range

Finite Difference MethodHighfrequency
range
High frequency range

Stochastic Green’s function method

Superposition

deterministic

Stochastic

The technical details on the hybrid method are summarized as the‘Recipe for strong-motion evaluation’, which are published by theearthquake research committee of Japan.

Characterized Source Model
Complicated source model

The complicated source model is simplified by thecharacteristic source model for strong-motion prediction.
Characterized source models are composed of asperities and abackground slip area surrounding the asperities. Asperities are
the main rupture areas in the fault zone.

Source parameters required to evaluate strong-motions byusing the characterized source model are classified into threeparts.
The first part is the set of outer parameters that show themagnitude and the fault shape of the earthquake.
The second part is the set of the parameters that describe thedegree of fault heterogeneity.
The third part is the set of the parameters to define thecharacteristics of the rupture propagation.

Modeling of underground structure
Surfacesoil

Seismic bedrock（Vs=3km/s）•The deep underground structure from the crust andplates up to seismic bedrock;•The structure of sediments from the seismic bedrock
up to engineering bedrock (Vs=400m/s～700m/s);•The structure of surface soils from the engineering
bedrock up to the ground surface.
Flowchart of structure modeling

Sediment

SourceDeep undergroundstructureEngineering bedrock（Vs=0.4～0.7km/s）

Site Amplification
2005～2008

2009

390,000 meshes

5,960,000 meshes

Mesh size
1km2

Mesh size

Site Amplification

0.25×0.25km2

Site Amplification

Subsurface modeling of deep sedimentary layers
Vp 2.1km/s

Vp 4.0km/s

Vp 2.5km/s

Vp 4.8km/s

Vp 3.0km/s

Vp 3.5km/s

Vp 5.5km/s

Initialmodel.
Velocity-structure of deep sedimentary layers from the seismic bedrock to the engineering bedrock greatly affects the characteristics
of relatively long period strong-motion.
We developed a velocity structure model of deep sedimentary layers of the whole of Japan for evaluation of strong motion.

Velocity structure model for deep sedimentary layers
To improve the initial model, with a focus on
predominant periods, by comparing the H/V spectral
ratio of seismic records (for M5.5 or greater) obtainedby the Kyoshin Network (K-NET, KiK-net) and the
H/V spectral ratio of fundamental to 4th higher-mode
Rayleigh waves obtained from velocity structure
models.
Comparing calculated waveforms with observed
waveforms for middle-scale earthquakes (around M5),
the validity of adjustments using H/V spectral ratios
was reviewed.

Depth contour of seismic bedrock

Development of Integrated Geophysical and Geological Information Database
Information on underground structure

000
000
500
000
500
000
500
000
500
000
500
000
500
000
00
00
00
00
00
0

9

9

9

9

9

Management system on sharing for Integrated Database
NIED
Database ofunderground structure

AIST
Database ofgeological information

PWRI
Database ofsoil dynamics

Coordination and integrationby the network
Municipalitie’sDB

Utilization of the database

ERI of
Tokyo University

Tokyo Institute ofTechnology

Reduction of natural disaster
Construction of safe, secure and sustainable society

JGS’s
database

The concept of Integrated Database
Image of Integration
Integration of data
contents from the original data
to model data
Integration of databases ofmultiple organizations

Integration of data
across the country

Integration byshared management
via the network
Integration in terms of
depth from the shallow
part to the deep part

Qualitative integrationof information on geology,
geophysical data, etc.

As we regards information on underground structure as ‘public assets of the nation’, we develop a
database that allows for mutual utilization and publication of data through a network of eachorganization’s databases. The keyword of this research project is ‘Integration’. The word ‘Integration’implies several meanings, as shown in this figure, the process of integration is to be carried out
following these six principles.

Diagram showing the concept of the management system on sharing
Search function, Map display function, Download
function

User

Applicable software: Browser, GIS

Image, GML

Portal site （NIED）
WMS: Web Map Service
WFS: Web Feature Service

Internal user

Existing
systemService integration, Data integration

Image, GML

Image, GML

Image, GML

Image, GML

WMS, WFS server(Example: MapServer)

WMS server
WFS server

WMS server
WFS server

WMS server
WFS server

Spatial database(Example: PostGIS)

Spatial database

Spatial database

Spatial database

Database(Example: PostgreSQL)
Spatial information
and attributes

Upgrading adapter

Internal user

Existing
system

Database
Spatialinformation
and attributes

Upgrading adapter

Internal user

Existing
system

Database
Spatialinformation
and attributes

Internal user

Spatialinformation
and attributes

Existing
systemUpgrading adapter

Database

Upgrading adapter

Database A

Database B

Database C

Database D

NIED (Head office)

AIST

PWRI

Municipality

Working group (Venue to discuss utilization and publication of data)

The configuration of the data sharing management system consists of database management
servers for individual organizations and a portal site.

Boring data collected and registered into database
The number of borehole data which werecollected and registered into data baseOrganization

CountryNO.

142,492

Prefecture

128,760

Municipality

36,090Other

93,719Total

401,061

DetailMLIT
MEXT（NIED）
Hokkaido area
Tohoku area
Kanto area
Hokuriku area
Chubu area
Kinki area
Shikoku area
Hokkaido
Tochigi
Chiba
Saitama
Kanagawa
Shizuoka
Niigata
Fukui
Ishikawa
FukuokaAcademic societies
Public corporation
Geological maps, etc.

Detail No.

90,542
51,950
11,242
8,229
77,1806,681
21,630
3,698
100
315
777
2,196
1,560
24,098
2,419
169
342
4,201
13
79,645
3,652
10,422The number of boring datathat have been registered in
the database is approximately
400,000 across the country.

Location map of boring data
which were collected andregistered into the database.

Japan Seismic Hazard Information Station

http://www.j-shis.bosai.go.jp
In order to promote the use of the national seismic hazard maps, an engineering applicationcommittee (Chairman: Prof. H. Kameda) was established by NIED. Under the committee guidance,
we developed an open web system to provide information interactively, and named this system asJapan Seismic Hazard Information Station, J-SHIS.
Our products are aimed to meet multi-purpose needs in engineering fields by providing informationof the probabilistic seismic hazard analysis.

Probabilistic Seismic Hazard Maps
Probabilities that seismic
intensity exceeds the JMA
scale 5-, 5+, 6- and 6+ in 30 or
50 years.
The JMA seismic intensity
corresponding to theexceedance probability of 3%
and 6% in 30 years and of 2%,
5%, 10% and 39% in 50 years.

Example of display of site amplification factor

By changing the transmission rate, background map
can be emphasized.

J-SHIS application for smart phone
GPS

3G/WiFi

WMSサービス
RestfulAPI

Japanese-Chinese-Korean cooperative joint researchcollaboration program
Title of cooperative research project (2010-2013)
Seismic Hazard Assessment for the Next Generation Map
Research Leaders
Hiroyuki Fujiwara (Japan, NIED)Tao Xiaxin (China, Harbin Institute of Technology)
Myung-Soon Jun (Korea, KIGAM)
Cooperative joint research
1. To review the data and methodologies adopted in SHA maps of the three countries, and reevaluate and improve the SHA in each of the countries.
2. To compare the data and the methodologies with the state of the art, and see if there
anything could be accepted for the next generation maps.
3. To develop a procedure to establish ground motion equations for maps.
4. To combine the probabilistic seismic hazard assessment and the scenario seismic approach,the latter is especially for near field of potential large earthquake.

Damage Assessment

Hazard Map

DRI for Earthquakes
DRI for Volcanic Eruption

Geospatial Information

Governments
History and Record of
Universities, Institutes
Companies, NPOs
Disaster……
Interoperable……
Information Environment
Institutions and Services“AIU(Japanese ABC)”
for BOSAI-DRIPAI

DRI for Floods
DRI for Landslides
DRI for Heavy Snow and Ice
Disaster-Risk Evaluation System

Clearinghouse for DRI

U

Disaster-Risk Management
System for Individual
災 危険度

タ

自宅の登
家族の登
自宅 耐震評価 備蓄登ァイル 編集 表示 ツ ル ヘル
緊急 震速報風 豪 予想危 度
大丈夫

Disaster-Risk Management
System for Local Community
DRMS forLC
DRMS for I
災

危険度

自宅の登
ァイル

DRMS for I
災

タ

家族の登
編集 表示

自宅
ツ ル

危 度
大丈夫

耐震評価
ヘル

危険度

自宅の登
ァイル

備蓄登

タ

家族の登
編集 表示

ツ

自宅
ル

耐震評価
ヘル

備蓄登

緊急

震速報

緊急

震速報

風

豪

風

豪

予想

危 度
大丈夫

予想

DRMS forLC

Utilization of information

Interoperability of information

Advancement of information

Disaster-Risk Information Platform (BOSAI-DRIP)

Thank you for attention.