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Seismic Hazard Assessment in Japan
Hiroyuki Fujiwara
National Research Institute for Earth Science and Disaster Prevention
National seismic hazard maps for Japan Long term evaluation
Probability of occurrence, magnitude, location
Strong-motion evaluation
Strong-motion, underground structure
Probabilistic Seismic Hazard Maps
・Showing the strong-motion
intensity with a given
probability, or the probability
with a given intensity.
・Considering all possible
earthquakes.
Scenario Earthquake Shaking Maps
・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, the Special 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 was established 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 disaster
prevention
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 engineering
and 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.
・Showing the strong-motion intensity with
a given probability, or the probability with
a given intensity.
・Considering all possible earthquakes.
・Showing comprehensive ground motions
caused by independent earthquakes
Example of probabilistic map
PSHM Feature
Evaluation of occurrence probability of earthquakes
by ERCJ
Flowchart of PSHA
Modeling of seismic activity
Evaluation of an EQ occurrence probability P(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 evaluation of an intensity level P(Yi > y|Ei)
Probabilistic Seismic Hazard Maps
Probability in 30 years. (≧JMA Seismic Intensity 6-)
Seismic Intensity with 3% probability of
exceedance in 30 year.
Probabilistic Seismic Hazard Maps
≧JMA SI 6- ≧JMA SI 6+
≧JMA SI 5- ≧JMA SI 5+
These maps show the
probability in 30 years
with the JMA seismic
intensity more than or
equal 5-, 5+, 6-, 6+,
respectively.
Classification into Earthquake category
Earthquake
category 1
Earthquake
category 2
Earthquake
category 3
Characteristic Subduction-zone Earthquakes
Fused Subduction-zone Earthquakes
Crustal Earthquakes
1/4 2/4 3/4 1/4 2/4 3/4 1/4 2/4 3/4
Hazard Map for each earthquake category
Probability in 30 years. (≧JMA Seismic Intensity 6-)
interquartle
The 2011 Tohoku-oki earthquake
Comparison between the hazard maps and observed strong motions
Seismic Intensity with 2% probability
of exceedance in 50 year.
Seismic Intensity with 5% probability
of exceedance in 50 year.
Modeling of seismic activity in the Pacific plate
M for characteristic earthquakes Max M for background earthquakes
M=8.0
M=7.7
M=8.2 Mt=8.2
M=7.5
M=7.4
M=7.0
?
?
Mu=7.0
Mu=7.5
Mu=7.0
Mu=7.2
Mu=7.5
Mu=7.1
Mu=7.3
Mu=7.0
Issues to be solved for improvement of
seismic 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 of
strong ground motions for mega-thrust earthquakes.
Scenario Earthquake Shaking Maps
The shaking maps are evaluated for 490 scenario earthquakes
of 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 to
show deviation of strong-motion evaluation due to uncertainties.
Theoretical approach for evaluation
of strong-motion
Amplification due to
thick sediment
Amplification due to soft soil near surface
Wave propagation in a
heterogeneous medium
Complicated
source process
Low frequency range
High frequency range
Hybrid method for evaluation of strong-motion
deterministic Stochastic
Finite Difference Method
Stochastic Green’s function method
Superposition
Low
frequency
range
High
frequency
range
Matching filter
The technical details on the hybrid method are summarized as the
‘Recipe for strong-motion evaluation’, which are published by the
earthquake research committee of Japan.
Characterized Source Model
Complicated source model
The complicated source model is simplified by the
characteristic source model for strong-motion prediction.
Characterized source models are composed of asperities and a
background slip area surrounding the asperities. Asperities are
the main rupture areas in the fault zone.
Source parameters required to evaluate strong-motions by
using the characterized source model are classified into three
parts.
The first part is the set of outer parameters that show the
magnitude and the fault shape of the earthquake.
The second part is the set of the parameters that describe the
degree of fault heterogeneity.
The third part is the set of the parameters to define the
characteristics of the rupture propagation.
Modeling of underground structure S
edim
ent
Source
Seismic bedrock
(Vs=3km/s)
Engineering bedrock
(Vs=0.4~0.7km/s)
Deep
und
ergro
und
structu
re S
urface
soil
Flowchart of structure modeling
•The deep underground structure from the crust and
plates 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.
Site Amplification 2005~2008 2009
Site Amplification Site Amplification
1km2 0.25×0.25km2
Mesh size Mesh size
390,000 meshes 5,960,000 meshes
Subsurface modeling of deep sedimentary layers
Vp 2.1km/s Vp 2.5km/s Vp 3.0km/s Vp 3.5km/s
Vp 4.0km/s Vp 4.8km/s Vp 5.5km/s
Initial
model.
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
Depth contour of seismic bedrock
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) obtained
by 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.
Development of Integrated Geophysical and Geological Information Database
NIED
Database of
underground structure
AIST
Database of
geological information
Municipalitie’s
DB
PWRI
Database of
soil dynamics
JGS’s
database
Coordination and integration
by the network
9 9 9 9 9
0
00
00
00
00
00
000
500
000
500
000
500
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500
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500
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500
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Information on underground structure
Reduction of natural disaster
Construction of safe, secure and sustainable society
Management system on sharing for Integrated Database
ERI of
Tokyo University
Tokyo Institute of
Technology
Utilization of the database
The concept of Integrated Database
Integration by
shared management
via the network
Integration of databases of
multiple organizations
Integration of data
across the country
Integration in terms of
depth from the shallow
part to the deep part
Qualitative integration
of information on geology,
geophysical data, etc.
Integration of data
contents from the original data
to model data
Image of Integration
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 each
organization’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
WMS: Web Map Service
WFS: Web Feature Service
Working group (Venue to discuss utilization and publication of data)
Service integration, Data integration Portal site (NIED)
User Search function, Map display function, Download
function
Image, GML Applicable software: Browser, GIS
AIST
Database
Spatial database
WMS server WFS server
Database B Database A
NIED (Head office)
Internal user
Existing system
Database
(Example: PostgreSQL)
Spatial database
(Example: PostGIS)
Spatial information
and attributes
WMS, WFS server
(Example: MapServer)
Upgrading adapter
Image, GML Image, GML Image, GML Image, GML
Spatial
information
and attributes Existing system
Upgrading adapter
Internal user
PWRI
Database
Spatial database
WMS server WFS server
Database C
Spatial
information
and attributes Existing system
Upgrading adapter
Internal user Database
Spatial database
WMS server WFS server
Database D
Spatial
information
and attributes Existing system
Upgrading adapter
Internal user
Municipality
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 were
collected and registered into data base
Location map of boring data
which were collected and
registered into the database.
Organization NO. Detail Detail No.
MLIT 90,542 MEXT
(NIED) 51,950
Hokkaido area 11,242 Tohoku area 8,229 Kanto area 77,180
Hokuriku area 6,681 Chubu area 21,630 Kinki area 3,698
Shikoku area 100 Hokkaido 315 Tochigi 777 Chiba 2,196 Saitama 1,560 Kanagawa 24,098 Shizuoka 2,419 Niigata 169 Fukui 342 Ishikawa 4,201 Fukuoka 13
Academic societies 79,645 Public corporation 3,652
Geological maps, etc. 10,422 Total 401,061
Country 142,492
128,760 Prefecture
Municipality 36,090
Other 93,719
The number of boring data
that have been registered in
the database is approximately
400,000 across the country.
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 application
committee (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 as
Japan Seismic Hazard Information Station, J-SHIS.
Our products are aimed to meet multi-purpose needs in engineering fields by providing information
of the probabilistic seismic hazard analysis.
Probabilities that seismic intensity exceeds the JMA scale 5-, 5+, 6- and 6+ in 30 or 50 years. The JMA seismic intensity corresponding to the exceedance probability of 3% and 6% in 30 years and of 2%, 5%, 10% and 39% in 50 years.
Probabilistic Seismic Hazard Maps
Example of display of site amplification factor
By changing the transmission rate, background map
can be emphasized.
GPS
WMSサービス
RestfulAPI
3G/WiFi
J-SHIS application for smart phone
Japanese-Chinese-Korean cooperative joint research
collaboration 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 re-
evaluate 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.
Disaster-Risk Information Platform (BOSAI-DRIP)
Disaster-Risk Management
System for Individual
災 危険度 タ
危 度大丈夫
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
災 危険度 タ
危 度大丈夫
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
……
……
Disaster-Risk Evaluation System
History and Record of Disaster
Interoperability of information
DRI for Earthquakes
DRI for Volcanic Eruption
DRI for Floods
DRI for Landslides
Universities, Institutes Governments
Companies, NPOs
Hazard Map Damage Assessment
Institutions and Services
Geospatial Information
Interoperable
Information Environment
DRMS for
LC
DRMS for
LC
Disaster-Risk Management
System for Local Community
Clearinghouse for DRI
DRMS for I
災 危険度 タ
危 度大丈夫
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
災 危険度 タ
危 度大丈夫
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
DRMS for I
災 危険度 タ
危 度大丈夫
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
災 危険度 タ
危 度大丈夫
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
I A U
“AIU(Japanese ABC)” for BOSAI-DRIP
DRI for Heavy Snow and Ice
Utiliz
ation o
f in
form
ation
Adva
ncem
ent of in
form
ation
Thank you for attention.
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