National Seismic Hazard Mapping Project of JAPAN

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National Seismic Hazard Mapping Project of JAPAN

• National Research Institute for Earth Science and
  Disaster Prevention (NIED)
• Hiroyuki Fujiwara

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Background of the Project

• Headquarters of Earthquake Research Promotion was
  established in accordance with Earthquake
  Disaster Management Special Measures Act (1995).
• Promotion of Earthquake Research
• -Comprehensive and Fundamental Measures for
  Promotion of Observation, Measurement and
  Research on Earthquakes-(April 23, 1999)
• Earthquake research requiring immediate
  promotion
• 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

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Structure of the Headquarters for Earthquake
Research Promotion
Headquarters
Policy Committee
Subcommittee for Survey and Observation Plans
Budget Subcommittee
Subcommittee for Instituting Results in Society
Earthquake Research Committee
Subcommittee for Long-term Evaluations
Subcommittee for Evaluations of Strong Ground
Motion
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System for the national seismic hazard mapping
project
Publication system for
hazard maps
Surveys for active faults
Surveys for underground structure
Advanced map
Long-term evaluations
Evaluation of methods for prediction of
strong-motion
Study on methods to make probabilistic seismic
hazard maps
Study on methods to make scenario earthquake maps
Evaluations of Strong-motion
General Seismic Hazard Map covering the whole
Japan
Duties of NIED
Duties of Earthquake Research committee
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Seismic hazard mapping project in NIED
Study on scenario earthquake maps
Study on probabilistic seismic hazard maps
Study on deaggregation
Development of publication system for seismic
hazard maps
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Probabilistic Seismic Hazard Map
An example of seismic hazard maps has shown
information predicting possibility that a certain
area is attacked by strong ground motion in a
certain term by means of probability.
(Comprehensive Fundamental Measures, 1999)
Feature
It is what has exhibited, by fixing two
parameters among term, strong-motion level and
probability, distribution of remaining one on the
map. Use of occurrence probability of each
earthquake. All possible earthquakes are
considered. It does not show ground motion
caused by an earthquake at the same time.
Example of probabilistic map
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Flowchart of SHA
Modeling of seismic activity (Earthquake research
committee)
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Strong-motion evaluation in SHA
Modeling of seismic activity
Attenuation relation (Si Midorikawa 1999)
PGV on the engineering bedrock
Site amplification (Matsuoka Midorikawa 1994)
PGV on the ground surface
Empirical formula (Midorikawa et al. 1999)
JMA seismic intensity
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Probabilistic Seismic Hazard Maps
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Probabilistic Seismic Hazard Maps
Major 98 active fault zones and the occcurance
areas of the subduction earthquakes considered to
study the seismic hazard map in western part of
Japan
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Treatment of occurrence probability of
earthquakes given by long-term evaluation the
earthquake research committee
Example of long-term evaluation of earthquake
activity
(Western Lake Biwa Fault zone)
Average recurrence interval (L) Elapsed time since the latest earthquake (T) Occurrence probability in 30 years (P)
1900 years 4500 years 2400 years 2800 years 0.09 9
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How should we treat the occurrence probability
given by an interval?
Are occurrence probabilities of earthquakes in 98
major active fault zones reasonable?
In 98 major active fault zones, 11 large
earthquakes occurred in last 200 years. Average
interval is 18.4 years. (Earthquake Research
Committee of Japan)
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How to calculate P from L and T given by
intervals? 1.P(Lmin,Tmax) (Maximum
case) 2.P(Lmed,Tmed) (Median case) 3.
4.(P(Lmin,Tmax)P(Lmax,Tmin))/2
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Case 1 11.6 / 200 years
Case 2 6.1 / 200 years
Case 3 5.7 / 200 years
Case 4 7.7 / 200
years
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(Case 2)
(Case 1)
JMA seismic intensity of 3 in 30 year
probability of exceedance (earthquakes in 98
major fault zones)
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Scenario Earthquake Shake Maps
Seismic hazard maps with specified seismic source
fault
Distribution of peak ground velocity on the
engineering bedrock.
Distribution of JMA seismic intensity on the
ground surface.
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Scenario Earthquake Shake Maps
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Theoretical approach for evaluation of
strong-motion
Amplification due to soft soil near surface
Complicated source process
Wave propagation in a heterogeneous medium
Amplification due to thick sediment
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Hybrid method for evaluation of strong-motion
Low frequency range
Finite Difference Method
Matching filter
Low frequency range
High frequency range
High frequency range
Stochastic Greens function method
??????
Superposition
deterministic
Stochastic
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Characterized Source Model
Complicated source model
Characterized source model
Characterized source model for Nankai Earthquake
Characterized source model for Tonankai Earthquake
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Modeling of underground structure
In modeling of underground structure, we consider
the deep underground structure from the crust and
plates up to seismic bedrock (Vs3km/s), the
structure of sediments from the seismic bedrock
up to engineering bedrock (Vs400m/s700m/s), and
the structure of surface soils from the
engineering bedrock up to the ground surface.
Flowchart of structure modeling
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Verification of methodology for strong-motion
evaluation
The Tokachi-oki earthquake (MJMA8.0) struck the
northern Japanese island of Hokkaido on 26th
September 2003. The 2003 Tokachi-oki earthquake
was the first large interplate earthquake
recorded by the nation-wide strong-motion
networks, K-NET and KiK-net.
Verification of methodology for strong-motion
evaluation of earthquakes in plate boundaries.
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The 2003 Tokachi-oki earthquake (2003 9/26 Mj
8.0)
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Rupture process of the 2003 Tokachi-oki
earthquake(Honda et al. 2004)

• Estimated total slip distribution

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Distribution of data for modeling underground
structure
Reflection surveys
Refraction surveys
K-NETKiK-net
Microtremor surveys
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Subsurface structure in Hokkaido Area
Vs700m/s
Vs1100m/s
Vs1700m/s
Vs2200m/s
Vs3200m/s
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Numerical simulation
Velocity waveformscm/s Filter 5-25s
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(No Transcript)
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Hybrid simulation (FDMSGM) using characterized
source model
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Comparison of Peak Ground Velocities
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Publication system for seismic hazard maps
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Seismic Hazard Station
Strong-motion Monitoring
Strong-motion simulator
Integrated Geological Information System


Seismic Hazard Station
Probabilistic
Scenario
Local government Hazard Assessment
University Research
Publication
Seismic Fragility
Seismic Risk Assessment
Seismic Risk Management