Seismic	
  Hazard	
  Assessment	  Issues	
  in	
  the	
  island	
  arc	  of	
  Taiwan	
  and	  Japan	  t year exceedance probability(logarithmic scale)

Probabilistic Seismic Hazard
Assessment in general issues

TEM-­‐NIED	  Workshop	
  	
  
At	
  NCU,	
  June	  4-­‐6	
  2012	  Ground motion intensity for agiven exceedance probability

Exceedance probability
for a given ground motion
Intensity	
  確率地震予測評価之課題	
  Ken XS Hao (郝憲生)独立行政法人 防災科学技術研究所

National Research Institute for Earth Science & Disaster Prevention

The	
  big	
  quakes	
  might	
  be	
  considered	  “black	
  swans”,	
  for	  they	  are	
  rare,	
  had	  an	
  extreme	
  impact	
  on	
  society.	
  But	  being	
  rare	  is	
  not	  the	
  same	  as	
  being	  an	
  outlier	
  that	  invalidates	
  a	
  par�cular	
  probability	
  model	  or	
  overturns	
  a	
  methodology.	
  Consequently,	
  it	
  is	
  not	
  obvious	
  that	  our	  models	
  and	
  methods	
  
are	
  in	
  need	  of	
  repair	  (Ellsworth,	
  2012).	

Ø1.

	
  Seismic	
  ac�vity	
  in	
  Island	
  arc	  of	
  Taiwan	
  and	  Japan	
  

Ø2.	
   	
  Probabilis�c	
  Seismic	
  Hazard	
  Assessment	  	  Ø Modeling	
  of	
  Seismic	
  Ac�vity	
  Ø Classiﬁca�on	
  into	
  3	
  category	  	  Ø EQ	
  without	
  speciﬁed	
  source	
  faults	
  Ø Uncertainty	
  Ø Reality	
  on	
  East	  Japan	
  

Ø3.	
   	
  Coopera�ve	
  works	
  on	
  PSHA	  	  Ø Historical	
  records	
  Ø Sharing	
  EQ	
  database	  Ø Person	
  exchange	  divergent	Subduc
�on	

conve
rgent
	

ISLAND	
  ARC	  OF	  TAIWAN	
  AND	  JAPAN		Ma	
  Kuo-­‐Fong,	
  2011,	
  GEM	

Four Plates of Eurasia, North American,
Pacific and Philippines joined in Japan with4,000 km of subduction zones

安芸灘（Akinada）ß-­‐-­‐-­‐-­‐à日向灘(Hyuganada)	

地震調査委員会（2004）	

Bathymetry and Tectonic Setting near TaiwanMa	
  Kuo-­‐Fong,	
  2011,	
  GEM	

2.	
  

	  Probabilis�c	
  Seismic	
  Hazard	
  Assessment	  	
  6 Modeling	
  of	
  Seismic	
  Ac�vity	  6 Classiﬁca�on	
  into	
  3	
  category	
  	
  
6 EQ	
  without	
  speciﬁed	
  source	
  faults	  6 Uncertainty	
  6 Reality	
  on	
  East	  Japan	  National seismic hazard maps for Japan		Long term evaluation	

Probability of occurrence, magnitude, location	

Probabilistic Seismic Hazard Maps
・Strong-motion intensity with agiven probability, or the
probability with a given
intensity.
・Considering all possible
earthquakes.

Strong-motion evaluation	

Strong-motion, underground structure	

Scenario Earthquake Shaking Maps	
・Strong-­‐mo�on	
  intensity	
  	
  around	  the	
  fault	
  	
  
for	
  a	
  speciﬁed	
  earthquake.	
  	
  
	
  
	

System for the national seismic hazard mapping project
Surveys forunderground structure

Study on methods tomake probabilistic
seismic hazard maps

Study on methods
to make scenario
earthquake maps

Evaluation of Strong-motion
National Seismic Hazard Maps for Japan
NIED

ERC

Advanced maps

Long-term evaluation

Japan Seismic Hazard
Information Station (J-SHIS)

Surveys for active
faultsTechnical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	
h�p://www.j-­‐shis.bosai.go.jp/en/downloads	
Table	  of	
  Contents	
  
	
  
1.	
  Introduc�on	
  Outline	
  	
  
	
  
2.	
  Seismic	
  Source	
  Fault	
  Models	
  for	
  Characteris�c	
  Earthquakes	
  in	  Long-­‐Term	
  Evalua�on
	
  
	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  (pp	  41)	  2.1	  Major	
  Ac�ve	
  Fault	
  Zones	  2.2	
  Subduc�on-­‐Zone	
  and	
  Eastern	  Margin	
  of	
  the	  Japan	
  Sea	  
	
  3.	
  Probabilis�c	
  Seismic	
  Hazard	
  Maps	  (PSHM)	
  	  	
  (pp	
  357)	
  3.1	
  Evalua�on	
  Procedure	
  and	
  Its	
  Result	
  Representa�on	
  3.2	
  Area	  Covered	
  by	
  the	
  PSHM	  and	
  Map	  Speciﬁca�ons	
  3.3	
  Seismic	
  Ac�vity	
  Evalua�on	
  Models	
  3.4	
  Earthquake	  Category	
  3.5	
  Ground	
  Mo�on	
  Evalua�on	
  Models	
  3.6	
  Change	
  Logs	  for	  the	
  Used	  Parameters	
  of	
  Probabilis�c	  	
  Seismic	
  Hazard	
  Maps	  3.7	
  Evalua�on	
  Results	  November 2009

Technical Note of the National Research Institutefor Earth Science and Disaster Prevention No.336

Technical Reports on National Seismic Hazard Maps for Japan

独立行政法人

防災科学技術研究所
National Research Institute for Earth Science and Disaster Prevention, Japan

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	
Table	  of	
  Contents	
  (Con�nued)	
  
	
  
4.	
  Seismic	
  Hazard	
  Maps	  for	  Speciﬁed	
  Seismic	
  Source	
  Faults	  	  	
  (pp	  36)	
  
	
  
	
  
	
  	
  
4.1	
  Procedure	
  and	
  Results	
  of	
  Evalua�on	
  &	
  Presenta�on	
  	
  Method	
  4.2	
  Areas	  Covered	
  by	
  the	  SHM	
  and	
  Its	  Speciﬁca�ons	
  Technical Reports on National Seismic Hazard Maps for Japan
4.3	
  Determina�on	
  of	
  the	
  Inner	  Source	  Parameters	
  and	  	  Others	
  of	
  Characteris�c	
  Earthquakes	
  Occurring	
  in	
  
	
  Major	
  Ac�ve	
  Fault	
  Zones	  4.4	
  Subsurface	  Structure	
  Models	  4.5	
  Method	  of	  Strong	
  Mo�on	  Simula�on	
  rela�on	
  4.6	
  Evalua�on	
  Results	
  5.	
  Japan	  Seismic	
  Hazard	
  Informa�on	
  Sta�on	
  (J-­‐SHIS)	
  (pp	  19)	  5.1	  Outline	
  5.2	
  Objec�ves	
  5.3	
  Technical	
  Background	
  5.4	
  J-­‐SHIS	
  System	  5.5	
  Toward	  Sending	
  Informa�on	
  on	
  Earthquake	
  Risk	  6.	
  Toward	
  the	  Future
	
  
	
  
	
  	
  	
  	
  	
  	
  	
  	
  (pp	  3)	  7.	
  Closing	  Remarks	
  Acknowledgments	  Appendix	  Strong	  Ground	
  Mo�on	  Predic�on	
  Method	
  ("Recipe")	
  for	
  Earthquakes	
  with	  Speciﬁed	
  Source	
  Faults	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  (pp	  50)	
  November 2009

Technical Note of the National Research Institutefor Earth Science and Disaster Prevention No.336

独立行政法人

防災科学技術研究所

National Research Institute for Earth Science and Disaster Prevention, Japan

Modeling
Seismic Activity
Modeling
ofofseismic
activity
Earthquakes of which the seismic source fault is specified(earthquakes occurring in major active fault zones, subduction-zone
earthquakes, and earthquakes at any other active faults)For	
  known	  	
  faults:	

Earthquakes without specified source faults

Unknown	
  faults:	

Target site

Target site

Target site

Magnitude i
distance j

Evaluation of the probabilities of magnitude, distanceand earthquake occurrence (frequency)

BPT distribution based on arenewal process
Stationary Poisson process

Magnitude

Distance

Earthquake occurrence probability P(Ek;t) or
occurrence frequency v(Ek)Probability function of the
distance where themagnitude is miPk(rj|mi)Probability

Probability function of
the magnitude Pk(mi)Probability

Probability function of the
distance where themagnitude is miPk(rj|mi)Probability

Probability

Probability function of
the magnitude Pk(mi)Magnitude

Distance

PoissonEarthquake occurrence frequency v(Ek)
G-R relation

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	
Probability distribution of groundmotion intensity

Probability that the ground motion intensity exceeds acertain level where earthquake k has occurredort-year exceedance
probability

Hazard curve for each earthquake
Probability that the ground motion intensity exceeds acertain level within t years as a result of the target
earthquake (earthquake cluster) k

Earthquake kt-year exceedance
probability

Distance

Exceedance Prob. of an
intensity level P(Y > y|Ek)

Prob. for each earthquake
P(Y > y)= P(Ek) P(Y > y|Ek)

Ground motion intensity

Hazard curve integrating the results for all
earthquakes

Prob. for all Eqs Ek
P(Y > y)=1-Π[1- P(Yi > y)]

Ground motion intensity for a given exceedance probability

Exceedance probability for a given ground motion Intensity

Ground motion intensity

12/06/13	
  Probability that the ground motion
intensity exceeds level y where themagnitude is mi and the distance is rj

Ground motion
intensity

Magnitude i
distance j
earthquake k

Classiﬁca�on	
  into	
  Earthquake	
  category		
EQ category I	

EQ category II	

EQ category III

Characteris�c	
  Subduc�on-­‐zone	  Earthquakes	

Fused	  Subduc�on-­‐zone	  Earthquakes	

Crustal	
  Earthquakes	

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	

3.3.3	  Earthquakes	
  occurring	
  on	
  Ac�ve	
  faults	Ø Determina�on	
  of	
  the	
  earthquake	
  occurrence	
  probability	
  Ø R	
  (year)	
  :	
  Mean	  recurrence	
  interval	
  
Ø R	
  =	
  D	
  /	
  S	
  *	
  1000
	
  
	
  	
  
Ø
	
   Where,	
  D	
  (m)	  =	  displacement	  per	
  event;	
  	
  
Ø S	
  (mm/year)=	
  average	
  slip	
  rate	  Ø log	
  R	
  =	
  log	
  L	
  /	
  S	
  +	
  1.9	  Ø	
   Where,	
  fault	
  length	
  L	
  

	
  	
  
	
  	
  

Ø

	
   log	
  L	
  =	
  0.6	  M	  -­‐	
  2.9;	
  	  (Matsuda,	
  1975)	
  Ø	
   log	
  D	
  =	
  0.6	  M	  -­‐	
  4.0	
  ;	
  	
  	
  	
  

Ø For	  the	
  unknown	
  of	
  average	
  slip	
  rate,	  	  Ø ac�vity	
  levels	
  are	
  grouped	
  as	
  	
  
Ø
	
   Class	
  A:	
  1	
  mm/y	  	  Ø	   Class	
  B:	
  0.25	
  mm/y	  	  Ø	   Class	
  C:	
  0.047	
  mm/y	  EQ category III

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	

EQ category II	
 3.3.4	
  Earthquakes	
  without	
  speciﬁed	
  source	
  faults	Ø The	  Earthquake	  Occurrence	
  Ra�o	
  	
  
Ø R	
  =	
  between	  Interplate	
  and	
  intraplate	

all earthquakes are regarded
earthquakes

urface of the

Area where distinction is made between interplate
earthquakes and intraplate earthquakes based on a ratio

Earthquakes deeper than this line
are regarded as intraplate
earthquakes

3.4.3-8 Idea of distinguishing between interplate earthquakes and intraplate earthquakes (SLTE/SESGM, ERC, 200

(a) Shallow earthquakes in the vicinity of Nansei-shoto islands

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	

Shallow earthquakes inthe vicinity ofNansei-shoto islands

Upper surface of thePhilippine Sea plate

Evaluated as earthquakes at thePhilippine Sea plate(Relatively deep earthquakes
from Kyushu to the vicinity ofNansei-shoto islands)

Relatively deep
earthquakes

Data for this area isincluded in shallow
earthquakes.

(b) Earthquakes in the vicinity of Yonaguni-jimaEarthquakes in thevicinity of
Yonaguni-jima

Upper surface of thePhilippine Sea plate

Occurrence	
  frequency	
  of	
  Earthquakes	
  (M>5)	
  without	
  speciﬁed	
  source	
  faults	
Since relatively deep earthquakes have notbeen modeled in the vicinity of
Yonaguni-jima, earthquakes shallower
than 100 km are treated collectively.

X 10-4 [times/year]
Figure 3.3.4.9-5 Occurrence frequency of earthquakes without specified source faults in the vicinity of Nansei-shoto islands (per0.1-degree square, M5.0 or more)

Figure 3.3.4.9-1 Target earthquakes of earthquakes without specified source faults in the vicinity of Nansei

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	

X 10-4 [times/year]

2009 version (data: - Dec. 2007)

X 10-4 [times/year]

Rate of change = (2009-2008)/2008

2008 version (data: - Dec. 2006)

Figure 3.3.4.10-2 Occurrence frequency of earthquakes without specified source faults in the Philippine Sea plate (Total for interplate and intraplate earthquakes)

Uncertainty:

U = Ur_+Uk	

１．Ur: Aleatory (Random) Uncertainty	
6Time of EQ occurrence

6

Location of EQ occurrence

6

Source properties (e.g. M) of EQ occurrence

6

Ground motion at a site

6

Given the median value of motion

6 Inner Source parameters，fault rupture process(e.g.,
direction of rupture 震源の微視的)	

２．Uk: Epistemic (Knowledge) Uncertainty 情報不足->不確定性 	
6 Geometry of seismotectonic and seismo-genic zones
6

Distributions describing source parameters(e.g., rate, b value, maximum M)

6Median value of ground motion given the source properties

6

Limits on ground shaking	Common logarithm standard deviation σ 	
σ = 0.23	
σ = 0.15	

Seismic intensity in 3% exceedance probability within 30 years	

Reduce uncertainty by using variance σ
depending on Velocity amplitudes	

Common logarithmic standard deviation

Random	  phenomenon	
  (Aleatory	  uncertainty	
  )	
  was	  considered	  in	
  hazard	  curve	
  calcula�on	
  Conventional value (0.23)

Value to be used for
the National Seismic
Hazard Maps forJapan

Estimated value of the peak velocity (cm/s)on the engineering bedrock (Vs = 600m/s)

Technical	
  reports	
  on	
  Na�onal	
  Seismic	
  Hazard	
  Maps	  for	  Japan	
  (2009)	
	
3.3.2	  Subduc�on-­‐zone	
  Earthquakes	
	
We did pointed out that a M7.4 to 8.0 earthquake in Miyagi-ken-Oki,area A, with probability of 99%, would be occur within 30 years.

B

D

A

C
A: Miyagi-ken-Oki
B: Northern Sanriku-Oki
C: Close to the offshoreE

trenches inSanriku-Oki
regionsF
G

Japan
TrenchHowever, the ruptures trigged areas A,
E, D, F, G and C simultaneously, over a
region of 500km x 200km, which was far
beyond our considerations.
The maximum M was underestimated.

the Northern
to Boso-Oki

D: Central Sanriku-Oki
E: Close to the offshore
trenchesin
Sanriku-Oki

Southern

F: Fukushima-ken-Oki
G: Ibaraki-ken-Oki
3.2-3 Areas covered in evaluation of the Miyagi-ken-Oki Earthquake and earthquakes in the Sanriku-Oki to Boso-Oki
regions.

Strong-motion maps considering low-probability earthquakes
	

1,000 years		

10,000 years		

100,000 years	
	

How	
  to	
  give	  the	
  warning	
  or	
  message	
  to	
  public,	
  	
  

for	
  unexpec�ng	
  event,	
  or	
  low	
  probability	
  but	  destruc�ve	
  events,	  	

Major	
  earthquakes	
  on	
  ac�ve	
  faults	
  and	
  subduc�on	
  zone	  with	  low-­‐probability.	
  	
  
	
  
Regarding	
  the	
  PSHA	  for	
  low	
  probability,	
  at	
  presen	
  it	
  is	
  insuﬃcient	
  to	
  evaluate	
  the	
  uncertainty	
  for	
  low	
  probability	
  of	
  M8-­‐class	
  earthquakes	
  and	  it	  is	
  necessary	
  to	
  improve	
  techniques	
  for	  them.	

convergent
	

ISLAND	
  ARC	  OF	  TAIWAN	
  AND	  JAPAN		Prepara�on	
  for	  the	
  next	
  M9	
  	

3.	
  
	
  

	
  Coopera�ve	
  works	
  on	
  PSHA	  	
  6 Historical	
  records	
  6 Sharing	
  EQ	
  database	  6 Person	  exchange	  What	
  lessons	
  we	
  have	  learnt	
  from	
  the	
  Tohuku	
  earthquake?	
  
	
  
	
  
	
  
“The	
  borderless	
  world	  of	
  Science”	
  à	
  enabling	  knowledge	
  and	
  data	  exchange	  each	
  others.	
  Subduc�on	
  zones	  à	  Crossing	  border	  connect	  the	
  world	  Earthquakes	
  without	
  speciﬁed	
  source	
  faults	
  in	
  the	
  vicinity	
  of	  	
  Ryukyu	
  islands	  Arrows	  -­‐>	
  Earthquake	
  occurrence	
  regions	  	
  W.-­‐J.	
  Huang,	
  et	
  al,	  2010	

地震調査委員会（2004）	

Subduction zones for Island arc

地震調査委員会（2004）	

New	
  Release	
  	
  	
  
www.j-shis.bosai.go.jp/intl/cjk	
Interna�onal	
  Coopera�on	
  	
  	
   	
  	
  
	
  à	
  
Trilateral	
  coopera�ve	
  program	  	
  enabling	
  knowledge	
  data	  exchange	
  Approved	
  and	
  supported	
  by	
  each	  individual	
  coun�es	
  
	
  à	
  	
  	
  SHA	
  	
  
	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  for	  Next	  Genera�on	
  	
  	
  	
  
	
  à	
  	
  	
  Welcome	
  to	
   	
  
	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  Coopera�on	
  with	  TEM	  	
  12/06/13