Workshop on
Seismic Hazard Assessment Issues in the island arc of
Taiwan and Japan

Earthquake Hazard Map of Taiwan
Thomas, Chin-Tung Cheng Ph.D.
鄭錦桐 博士Disaster Prevention Technology Research Center (DPTRC)
Sinotech Engineering Consultants, INC.
Taipei, Taiwan
0CONTENTS
 What’s SHA
 Why PSHA?
 Lesson Learned from Chi-Chi Earthquake Taiwan PSHA Model
Earthquake Sources
Catalogue Completeness and aftershock removal
GMPEsLogic Tree - Uncertainty HandlingTaiwan PSHA Result

 Future Tasks
1

What’s SHA?

2

Earthquake Hazard and Risk
斷層破裂Fault ruptureHazard:Potential for earthquake related natural
phenomena
Ground motion () PGA, PGV, PGD, Sa, Ia
Fault ruptureLiquefaction
LandslideTsunami

液化Liquefaction

山崩LandslideKey questions:How severe is the ground motion?
How often does it happen?

海嘯Tsunami

3

Earthquake Hazard and Risk
Risk: Probability of loss to society due tohazards and vulnerability
GEM (Global Earthquake Model)TEM (Taiwan Earthquake Model)
TELES (Taiwan Earthquake Loss Estimation
System)4

Seismic Hazard Analysis
 Quantitative estimation of ground motion at a site
 Design earthquake (response spectra)
 SHA involves the following steps
Seismic Source Characterization: Evaluate all potential
earthquake sources close to the site
 Earthquake activity rate Fault slip rate
 Location, orientation, and style of faulting Magnitudes
 By geologists and seismologists

5What is Seismic Hazard Analysis?

Two Components:(1) Earthquake Forecast
logN=a-bM
Probability in time andspace of all M≥5 events(2) Ground-Motion Estimation
Experience
Intensity Measure(PGA, Sa) Regressions

Simulation
Fullwaveformmodeling

6

Variables that Influence
Strong Ground Motion

Y=f (M, R)

BridgeShallow Geology

Earthquake Source• Fault Size, Slip Distribution,
Rise Time, Style-of-Faulting• Rupture Propagation

Site Response (100 m)• Soil Depth & Type• Wave Velocity• Non - Linearity

R

M

Wave Propagation*• Crustal Velocity Structure• 3 - D Sedimentary Basin• Small - Scale Heterogeneity(Wave Scattering)7

Uncertainties in SHA
 Uncertainties considered in SHA
A fault is active or not (include or exclude from further
consideration)
Possible magnitudes
 Rupture the entire fault or part of the fault

Likelihood of occurrence of a given magnitude
earthquake during the life span of structure -- Howoften does the earthquake occur? (earthquake
recurrence rate)
Distance to the earthquake source (location of source)
 Areal source (random location)
 Rupture location along the fault

8Uncertainties in SHA
Uncertainties encountered when conducting
SHA (cont)Variability of ground motion

強
地
動
值
lnZ

ln(z)

強
地
動
值
lnZ

ln(z)

m1
r

m

m2
r1
距離, log( r)r2
距離, log( r)9Two Approaches to SHA
 Deterministic (DSHA) & Probabilistic (PSHA) Use the same source characterization andattenuation relation
 Differ in the way uncertainties are handledDeterministic: Pick a conservative value
Probabilistic: Explicitly treat all the possible scenariosand pick the design motion based on acceptable hazard

10Deterministic Seismic Hazard Analysis(DSHA)
Make a conservative
selection of Source
Active fault (Late Pleistocene)Taiwan: 100,000 yrs (Taiwan,
CGS’s active fault map)Japan: 100, 000yrs
Caltrans: 70,000 yrs
Cal. state fault map: 11,000 yrs
COE: 35,000 yrs
USBR: 100,000 yrs

Wells and Coppersmith (1994)

magnitude and distanceRupture the entire mapped fault
lengthRupture ½ the mapped fault
length11

Deterministic Seismic Hazard Analysis(DSHA)
Selection of GMPEs
Mag., Dis.

Variation of GMPEs,

conservative?
84% (medium + 1  )50% (medium)12

Deterministic Seismic Hazard Analysis(DSHA)
Who makes the decision? How?
Consultants: precedence and expert’s opinion
Owners
Regulatory agency
Safety/performance and cost
MCE, DBE, OBE

The level of conservatism is not quantified
Don’t know if design motion is reasonable

13

Why PSHA?

14

The “Worst-case” Ground Motion
 PGA of 2 standard deviations () above mediancan and do occur
 But not very often
Magnitude M 7
at distance R = 5 km
Number of above
medianPGA (g)Probability(How often?)

0

0.52

50%

1

0.79

16%

2

1.18

2.6%

Peak Ground Acceleration (g)+1 1median-1 

0.1
Sadigh et al. (1997)
M6.7, Median - 1 Sigma

M6.7, MedianM6.7, Median + 1 Sigma
Northridge Data

0.01
1

10

Distance (km)

15

100

Motivation To Conduct a PSHANeed to back-off from the worst-casemotion and select a ‘reasonable’ design
motionSelection should be based on the joint
consideration of ‘rate of occurrence’ andperformance goal
• More safety• More economical

PSHA is a methodology that provides
information needed for such rational
selection

16

What is Probability Seismic Hazard Map?
Source+Attenuation(path)+
Site=
Hazard17

PSHA METHODOLOGY
The probability (P) of exceeding ground motion amplitude (Z) in agiven period of time (T) is related to annual frequency of
exceedance v(z) by the equation:

P( Z  z T )  1.0  e v( z )  T  v( z )  T

Poisson Process

T=50yr, P=10%  v(z)=1/475  return period 475yr
T=50yr, P= 2%  v(z)=1/2475  return period 2475yr
Nv( z )  n 1

rj rmax
 λn (mi )    Pn ( R  r j mi )  P( Z  z mi ,r j )
mi  m0 rj 0

mi  muThere are N sources n=1~Nλn(mi) is the annual frequency of nth source in magnitude bin mimi from lower bound magnitude m0 to upper bound magnitude mu
Pn(R=rj|mi) is the probability density function of nth source within rj while magnitude mi
Pn(Z>z|mi, rj) is the probability of ground motion Z exceed z at mi and rj.

18

Lesson Learned form Chi-Chi Earthquake

19

Hangingwall EffectReverseStrong Ground motion is higher in HW
Intensity map of Chi-Chi Eqk.

20

Hangingwall EffectFault Rupture
Line

FootwallHangingwall
21

Magnitude of Earthquake

ML
MS
Mw 

Magnitude of
Chi-Chi Eqk.
ML7.3(CWB)
Mw7.6 or 7.7(CMT, USGS)
22

Scaling With Distance: Distance Metric Hypocentral distance –outdated (X) Closest distance to thefault () Closest distance to thesurface projection of
fault – Joyner-Boore
Distance ()23Previous PSHA Model in Taiwan(Tsai et al., 1986)

CampbellForm
475 years

24

Previous SHA Model in Taiwan(Cheng, 1996)

Campbell Form
475 years

0.42

0.34

25

PSHA After Chi-Chi earthquake (rock site)
Without Faults

Consideration of Fault Activity

26

Taiwan Building Code Revising Progress
1997

2000

(before Chi-Chi Eqk)

(after Chi-Chi Eqk)

Updated in 2006

27

Taiwan PSHA Model28

Flow Chart for Probabilistic Seismic Hazard Analysis (PSHA)

29

Plate Tectonics
in Taiwan
30

Seismotectonic framework of Taiwan

Data source:
1.Central Weather Bureau(CWB)
2.Institute of Earth Sciences, Academia
Sinica31

Geology of
TaiwanTaiwan orogeny started at Late
Miocene and is presently active.
The Central Range consists ofmetamorphic complex and a
Paleogene slate belt.
Bordering the Central Range is theWestern Foothills, consisting ofNeogene sedimentary formations,and the Eastern Coastal Range,
which is also made of Neogene
sedimentary strata.

The Longitudinal Valley locatedbetween the Central Range and theEastern Coastal Range is the suturezone between two plates.
32

33

1990-1995

台灣地區各GPS站相對於澎湖站之移動速度

200834

中研院GPS監測成果統合資料

CGS

NCU
(Modified from Lee, 1999)(Chang et al., 2000)
35

Earthquake Sources
Earthquake
Recurrence model

Source Categories

Source Geometry

 Shallow Crustal Sources Deep Sources

Regional/
Areal Sources

Truncated Exponential
Model

Planar/3D
Sources

Characteristic Eqk.
Model

 Subduction Zone Sources Interface sources Intraslab sources

 Active Faults

36

Active Faults Map of Taiwan

Active Fault (#47)

37

Shallow crustal sources（depth≦35km)(# 25)

Shyu et al. (2005)

38

Illustration of Subduction zone system(Byrne et al., 1988)
39

Deep sources（depth>35km)(#7)

Subduction Zone Sources (#16)

Intraslab
Interface

Intraslab

Interface40

41

Completeness of Catalogue
 Adopt the earthquake catalogue 1900~1999
 Eqk. Magnitude convert to MW
 Catalogue divided into four stages
(Yeh et al., 1995 and Tsai, et al., 2000)
Seismic Monitoring Network
distribution density of instrument
accuracy of instrument(1) 1900~1935：whole region Mw6.0；(2) 1936~1972：inland Mw5.0，offshore Mw5.5；(3) 1973~1991：inland Mw3.5，offshore Mw4.0；(4) 1992~：inland Mw2.5，offshore Mw3.5。
42

Foreshock and Aftershock Removal
100

Arabasz and Robinson (1976)
Gardner and Knopoff (1974)
Uhrhammer (1986)

Wyss (1979)
Gradner and Knopoff (1974)
Uhrhammer (1986)

100

Distance( km)T ime( days)

1000

10

10

1
0

2

4

Magnitude

6

8

0

2

4

6

8

Magnitude
43

國外常用的(a)時間域與(b)空間域上的去除前震及餘震的地震序列經驗準則。

Estimate fault activity / recurrence rate

(Schwartz與Coppersmith, 1984)

44

Estimate fault activity / recurrence rate releasesame M0
Truncated exponential
model

Char. Eqk. Model

Paleo-seismology

45(Youngs and Coppersmith, 1985)

Characteristic Earthquake Modelfor Interface/Active Fault Sources

46

Summary of Active Faults in Taiwan (1/3)(Lee, 1999)

47

Summary
ActiveFaultsin Taiwan(Lee, 1999)
Summaryofof
ActiveFaultsin Taiwan(2/3)(Lee, 1999)

48

Summaryof Active
FaultsTaiwan (3/3)
Summaryof Active
FaultsininTaiwan(Lee, 1999)

49

dip

Fault mechanism

Fault length (km)Top

Bottomfault rupture width(km)displacement (m)Max. rupture area(km2)

fault slip rate(mm/yr)
Associated Weights (inParentheses)

Max. Magnitude Mu
Associated Weights (inParentheses)

Younngs andCoppersmith,
1985

Matsuda, 1975

Bolina, 1970

fault rupture
depth(km)Dip (Degree)

36

0

15

17

1.8

624

1.0(0.2) 2.0(0.6) 3.0(0.2)

6.8(0.2) 7.0(0.6) 7.2(0.2)

543

746

568

StrikeNorma &
Sinistral

Nankan

NNW 80NW

80

Normal&Dextral

22

0

10

10

0.7

223

0.2(0.2) 0.4(0.6) 0.6(0.2)

6.3(0.2) 6.5(0.6) 6.7(0.2)

1352 1896 1492

05

Shuanglienpo
Yangmei
Hukou
Hsinchu
Tapingti
Chutung
Hsincheng
Touhungping
SzetanShinchoshan

ENE 50SE

50

Reverse

12

2

10

10

0.4

125

0.2(0.2) 0.5(0.6) 0.8(0.2)

6.0(0.2) 6.2(0.6) 6.4(0.2)

567 1036

ENE 50NW

50

Reverse

20

2

10

10

0.8

261

0.2(0.2) 0.5(0.6) 0.8(0.2)

6.4(0.2) 6.6(0.6) 6.8(0.2)

1082 1704 1334

ENE 45SE

45

Thrust

32

0

12

17

1.5

543

0.5(0.2) 1.0(0.6) 1.5(0.2)

6.7(0.2) 6.9(0.6) 7.1(0.2)

733 1362 1041

E-W 45S

45

Thrust

28

0

12

17

1.4

475

0.8(0.2) 1.5(0.6) 2.3(0.2)

6.6(0.2) 6.8(0.6) 7.1(0.2)

395

NNE 45SE

45

Thrust

15

0

12

17

0.8

255

0.3(0.2) 0.6(0.6) 0.9(0.2)

6.3(0.2) 6.5(0.6) 6.8(0.2)

653 1378 1080

NE 50SE

50

Reverse

14

0

12

16

0.7

219

0.3(0.2) 0.6(0.6) 0.9(0.2)

6.3(0.2) 6.5(0.6) 6.7(0.2)

760 1249

983

N40E 45SE

45

Thrust

22

0

12

17

1.1

373

1.0(0.2) 2.0(0.6) 3.0(0.2)

6.5(0.2) 6.7(0.6) 7.0(0.2)

267

532

412

E-W 80S80

Dextral

27

0

12

12

1.0

329

1.3(0.2) 2.5(0.6) 3.8(0.2)

6.5(0.2) 6.7(0.6) 6.9(0.2)

242

392

304

N10E 75W

75

Reverse

35

0

12

12

1.3

435

1.3(0.2) 2.5(0.6) 3.8(0.2)

6.6(0.2) 6.8(0.6) 7.0(0.2)

259

471

362

N10E 60E

60

Reverse

16

0

12

14

0.7

222

1.3(0.2) 2.5(0.6) 3.8(0.2)

6.3(0.2) 6.5(0.6) 6.7(0.2)

180

302

238

37

2

15

26

2.6

962

2.5(0.2) 5.0(0.6) 7.5(0.2)

7.0(0.2) 7.2(0.6) 7.4(0.2)

223

397

298

368

287

06
07
08
09
10
11
12
13
14

832

831

639

14BT

Miaoli blind thrust

N10E 30E

30

Reverse &Dextral15

N60E 9090

Dextral

20

0

15

15

0.9

300

1.3(0.2) 2.5(0.6) 3.8(0.2)

6.4(0.2) 6.6(0.6) 6.8(0.2)

226

NNE 40E

40

Thrust

22

0

15

23

1.5

513

0.5(0.2) 1.0(0.6) 1.5(0.2)

6.7(0.2) 6.9(0.6) 7.1(0.2)

940 1313 1005

N-S 40E

40

Thrust

90

0

20

31

6.8 28008(0.2) 15(0.6) 23(0.2)

7.5(0.2) 7.7(0.6) 7.9(0.2)

182

268

194

18

Tuntzechiao
Sanyi
Chelungpu
Changhua

NNS 30E

28

Thrust

85

2

15

28

5.4 23548(0.2) 15(0.6) 23(0.2)

7.4(0.2) 7.6(0.6) 7.8(0.2)

153

226

165

19

Tamopu-HsuangtungN-S 45E

45

Thrust

70

0

15

21

3.8 1485 0.4(0.2) 0.8(0.6) 1.2(0.2)

7.2(0.2) 7.4(0.6) 7.6(0.2)

2282 3306 2444

20

N-S 50E

50

Thrust

32

0

15

20

1.8

627

0.3(0.2) 0.6(0.6) 0.9(0.2)

6.8(0.2) 7.0(0.6) 7.2(0.2)

1810 2495 1898

N-S 50E

50

Thrust

36

0

15

20

2.0

705

0.4(0.2) 0.8(0.6) 1.2(0.2)

6.8(0.2) 7.0(0.6) 7.3(0.2)

1207 2023 1533

NE 60SE60

Normal

30

0

15

17

1.5

520

0.8(0.2) 1.5(0.6) 2.3(0.2)

6.7(0.2) 6.9(0.6) 7.1(0.2)

623

882

675

NE 60SE60

Normal

25

0

15

17

1.3

433

1.0(0.2) 2.0(0.6) 3.0(0.2)

6.6(0.2) 6.8(0.6) 7.0(0.2)

397

587

452

41a

Shuilikeng
Chenyulanchi
Ilan
ChiaochiLishan(a)NNE 60E

60

Normal

30

0

15

17

1.5

520

0.8(0.2) 1.5(0.6) 2.3(0.2)

6.7(0.2) 6.9(0.6) 7.1(0.2)

623

882

675

41b

Lishan(b)NNE 60E

60

Normal

25

0

15

17

1.3

433

0.6(0.2) 1.2(0.6) 1.8(0.2)

6.6(0.2) 6.8(0.6) 7.0(0.2)

666

978

753

41c

Lishan(c)NNE 60E

60

Normal

30

0

15

17

1.5

520

0.5(0.2) 1.0(0.6) 1.5(0.2)

6.7(0.2) 6.9(0.6) 7.1(0.2)

940 1323 1013

41d

Lishan(d)NNE 60E

60

Normal

30

0

15

17

1.5

520

0.5(0.2) 1.0(0.6) 1.5(0.2)

6.7(0.2) 6.9(0.6) 7.1(0.2)

940 1323 1013

17

S06

60

Characteristic
Earthquake
recurrence
interval(year)

04

16

21
39

S14A

Huangchi + Hsiaoyukeng
NNE 60SE+ Sanchiao

Fault Name

Fault No.

Reginal source
S05

S04

01+02+03

S09

Characterization of Active Fault Sources in Taiwan

Weighting inside the parentheses

40

50

Truncated Exponential Modelfor Regional/Areal, Intraslab Sources

51

Characterization of Shallow Crustal areal Sources
in Northern Taiwan Depth less than 35km
N ( mo ) ( N (mo ) )mu

The largest(Associated Weights in
Parentheses)

recorded

Source
No.

mo

S01

3.5

1.343(±0.218)

0.849(±0.118)

S04

2.5

3.796(±0.532)

0.800(±0.084)

6.4(1.0)

5.6

S05*

2.5

7.038(±0.507)

0.916(±0.059)

5.0(1.0)

7.1

S06*

2.5

18.550(±1.144)

0.740(±0.035)

6.5(1.0)

7.6

S09*

2.5

2.959(±0.441)

0.577(±0.066)

6.5(0.0)

6.7

S13

3.0

1.247(±0.266)

0.689(±0.076)

6.3(0.2) 6.5(0.6) 6.7(0.2)

5.8

S14A*

2.5

4.378(±0.657)

0.638(±0.067)

6.5(1.0)

6.5

S14B

3.5

2.385(±0.338)

0.593(±0.056)

7.4 (0.2) 7.6 (0.6) 7.8 (0.2)

7.5

S15

3.5

9.262(±0.8031)

0.658(±0.045)

7.4 (0.2) 7.6 (0.6) 7.8 (0.2)

6.6

S16*

3.5

9.885(±0.828)

0.644(±0.039)

7.0 (1.0)

8.2

S17A*

3.5

1.328(±0.293)

0.520(±0.086)

6.5(1.0)

7.2

S17B

3.5

3.790(±0.516)

0.681(±0.070)

7.3 (0.2) 7.5 (0.6) 7.7 (0.2)

7.2

b(b)

6.5 (0.2)

6.6 (0.6)

6.7 (0.2)*There was at least one active fault within the areal source. Any magnitude of events were larger
than mu (maximum magnitude) would be triggered by active faults as characteristic earthquakes.
52
Therefore, magnitude of event bellow mu assumed as background earthquakes.

MW
6.2

Characterization of deep areal Sources in Northern Taiwan
Depth large than 35km

SourceNo.

moN (mo ) ( N (mo ) )b(b)

mu

The largest(Associated Weights inrecordedParentheses)

MW

D01

3.5

3.311(±0.543)

1.043(±0.132)

6.5 (0.2) 6.6 (0.6) 6.7 (0.2)

6.0

D02

3.0

3.808(±0.373)

0.896(±0.080)

6.5 (0.2) 6.6 (0.6) 6.7 (0.2)

6.0

D04

3.5

1.702(±0.244)

0.734(±0.090)

7.0 (0.2) 7.2 (0.6) 7.4 (0.2)

6.7

D05*

3.5

5.312(±0.436)

0.707(±0.049)

6.8 (0.2) 7.0 (0.6) 7.2 (0.2)

6.3

D06

3.5

2.107(±0.275)

0.764(±0.081)

6.8 (0.2)

6.3

7.0 (0.6) 7.2 (0.2)

Note: D05 and S16 are located in the same Top-View place, but their focal depth are
different. Focal depth of D05 is greater 35km and S16 is bellow 35km.
53Characterization of Subduction Zone Sources
in Northern Taiwan
Interface Earthquake source
NO

T01*

Name

Interfacemo

6.5

Slip rate(mm/yr)

Dip-angle(degree)30(0.2)40(0.6)50(0.2)18(0.3)20(0.4)22(0.3)

Seismogenic
depth
10~40km

The largestbmu

recordedMW

0.7

7.8 (0.2)
8.0 (0.6)
8.2 (0.2)

8.2

 T01 interface source is within regional source S16. The earthquakes would be assumed as interface source while
the magnitude is grater than MW6.5.
 The dip-angle of interface-plate was illustrated by the depth distribution of seismicity.
 The slip-rate was estimated by Kao et al.(1998) and Kao et al.(2000).

Intraslab Earthquake sourcesNO

Depth RangemoN (mo ) ( N (mo ) )The largestb(b)

murecorded
MWNP135-50km4.0

3.000(±0.318)

0.884(±0.077)

7.6 (0.2)

7.7 (0.6)

7.8 (0.2)

7.4

NP2

50-70km

4.0

2.441(±0.294)

0.826(±0.085)

7.6 (0.2)

7.7 (0.6)

7.8 (0.2)

6.2

NP3

70-90km

4.0

1.313(±0.214)

0.778(±0.097)

7.6 (0.2)

7.7 (0.6)

7.8 (0.2)

7.2

NP4

90-110km

4.0

0.576(±0.133)

0.797(±0.068)

7.7 (0.2)

7.8 (0.6)

7.9 (0.2)

7.3

NP5

110-130km

4.0

0.309(±0.103)

0.824(±0.071)

7.7 (0.2)

7.8 (0.6)

7.9 (0.2)

7.6

NP6

130-150km

4.0

0.282(±0.0998)

0.861(±0.071)

7.7 (0.2)

7.8 (0.6)

7.9 (0.2)

6.0

NP7

150-170km

4.0

0.409(±0.118)

0.801(±0.070)

7.7 (0.2)

7.8 (0.6)

7.9 (0.2)

7.6

NP8

170-190km

4.00.410(±0.114)

0.894(±0.070)

7.7 (0.2)

7.8 (0.6)

7.9 (0.2)

5.4

NP9

190km~

4.0

0.870(±0.174)

0.884(±0.067)

7.7 (0.2)

7.8 (0.6)

7.9 (0.2)

5.9

54

To summary the annual numberof all active faults within areal
source S06.

To avoid double counting therate of seismicity:

Trun. Exp. Model

Char. Eqk.
ModelM>6.5, Char. Eqk. Model, related
to active faultM<=6.5, trun. Exp. Model, related
to background seismicity

55

Ground-Motion Estimation after Chi-Chi
Chi-Chi earthquake and its after shockprovide a great number of ground motion
data recorded by TSMIP.
Site Classification Vs30
 Average shear-wave velocity of the top 30m ofsoil NEHRP’s drilling of TSMIP stations
Site categories B, C, D, E, F (Lee et al., 2001)

Near fault ground motion data are very
valuable for developing ground motion
prediction model.
56

Site Classification for TSMIP Stations (Lee et al, 2001)– Capture stable differences invelocity through site categories– Surficial geology– Rock vs. Soil
– Age, depositional
environment, texture– Vs30 (Average shear-wave
velocity of the top 30m of soil)(NEHRP)

57

Comparisonof PGA Attenuation Relations
3.3 強地動衰減式：地殼震源
Crustal Sources

Subduction Zone Sources
Global Intraslab

FootwallThis study hangingwall (rock site)
This study footwall (rock site)
Jean and Loh, 1998
Loh et al., 1997
Tsai et al., 1987 Kanai
Tsai et al., 1987 Campbell
Tsai et al., 1987 Joyner and Boore
Tsai et al., 1987 Japan Rock Site

PEAK GROUND ACCELERATION(G)PEAK GROUND ACCELERATION(G)Hangingwall
Global Interface

Taiwan Intraslab

Taiwan Interface

Intraslab (soft site), This study
Intraslab (rock site), This study
Interface (soft site), This study
Interface (rock site), This study
Chang et al., 2001
Intraslab (soft site), Youngs et al., 1997
Intraslab (rock site), Youngs et al., 1997
Interface (soft site), Youngs et al., 1997
Interface (rock site), Youngs et al., 1997
Molas and Yamazaki, 1995
58
Crouse, 1991

Logic tree used in the PSHA for handling theuncertainty of parameters and models
Source Model

Attenuation
Model

S01
S02
S03

Shallow and deeparea sources

D01
D02
D03
D04

( Regional
Source)

LOH98
(1.0)

N0.5
NO.17

( Planar source)

Subducting plateinterface source

North-east
subducting plate
intraslab sources( Planar source)

NP1
NP2
NP3
NP4

South subducting
plate intraslab
sourceSP1
SP2(Planar source)

Dip of fault

b valueSlip rate /Earthquake
recurrence N(m0)

LOH98
(1.0)

10 km
(0.28)
15 km(0.16)
20 km(0.14)
25 km(0.12)
30 km(0.06)
35 km(0.04)

Top 0 kmBottom 20 km(1.0)

Truncate
exponential model

Maximum (mu)earthquake

0.811(0.185)19.515(0.185)M w6.5(0.20)

0.855(0.63)

20.970(0.63)

M w 6.6(0.60)

0.899(0.185)22.425(0.185)

M w 6.7(0.20)

35 °
(0.2)

0.75
(0.2)

6 mm/yr
(0.2)

M 7.5
w
(0.20)

40 °
(0.6)

0.80
(0.6)

12 mm/yr(0.6)

M w 7.7(0.60)

45 °
(0.2)

0.85
(0.2)

18 mm/yr(0.2)

M w 7.9(0.20)

Random
(1 .0)

Characteristic
earthquake model(1.0)

Aleatory Variability (random)
Epistemic Uncertainty (scientific)
T01( Planar source)

Earthquake magnitude
distribution

5 km(0.20)

NO.1+2+3
NO.4

Fault source

Source Depth

TWYG02(Interface)(1.0)

TWYG02(Intraslab)(1.0)

TWYG02(Intraslab)(1.0)

Top 5 kmBottom 35 km(1.0)

Top 70 km
Bottom 90 km(1.0)

Top 35 km
Bottom 70 km(1.0)

Characteristic
earthquake model(1.0)

Truncate
exponential Model(1 .0)
Truncate
exponential
Model(1 .0)

M w7.5(0.16)

10 °
(0.3)

0.75
(0.2)

28 mm/yr(0.185)M w7.7(0.48)

15 °
(0.4)

0.8
(0.6)

32 mm/yr(0.63)

M w 7.9(0.16)

20 °
(0.3)

0.85
(0.2)

36 mm/yr(0.185)

M w 8.0(0.1)
M w8.2(0.10)

45 °
(0.2)

1.099
(0.185)0.681(0.185)M w7.5
(0.2)

50 °
(0.6)

1.313
(0.63)

0.778(0.63)

M w 7.6
(0.6)

55 °
(0.2)

1.527
(0.185)0.875(0.185)

M w 7.7
(0.2)

45 °
(0.2)

2.315
(0.185)0.713(0.185)

M w 7.6
(0.2)

50 °
(0.6)

2.618
(0.63)

0.785(0.63)

M w 7.7
(0.6)

55 °
(0.2)

2.921
(0.185)0.857(0.185)59

M w 7.8(0.2)

PSHA Result (PGA , rock site)

60

PSHA Result (Fault Sources are Important)

61

Result of PSHA without considering fault source

Result of PSHA considering fault source

PSHA Result (Sa=1.0sec, rock site)

62

PSHA Result (Sa=0.2 sec, rock site)

63

PSHA of Northern Taiwan

RTP=475yr

PGA, 10% Prob. of Exceedance in 50 years, rock

SanChaio Fault

RTP=2475yr

Taipei

PGA, 2% Prob. of Exceedance in 50 years, rock

SanChaio Fault

Taipei64

Using subduction zone source
attenuation relationship

Subduction zone
attenuation relationshipneed to be considered
individually

Without using subduction zone
source attenuation relationship

65

PSHA of Taipei Metropolis
PE = 63% in 50yr return period = 50yr

Taipei, 2 sigma use new attenuation SOIL

Annual Probability of Exceedance

1E+000
5th and 95th
Total mean
Interface
N_Intraslab
FaultsArea_total
S04
S14B
S14A

1E-00150yr

PE = 10% in 50yr return period = 475yr

1E-002475yr
1E-0032475yrPE = 2% in 50yr return period = 2475yr
1E-004

1E-005
0.0

0.2

0.4

0.6

PGA(g)

0.8

1.0

1.2

66

Future Tasks
Next Generation of
Taiwan Earthquake Hazard Map

67

Future Tasks
 Revision of Seismogenic/Areal Source Develop the spatial and temporal relationship of mainsock
and aftershock Analysis the completeness of earthquake catalogue Historical earthquake research Development of Taiwan GMPEs (TNGA)
 Max magnitude of Subduction zone (Mega-thrust) Active fault parameters (geometry, slip rate) updating
 Time-dependent earthquake probability models (WGCEP,
NIED)
68

Reference 鄭錦桐(2002)台灣地區PSHA的不確定分析與參數拆解，中央大學地球物理研究所博
士論文，共227頁。
 Lee, C. T. (1999). “Neotectonics and active faults in Taiwan,” Workshop on Disaster
Prevention/ Management and Green Technolgy, Foster City, CA, U.S.A., 61-74.
 Lee, Chyi-Tyi, Cheng, C.T., Liao, C. W., Tsai, Yi-Ben (2001)Site Classifications of
Taiwan Free-Field Strong-Motion Stations, 2001 Bull. Seism. Soc. Am., 91(5), 1283-1297.
(SCI) Cheng, Chin-Tung, Chiou, Shian-Jin, Lee, Chyi-Tyi, Tsai, Yi-Ben (2007) Study on
probabilistic seismic hazard maps of Taiwan after Chi-Chi earthquake, Journal of
GeoEngineering, Vol. 1, No. 2. (EI) Cheng, Chin-Tung, Lee, Chyi-Tyi, Lin, Po-Shen, Lin, Bor-Shiun, Tsai, Yi-Ben, Chiou,
Syi-Jang (2009) Probabilistic Earthqauke Hazard in Taipei Metropolis and Its Surrounding
Regions. TAO (Terrestrial, Atmospheric and Ocecnic Sciences), Vol. 21. (SCI) Lin, P.S., Lee, Chyi-Tyi (2008) Ground-motion attenuation relationships for subduction
zone earthquakes in northeastern Taiwan, Bulletin of the Seismological Society ofAmerica, 98(1), 220-240, February, 2008. (SCI) Lin, P.S., Lee, Chyi-Tyi, Cheng, C.T., Song, C.H. (2011) Response spectral attenuation
relations for shallow crustal earthquakes in Taiwan, Engineering Geology, 121, 150-164.
(SCI)
69

Thomas, Chin-Tung Cheng Ph. D. (鄭錦桐)Email: ctcheng@sinotech.org.tw
TEL: +886-2-27580568#237
http://dptrc.sinotech.org.tw
Disaster Prevention Technology Research Center
Sinotech Engineering Consultants, INC., Taipei, Taiwan
70

台灣早期不同版本活動斷層分布圖之比較Bonilla, 1975

Hsu and Chang, 1979

Chang et al., 199871

台灣不同版本活動斷層套疊圖(1998)

72

台灣本島及鄰近海域之活動斷層

藍色斷層: 李錫堤 (1998) 提供
黑色斷層: 劉家軒 (1998) 提供
紅色斷層: 黃旭燦 (1998) 提供
全圖見於宋國城等人 (1998)
台灣活斷層研究規劃報告

73

Scaling of Spectral Acceleration- With Distance-

MW=7.074

Scaling of Spectral Acceleration- With Magnitude -

50km

75

Scaling of Spectral Acceleration-With Tectonic Environment -76

Epistemic Uncertainty: Example ofUnknown Die
 Assume you have not seen the die, but you haveseen the results of four previous rolls 2, 3, 3, 4

 What is the model for this die?
 Assume this is a standard 6 sided die
Sparse data (4 observations) do not rule out this model Empirical approach
Assume five sided die, loaded so that 3 comes up
most often

77

「骰子」是甚模樣？

目前擲出骰子四次出現點數
3, 4, 4, 5
可瞭解骰子樣式？可建立骰子的統計模型？

依據過去的點數統計，預測未來出現各點數
的機率？(Aleatory)
可能的骰子樣式，六面體？ (Epistemic)

78

「骰子」是甚模樣？

79

不確定性處理—邏輯樹
美國PG&E電廠進行Diablo Canyon核電廠PSHA時使用邏輯樹結構

0.00156
0.002340.001008

0.001512

0.00032480

0.000486

Sum ( weighting ) = 1

Seismic Hazard Analysis (Cont)
Estimate likely motion from each potential earthquake
source (Mag,Dist,Soil) Use attenuation relation; sometimes simulate motion
 Consider uncertainty
 Evaluate potential site effects
Conduct site specific 1-D site response analysis (if not
generic rock/soil captured by attenuation relation)(SHAKE, RASCALS)
Sedimentary basin, topography (FE or FD)

Consolidate all scenarios and select design motion

81

傾角

（）
(楊耿明等，2003)

35(0.2)

傾角40(0.6)45(0.2)82

Characteristic EQ, Mw=7.6
Recurrence Interval = 180y
Rupture area, Af= 2800km2
Slip-rate S=15mm/yr
Moment rate = 1.0e25
b = 0.74

Exponential ModelbN (m0 )  exp(   (mu  m0 ))  M 0 (mu )
M 0  Af S (c  b)(1  exp(   (mu  m0 ))).

Annual Rate, logN(m0)μ is the rigidity, Af is fault rupture area, S is fault slip-rate,

Exponentialmodel

mu is upper bound earthquake, m0 is lower bound earthquake, β= bln10.

Characteristic Earthquake model
Characteristic
Earthquake modelN ( m)  N eexp(   (m  m0 ))  exp(   (mu  1/ 2  m0 )) c
 N , for1  exp(   (mu  1/ 2  m0 ))m mN (m)  N c u
1/ 2

for

m0  m  mu 

mu 1 m  mu ,2b ln 10  exp(   (mu  3 / 2  m0 ))1N c  N e2
(1  exp( mu  1/ 2  m0 ))Chelungpu fault
Moment Magnitude, Mw

Ne  Af S (1  exp(   (mu  m0  1/ 2))),b10 c / 2 b exp(  )(1  10 c / 2 )exp(   (mu  m0  1/ 2)) M 0 (mu )[( c  b)



c

1
,
2

]

83
Youngs and Coppersmith (1985)

Traditional Method

Uniform Hazard Response Spectrum

PGA is not the only
parameter for seismic design85台灣地區強地動加速度衰減式一覽表 (Lee et al, 2001)
衰減式名稱

衰減式

標準
差σlny

地殼震源堅硬地盤斷層
上盤強地動衰減式

ln y =-3.25+1.075MW -1.723 ln(R+0.156 exp(0.62391MW))

0.577

地殼震源堅硬地盤斷層
下盤強地動衰減式

ln y =-3.20+1.115MW -1.773 ln(R+0.206 exp(0.62888 MW))

0.582

地殼震源鬆軟地盤斷層
上盤強地動衰減式

ln y =-3.55+0.925MW -1.383 ln(R+0.066 exp(0.66884 MW))

0.543

地殼震源鬆軟地盤斷層
下盤強地動衰減式

ln y =-3.40+0.945MW -1.433 ln(R+0.116 exp(0.65946 MW))0.552

隱沒板塊介面地震堅硬
地盤強地動衰減式

ln y =-2.5+1.205MW -1.905 ln(R+0.51552 exp(0.63255)MW))+0.0075H

0.526

隱沒板塊介面地震鬆軟
地盤強地動衰減式

ln y =-0.9+1.000MW -1.900 ln(R+0.99178 exp(0.52632)MW))+0.004H

0.627

隱沒板塊內部地震堅硬
地盤強地動衰減式

ln y =-2.5+1.205MW -1.905 ln(R+0.51552exp(0.63255)MW))+0.0075H+0.275

0.526

隱沒板塊內部地震鬆軟
地盤強地動衰減式

ln y =-0.9+1.000MW -1.900 ln(R+0.99178 exp(0.52632)MW))+0.004H+0.31

0.627

註：MW地震矩規模，R測站到斷層破裂面最短距離，H震源深度，y尖峰地動加速度。
86

Chi-Square Test of Mainshock Catalogue
原
始
地
震
目
錄

獨
立
主
震
目
錄
87

隱沒帶地震與地殼地震MW與ML關係式
MLMW
10

10

Liu, 1999
Wu, 2001
This Study
1:1

8

CWB_MLCWB_ML

8

6

4

地殼地震

2

Liu, 1999
Wu, 2001
This Study
1:1

6

4

隱沒帶地震

2

0

0
0

2

4

6

8

10

0

2

4

6

8

HVD_MW

HVD_MW

Shallow earthquake events

Deep earthquake events

88

10

Uncertainties in SHA

 Uncertainties considered in SHA
A fault is active or not (include or exclude from further
consideration)
Possible magnitudes
 Rupture the entire fault or part of the fault

Likelihood of occurrence of a given magnitude
earthquake during the life span of structure -- How often
does the earthquake occur? (earthquake recurrence rate)
Distance to the earthquake source (location of source)
 Areal source (random location)
 Rupture location along the fault
89Uncertainties in SHA
 Uncertainties encountered when
conducting SHA (cont) Variability of ground motion

機率

機率

強
地
動
值
lnZ

ln(z)

機率

強
地
動
值
lnZ

ln(z)

m1
r

m2

m
r1

r2
90

距離, log( r)

距離, log( r)Improvement on Taiwan Seismic Hazard Map
 Saturation of local magnitude (ML) : Chi-Chi earthquake ML7.3MW7.7
 local magnitude is saturated at a large magnitude.

 Significant hanging wall effect: It shows much higher groundmotion amplitude at hanging wall than at footwall.
 The need to emphasize the fault source: fault slip rate(activity) and geometry.
 The need to use the closest-distance to fault plane for groundmotion attenuation prediction.
 What’s is the “Worst-case” Ground Motion, PGA> 1.0g ?
 Apply PSHA for engineering design

 PGA is not only one ground motion parameter for seismic
design.
 Prediction of spectral acceleration (Sa) at various periods for seismic
design is needed.
91

.23
.37

.21
.20

1.13 .63

.30

>1
.17

.23

.55

.31

.25

.84

.17

1.31
.16

.22

.49
.13

.16
.28

.10

.85
.43

.51
.45

.85

.33

.21

.82

.23

.63
.58
.58
.30
.25
.39

.25
.12

.11

.08

2004 Parkfield

93
Courtesy of N. Abrahamson

Motivation To Conduct a PSHAWhy don’t we design for the “worst-case” peakacceleration (> 1.2 g)?
ex. 2004 Parkfield earthquake in CA. (PGA> 1.2 g)

Because it is “unreasonable”
Occurrence of “worst-case” motion is too rare AND
it is too costly to design for

94