Kuo-Fong Ma
馬國鳳
Institute of Geophysics
National Central University

Damaging Earthquakes in Taiwan
since1700s
Relative quiet in seismicity

M>7 inlandearthquake~ every 100years

WesternTaiwan~every30-40years

Three M>7earthquakes
in twomonths

Bathymetry and Tectonic Setting surrounding Taiwan

TaiwanHsu and Sibuet, 2005
Fig. 1. Geodynamic context of the 2004 Sumatra great earthquake and similar geodynamic context
between Japan and Taiwan. Yellow stars indicate the 2004 Sumatra earthquake and the expectedtocome Tokai earthquake [Le Pichon et al., 1996]. Yellow circles indicate the 2004 Sumatra
aftershocks; the data are from the U.S. Geological Survey. Indonesian geodynamic context is fromInstitut de Physique du Globe de Paris (IPGP) and Ecole Normale Supérieure (ENS) de Paris.
IN, India; B, Burma; EU, Eurasia; PH, Philippine; OJ, Okinawa-Japan; MTL, Median Tectonic Line.

Bathymetry and Tectonic Setting near Taiwan

Taiwan Seismic and GPS Network since 1991

Broadband Stations > 60
Strong Motion Stations> 900
Short-Period + Boreholes Stations
Continuous GPS ~ 400
Strainmeters~ 15

Ground Motion Simulation and PredictionForward Modeling:
Ground Motion Prediction

場址路徑

震源: 斷層機制 幾何 滑移分布
Strong-motion simulation is more precise when considering asperity distanceto site. (Cohee et al., 1991)
Predicting strong ground motions with a “Recipe”. (Irikura, K., 2006)

Earthquake Physics and Seismotectonics Laboratory

TSMIP
1999 Chi-Chi Earthquake

VIII IX

• Scenario earthquake simulations increase
understanding of ground motions• Computes seismograms from 0-10 Hz• Valuable in determining seismic hazard

Simulation of1999 Chi-Chi
Earthquake

11

Slip models
in Taiwan region
Total event number : 20DipFault typenum.

eq.

Strike8715

13Reverse(14)Normal (1)7.75 x 1015 Nm Mw(4.6)~ 3.79 x 1020 Nm Mw(7.7)

Background Seismicity ML>3 (1990-2007)(finite-fault inversion from Ma’s group, and Chi et al., 2003)

Scaling using AREA
Taiwanh : seimogenic depthβ: scaling parameter related
to the effective fault width- Small-Moderate earthquakes
Mw ~ LogA- Large earthquakes
Mw ~ 4/3logA- Extra largest earthquakes
Mw ~ 2/3logA(Shaw, 2009)

Const.: Stress drop related constant

California

Predict Ground Motion of a large event from smaller event
Simulation from EGF (high and regular stress drop events)
Latigude(deg)Longitude(deg)

depth(km)NO.

Date(UTC)

MLMw

strikediprakeM1(16)

1999/10/22 03:10

120.43123.533

16.74

6.00

5.90

45.00

90.00

170.00m1a1

1999/10/23 21:53

120.433

23.540

14.83

4.46

4.05

346.76

56.41

16.18

M2 (6)

1998/07/17 04:51

120.660

23.500

2.80

6.20

5.88

45.00

50.00

110.00m2a1

2004/01/23 07:51

120 648

23 458

13 06

4 34

3 73

51 97

30 37

104.56

Method for characterizing source(strong motion generation area, SMGA)ω2 model ( constant stress drop)(Aki, 1967; Brune, 1970, 1971;
Hanks and Kanamori, 1979)

ω2 model ( various stress drop)

Empirical Green’s Function method(Irikura, 1983, 1986)(Irikura and Kamae, 1994;
Kamae and Irikura, 1998)

Results of assessed SMGA,
Simulated ground motions
and spectra

608.60 bars (10.00 km2)
643.00 bars ( 9.64 km2) Yen&Ma, 2011

觀測推算

Subduction slab events, Inter-plate and Intra-plate Earthquakes-Similar size Inter-plate and Intra-plate Earthquakes。The event with deeper and smaller inmagnitude for Intra-plate earthquake had higher PGA than the Inter-plate event。

Ground Motion Prediction from EGF

m1
1996/07/29 Global CMT
Lon: 122.35 ；Lat:24.49
Depth:63km
Mw5.34ML6.14
m1a1
2001/12/16 BATS
Lon: 122.38 ；Lat:24.52
Depth:53km
Mw4.28ML5.1

Black:observations
Red: synthetics

Development of 3D wave propagation
modeling: 3D Ground Motion Simulation
For Taipei Basin in different Models
Basement +SunShang Formation

Only Basement

Layered Half-Space

By 李憲忠 Lee et al. (2009)

Active Fault Mapping（by 徐澔德, Shyu et al., 2005）

Active Fault MappingTaiwan Earthquake Model (link with GEM)

HazardRisk(faulting & shaking)(deaths & damage)

Active faults
Instrumental quakes
Historical earthquakes

 Exposure

Geodetic strain



Ground motion
prediction equations

Shaking ampliﬁcation
in soil and basins(change actions) Decision tools

Population

 Urban scenarios

Buildings

 Risk transfer tools

Remote sensing Building designcodes

 VulnerabilitySocial Impact

Damage data
Fragility functions

Objectives• What do engineers and social scientists need forrisk management and social impact?
- Earthquake Engineering Requirements• What can Earthquake scientists provide?
- How and in what way scientists can reach theirneeds?
• Build up Earthquake Sciences/Engineers
Inventory and community models- Discuss what, how and when?
• Giving a scenario example from Hazard to Risk
to Impact?
- Selecting a historical earthquake as a test
event?
- a Scenario earthquake from ??

trench segments
Tsunami Potential

Taiwan Historical Tsunami: 1867 Keelungtsunami mapping

資料來源： 淡水廳誌

1960 Chili M9.5 Earthquake Tsunami to Taiwan:
News report時間 海 嘯 侵 襲 之 地 區 出處及文獻所提供之信度、海嘯規模（ M t ） 或 浪 高 （ H）

Historical Tsunamis

1076年(10月31日-11月28日)

海陽、潮陽

宋史五行志（李善邦，1981）

1353年8月1日

泉州

元史五行志（李善邦，1981）

1604年12月29日

台灣海峽北部（包澄瀾等，1991）

1640年（9月16日−10月14日）

廣東揭陽、澄海、潮陽

Mt = 0，信度 = 4（包澄瀾等，1991）

1641年（9月16日−11月26日）

廣東澄海、潮陽（包澄瀾等，1991）

1661年1月8日

安平

Mt = 1，信度 = 4（包澄瀾等，1991）
Mt = 0，信度 = 4（游明聖，1994）

1721年1月5日

台南

Mt = -1， 信度 = 4 （游明聖，1994）

1721年9月

台南（包澄瀾等，1991）

1754年4月

淡水

Mt = 1，信度 = 3（包澄瀾等，1991）

1771年2月24日

日本石垣島

日本石垣島宮良村85.4公尺（宇佐美龍夫，1977）
日本石垣島85公尺（徐明同，1981）

1781年4-5月

高雄地區

Mt = 1，信度 = 3（包澄瀾等，1991）
Mt > 2， 信度 = 4（游明聖，1994）

1792年8月9日

彰化地區

（包澄瀾等，1991）
Mt > 2， 信度 = 4（游明聖，1994）

1866年6月11日

高雄地區

Mt = 0， 信度 = 4（游明聖，1994）

1867年6月11日

基隆地區

Mt = 2， 信度 = 4（包澄瀾等，1991）
Mt = 2， 信度 = 4（徐明同，1981）
Mt = 2， 信度 = 4（游明聖，1994）

Simulate 1771 Yaeyama
TsunamiSouthEastMw

7.8

7.6Φ (strike)

80°

135°

δ (dip)

70 °

70 °

λ (rake)

90 °

270 °

Dip-slip

8m

8m

Strike-slip

0km

0km

Fault depth

0m0m

L (fault length)

66km

50km

W (fault width)

33km

25km

The top edge ofthe fault

124.27°E 124.38°E,,
24.09°N 24.63°N

East

Snapshot of the results (east)SoutheastSnapshot of the results (southeast)

Conclusions•

Compilations of historical earthquakes and tsunamis-Documentation and simulations
Preparation and Warning!!

•Build up earthquake source scaling-Compilation of earthquake finite-fault models•Understanding of the Tectonic Setting-Investigation of near-offshore bathymetry-Identification of potential region for large earthquakes•

Ground Motion Simulation of Scenario earthquakes-Accurate velocity structure and site response•

Incorporation with other Geophysical Components-GPS, Active Fault => Recurrence Interval- Probability and Dynamic Earthquake Hazard Mapping=> Taiwan Earthquake Model (TEM)

35

THANK YOU!