New seismogenic source and deep structures revealed by the 1999 Chia-yi earthquake sequence in southwestern Taiwan

Yue Gau Chen, Yu Ting Kuo, Yih Min Wu, Hsiung Lin Chen, Chien Hsin Chang, Ron Yu Chen, Po Wen Lo, Kuo-En Ching, Jian Cheng Lee

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

In a tectonically active setting large earthquakes are always threats; however, they may also be useful in elucidating the subsurface geology. Instrumentally recorded seismicity is, therefore, widely utilized to extend our knowledge into the deeper crust, especially where basement is involved. It is because the earthquakes are triggered by underground stress changes that usually corresponding to the framework of geological structures. Hidden faults, therefore, can be recognized and their extension as well as orientation can be estimated. Both above are of relevance for assessment on seismic hazard of a region, since the active faults are supposed to be re-activated and cause large earthquakes. In this study, we analysed the 1999 October 22 earthquake sequence that occurred in southwestern Taiwan. Two major seismicity clusters were identified with spatial distribution between depths of 10 and 16 km. One cluster is nearly vertical and striking 032°, corresponding to the strike-slip Meishan fault (MSF) that generated the 1906 surface rupture. Another cluster strikes 190° and dips 64° to the west, which is interpreted as west-vergent reverse fault, in contrast to previous expectation of east vergence. Our analysis of the focal solutions of all the larger earthquakes in the 1999 sequence with the 3-D distribution of all the earthquakes over the period 1990-2004 allows us reinterpret the structural framework and suggest previously unreognized seismogenic sources in this area. We accordingly suggest: (1) multiple detachment faults are present in southwestern Taiwan coastal plain and (2) additional seismogenic sources consist of tear faults and backthrust faults in addition to sources associated with west-vergent fold-and-thrust belt.

Original languageEnglish
Pages (from-to)1049-1054
Number of pages6
JournalGeophysical Journal International
Volume172
Issue number3
DOIs
Publication statusPublished - 2008 Mar 1

Fingerprint

Taiwan
Earthquakes
earthquakes
earthquake
seismicity
Strike-slip faults
coastal plains
detachment fault
stress change
fold and thrust belt
reverse fault
Geology
geology
active fault
geological structure
basements
seismic hazard
strike-slip fault
detachment
coastal plain

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

Chen, Yue Gau ; Kuo, Yu Ting ; Wu, Yih Min ; Chen, Hsiung Lin ; Chang, Chien Hsin ; Chen, Ron Yu ; Lo, Po Wen ; Ching, Kuo-En ; Lee, Jian Cheng. / New seismogenic source and deep structures revealed by the 1999 Chia-yi earthquake sequence in southwestern Taiwan. In: Geophysical Journal International. 2008 ; Vol. 172, No. 3. pp. 1049-1054.
@article{b7a23a0f0e6d49e9ac33416ef2e96192,
title = "New seismogenic source and deep structures revealed by the 1999 Chia-yi earthquake sequence in southwestern Taiwan",
abstract = "In a tectonically active setting large earthquakes are always threats; however, they may also be useful in elucidating the subsurface geology. Instrumentally recorded seismicity is, therefore, widely utilized to extend our knowledge into the deeper crust, especially where basement is involved. It is because the earthquakes are triggered by underground stress changes that usually corresponding to the framework of geological structures. Hidden faults, therefore, can be recognized and their extension as well as orientation can be estimated. Both above are of relevance for assessment on seismic hazard of a region, since the active faults are supposed to be re-activated and cause large earthquakes. In this study, we analysed the 1999 October 22 earthquake sequence that occurred in southwestern Taiwan. Two major seismicity clusters were identified with spatial distribution between depths of 10 and 16 km. One cluster is nearly vertical and striking 032°, corresponding to the strike-slip Meishan fault (MSF) that generated the 1906 surface rupture. Another cluster strikes 190° and dips 64° to the west, which is interpreted as west-vergent reverse fault, in contrast to previous expectation of east vergence. Our analysis of the focal solutions of all the larger earthquakes in the 1999 sequence with the 3-D distribution of all the earthquakes over the period 1990-2004 allows us reinterpret the structural framework and suggest previously unreognized seismogenic sources in this area. We accordingly suggest: (1) multiple detachment faults are present in southwestern Taiwan coastal plain and (2) additional seismogenic sources consist of tear faults and backthrust faults in addition to sources associated with west-vergent fold-and-thrust belt.",
author = "Chen, {Yue Gau} and Kuo, {Yu Ting} and Wu, {Yih Min} and Chen, {Hsiung Lin} and Chang, {Chien Hsin} and Chen, {Ron Yu} and Lo, {Po Wen} and Kuo-En Ching and Lee, {Jian Cheng}",
year = "2008",
month = "3",
day = "1",
doi = "10.1111/j.1365-246X.2007.03686.x",
language = "English",
volume = "172",
pages = "1049--1054",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Wiley-Blackwell",
number = "3",

}

New seismogenic source and deep structures revealed by the 1999 Chia-yi earthquake sequence in southwestern Taiwan. / Chen, Yue Gau; Kuo, Yu Ting; Wu, Yih Min; Chen, Hsiung Lin; Chang, Chien Hsin; Chen, Ron Yu; Lo, Po Wen; Ching, Kuo-En; Lee, Jian Cheng.

In: Geophysical Journal International, Vol. 172, No. 3, 01.03.2008, p. 1049-1054.

Research output: Contribution to journalArticle

TY - JOUR

T1 - New seismogenic source and deep structures revealed by the 1999 Chia-yi earthquake sequence in southwestern Taiwan

AU - Chen, Yue Gau

AU - Kuo, Yu Ting

AU - Wu, Yih Min

AU - Chen, Hsiung Lin

AU - Chang, Chien Hsin

AU - Chen, Ron Yu

AU - Lo, Po Wen

AU - Ching, Kuo-En

AU - Lee, Jian Cheng

PY - 2008/3/1

Y1 - 2008/3/1

N2 - In a tectonically active setting large earthquakes are always threats; however, they may also be useful in elucidating the subsurface geology. Instrumentally recorded seismicity is, therefore, widely utilized to extend our knowledge into the deeper crust, especially where basement is involved. It is because the earthquakes are triggered by underground stress changes that usually corresponding to the framework of geological structures. Hidden faults, therefore, can be recognized and their extension as well as orientation can be estimated. Both above are of relevance for assessment on seismic hazard of a region, since the active faults are supposed to be re-activated and cause large earthquakes. In this study, we analysed the 1999 October 22 earthquake sequence that occurred in southwestern Taiwan. Two major seismicity clusters were identified with spatial distribution between depths of 10 and 16 km. One cluster is nearly vertical and striking 032°, corresponding to the strike-slip Meishan fault (MSF) that generated the 1906 surface rupture. Another cluster strikes 190° and dips 64° to the west, which is interpreted as west-vergent reverse fault, in contrast to previous expectation of east vergence. Our analysis of the focal solutions of all the larger earthquakes in the 1999 sequence with the 3-D distribution of all the earthquakes over the period 1990-2004 allows us reinterpret the structural framework and suggest previously unreognized seismogenic sources in this area. We accordingly suggest: (1) multiple detachment faults are present in southwestern Taiwan coastal plain and (2) additional seismogenic sources consist of tear faults and backthrust faults in addition to sources associated with west-vergent fold-and-thrust belt.

AB - In a tectonically active setting large earthquakes are always threats; however, they may also be useful in elucidating the subsurface geology. Instrumentally recorded seismicity is, therefore, widely utilized to extend our knowledge into the deeper crust, especially where basement is involved. It is because the earthquakes are triggered by underground stress changes that usually corresponding to the framework of geological structures. Hidden faults, therefore, can be recognized and their extension as well as orientation can be estimated. Both above are of relevance for assessment on seismic hazard of a region, since the active faults are supposed to be re-activated and cause large earthquakes. In this study, we analysed the 1999 October 22 earthquake sequence that occurred in southwestern Taiwan. Two major seismicity clusters were identified with spatial distribution between depths of 10 and 16 km. One cluster is nearly vertical and striking 032°, corresponding to the strike-slip Meishan fault (MSF) that generated the 1906 surface rupture. Another cluster strikes 190° and dips 64° to the west, which is interpreted as west-vergent reverse fault, in contrast to previous expectation of east vergence. Our analysis of the focal solutions of all the larger earthquakes in the 1999 sequence with the 3-D distribution of all the earthquakes over the period 1990-2004 allows us reinterpret the structural framework and suggest previously unreognized seismogenic sources in this area. We accordingly suggest: (1) multiple detachment faults are present in southwestern Taiwan coastal plain and (2) additional seismogenic sources consist of tear faults and backthrust faults in addition to sources associated with west-vergent fold-and-thrust belt.

UR - http://www.scopus.com/inward/record.url?scp=39049093097&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=39049093097&partnerID=8YFLogxK

U2 - 10.1111/j.1365-246X.2007.03686.x

DO - 10.1111/j.1365-246X.2007.03686.x

M3 - Article

VL - 172

SP - 1049

EP - 1054

JO - Geophysical Journal International

JF - Geophysical Journal International

SN - 0956-540X

IS - 3

ER -