Source Process of the Chi-Chi Earthquake: A Joint Inversion of Strong Motion Data and Global Positioning System Data with a Multifault Model

Research Article| October 01, 2001 Source Process of the Chi-Chi Earthquake: A Joint Inversion of Strong Motion Data and Global Positioning System Data with a Multifault Model Changjiang Wu; Changjiang Wu Earthquake Research Institute University of Tokyo 1-1-1 Yayoi, Bunkyo, Tokyo, 113 Japan wuchang@eri.u-tokyo.ac.jp takeo@eri.u-tokyo.ac.jp ide@eri.u-tokyo.ac.jp Search for other works by this author on: GSW Google Scholar Minoru Takeo; Minoru Takeo Earthquake Research Institute University of Tokyo 1-1-1 Yayoi, Bunkyo, Tokyo, 113 Japan wuchang@eri.u-tokyo.ac.jp takeo@eri.u-tokyo.ac.jp ide@eri.u-tokyo.ac.jp Search for other works by this author on: GSW Google Scholar Satoshi Ide Satoshi Ide Earthquake Research Institute University of Tokyo 1-1-1 Yayoi, Bunkyo, Tokyo, 113 Japan wuchang@eri.u-tokyo.ac.jp takeo@eri.u-tokyo.ac.jp ide@eri.u-tokyo.ac.jp Search for other works by this author on: GSW Google Scholar Author and Article Information Changjiang Wu Earthquake Research Institute University of Tokyo 1-1-1 Yayoi, Bunkyo, Tokyo, 113 Japan wuchang@eri.u-tokyo.ac.jp takeo@eri.u-tokyo.ac.jp ide@eri.u-tokyo.ac.jp Minoru Takeo Earthquake Research Institute University of Tokyo 1-1-1 Yayoi, Bunkyo, Tokyo, 113 Japan wuchang@eri.u-tokyo.ac.jp takeo@eri.u-tokyo.ac.jp ide@eri.u-tokyo.ac.jp Satoshi Ide Earthquake Research Institute University of Tokyo 1-1-1 Yayoi, Bunkyo, Tokyo, 113 Japan wuchang@eri.u-tokyo.ac.jp takeo@eri.u-tokyo.ac.jp ide@eri.u-tokyo.ac.jp Publisher: Seismological Society of America First Online: 03 Mar 2017 Online ISSN: 1943-3573 Print ISSN: 0037-1106 Copyright © 2001 by the Seismological Society of America Bulletin of the Seismological Society of America (2001) 91 (5): 1128–1143. https://doi.org/10.1785/0120000713 Article history First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Changjiang Wu, Minoru Takeo, Satoshi Ide; Source Process of the Chi-Chi Earthquake: A Joint Inversion of Strong Motion Data and Global Positioning System Data with a Multifault Model. Bulletin of the Seismological Society of America 2001;; 91 (5): 1128–1143. doi: https://doi.org/10.1785/0120000713 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract The Chi-Chi, Taiwan, earthquake of 21 September 1999 was a large thrust earthquake that caused disastrous damage. The surface fracture trace runs along the Chelungpu fault, which strikes N5°E along most of the faulting area but turns to the northeast while approaching its northern end. It finally presents a horsetaillike faulting system and bends to an east-northeast direction at the northern end. Both strong-motion and Global Positioning System (GPS) data recorded large displacements in the northern part. In this study, we use a multifault model to simulate the observed large strong-motion and GPS data. The results of the joint inversion reveal that in the southern part, slip occurred mainly in the shallow portion, reaching a maximum about 20 m on the ENE fault, where the rupture propagated to the deep part of the fault. There was obviously slip vector rotation from south to north, such that the slip on the branched fault plane was almost purely reverse faulting. The seismic moment, a total of 2.7 × 1020 N m, was released in less than 40 sec during the mainshock. Aftershocks occurred mainly in areas where little or no slip occurred. Slip vector rotation can be explained by the complexity of regional tectonic stress. Changes in tectonic stress at the northern end of the fault inhibited the northward propagation of the rupture and favored the rupturing of the ENE fault. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.