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Characteristics of strong ground motion across a thrust fault tip from the September 21, 1999, Chi‐Chi, Taiwan earthquake
Author(s) -
Huang BorShouh,
Chen KouCheng,
Huang WinGee,
Wang JeenHwa,
Chang TaoMing,
Hwang RueyDer,
Chiu HungChie,
Tsai ChuChuan Peter
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl011396
Subject(s) - seismology , geology , fault (geology) , thrust , waveform , kinematics , seismic gap , thrust fault , slip (aerodynamics) , geodesy , strong ground motion , surface rupture , fault plane , ground motion , physics , radar , engineering , telecommunications , classical mechanics , thermodynamics
Near fault tip strong motion records from the northern part of the major earthquake (Mw = 7.6), namely the Chi‐Chi earthquake on September 21, 1999 in central Taiwan demonstrated systematic differences on the hanging wall and footwall, and simulated by the finite element method. The extraordinary ground motion differences on either side of the northern fault tip can be explained by a 2‐dimension kinematic source model with fault rupture breaking to surface. In this study, the earthquake faulting was considered as bilateral from the center of a low angle thrust fault which is 30 km in length with a dip angle of 31°. Based on waveform modeling, the source rupture velocity, rise‐time and dislocation of 2.0 km/sec, 5 sec and 6 meters, respectively are suggested. The results of this study show that on the northern part of the Chi‐Chi earthquake fault there was lower rupture velocity and longer rise‐time of the fault slip than that previously reported. Furthermore, the effects of surface breaking from the fault movement contributed large ground deformations near the fault tip and, consequently, induced extensive damage.