Bulletin of the Seismological Society of America; August 2007; v. 97; no. 4;
p. 1233-1244; DOI: 10.1785/0120060042
© 2007 Seismological Society of America
A Dynamic Study of Frictional and Viscous Effects on Earthquake Rupture: A Case Study of the 1999 Chi-Chi, Taiwan, Earthquake
Jeen-Hwa Wang1
1 Institute of Earth Sciences
Academia Sinica
P.O. Box 1-55
Nangang, Taipei, Taiwan 115
Friction is commonly considered an important factor in controlling earthquake
rupture. In this work, it is assumed that viscosity is also a significant
factor. A strike-slip-type, two-body spring-slider model in the presence of both
friction and viscosity is applied to approximate the rupture processes of an
earthquake along the fault-striking direction. Results show that in addition to
friction, viscosity is also an important factor in controlling rupture. The
Ms 7.6 Chi-Chi earthquake which struck central Taiwan on 20
September 1999, ruptured a 100-km-long east- dipping transpressive fault (the
Chelungpu fault). Measured and inferred results show that there are differences
in physical properties between the northern and southern segments of the fault.
Simulation results from a two-body model can explain the differences in
displacement, velocity, acceleration, and predominant period between the two
fault segments.
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