THE 16 SEPTEMBER 1994 TAIWAN STRAIT EARTHQUAKE - A SIMPLE RUPTURE EVENT STARTING AS A BREAK OF ASPERITY

In this paper we give a detailed study of the 16 September 1994 Taiwan Strait earthquake using a broad-band body-waveform inversion. An adap tive hybrid global search algorithm was used to solve the nonlinear pr oblems of inverting the spatial distributions of slip amplitude, rake, slip duration and rupture time on a finite fault. The best-fitting so lution reveals that the largest slip of 14 m took place in the hypocen tre region, in which the rise rime is short. The slip amplitude decrea ses and the rise time increases from the initiation point outward. A s uggested mechanism is that the rupture initiated as a breaking of a st rong asperity with low dynamic friction and was arrested by large fric tion around the asperity. The hypocentre is a region of high frequency radiation. We examined the sensitivity by comparing the inversion sol utions utilizing varied parameterizations and constraints. These numer ical tests show that the major features of the rupture model are bette r resolved. (C) 1998 Elsevier Science B.V. All rights reserved.