The Kinematic Source Process of the MW 5.9, 1999 Chia-Yi Taiwan Earthquake from Teleseismic Data Using the Hybrid Blind Deconvolution Method

Abstract

The kinematics rupture process of the Chia-Yi earthquake occurred on October 22, 1999 (Mw 5.9) in Taiwan is investigated. The hybrid blind deconvolution technique is applied to the teleseismic waves to invert source parameters, including slip amplitudes, rise times and rupture velocities on the fault. From the directivity effect of the fault, the actual fault plane is determined as east dipping. According to the derived ASFT, the total duration of the rupture process is 6.5 sec. A good correlation notices that the larger slip amplitude corresponds to the longer rise time of the subfault. By using the inverted source parameters and combining the stochastic method for finite fault, the strong ground motions of 12 stations at epicentral distances ranging from 3.28 to 29 km are simulated. The results show that the agreements between simulated and recorded spectra are quite satisfying. It means that the inverted source parameters are reliable and the stations where located at near source distance are dominated by source effects. The inhomogeneous distribution of slip and the variable corner frequency could play important roles in the simulation process. Although the source effects are dominant, there are some significant discrepancies existing at stations, implying the site effects are influential.