HR: 0830h
AN: S21F-0385    [PDF]
TI: Tectonic Implications of 1999 Chiayi earthquake sequence, Taiwan
AU: * Weng, S
EM: strong@eq.ccu.edu.tw
AU: Chen, C
EM: seichen@eq.ccu.edu.tw
AB: In this study, we adopt damping least-square inversion method to investigate the Vp structures and Vp/Vs ratios of the crust and upper mantle beneath Chia-Nan area, Taiwan. From many studies, the velocity structure can be used as an indicator of the geometry of fault and the general aspect of tectonics. Therefore, the first goal of this research is to analyze the degree of correlation between the velocity structure and the characteristics of seismicity, and its tectonic implications. The second intention is to study the relationship between the Vp/Vs ratio and the pressure change of crack opening in deeper crust. Finally, the distribution of Vp/Vs ratio and its association with fault activities is also investigated. Our results indicate that the variation of velocity structure beneath Chia-Nan area is caused by local geological structures, fault crossing and the existence of Ben-Kong High area in northwest. We also observe that earthquakes occur in the area that has Vp/Vs gradient varying rapidly. And according to distribution of the earthquake source, there may exist a west-dipping fault in the western of Chukou fault, however this argument needs to be investigated more in our future study.
DE: 7200 SEISMOLOGY
SC: Seismology [S]
MN: 2003 Fall Meeting