| Summary: | 碩士 === 國立中正大學 === 地震研究所暨應用地球物理研究所 === 97 === We analyze the coseismic slip of Taitung earthquake on April 1st, 2006 by using isochron waveform inversion method to derive slip distribution on the rupture plane. The hypocenter of Taitung earthquake (ML=6.2) was located 7 km north of the Beinan strong motion site with depth of 7.2km. Waveforms of this earthquake recorded by Taiwan strong motion instrumentation program (TSMIP) of Central Weather Bureau, are bandpass filtered from 0.25 to 0.80Hz for simulation. We compare the original and the synthetic waveforms cross correlation which are chosen from strong motion sites. The optimal fitness, which is defined by the cross correlation between the observed and synthetic waveforms, indicates that the most likely model rupture for Taitung earthquake is characterize by strike-slip motion with maximum slips distributed to the south of the hypocenter on the rupture plane .
To understand the mechanism of nucleation of Taitung earthquake, we calculate the static stress transfer between Chengkung earthquake in December, 2003 and Taitung earthquake. We find that the static stress transfer of Chengkung earthquake could enhance the Coulomb failure stress change (ΔCFS) at hypocenter of Taitung earthquake. Similarly, Taitung earthquake were able to elevate the static stress at the site of a thrust event with ML=6.0 offshore of Taitung occurred 15 days after the Taitung earthquake. This finding implies that stress transfer did occur between Central Range and Coastal Range fault system. Several similar results also have been reported around the world.
These observations suggests that stress transfer and probable earthquake triggering between a strike-slip and a thrust fault systems at oblique convergent plate boundaries may be a common phenomenon.
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