Estimating the Radiated Seismic Energy of the 2010 ML 6.4 JiaSian, Taiwan, Earthquake Using Multiple-Event Analysis

Through a proposed multiple-event analysis of teleseismic P-waves, this study investigated the radiated seismic energy and rupture process of the 2010 JiaSian earthquake. Results showed that the earthquake comprised at least two sub-events. The first sub-event was followed by the second sub-event, similar to 1.7 s later. The entire source duration was 5.4 s. Let the two sub-events occur on the same fault plane with a strike of 304 degrees and a dip of 2 degrees 8; the first sub-event had a relatively smaller seismic moment (M-o) and larger radiated seismic energy (E-s) than the second sub-event, and this leads to the E-s/M-o of the first sub-event larger than that of the second sub-event thus. This feature implies that the first sub-event probably had a higher static stress drop during faulting. The total M-o was estimated to be 2.17 x 10(18) Nm, corresponding to M-w = 6.15, and the total E-s was similar to 2.91 x 10(13) Nm, larger than that estimated only from a single source. Subsequently, the E-s/M-o was approximately 1.3 x 10(-5), lower than ordinary earthquakes. The low static stress drop was probably responsible for the low E-s/M-o. Overall, the 2010 JiaSian earthquake was characterized by a relatively low E-s/M-o and low static stress drop, and then the partial stress drop model would be relatively appropriate to interpret its rupture process.