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

Abstract

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, ~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¢X and a dip of 28¢X; the first sub-event had a relatively smaller seismic moment (M0) and larger radiated seismic energy (ES) than the second sub-event, and this leads to the ES/M0 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 M0 was estimated to be 2.17 ¡_ 1018 Nm, corresponding to MW = 6.15, and the total ES was ~2.91 ¡_ 1013 Nm, larger than that estimated only from a single source. Subsequently, the ES/M0 was approximately 1.3 ¡_ 10-5, lower than ordinary earthquakes. The low static stress drop was probably responsible for the low ES/M0. Overall, the 2010 JiaSian earthquake was characterized by a relatively low ES/M0 and low static stress drop, and then the partial stress drop model would be relatively appropriate to interpret its rupture process.

Keywords

• JiaSian earthquake
• Radiated seismic energy
• Multiple-event analysis