Source characteristics of moderate-to-strong earthquakes in the Nantou area, Taiwan: insight from strong ground motion simulations

Abstract

In Taiwan, the Nantou area is a seismically active region where several moderate events have occurred, causing some disasters during the past century. Here, we applied the strong ground motion simulation with the empirical Green's function method to investigate the source characteristics for the eight moderate blind-fault events that struck the Nantou area in 1999 and 2013. The results show that for these Nantou events, a high stress drop and focal depth dependence were noted, which might be related to the immature buried fault in this area. From the viewpoint of seismic hazard prevention and preparation, future earthquake scenarios that include high stress drop should be applied to more analyses, especially the moderate-to-large events originating from the immature blind faulting.

Source and strong-motion characteristics of two M > 6 buried earthquakes in southwest Taiwan

“…Relationship of focal depth versus stress drop on SMGA fromWen et al (2017). Dots indicate our results for the 2010 Jiashian and 2016 Meinong earthquakes superimposed on the figureFig.…”

“…Although the 2010 Jiashian and 2016 Meinong earthquakes were both moderate-sized blind-fault events, the strong ground acceleration reached > 400 gal. Cotton et al (2013) demonstrated that PGA is proportional to stress drop, and Radiguet et al (2009) and Somerville (2003) found that the buried faults strengthen strong ground shaking, especially for a period range of approximately 1 s. Moreover, Wen et al (2017) revealed that moderate blind-fault earthquakes in the Nantou area of Taiwan exhibit focal-depth dependence and a high-stress drop. In this study, we calculated the stress drops in the SMGA for the 2010 Jiashian and 2016 Meinong events and obtained the values of 26.2 and 17.0 MPa (Table 3), respectively; Fig.…”