Quantifying factors that cause severe damage in Tainan city during the 2016 M6.4 Meinong, Taiwan earthquake by spontaneous rupture modeling

Several factors have been proposed to cause severe damage in Tainan city during the 2016 M6.4 Meinong, Taiwan earthquake. These include rupture directivity, local site effects, and/or a triggered sub-event. In this study, we build spontaneous rupture models of the earthquake in the realistic 3D velocity structure of the region to quantify contributions of these factors to severe damage in Tainan city. We also test if an attenuation model proposed earlier for Southern California is applicable to Southwest Taiwan. We use a parallel finite element method to investigate these issues. Our preliminary results with a relatively coarse element size can reproduce source characteristics well, including two asperities of the slip distribution and a triggered sub-event. Synthetic seismograms at various stations show similarity with real recordings. These preliminary results are encouraging. We will further quantify contributions of these factors and test the attenuation model by varying source characteristics, adopting more refined velocity structure, and using finer element sizes. We expect to get improved understanding of these factors on severe ground shaking some distance away from the earthquake source in this earthquake, and shed light onto other earthquakes worldwide.