Imaging the Rupture Front and Slip Distribution by the Back-projection of P-wave Amplitude from Strong-motion Records: A Case Study for the 2010 Jiasian, Taiwan, Earthquake

We propose a new approach of imaging earthquake source rupture process by direct back-projection of local P-wave displacement in strong-motion records. This approach is applied to estimate the slip distribution of an earthquake occurred in March 4, 2010, in Jiasian in southern Taiwan. Hypocenter of the Jiasian earthquake (Mw=6.0 and M_L=6.4) is located at 22.96°N and 120.70°E with a focal depth of 23 km. Source imaging result shows that the rupture initiated from the hypocenter, and then a relatively small slip occurred in the northern part of the fault zone, and final propagated in the northwestern direction, in agreement with the distribution of aftershocks. Majority of the slip occurred in the western part of the epicenter, consistent with the dislocation model obtained from geodetic observations. This approach is computationally efficient and automatic. It allows for rapid determination of rupture front propagation and slip distribution after earthquakes using real-time strong-motion records, and provides important and useful information for seismic hazard mitigation.