Strong Ground Motion Simulation of the 2008 MS 8.0 Wenchuan, China, Earthquake

Wednesday, 17 December 2014
Wenbo Zhang, Xiaodong Yao and Xiangwei Yu, University of Chinese Academy of Sciences, Beijing, China
The near source strong ground motions of the 2008 MS 8.0 Wenchuan, China, earthquake are simulated using empirical Green's function (EFG) method. At first, we estimate the locations of strong motion generation areas (SMGA) based on the teleseismic data inversion results by some other researchers. Then, preliminarily determine the total areas of SMGA referring to the scaling law introduced by Somerville et al. (1999). Finally, we implement the genetic algorithm searching for the optimized source parameters. Based on the source models, we synthetize the waveforms for the 18 stations located near the source region. Our results show that the comparison between the synthetic waveforms and the observed records agree each other very well. We find that there are five obvious SMGAs on the fault. The locations of the two of them are similar with the asperities from the teleseismic data inversion. However, the combined strong motion generation areas and the rise time we obtained are smaller than those values predicted by the extension value of the scaling law by Somerville et al. (1999).