Influence of actual topography on the source dynamic rupture process and strong ground motion of the 2010 Yushu M_S7.1 earthquake

Based on the source dynamic models, the curved grid finite-difference method was implemented to simulate the dynamic rupture process and the resultant ground motions of the 2010 M_S7.1 Yushu earthquake with horizontal free surface and actual topography respectively. Then the rupture propagation, final slip distribution and distribution of peak ground velocity were obtained to investigate the effect of actual topography on the dynamic rupture process of the Yushu earthquake and the resultant strong ground motions. Based on our models, the results show that the super-shear rupture occurred during the rupture propagation process, which was mainly induced by high stress drop on fault plane. The actual topography has prevented the generation of super-shear induced by free surface and has a great influence on the final slip distribution and slip rate on fault plane, then will affect the characteristics of ground motions as well as reduce the peak values of ground motions to a certain extent. The fault-parallel component of ground motion is relatively more affected. The investigation about the fault rupture dynamics will help us to understand well about the source rupture process and explain the characteristics of its strong ground motions, which is of great significance to more reasonably predict the ground motions of possible destructive earthquakes in the future.