Dynamic Rupture Simulations of the 2008 Mw 7.9 Wenchuan Earthquake by the Curved Grid Finite-Difference Method

摘要

Enough investigations and observations have been undertaken to suggest that the great 2008 Mw 7.9Wenchuan earthquake of China ruptured in a highly complex pattern. The causative fault of the Wenchuan earthquake has a complex geometry, divided into several segments with offsets of a few kilometers. Modeling the dynamic rupture of this earthquake with geometrical complexity is a challenge. In this work, we simulated the dynamic rupture on the geometrically complex fault of the 2008 Mw 7.9 Wenchuan earthquake of China by the curved grid finite-difference method. In our modeling, a uniform background tectonic stress field with tapering at shallow depth and slip-weakening law with homogeneous friction coefficients are utilized.We found that the typical heterogeneous spatial distribution of the final seismic slip on the fault can be generated by the nonplanar complex geometry of the fault plane. Moreover, we discussed the geometrical effects of theWenchuan earthquake on the rupture dynamics and strong ground motion.We found that the complexity of fault geometry results in the rupture complexity of the greatWenchuan earthquake. This work provides us with a new insight into the rupture dynamics of the Wenchuan earthquake.