Research on the Ability of Geodetic Records to Explain the Slip Distribution of Wenchuan, China, Earthquake

Abstract

We establish a reasonable 3D complex fault model. The Global Positioning System (GPS) data is adopted to reproduce the slip distribution of the 2008 Mw7.9 Wenchuan earthquake. Utilizing the nonnegative least square method, the slip distribution of the fault plane is recovered. The results are as follows: (1) The released seismic moment of Wenchuan earthquake is $0.959\times {10}^{21}\text{N}·\text{m}$ . The deep of the rupture is mainly within 15 km. (2) The rupture mainly occurred along the Beichuan fault, indicating that the Beichuan fault is the main rupture fault. On the southern section of the Beichuan fault, the rupture is concentrated from Yingxiu to Longmenshan and from Yuejiashan to Qingping areas, with mainly thrust slip. On the northern section of the Beichuan fault, the slip is concentrated near the surface of Beichuan and Nanba areas, with thrust and strike slip. On the Pengguan fault, the slip is mainly located near Hanwang with thrust and strike slip. (3) The GPS data are useful for defining the slip in the shallow part but are useless to determine the slip in the deep part. Meanwhile, the time information of the rupture cannot be reproduced.