In this paper, using discontinuous deformation analysis, we simulate numerically the processes of the 1975 Ha- icheng earthquake and the 1999 Xiuyan earthquake in the tectonic environment of North China where blocks re- strict each other by DDA+FEM. Based on the research on the distribution of foreshocks and recent aftershocks of Xiuyan earthquake and the results from our study and other study on Haicheng earthquake, we present a tectonic block model of Haicheng and Xiuyan earthquakes. The results from numerical simulation include the variation of principal stress field released by these two earthquakes, contour patterns of maximum shear stress change, varia- tion patterns of displacement vectors before and after the earthquakes and variation of the earthquake fault slip with time, which agree basically with the focal mechanisms, macroscopic isoseismal and horizontal displacement characters from observations.
展开▼
