The paper presented a new regular pattern （network structure ） of great earthquakes occurred in China's Mainland during the past 700 years, which may be helpful to improve the understanding of great earthquakes and can serve as a base for the study of prediction of future great earthquakes. It can be done because there are quite complete and confident records of historical and recent earthquakes in a wide extent in China.
After Wenchuan Ms8.0 earthquake,the surface fractures have been investigated in Beichuan City and Yingxiu Town.It was found that the Beichuan-Yingxiu earthquake fracture zone trends northeastward,dipping to northwest.The earthquake fracture zone is mainly characterized by thrust faulting with small amounts of strike-slip movement,and demonstrating various complexities for different areas.The phenomena related to dextral strike-slip displacement are found in Beichuan City and those related to left-lateral strike-slip movement in Yingxiu Town.The compressive shortening of the two surface fracture zones in Beichuan City is 2.8―3.9 m and the left-lateral strike-slip displacement of the surface fractures in Yingxiu Town is 0.52 m.
DENG ZhiHuiYANG ZhuEnSUN ZhaoMinCHEN GuiHuaMA WenTaoSUN Qian
