AN ANALYSIS ON M_S 8.0 WENCHUAN EARTHQUAKE FAULT AND SEISMIC DISASTER

Complex spatial distribution of seismic motion near faults has always been a concern to scientists,and it still remains as an uncertain problem due to insufficiency of events and information.The paper presents the main cases of seismic disaster by field investigations of MS 8.0 Wenchuan earthquake,analyzes and discusses the relationship among earthquake fault,ground motion and earthquake disaster near the fault fractured zone,based on previous research of source rupture processes and source inversion of Wenchuan earthquake.Intensive deformation and ground surface rupture along the earthquake fault have caused obvious damage to buildings,so it is necessary to introduce the safety distance away from active fault and other measures.Possible reasons for buildings near surface rupture zone having withstood the strong earthquake are as follows:other than their performance of seismic resistance,firstly,most of them locate at hard sites or on bedrock in the surface rupture zone,and secondly,the effective stress drop and low rupture velocity may exist in the shallow asperities,resulting in a relatively lower ground motion at the period about 1 sec.