利用静态库仑应力触发准则确定地震断层面

Determining Seismic Fault Plane Using Static Coulomb Stress Triggering Criterion

震源机制解存在2个节面,通过地震波记录难以确定哪个节面为地震断层面。地震静态应力触发的相关研究表明,主震对后续余震有较为明显的触发作用。余震的空间分布也可以为确定震源机制节面中的断层面提供有效信息。以汶川、玉树地震为例,按照余震最大应力触发准则来确定震源机制2节面中的断层面。研究发现,采用上述准则确定的断层面与余震分布、地表观测一致。为快速判定地震断层面提供了一种途径。

The focal mechanism solution has two nodal planes,one of which is the fault plane of the earthquake and is difficult to be determined using seismic waveform data.Study on seismic static stress triggering shows that main-shock has relatively obvious trigger effect on its subsequent aftershocks.The spatial distribution of aftershocks provides effective information for the fault plane determination.In this study,the Wenchuan earthquake sequence and Yushu earthquake sequence are used as examples to investigate the possibility of determining the fault plane from the two nodal planes of the focal mechanism through maximum stress triggering criterion of the aftershock.The study of two cases shows that,the fault plane determined using above the method is consistent with the aftershock distribution,surface observation.This study may provide a way for the rapid determination of earthquake fault plane.