2011年5月20日山东安丘M_L3.7地震发震断层参数测定

Fault Plane Determination for the 2011 M_L3.7 Anqiu Earthquake,Shandong Province

在一维单侧有限移动震源模式下,根据拐角频率随方位的变化,利用相关系数法研究了2011年5月20日山东安丘ML3.7地震的发震断层面参数。结果表明,这次地震的断层面破裂方向为112.2°,与震源机制的EW向节面一致。地震马赫数v/c约为0.2695,即平均破裂速度大约为S波速度的1/4。若取横波速度为3.5km/s,则破裂长度约为0.1162km。

By considering 1D finite moving source model propagating unilaterally,the corner frequency is employed to determine the azimuth of rupture propagation direction and the parameters of fault plane of the Shandong Anqiu ML3.7 earthquake on May 20,2011,by means of correlation coefficient method.The results show that the azimuth angle of the fault plane for this event is about 112.2°,consistent with the EW nodal plane of the focal mechanism solution.The seismic Mach number v/ c is about 0.2695,which means that the average rupture velocity is about a quarter of the S-wave velocity.Given the velocity of S wave 3.5 km/s,the fault length is about 0.1162 km.