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利用汶川地震序列周围450km范围内6个台站记录的宽频带波形数据,通过时间域矩张量反演方法,得到该地震序列88个地震的矩张量解.结果显示震源机制解类型具有明显的空间分段特征.沿着主破裂带方向自西南至东北共分为6段,震源机制类型由开始的逆冲为主,经过各种震源机制类型交替出现的过渡带,转变为以右旋走滑为主.在小鱼洞镇附近出现与主破裂正交的左旋走滑型地震.利用FMSI程序分别反演各段的应力场,发现沿着主破裂带方向自西南至东北,最大主应力方向由近EW向逐渐转变为NW-SE向,最后又转变为近EW向.
Using the broadband waveform data recorded by 6 stations in the 450km range around the Wenchuan earthquake sequence, the moment tensor solutions of 88 earthquakes in this earthquake sequence are obtained by the time-domain moment tensor inversion method. The results show that the focal mechanism solution types have obvious , Which is divided into 6 segments from southwest to northeast along the direction of the main rupture zone.The types of focal mechanisms are mainly from the initial thrusting, and after transitional zones alternating with various focal mechanism types, Strike-slip, and the left-slip strike-slip earthquake orthogonal to the main rupture occurs in the vicinity of Xiaoyutong town.The stress fields of each section are respectively inverted by FMSI program and found to be along the direction of the main rupture zone from southwest to northeast, The stress direction gradually changes from near EW to NW-SE and finally to near EW.