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综合利用震后应急流动台阵和青海台网部分固定台站观测数据,采用多震相走时层析成像方法,对玉树震区地壳三维速度结构和玉树MS7.1级地震余震震源位置参数进行了联合反演,获得了研究区上地壳三维速度结构图像和余震序列重新定位结果.结果显示:玉树MS7.1级地震余震整体沿北西向玉树-甘孜断裂呈条带状分布,长约120km;以隆宝镇为界,呈现两段不同的分布特征;震区上地壳速度分布存在横向非均匀性;沉积层厚约6～7km,壳内存在厚约为7～8km的低速层;地震多发生于低速层上方即高、低速过渡区域,区内多条断裂走向与高低速过渡带一致.
Based on the observation data of post-earthquake emergency flow array and some fixed stations of Qinghai-Taiwan network, the multi-seismic facies tomography method was used to analyze the crustal 3D velocity structure and the location of the Yushu MS7.1 earthquake aftershocks The results show that the aftershocks of the Yushu MS7.1 earthquake are distributed along the NW-trending Yushu-Garzê fault in a strip pattern with a length of about 120 km. Based on the results of the three-dimensional velocity structure images and aftershock sequence reorientation of the upper crust in the study area, There are two different distributional features in the area of Longbao town. There is horizontal heterogeneity in the velocity distribution of the upper crust in the earthquake zone. The sedimentary layer is about 6 ~ 7km thick with low velocity layer with a thickness of 7 ~ 8km in the crust. Above the low velocity layer, ie, high and low speed transition areas, a number of faults in the area are consistent with high and low speed transitional zones.