2003年新疆巴楚—伽师地震序列的双差法重新定位研究

Relocation of the Bachu-Jiashi, Xinjiang earthquake sequence in 2003 using the double-difference location algorithm

将近台记录和区域台网数据联合用于双差地震定位算法，对2003年新疆巴楚-伽师M56．8强震后404个ML≥3．5余震序列进行双差法重新精确定位，并对其进行了理论上的可行性分析．精定位后定位结果与传统定位方法的原始定位结果进行比较发现：（1）精定位后震中分布图像更加集中，与当地的烈度考察和震源机制解结果更加协调；（2）震源深度优势分布集中在15-25km以内，与当地存在深度为10km以上低速沉积层的地质构造情况相一致；（3）精定位后定位残差由原来的3．94s降为0．24s，水平向估算误差平均可控制在1．1km以内，垂直向估算误差平均可控制在2．4km．

Combining the data recorded at the mobile seismic network with those from the regional network, we relocated the 404 aftershock sequence including 404 events of ML ≥ 3.5 for the 2003 Bachu-Jiashi, Xinjiang Ms6.8 earthquake by the double-difference method and made theoretical analysis of the feasibility. We got a result of significant improvement. Compared with the original result, the relocation makes the image of earthquake distribution become more convergent and source mechanism. The dominant distribution of focal more consistent with the intensity investigation and the depths is in the range 15 - 25km and the result is more consistent with the local geologic setting that there is a low velocity sediment layer above the depth 10 km. The arrival time residuals reduce to 0.24s from 3.94s. The horizontal average error is estimated to be less than 1. l km and the vertical average error can been controlled less than 2.4km.