2013年吉林前郭5.8级震群精定位及发震构造分析

Relocations of Qianguo earthquake sequence and its seismotectonic analysis

摘要:

利用吉林区域数字地震台网和流动台网的观测数据，采用HypoDD方法精确定位了2013年10月31日～12月10日发生在吉林前郭地区343次地震事件的震源位置。重新定位结果显示，地震序列优势分布方向为NW向，平行于查干泡-道字井断裂北支。重新定位后的震源分布更趋集中在断裂带附近，且深度多集中在6～14km范围内，表明研究区的孕震层主要集中在中上地壳，与该区的地下介质性质关联明显。以同样的方法修正了5.5级和5.8级地震序列的震中位置和震源深度，重定位后2次序列的优势方向、优势深度和破裂长度均存在明显差异。基于震源机制解及震源深度剖面图初步推测此次地震的发震构造应为NNW向的查干泡-道字井断裂。

Abstract:

Combining the data recorded by the mobile observation instruments and digital observation station，we relocated the 343 earthquakes occurred in Qianguo，Jilin Province between October 31～December 10,2013 with double-difference location algorithm，and finally obtained 336 relocated earthquakes. Our result shows that the advantage distribution direction is NW paralleled to the northern segment of Chaganpao-Daozijing fault zone. The relocated earthquake sequence are more concentrated on obvious strip around the fault，while most of them occur at the depth of 6～14km. This shows that the seismogenic layer in this region is in the mid-upper crust contacting significantly with the regional underground media. The earthquake location and depths about the MS5.5 and MS5.8 earthquake sequences have been improved with the same way. It shows significant differences on advantage direction，advantage depths and rupture length of the two relocated earthquake sequences. The seismotectonics of the earthquake sequence is in NNW for the Chaganpao-Daozijing fault through the focal mechanism solution and relocated profile map.