2022年青海德令哈MS6.0地震序列重定位及发震背景分析

(1.青海省地震局,青海 西宁 810017; 2.山西省地震局,山西 太原 030021)

德令哈地震; 地震重定位; 震源机制; 发震背景; 青海

Earthquake Relocation and Seismic Tectonic Background of the 2022 Delingha MS6.0 Earthquake Sequence
HUANG Hao1,YUAN Fuquan1,LI Li2,ZHAO Yanjie1,WAN Yujie1,MA Jianxin1,LI Qilei1,HU Weiyun1,GUO Yingxia1

(1.Qinghai Earthquake Agency,Xining 810017,Qinghai,China)(2.Shanxi Earthquake Agency,Taiyuan 030021,Shanxi,China)

the Delingha earthquake; earthquake relocation; focal mechanism; seismic tectonic background; Qinghai

DOI: 10.20015/j.cnki.ISSN1000-0666.2023.0050

备注

2022年1月23日、3月26日和4月15日青海省德令哈市分别发生MS5.8、MS6.0和MS5.4地震。采用CAP方法反演了MS6.0地震及6次MS≥3.7地震的震源机制解和震源矩心深度,利用双差定位方法重新定位了德令哈MS6.0地震序列的震源位置,初步分析了德令哈MS6.0地震序列的发震背景。震源机制结果显示,MS6.0地震震源机制解节面Ⅰ:走向174°/倾角80°/滑动角-156°,节面Ⅱ:走向79°/倾角66°/滑动角-11°,矩心深度6 km。地震重定位结果显示,德令哈MS6.0地震序列震中呈NS向展布、震源区北部为主体破裂区域。基于震源机制解、地震重定位结果和震源区附近局部发育NS向构造的特征,分析认为德令哈MS6.0地震序列的发震构造为一条NS向、高倾角的右旋走滑隐伏断层。
A 5.8-magnitude,a 6.0-magnitude,and a 5.4-magnitude earthquake occurred respectively on Jan.23,Mar.26 and Apr.15,2022 in Delingha city of Qinghai province.We firstly inverted the focal mechanisms and the centroid depth of the source of the MS6.0 main shock and other 6 MS≥3.7 aftershocks by the CAP method,then we relocated the sources of the MS6.0 earthquake sequence by the hypoDD method,and analyzed the characteristics of the focal mechanisms,the relocated source parameters and the seismogenic structure.The focal mechanism of the Delingha MS6.0 earthquake has 2 solutions:for the first nodal plane,strike is 174°,dip is 80°,rake is -156°.For the second nodal plane,strike is 79°,dip is 66°,rake is -11°.The centroid depth is 6 km.The sources of the MS6.0 earthquake sequence are mainly distributed in North-South direction.According to the focal mechanism,relocated source parameters,and the geological structure in the source region,the seismogenic structure of the MS6.0 earthquake sequence is a hidden fault with high dip angel in North-South direction.