2021年3月30西藏双湖地震(Ms5.8)的发震构造研究

Study on Seismogenic Structure of Shuanghu Earthquake (Ms5.8) in Tibet on March 30, 2021

2021年3月30日,西藏那曲市双湖县发生5.8级地震,为研究本次地震的发震断裂,分析了此次西藏那曲市双湖县地区周围的主要断裂以及三家不同研究机构给出的震源机制解反演结果,确定此次地震的控制断裂,以及推测此次地震的发震模式。研究结果说明:双湖地震的震源机制解属于左旋正断型地震,结合该地区的地质构造,余震序列分布,推测主发震构造为琵琶湖-映天湖断裂带,且此次地震的发震可能与2015年尼泊尔8.1级强震所引起的库伦应力的增加有关。这一系列的应力传递也可以印证Tapponnier和Molnar提出的地壳侧向向东挤出模式。

On March 30,2021,an earthquake of magnitude 5.8 occurred in Shuanghu County,Naqu City,Tibet,in order to study the control fault of this earthquake,major faults and inversion results of the focal mechanism solutions given by three different research institutions around the Shuanghu County area of Naqu City,Tibet are analyzed,determine the controlling fault of this earthquake,and infer the seismic mode of this earthquake.The results show that:the focal mechanism of Shuanghu earthquake belongs to left-lateral normal fault type earthquake,combined with the geological structure and aftershock sequence distribution of the area,it is speculated that the main seismogenic structure of the Shuanghu earthquake is the Pipa Lake-Yingtian Lake fault zone,the occurrence of this earthquake may be related to the increase of Coulomb stress caused by the strong earthquake of Ms8.1 in Nepal in 2015.This series of stress transfer can also confirm the lateral eastward extrusion mode of the crust proposed by Tapponnier and Molnar.