基于Sentinel-1A的2021年双湖MW5.7地震同震破裂模型

利用Sentinel-1A SAR数据提取2021年西藏双湖县M_W5.7地震同震形变场及2.5D形变场，反演断层滑动分布模型。计算不同节面解为接收断层产生的库仑应力变化差异确定发震构造，并结合余震分布信息评估未来地震风险性。结果表明，地震震中为34.37°N、87.71°E，震源深度6.51 km，发震断层倾向东、走向33°、倾角50°、平均滑动角-74°，以倾滑为主兼有少量左旋走滑分量，最大滑动量0.26 m。短时间内，震区南部地震风险较小，北部则需要结合更多资料进一步分析。本次地震是在羌塘块体持续向东扩张的背景下，受EW向拉伸作用使得黄水湖正断层发生的一次弥散型变形活动，SN向地堑得到进一步扩张。

Coseismic Rupture Model of the 2021 Shuanghu Mw5.7 Earthquake Based on Sentinel-1A

We employ Sentinel-1A SAR data to extract the coseismic deformation field and 2.5D deformation field of the 2021 Shuanghu, Tibet M_W5.7 earthquake for further inversion to obtain the fault slip distribution model. The seismogenic structure is determined by calculating the difference of Coulomb stress changes caused by different nodal solutions for receiving faults, and combining the aftershocks distribution to evaluate the future seismic risk. The results show that the epicenter is 34.37°N, 87.71°E, the focal depth is 6.51 km, and the seismogenic fault tends to the east, strike is 33°, dip is 50°, and average slip angle is -74°. There is a small amount of sinistral strike-slip component; the maximum slip is 0.26 m. In a short period, the seismic risk in the southern part of the earthquake area is relatively small, but the seismic risk in the northern part needs to be further analyzed with more data. The 2021 Shuanghu earthquake is a dispersive deformation on the Huangshuihu normal fault, resulting from the continuous EW-direction extension of the Qiangtang block, and the SN-direction graben in Huangshuihu is further expanded.