利用InSAR获取2020年新疆于田Mw6.3地震同震形变场与断层滑动分布反演

本文基于InSAR技术, 利用欧空局Sentinel-1A/ B升降轨SAR数据, 提取了2020年6月26日新疆于田M_W6.3地震的同震形变场。 利用升、 降轨同震形变场约束, 分别采用MPSO算法和Bayesian方法反演此次地震发震断层均匀滑动的几何参数, 并进行对比。 然后采用SDM方法获得发震断层非均匀滑动分布, 并分析了同震库仑应力变化及其对周边断层的应力扰动。 结果表明, 同震形变场以NS向为长轴, 总体呈现西部沉降而东部隆升的特点, 而且隆升量明显小于沉降量; 滑动分布反演表明发震断层的平均滑动量为0.13 m, 平均滑动角为-104.56°, 此次地震为典型的正断破裂事件, 最大滑动量约0.55 m, 最大滑动量处滑动角为-105.2°, 位于断层倾向深度14.42 km, 释放的地震矩能量约3.65×10¹⁸ N·m, 相当于矩震级M_W6.3; 同震库仑应力变化对西部琼木孜塔格断层、 硝尔库勒南缘断层等起到应力卸载作用, 对北部的木孜鲁克—鲸鱼湖断层起到应力加载作用, 结合同震库仑应力对周围断层的扰动情况, 此次地震可能对琼木孜塔格断裂带和木孜鲁克—鲸鱼湖断裂带的西端影响较大。

InSAR Coseismic Deformation and Fault Slip Distribution Inversion of the 2020 Yutian Mw6.3 Earthquake,Xinjiang

Coseismic deformation field of the Yutian M_W6.3 earthquake, occurred in Xinjiang on June 26, 2020 was extracted using Sentinel-1A/B SAR data through InSAR processing. Using the co-seismic deformation field constraints of the ascending and descending orbits, the MPSO algorithm and the Bayesian method were used to invert the geometric parameters of the seismogenic fault. Then, the SDM method was used to obtain the non-uniform slipdistribution of the seismogenic fault, and the co-seismic Coulomb stress change and the stress disturbance to surrounding faults were analyzed. The results show that the coseismic deformation field takes the NS direction as the long axis, showing the characteristics of subsidence in the west and uplift in the east, and the uplift is significantly smaller than the subsidence. The inversion of non-uniform slip shows that the average slip of the seismogenic fault is 0.13 m. The average slip angle is -104.56°. The 2020 Yutian earthquake is a typical normal fault rupture event. The maximum slip is about 0.55 m, and the slip angle at the maximum slip is -105.2° at a vertical depth of 14.42 km.The released seismic moment energy is about 3.65×10¹⁸ N·m, which is equivalent to the moment magnitude M_W6.34. The co-seismic Coulomb stress change has a stress unloading effect on the Qiongmuzitag fault in the west and the Nierkule southern margin fault, and it has a stress loading effect on the Muziluk-Whale Lake fault in the north, combined with the coseismic Coulomb stress Regarding the disturbance of the surrounding faults, the earthquake may have a greater impact on the western end of the Qiongmuztag fault and the Muzluk-Whale Lake fault.