2024年新疆乌什Ms 7.1地震InSAR同震形变探测与断层滑动分布反演

Coseismic deformation and slip distribution of the 2024 Ms 7.1 Wushi earthquake based on InSAR observations

2024年1月23日,新疆维吾尔自治区乌什县发生Ms 7.1地震,快速查明其同震形变场与发震断层滑动特征,有助于科学认识此次地震发震机理。利用Sentinel-1卫星升、降轨雷达影像,采用合成孔径雷达差分干涉测量技术获取了本次地震的同震形变场,进而基于Okada弹性位错模型,确定了本次地震的震源参数,并基于分布式滑动模型反演了本次地震断层面上的滑动分布。结果表明,升、降轨同震形变场沿视线向最大形变量分别为75 cm和48 cm,断层最大滑动量为4.2 m,主要集中在地下3~20 km区域;模型正演结果表明,此次地震在垂直方向最大抬升约53 cm,最大沉降约12 cm;发震断层运动以逆冲为主,兼具少量左旋走滑,根据InSAR结果及地质资料综合判断,本次发震断层为迈丹断裂。

An Ms 7.1 earthquake occurred in Wushi County in the Xinjiang Uygur Autonomous Region of China on January 23,2024.The rapid and accurate identification of its coseismic deformation field and the sliding characteristics of the originating faults can helpto scientifically understand the mechanism of origination of this earthquake.In this study,we obtain the coseismic deformation field of the earthquake by using radar images from the Sentinel-1 satellite in ascending and descending orbits as well as the differential interferometric synthetic aperture radar(D-InSAR).We then identify the parameters of the seismic source of the earthquake based on the Okada elastic dislocation model,and invert the slip distribution on the fault plane of the earthquake by using a model of slip distribution.The results showed that the maximum deformations of the coseismic deformation fields along the line of sight from the ascending and descending orbits were 75 cm and 48 cm,respectively,while the maximum slip on the faults was 4.2 m.The latter was mainly concentrated in the region 3~20 km below the surface of the ground.The results of model normalization showed that the maximum uplift of the earthquake was 53 cm in the vertical direction,while the maximum subsidence was 12 cm.The motion of seismic faults was mainly retrograde,with a small number of left-rotation strike-slip deformations.We used the results of InSAR and geological data to conclude that the Maidan Fault was the main fault of the earthquake.