基于多源SAR数据的2022年门源Ms6.9地震同震破裂模型反演研究  

Slip Model of the 2022 Menyuan Ms6.9 Earthquake Constrained by Mulit-Source SAR Data

作　　者：余鹏飞 陈威[2,3,4] 乔学军[2,3,4] 赵斌 李刚[5] 熊维 YU Pengfei;CHEN Wei;QIAO Xuejun;ZHAO Bin;LI Gang;XIONG Wei(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Institute of Seismology,China Earthquake Administration,Wuhan 430071,China;Key Laboratory of Earthquake Geodesy,China Earthquake Administration,Wuhan 430071,China;Hubei Earthquake Administration,Wuhan 430071,China;School of Geospatial Engineering and Science,Sun Yat-Sen University,Zhuhai 519082,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]中国地震局地震研究所,湖北武汉430071 [3]中国地震局地震大地测量重点实验室,湖北武汉430071 [4]湖北省地震局,湖北武汉430071 [5]中山大学测绘科学与技术学院,广东珠海519082

出　　处：《武汉大学学报（信息科学版）》2022年第6期898-906,共9页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(42130101,41731071,41874018,42074015);中国地震局地震研究所基本科研业务费专项(IS201956148)。

摘　　要：2022年1月8日青海省海北州门源县发生Ms 6.9地震,震中位于青藏高原东北缘祁连-海原断裂中段,属历史地震空区,基于多源合成孔径雷达(synthetic aperture radar,SAR)遥感数据研究该地震的破裂模式对理解青藏高原东北缘构造变形机制、应变释放过程以及地震危险性评估具有重要意义。首先利用Sentinel-1数据和合成孔径雷达差分干涉测量(differential interferometry synthetic aperture radar,D-InSAR)技术获取了门源地震的同震形变场,视线(line of sight,LOS)向形变场显示此次地震造成了约20 km长的地表破裂,最大形变约0.75 m;然后基于Sentinel-2卫星数据,利用光学影像配准和相关技术获取了本次地震的东西向同震形变场,最大同震位移达2.5 m;最后基于均匀弹性半无限位错模型,以LOS向形变场为约束反演了断层的滑动分布模型。结果显示,门源地震是一次典型的左旋走滑型地震,地震破裂主要集中在0~10 km深度范围,最大滑动量3.25 m,滑动角10.44°,对应深度4.89 km;反演给出的矩震量为1.07×10^(19)N·m,对应矩震级Mw6.6。结合野外考察和地质资料,初步判定发震断裂为冷龙岭断裂,并引起托莱山断裂发生同震滑动。同震库仑应力结果显示,冷龙岭断裂东段和托莱山断裂西段应力状态为加载,未来具有发生强震的风险。Objectives:On January 8th 2022,an Ms 6.9 earthquake struck Menyuan,Qinghai Province,China.The epicenter is located in the middle section of Qilian-Haiyuan fault in the northeast margin of the Tibetan Plateau,which is a seismic gap.It is of great significance to study this earthquake for under‐standing the tectonic deformation mechanism,strain release process and seismic hazards of the NE Tibetan Plateau.Methods:Differential synthetic aperture radar interferometry(D-InSAR)is used to obtain the coseismic deformation along the line of sight(LOS)of the Menyuan earthquake from Sentinel-1 satellite images.The co-registration of optically sensed images and correlation are used to obtain the EW coseismic deformation from the multi-temporal Sentinel-2 data.Based on the coseismic deformation field derived from InSAR interferograms,we invert the slip distribution.Results:The LOS deformation fields showed that the Menyuan earthquake caused a surface rupture of about 20 km long and the maximum LOS displacement was 0.75 m.The maximum EW displacement derived from optical images was 2.5 m.The slip distribution model showed that the Menyuan earthquake was dominated by a sinistral strike-slip.The coseismic slip is concentrated at a depth of 0-10 km.The maximum slip was 3.25 m at a depth of 4.89 km and the rake angle was 10.44°.The estimated total seismic moment is 1.07×10^(19)N·m,corresponding to a magnitude of Mw 6.6.Conclusions:According to the results from aftershock relocation,field investigation and tectonic background,we infer that the seismogenic fault is the Lenglongling fault and the eastern segment of Tuolaishan fault is also ruptured.The stress on the eastern segment of the Lenglongling fault and the western segment of the Tuolaishan fault is enhanced,implying that there is the possibility of strong earth‐quakes in this region in the future.

关 键 词：2022年门源地震 合成孔径雷达干涉测量 同震形变 滑动分布 

分 类 号：P315[天文地球—地震学]