基于Sentinel数据的阿尔金断裂中段中强地震同震变形特征  

Co-seismic deformation of moderate and strong earthquakes in the middle segment of the Altyn Tagh Fault:Analysis based on Sentinel data

作　　者：孔雪 戴炜[3] 杨晓亮 戴霜 李家胜 方艳秋 KONG Xue;DAI Wei;YANG Xiaoliang;DAI Shuang;LI Jiasheng;FANG Yanqiu(Key Laboratory of Strategic Mineral Resources of the Upper Yellow River,Ministry of Natural Resources,School of Earth Sciences,Lanzhou University,Lanzhou 730000,Gansu;Northwest Institute of Nuclear Technology,Xi'an 710024,Shaanxi;Earthquake Disaster Risk Prevention and Control Center of Gansu Earthquake Agency,Lanzhou 730013,Gansu)

机构地区：[1]兰州大学地质科学与矿产资源学院,自然资源部黄河上游战略性矿产资源重点实验室,甘肃兰州730000 [2]西北核技术研究所,陕西西安710024 [3]甘肃省地震局震灾风险防治中心,甘肃兰州730013

出　　处：《第四纪研究》2022年第3期744-754,共11页Quaternary Sciences

基　　金：科技部第二次青藏高原综合科学考察研究项目(批准号:2019QZKK0704);国家自然科学基金项目(批准号:41972213);中央高校基本科研业务费专项项目(批准号:lzujbky-2021-it07)共同资助。

摘　　要：阿尔金断裂中段中强地震频发,是研究中强地震地表变形特征的天然试验场。文章基于Sentinel数据对该段4次中强地震(2019年9月27日新疆若羌4.8级地震、2019年3月28日青海茫崖5.0级地震、2021年6月16日青海茫崖5.8级地震、2021年8月26日甘肃阿克塞5.5级地震)开展了D-InSAR同震变形分析。结果显示,该方法能有效提取阿尔金断裂中段3次M_(S) 5.0以上地震的同震变形场(2019年茫崖地震、2021年茫崖地震和2021年阿克塞地震),同震变形区均由抬升区和沉降区两部分组成,发震断层大致沿NW-NWW向展布,指示区域应力方向以NE-SW向为主。3次地震宏观震中定位偏差均在7 km以内,表明D-InSAR技术具有较高的水平定位精度。3次地震发震机制均为逆冲型,同震变形特征与CMT震源机制解相一致。同时,利用SBAS时序变形结果和不同分辨率参考DEM数据解算结果进行误差影响分析,结果显示,大气延迟相位误差对该区域同震变形解算影响较小,而残余地形影响较大,震后余滑与粘弹性松弛效应不明显。该研究结果对认识阿尔金断裂中段构造和地震活动,以及利用InSAR技术识别中强地震变形特征具有参考意义。The middle segment of the Altyn Tagh Fault is prone to moderate and strong earthquakes,which makes it a natural testing ground for studying the surface deformation characteristics of moderate and strong earthquakes.Based on Sentinel data,D-InSAR technique is used to carry out co-seismic deformation analysis of 4 moderate and strong earthquakes(27 September 2019 Ruoqiang MS4.8 Earthquake in Xinjiang,28 March 2019 Mangya MS5.0 Earthquake in Qinghai,16 June 2021 Mangya MS5.8 Earthquake in Qinghai,26 August 2021 Akesai MS5.5 Earthquake in Gansu)in this region.The results show that it can effectively extract the co-seismic deformation fields of the 3 earthquakes with MS≥5.0.The co-seismic deformation fields are all composed of two parts:the lifting zone and the settlement zone,and the causative faults are roughly spread along the NW-NWW direction,indicating that the direction of regional compressive stress is mainly NE-SW.The deviations of the macroscopic epicenter location of 3 earthquakes(2019 Mangya Earthquake,2021 Mangya Earthquake and 2021 Akesai Earthquake)are all within 7 km,which proves that D-InSAR technique has high horizontal positioning accuracy.The seismogenic mechanisms of the 3 earthquakes are all thrust,and the co-seismic deformation characteristics are consistent with the CMT focal mechanism solutions.The error analysis of the results is also carried out by using SBAS technique and DEM data with different resolutions.The analysis reveals that the atmospheric delay phase error has little effect on the co-seismic deformation calculation in this region,while the residual topography has a great effect.At the same time,the post-earthquake residual slip and viscoelastic relaxation effect is not obvious.This study can provide a reference for understanding the tectonic activity and seismic activity in the middle segment of the Altyn Tagh Fault,as well as identifying the deformation characteristics of moderate and strong earthquakes using InSAR technology.

关 键 词：INSAR 同震变形 阿尔金断裂 中强地震 

分 类 号：P546[天文地球—构造地质学]