时序InSAR与GNSS联合约束下的亚东-谷露断裂运动特征  

The characteristic of the Yadong-Gulu faults motion constraints by InSAR timeseries and GNSS observations

作　　者：周苍海 田镇[1] 石震[1] 哈衣那尔·托坎 ZHOU Canghai;TIAN Zhen;SHI Zhen;Hayinaer TUOKAN(School of Geology and Geomatics,Chang an University,Xi an 710064,China)

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710064

出　　处：《测绘学报》2024年第5期933-945,共13页Acta Geodaetica et Cartographica Sinica

基　　金：国家自然科学基金(42104003,42174054);地震动力学国家重点实验室资助项目(LED2022B02);中国博士后科学基金(2022M710012,2023T160557);长安大学中央高校基本科研业务费专项(300102262909,300102262902);陕西省自然科学基础研究计划(2022JZ-17)。

摘　　要：亚东-谷露断裂作为青藏高原东南部自新生代以来规模最大、活动性最强的拉张断裂,在青藏高原的构造变形与物质运移等过程中起着重要的调节与转换作用。但由于以往大地测量资料的不足,导致对亚东-谷露断裂整体运动特征的定量化分析较为匮乏。因此,本文收集并处理了亚东-谷露断裂地区2017年10月至2022年4月的哨兵影像数据,并联合GNSS速度场,解决了不同参考系下的形变场融合问题,获取了覆盖整个亚东-谷露断裂的高精度、高分辨率震间地壳形变场。进一步基于弹性微块体模型,精细厘定了亚东-谷露断裂现今活动特征:断裂整体以东倾为主,最佳倾角为68°,现今以拉张运动为主,速率为2~6 mm/a,并由南到北逐渐递增。另外,该断裂中段和北段的闭锁深度约为14 km;但南段可能受到主喜马拉雅逆冲断裂的影响,导致闭锁区域较浅,深度仅为4 km。最后,基于断裂的滑动亏损率与历史地震分布,分析得到断裂北段的地震危险性更高,为区域的地质灾害评估提供了重要参考。As the largest and most active extension fault in the southeast of the Qinghai-Tibet Plateau since Cenozoic Era,the Yadong-Gulu faults play an important role in regulating and transferring the tectonic deformation and material migration in the Qinghai-Tibet Plateau.However,due to the lack of geodetic observations,the estimates on the overall motion characteristics of the Yadong-Gulu fault is insufficient.Therefore,in this paper,we collected and processed the Sentinel data from October 2017 to April 2022 around the Yadong-Gulu fault,combined with the GNSS data to estimate and merge the crustal deformation in the different reference frames,and obtained the high-precision and resolution interseismic deformation covering the entire Yadong-Gulu fault region.Based on the elastic micro-block model,the present activity characteristics of the Yadong-Gulu fault are determined:the fault mainly dips to the east,with an optimum dip angle of 68°.The extensional slip rate is close to 2~6 mm/a,and gradually increases from south to north.In addition,the locking depth of the middle and north segments of the fault is about 14 km.However,the southern segment may be affected by the main Himalayan thrust,resulting in a shallow locking area(only 4 km).Finally,based on the slip deficit rate on the fault and the historical earthquakes,we infer that the future earthquake risk is higher in the northern segment,which provides an important reference for the regional geological hazard assessment.

关 键 词：亚东-谷露断裂 GNSS INSAR 拉张速率 闭锁深度 

分 类 号：P227[天文地球—大地测量学与测量工程]