InSAR数据约束的沂沭断裂带闭锁程度及地震危险性分析  

Locking degree and seismic risk analysis of yishu fault zone constrained by InSAR data

作　　者：颜丙囤 殷海涛[2] 杨玉永[2] 连凯旋[1] 温丽媛[1] 郭宗斌 YAN Bingdun;YIN Haitao;YANG Yuyong;LIAN Kaixuan;WEN Liyuan;GUO Zongbin(Liaocheng Earthquake Monitoring Center Station of Shandong Earthquake Agency,Liaocheng 252000,China;Shandong Earthquake Agency,Jinan 250014,China)

机构地区：[1]山东省地震局聊城地震监测中心站,山东聊城252000 [2]山东省地震局,山东济南250014

出　　处：《测绘通报》2024年第7期129-133,共5页Bulletin of Surveying and Mapping

基　　金：中国地震局监测、预报、科研三结合课题(3JH-202401053);国家自然科学基金(41974105);山东郯城巨震区低速率挤压逆冲构造野外科学观测研究站科研平台。

摘　　要：本文首先利用2021年10月至2023年4月覆盖沂沭断裂带区域60景的Sentinel-1A数据,采用SBAS-InSAR技术,获取大范围地表LOS向形变结果,并对InSAR形变场进行降采样;然后基于负位错模型,采用TDEFNODE软件计算沂沭断裂带断层闭锁程度和滑动亏损分布,并结合地震的时空分布,精细刻画断层面的运动特征,定量判定断裂的分段地震危险性。结果表明,安丘—莒县断裂北段安丘以北区域的断层闭锁程度较高,闭锁深度较深,最大闭锁深度约为24 km,安丘至郯城段断层闭锁较弱,基本处于蠕滑状态;沂沭断裂带安丘以北区域右旋滑动亏损速率为0.5~1.5 mm/a,是1668年郯城地震的未破裂段,具有地震活动空区的特点,易于应力积累,该段的地震危险性值得关注。与以往研究结果对比发现,沂沭断裂带郯城以北的段落闭锁程度有所减弱,分析主要与2011年3月11日日本宫城Mw9.0地震的影响有关,日本大地震的发生对太平洋板块西向俯冲挤压起一定的缓解作用,导致郯庐断裂带区域应力应变场发生变化。In this paper,the Sentinel-1A data covering 60 scenes of the Yishu fault zone from October 2022 to April 2023 are used to obtain large-scale surface LOS deformation results by SBAS-InSAR technology,and the InSAR deformation field is down-sampled.Then,based on the negative dislocation model,TDEFNODE software is used to calculate the fault locking degree and slip loss distribution of Yishu fault zone,and combined with the temporal and spatial distribution of earthquakes,the movement characteristics of fault plane are described in detail,and the segmental seismic risk of the fault is quantitatively determined.The results show that the fault locking degree is high and the locking depth is deep in the area north of Anqiu in the northern segment of Ju county fault,the maximum locking depth is about 26°,and the fault locking is weak in the segment from Anqiu to Tancheng,which is basically in creep slip state.The area north of Anqiu in Yishu fault zone has a dextral slip loss rate of 0.5~1.5 mm/a,which is the unruptured segment of 1668 Tancheng earthquake.It has the characteristics of seismicity gap and is easy to accumulate stress.The seismic risk of this segment deserves attention.Compared with the previous studies,it is found that the locking degree of the section north of Tancheng in Yishu fault zone is weakened,which is mainly related to the influence of Miyagi Mw9.0 earthquake on March 11,2011.The occurrence of Japan earthquake plays a certain role in relieving the westward subduction and compression of Pacific plate,resulting in the change of regional stress-strain field of Tanlu fault zone.

关 键 词：沂沭断裂带 SBAS-InSAR 负位错模型 断层闭锁 滑动亏损 

分 类 号：P237[天文地球—摄影测量与遥感]