InSAR约束的青海门源M_(w) 6.7级地震同震断层滑动反演与三维形变场模拟  

Coseismic slip distribution and 3D deformation field simulation of the Menyuan M_(w) 6.7 earthquake in Qinghai based on InSAR constraint

作　　者：曾锐 蒋亚楠 燕翱翔 程燕 罗袆沅 ZENG Rui;JIANG Yanan;YAN Aoxiang;Cheng Yan;LUO Huiyuan(College of Earth Science,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;Institute of Cold Regions Science and Engineering of Northeast Forestry University,Harbin 150040,China)

机构地区：[1]成都理工大学地球科学学院,成都610059 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059 [3]东北林业大学寒区科学与工程研究院,哈尔滨150040

出　　处：《地质科技通报》2024年第6期212-225,共14页Bulletin of Geological Science and Technology

基　　金：四川省重点研发计划(2023YFS0435,2023YFS0439)。

摘　　要：2022年1月8日,青海省门源回族自治县发生M_(w) 6.7地震,地表破裂明显并导致兰新高铁停运。为研究门源地震的震源机制,通过差分干涉测量技术(D-InSAR)处理Sentinel-1A升降轨SAR数据得到地震同震形变场,并在InSAR形变约束下,通过两步反演法获取了地震断层几何参数和精细同震滑动分布,计算了同震静态库仑应力变化,进一步分析讨论了发震构造及区域地震危险性。结果表明:InSAR LOS向同震形变场长轴呈WNW-ESE向,初步判断具有左旋走滑的运动特征,在其约束下的精细双断层滑动分布结果显示冷龙岭破裂段与托莱山破裂段均以高倾角左旋走滑为主;为进一步阐明地震变形模式,基于弹性位错模型及黏弹性分层介质模型分别模拟得到同震地表三维形变场,考虑地壳分层结构模拟的三维形变更准确。同震库伦应力变化结果表明:托莱山断裂西端、冷龙岭断裂东端及兰新高铁大梁隧道地震风险性增强,未来发生破裂的风险仍较高。研究结果为进一步了解门源地震三维地壳形变及相关地震研究提供参考依据。On January 8,2022,a M_(w) 6.7 earthquake stuck Menyuan Hui Autonomous County,Qinghai Province,resulting in extensive surface ruptures and the closure of the Lanzhou-Xinjiang high-speed railway.[Objective]This study aims to investigate the focal mechanism of the Menyuan earthquake.[Methods]D-InSAR technology was employed to process ascending and descending SAR data from Sentinel-1A,producing a coseismic deformation field.Using InSAR LOS deformation as a constraint,a two-step inversion method was applied to determine the geo-metric parameters of the earthquake fault and the detailed coseismic slip distribution.Additionally,the coseismic static Coulomb stress changes were calculated,and the seismogenic structure,along with the regional seismic haz-ard,was further analyzed.[Results]The findings reveal that the long axis of the InSAR coseismic deformation field is oriented WNW-ESE,indicating left-lateral strike-slip movement.The refined double-fault slip distribution shows that both the Lenlongling and Tuolaishan rupture segments exhibit high-inclination left-lateral strike-slip mo-tion.To better understand the seismic deformation patterns,this study employs anelastic dislocation model and a viscoelastic half-space layered medium model to simulate the three-dimensional coseismic surface deformation,in-corporating more accurate three-dimensional deformation from crustal layered models.The coseismic Coulomb stress changes suggest an earthquake risk at the western end of the Tuolaishan fault,the eastern end of the Lenlongling fault,and near the Daliang tunnel of the Lanzhou-Xinjiang high-speed railway,indicating a heightened potential for future rupture.[Conclusion]The research results can provide a reference for enhanced understanding of the three-dimensional crustal deformations associated with the Menyuan earthquake and the related seismic research.

关 键 词：青海门源M_(w)6.7地震 断层滑动分布 同震三维形变场 静态库仑应力变化 兰新高铁 INSAR 

分 类 号：P315.7[天文地球—地震学] P237[天文地球—固体地球物理学]