2021年云南漾濞M_(w)6.4级地震的InSAR监测与反演  

InSAR Monitoring and Inversion of 2021 Yangbi M_(w)6.4 Earthquake in Yunnan,China

作　　者：魏云杰[1] 王婷 杨成生[2] 吕森 WEI Yun-jie;WANG Ting;YANG Cheng-sheng;LYU Sen(China Institute of Geo-environment Monitoring,Beijing 100081,China;School of Geological Engineering and Geomatics,Chang an University,Xi an 710054,Shaanxi,China)

机构地区：[1]中国地质环境监测院,北京100081 [2]长安大学地质工程与测绘学院,陕西西安710054

出　　处：《地球科学与环境学报》2022年第3期558-567,共10页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(42174032);中国地质调查局地质调查项目(DD20190637);国家重点研发计划项目(2018YFC1504805);第二次青藏高原综合科学考察研究专题(2019QZKK0904)。

摘　　要：2021年5月21日,云南漾濞地区发生M_(w) 6.4级地震,然而发震区的活动构造前期研究薄弱。针对此次地震开展监测与震源参数反演研究,对深入掌握漾濞地区及其邻近区域的孕震及发震机理和构造活动特征具有十分重要的科学意义。利用欧洲航天局两个轨道的Sentinel-1A SAR卫星影像获取了升、降轨的同震形变场,并利用Okada矩形弹性位错模型反演了震源参数以及同震的滑动分布。监测结果显示,同震破裂引发的最大隆升和最大下沉形变均超过10 cm。同震位错模型反演结果表明:漾濞M_(w) 6.4级地震是由长度12.2 km、宽度5.0 km、走向132°、倾角83°的断层引发的;此次地震是一次显著的右旋走滑运动的破裂事件,其平均滑动量为0.19 m,平均滑动角为-153.6°,矩震级为M_(w) 6.1,与美国地质调查局(USGS)、全球矩心矩张量(GCMT)计划等公布的震源机制解结果一致。同时,同震库伦应力变化计算结果显示,同震引发的库伦应力变化为4.21×10^(25)dyne·cm^(-1),相当于矩震级M_(w) 6.38,并且库伦应力分布反映出此次地震以应力释放为主,进一步触发走滑地震的可能性不大。On May 21,2021,Yangbi M_(w) 6.4 earthquake occurred in Dali area of Yunnan,China.However,the pre-research on the geological structure in the seismogenic area of this earthquake is weak.It is scientific significance for the in-depth understanding of the seismogenic,seismogenic mechanism and characteristics of tectonic activity in Yangbi area and its adjacent areas to monitoring and inversing source parameter for this earthquake.The Sentinel-1A SAR satellite images of ESA were used to obtain the co-seismic deformation field of the earthquake from different orbits,and the Okada rectangle elastic dislocation model was used to invert the earthquake source parameters and the co-seismic slip distribution.The results show that the maximum uplift and maximum subsidence deformation caused by co-seismic rupture are both over 10 cm.The inversion results of the co-seismic show that the earthquake is caused by the rupture of a fault with a length of 12.2 km,a width of 5.0 km,a strike of 132°and a dip angle of 83°;the earthquake is a significant right-lateral strike-slip movement.The average slip is 0.19 m and the average slip angle is-153.6°,and the magnitude is M_(w) 6.1,which is consistent with the focal mechanism solution published by USGS and GCMT.At the same time,Coulomb stress of co-seismic is 4.21×10^(25) dyne·cm^(-1),which is equivalent to M_(w) 6.38;and Coulomb stress distribution reflects that the earthquake is dominated by stress release,which further triggers strike-slip earthquake unlikely.

关 键 词：大地测量 地震 震源参数 同震形变场 INSAR 断层参数 库伦应力 漾濞地震 

分 类 号：P315[天文地球—地震学] P22[天文地球—固体地球物理学]