地质力学学报2025，Vol.31Issue(2)：287-300,14.DOI:10.12090/j.issn.1006-6616.2024127
2023年甘肃肃北MS 5.5地震InSAR同震形变场与构造意义
InSAR coseismic deformation field and tectonic implications of the 2023 MS 5.5 Subei Earthquake,Gansu,China
摘要
Abstract
[Objective]On October 24,2023,an MS 5.5 earthquake occurred in Subei County,Jiuquan City,Gansu Province.The epicenter was located in the Qilian mountain seismic belt at the northeastern margin of the Qinghai-Tibet Plateau.Understanding the seismogenic mechanism of this earthquake and its relationship with the tectonic stress field is crucial for analyzing the seismic hazard in the region.[Methods]The InSAR coseismic deformation field of the MS5.5 earthquake in Subei was obtained using ascending and descending Sentinel-1 SAR data,and the parameters of the seismogenic fault were determined based on a uniform slip model.Subsequently,a distributed slip inversion method was applied to obtain a detailed slip distribution of the seismogenic fault.Furthermore,the earthquake-induced changes in the Coulomb stress and the regional interseismic strain rate were determined.[Results]The results indicate that the surface deformation values generated by this earthquake reached 12 cm and 9 cm in the ascending and descending InSAR line of sight,respectively.The deformation primarily manifests as surface uplift;the seismogenic fault is a concealed fault located between the Shule Nanshan Fault and the northern margin fault of the Central Qilian,the strike is approximately 166.97°,the dip angle is around 68.69°,and the slip angle is about 110.39°;the fault slip is primarily concentrated within the depth range of 1.2 km to 4.9 km,with a maximum slip of 0.58 m occurring at a depth of approximately 2.56 km;the moment magnitude obtained from the inversion is MW 5.6,and the coseismic rupture is primarily characterized by thrust motion with a minor component of right-lateral strike-slip.This seismic event resulted in regional Coulomb stress changes between the northern margin fault of the Central Qilian and the Shule Nanshan Fault,as well as in the northern area of the Shule River Fault Zone.Additionally,the regional surface strain rate exhibited a distinct compressive trend before the earthquake,with higher surface strain and maximum shear strain rates observed on the northern side of the seismic zone.[Conclusion]The continuous accumulation of strain leads to an increased seismic hazard,with historical earthquakes often occurring in gradient zones where strain values transition from high to low.Considering the regional strain distribution characteristics and seismic activity,the seismic hazard in this area remains significant in the future and should not be overlooked.[Significance]The research findings have a certain guiding significance for understanding the tectonic background of the Qilian Block and its seismic hazard.关键词
祁连地块/肃北MS 5.5地震/InSAR/滑动分布/库仑应力变化/应变率Key words
Qilian Block/Subei MS 5.5 Earthquake/InSAR/slip distribution/Coulomb stress change/strain rate分类
地球科学引用本文复制引用
熊国华,季灵运,陈玉鑫,朱良玉,刘传金,徐晶,蒋锋云,徐国彬..2023年甘肃肃北MS 5.5地震InSAR同震形变场与构造意义[J].地质力学学报,2025,31(2):287-300,14.基金项目
国家自然科学基金项目(42474013,42104061) （42474013,42104061）
中国地震局震情跟踪定向工作任务项目(2024010206)This research is financially supported by the National Natural Science Foundation of China(Grant Nos.42474013 and 42104061)and the Earthquake Tracking Task of CEA(Grant No.2024010206) （2024010206）
