Coseismic Deformation And Fault Kinematics Of Moderate Earthquakes In And Around The Tibet Plateau Using InSAR And Bayesian Inversion

The uplift and strong deformation of the Tibetan Plateau were caused by the northward pushing and wedging after the continuous collision between the Indian plate and the Eurasian plate,which resulted in the wide distribution,high frequency,high intensity and shallow seismic activity on the Tibetan Plateau,making it a typical area where strong earthquakes occur.he stress concentration zone of the Tibetan Plateau is the orogenic belt in its periphery,and the large strike-slip and thrust faults in the periphery make the seismic activity occur frequently.Moderate and strong earthquakes occur in the Tibetan Plateau with high seismogenic frequency and wide distribution,but the degree of study is much lower than that of large earthquakes.The purpose of obtaining the source parameters and slip distribution of medium and strong earthquakes is to better study the earthquake mechanism,causes and triggering relations,and to conduct more in-depth research on the rupture process of the source,the interaction of stress between earthquakes and its influence on the structure.In recent years,a new geodetic technology,Interferometric Synthetic Aperture Radar(In SAR),has been developed,which can better penetrate the vegetation and the surface of the earth without changing with the weather and cloud cover.It has been widely used in deformation monitoring at each stage of seismic cycle.Based on the Tibetan plateau as the study area,in view of the Tibetan plateau area between January 2016 and June 2020,since the type of 20 times of moderate and strong earthquake(5.5?Mw?6.5),according to the Sentinel-1 A/B by means of In SAR data reconstruction of the ascending and descending rail 7 earthquakes of coseismic deformation field,again through the bayesian non-linear inversion and SDM inversion method to get optimal geometric parameters and kinematic parameters of the seismogenic fault,and gain distribution of fault slip.The 7earthquakes included 3 normal fault earthquakes,3 thrust earthquakes and 1 strike slip earthquake respectively.Based on the results of focal mechanism solutions we inversion results compared with seismology method,we found that:(1)the strike-slip type earthquake and normal fault type earthquake using In SAR means that moment magnitude and seismology means the results were similar,most of the moment magnitude events result are consistent,and thrust type we were greater than the moment magnitude earthquake seismology means the results;(2)The focal depth determined by In SAR is all shallower than that obtained by GCMT and USGS,usually less than 12km;(3)For In SAR research,the focal mechanism solution in GCMT/USGS directory is generally used as the initial value,and then inversion of In SAR data is carried out.Through the research and analysis of these earthquakes,there is no significant difference between the two inversion methods,and there is no obvious difference.