Research And Application Of Key Technologies For InSAR Coseismic Deformation Extraction

After the occurrence of large earthquakes,how to quickly obtain co-seismic deformation and focal parameters is of great significance to the decision-making of service rescue and disaster relief.Radar interferometry technology can overcome the harsh weather environment and provide an effective way for fast acquisition of seismic deformation information.Combining seismic deformation with seismic parameters(such as fault parameters,focal mechanism solutions,etc.) can better determine the key areas of disaster relief,thus effectively reducing post-earthquake casualties and economic property losses.At present,the application of InSAR technology in seismology is mainly concentrated on seismic coseismic deformation field acquisition,but there is less joint analysis of static deformation and seismic dynamics.How to break through the limitations of static observation of traditional remote sensing technology,make radar interference technology serve seismic dynamics research,realize the intersection of geodesy and seismology,and more efficient and rapid acquisition of seismic earthquake information is an urgent problem to be solved.In this paper,based on InSAR technology and the need of seismic emergency information acquisition,the key technologies of InSAR high-precision deformation field extraction and seismological application are mainly studied,including: decoherence recovery technology,seismic three-dimensional deformation field calculation,high-precision fault slip distribution inversion method based on InSAR deformation field,etc.The details are as follows:(1)Decoherence is an inevitable problem in current InSAR processing technology.Deformation field decoherence easily leads to the lack of deformation information in the extreme seismic region.This paper analyzes the different causes of the incoherence of the InSAR deformation field,combined with the special spatial form of the seismic deformation field.A Support Vector Regression(SVR) decoherence recovery process and method considering the characteristics of seismogenic faults and deformation field are proposed to overcome the lack of fault property constraints in Kriging interpolation and improve the reliability of decoherence recovery.(2)InSAR technology can directly obtain the line-of-sight deformation information,and its orbital attitude determines that InSAR is not sensitive to the north-south deformation,so the observation dimension of the surface deformation caused by the earthquake is limited.In this paper,the least squares adjustment theory is introduced,and the high-precision 3D coseismic deformation field solution is solved based on InSAR technology to improve the observation accuracy of InSAR in the north-south deformation.For the case of SAR data only,three-dimensional deformation field solution is jointly performed based on multiple InSAR technologies.For multi-source data,the InSAR,GPS and strong earthquake data are normalized,and the deformation and orbit errors are modeled for the deformation field.Right,and then use the least squares method to obtain high-precision three-dimensional deformation field.(3)At present,the application of InSAR in seismology mainly focuses on surface deformation observation,and there are few studies combined with deep seismic response process.How to further explore the deep structure and rupture process of earthquake based on InSAR results is an urgent problem to be solved.In this paper,the inversion method of seismogenic fault motion pattern based on the fusion of InSAR surface deformation field with GPS,strong earthquake observation and other multi-source data is established.The weighting problem in multi-source heterogeneous data fusion is discussed.The appropriate weighting parameters are given based on analytic hierarchy process.Based on the improved stochastic search particle swarm optimization algorithm,the combination of static surface deformation field and seismic wave observation data is established.Inversion method is used to obtain fault slip distribution model and focal mechanism solution.Aiming at the problem that the errors of input data of traditional pseudo-three-dimensional deformation field("Line of sight + Azimuth" decomposition) will accumulate continuously in the inversion of source slip model,an improved inversion method of source slip based on true three-dimensional(Vertical + East-West + North-South) deformation field constraints is proposed,which can obtain high-precision fault slip distribution model through three-dimensional deformation field constraints and effectively reduce the inversion.The uncertainty of model parameters in the process of simulation can improve the data resolution.(4)Based on the inversion results of fault slip distribution,the correlation between Coulomb stress variation and aftershocks is explored.Based on the inversion results,the regional ground motion is simulated by using the stochastic vibration finite fault model,and verified and constrained by strong seismic station data,a high precision and clear detail intensity simulation map is produced,which overcomes the sparse density and emptiness of station facing traditional instrument intensity acquisition.There are some limitations,such as the lack of obvious distribution details,which can provide a reference for the rapid research of earthquake information.