Research On Surface Deformation Monitoring By DInSAR Of Sentinel-1A

The geological disasters caused by surface deformation are concerned in China.The large-scale and long-term monitoring of surface deformation is essential linked.There are three types of surface deformation including earthquakes,ground subsidence caused by over-exploitation of groundwater and surface subsidence caused by mineral exploitation.The geological disasters are caused by natural factors or human factors.There is a huge impact to the safe and stable development of society and people's life.In order to make up for the shortcomings of traditional leveling and GPS deformation monitoring,the dissertation uses Differential Interferometric Synthetic Aperture Radar(DInSAR)to study the seismic surface deformation,urban land subsidence and mine surface subsidence monitoring respectively.The main work and innovations include:1.The background and advantages of DInSAR technology to monitor the surface deformation are introduced.The influence of surface deformation,the satellite orbit error,the DEM error and the atmospheric delay on the interference phase are analysed based on the principle of DInSAR technology.The PS-InSAR and SBAS-InSAR technology are described in detail.2.Coseismic deformation field and fault parameter inversion are studied with Sentinel-1A data.Based on the Okada elastic half-space dislocation model theory,the Levenberg-Marquardt least squares optimization algorithm is introduced to solve the geometrical parameters of the fault.The linear inversion is used to obtain the fine slip distribution of the fault.Taking the earthquake ofM_w 5.9 in Menyuan Qinghai Province on January 21 2016 as an example,the deformation field and fault parameters are obtained from the Sentinel-1A satellite IW model data.The fitted seismic source parameters are compared with these published by the China Earthquake Administration,indicating that the results are reliable.In addition,combined with geological field data,it is found that the fault occurred as a reverse fault near the fault on the north side of the Lenglongling.3.Permanent Scatteres InSAR(PS-InSAR)technique is used for subsidence monitoring on the study area over Tianjin via 23 Sentinel-1A satellite IW mode images.The deformation rate of subsiding areas from 2015-05 to 2016-02 is reconstructed.Combined with hydrological data,the timing deformation characteristics and causes of key subsidence area are analyzed in detail.The results show that the technology can effectively obtain the ground subsidence information of urban area.4.The suitability analysis of the deformation monitoring is proposed by using Sentinel-1A data on the basis of the deformation gradient function model.In order to solve the problems of applicability of DInSAR monitoring in mining area,the applicability analysis of DInSAR technology is carried out with Sentinel-1A data.Specifically,the deformation gradient function model is used to analyze the relationship between SAR data coherence,ground deformation gradient and DInSAR monitoring applicability.The study will initially assist in the selection of reasonable data distributions in InSAR applications based on the study target ground type and monitoring season.5.Aiming at the surface subsidence of Jiaozuo mining area,the method of combining SBAS-InSAR technique and DInSAR technique is designed to monitor the surface subsidence.For surface sedimentation center with the serious subsidence in mine area,a joint analysis method of differential interferogram and velocity map is designed.Based on the Sentinel-1A satellite IW model data from June 2015 to May 2016 in Henan Province,the SBAS-InSAR is carried out to obtain the land subsidence rate of the mining area.The differential interferogram images reveals the development and evolution of the settlement funnel in the mining area.Finally,using the level data,the results of SBAS-InSAR are verified,and the reliability of results is proved.