InSAR Monitoring Of Land Subsidence And Risk Assessment In Jiangsu Province

As a kind of geological disaster,land subsidence will cause serious hazards such as wall tilt,ground cracking,seawater backflow,traffic facilities deformation,which has the characteristics of continuity and accumulation and is difficult to detect its impact in a short time,but can be observed through a long time series different from collapse and debris flow.Therefore,it is of great significance to monitor land subsidence regularly.It has the advantages of macro,fast and accurate in land subsidence monitoring by using remote sensing technology,so this study uses the data of European Space Agency's earth observation satellites Sentinel-1A to study the land subsidence inversion of the research area getting the subsidence rate and accumulated land subsidence based on the in-depth study of the principle and method of InSAR land subsidence inversion at home and abroad,taking Jiangsu Province as the research area,which to analyze the key areas and make the risk assessment.(1)The land subsidence rate and accumulated subsidence from 326 SAR images of November 2015 to December 2018 are inversed by using MCTSB-InSAR technology based on GDEMSI software the imaging characteristics of Sentinel-1A image tops,There are multiple settlement funnels in the area,with the maximum settlement rate of-215mm/year,and the maximum cumulative settlement of-676mm.In addition,the mean square deviation of the error is 4.6mm/year,less than 5mm/year,which meets the experimental accuracy requirements of land subsidence monitoring,and the monitoring results are reliable.(2)At the same time,the settlement extraction and spatial characteristics analysis are carried out for the key prefecture level cities such as Nanjing and Suzhou,which has mostly 1-2settlement funnels in the area tending to expand outward.The settlement center is mostly located in the mining area or groundwater mining area..(3)This study uses a risk assessment model of land subsidence,which comprehensively considers the probability that land subsidence may evolve into geological disaster(subsidence risk)and the possible loss(subsidence vulnerability)caused by land subsidence,which helps me to complete the risk assessment of land subsidence in Jiangsu Province combined with social and economic data.The area of large-risk area is 38.98km2,the area of high-risk area is 150.67km2,and the area of medium risk area is 455.75km2 in Jiangsu Province where the trend and causes of high-risk area are analyzed by comparing with high-risk area and corresponding settlement rate results.The result shows that Nanjing belongs to "high risk and high vulnerability area",Suzhou-Wuxi-Changzhou belongs to "medium risk and medium vulnerability area",Lianyungang belongs to "high risk and high vulnerability area",and Xuzhou belongs to "high risk and low vulnerability area".