Application Of InSAR Technology In Monitoring Southwest Surface Deformation

The karst landforms in China are widely distributed.The southwestern region,as the largest karst area in China,is mostly mountainous.The geological and topographic environment is complex,the ecosystem is fragile,and the surface stability is poor.Guizhou is located in the southwest of China.It is one of the most active areas for karst landform development in China.Therefore,Guizhou's underground and surface karst activities are very frequent,resulting in very small movements in this area and frequent geological disasters.It is very necessary to carry out geological survey and monitoring of this area,while the southwest area is mainly mountainous,and the conventional survey methods have a great demand for manpower and material resources,which is difficult to achieve.Synthetic Aperture Radar Interferometry is a new type of earth observation technology that began to develop in the middle and late last century.This technology is an active remote sensing technology,not limited by time and space,and has the advantages of large-scale and high-precision monitoring.It has been successfully used in mining areas,volcanic movements,landslides,glaciers movement,frozen soil monitoring and urban deformation monitoring.However,due to the limitations of its imaging principle,coupled with the mountainous areas in the southwest,the complex and diverse terrain,the lush vegetation,and the humid climate,during the monitoring of InSAR,the atmospheric effect is relatively serious,and there are many shadows and overlapping areas.As a result,the coherence of the interference image is poor and the loss of correlation is serious.Therefore,InSAR technology still has many problems in high-precision surface deformation monitoring in southwest China.This paper aims at the problems of InSAR technology in the monitoring of mountainous deformation,taking Liupanshui in Guizhou as an example to use InSAR technology to identify geological instability points and further research on some deformation areas in Panzhou City,using different data and methods Monitoring and processing,and according to different types of data combined with InSAR imaging law to decompose the two-dimensional deformation of the area,the main research content includes the following aspects:(1)Using Stacking-InSAR technology to monitor 82 ALOS-1 data of 7 different orbits and frame numbers in Liupanshui City on a large scale,and obtain the average annual subsidence rate of the region from 2007 to 2009 to obtain the city's geology Unstable point distribution,and overlay the city's geological development map,mining area distribution map and geological environment zoning map,combined with field survey data to compare and analyze the cause of the city's deformation.(2)In order to study the surface deformation of panzhou City of Liupanshui City,SBAS-InSAR technology was used for alos-2 data,PS-InSAR technology for short time and space baseline was used for alos-1 data and sentinel ascending and descending orbit data,and the accumulated settlement amount and annual average settlement rate map for different data periods were obtained.A deformation zone was selected for the deformation zone studied in Panzhou City for further study.The AB profile and P1-P7 feature points in this area were studied to obtain the annual average settlement rate map and cumulative settlement of four different data profiles.In time series,perform time series analysis on P1-P7 feature points to obtain the corresponding cumulative settlement.And the sectional line and feature point data were compared,the reasons for the differences in the data were analyzed,and the reasons for the deformation in the Panzhou study area were analyzed.The results show that the main deformation factors in the study area are mining,groundwater mining,human activities,and karst karst processes.In Karst,a special geological environment,there are different correlations between the surface deformation rate with temperature,precipitation and soil moisture.(3)For the radar data can only accurately obtain the imaging method of one-dimensional line-of-sight surface deformation,a deformation area was selected for two-dimensional deformation decomposition of sentinel ascending and descending orbit data to obtain the annual average deformation rate graph and cumulative deformation variable graph in the east-west and vertical directions,and obtained the annual average settlement rate graphs and cumulative settlement graphs of the AB and CD profiles and P1-P7 feature points in the east-west and vertical directions.Comparing the vertical deformation of the two-dimensional decomposition of the AB and CD section lines with the vertical deformation of the sentinel ascending and descending orbit data proved the necessity of multidimensional decomposition when there was horizontal deformation.And analyzed the reason of the east-west deformation after two-dimensional decomposition.