Deformation Monitoring Of Geothermal Resources Based On Time Series InSAR Technology

Geothermal energy has become a new type of green renewable energy that can replace mineral fuels,and is an important energy source after solar energy,nuclear energy and other energy sources.China has rich geothermal resources.After years of practice,it has been shown that the rational development and utilization of geothermal resources has produced significant economic,social and environmental benefits.However,the development of geothermal resources is likely to cause uneven settlement of the ground.To this end,deformation monitoring of geothermal resource development areas is needed.Geothermal resources are generally extracted by geothermal wells,and the deformation monitoring is generally based on traditional means(GPS network,leveling network,etc.).However,traditional monitoring methods have the disadvantages of sparse sampling density,inability to comprehensively assess the impact of geothermal resource extraction,and high labor and material costs.The emergence of InSAR monitoring technology can make up for the above shortcomings.The technology has the characteristics of large monitoring area,high frequency,high accuracy,and low cost.The technology has been applied to many research fields.The Xiongan New Area contains rich geothermal resources,and the establishment of the Xiongan New Area has promoted the urbanization process of the area.It is bound to vigorously develop geothermal resources,and there is a certain potential surface deformation risk.In the past,the research work on geothermal resource exploitation and deformation in Xiongan New Area is scarce.It is of great significance and practical value to use InSAR technology to study surface deformation information in Xiongan New Area,which is rich in geothermal resources.This article first used SBAS-InSAR technology combined with 49 scenes of Sentinel-1 and 10 scenes of ALOS-2 satellite images to extract surface deformation information from the Xiongan New Area from July 2015 to December 2019.The SBAS-InSAR results indicated that there are many different levels of surface subsidence in the Xiongan New Area.But the overall settlement is relatively small,with an average annual settlement rate of less than 30mm/a in 94.82% of the area.Only 5.18% of the areas have more serious settlements.Among them,Daying Township in Xiong County and Beifeng Village in the south of Anxin County have the most severe settlements.The maximum settlement is 485.9mm,and the average annual settlement rate is 121.9mm/a.Through profile and time series analysis,it is found that the distribution of geothermal fields in the Xiong'an New Area is highly consistent with the distribution of the severely subsidence areas retrieved by the SBAS-InSAR technique.It is caused by the extraction of geothermal resources.The SBAS-InSAR deformation results of Sentinel-1 and ALOS-2 satellite images were used for cross-validation,and the reliability and monitoring accuracy of the deformation results of the SBAS-InSAR technology inversion were evaluated.