| Xingguo County is located in south central Jiangxi Province,north of Ganzhou City.County area for the main terrain of low mountains and hills,the surface is vulnerable to erosion,and abundant precipitation,easy to breed geological disasters.Frequent geological disasters,such as landslides and collapses,restrict local social construction and economic development,but also pose a serious threat to the daily life and property safety of the county people.Therefore,effective geological disaster monitoring and prevention work is of great significance to ensure local people’s lives and social construction.The precondition of monitoring and prevention of geological disasters is to obtain the spatio-temporal source of disaster threat by analyzing the spatio-temporal evolution characteristics of geological disasters comprehensively and systematically.At the same time,it is necessary to adapt to local conditions and take different prevention and control measures in different regions with different pregnancy disaster conditions.The time-series InSAR technology has obvious advantages over traditional deformation measurement methods,such as large-scale monitoring,high spatio-temporal resolution and not being affected by weather conditions,and can monitor the surface deformation in Xingguo County for a long period of time.In addition,based on regional historical disaster data,screening of major disaster-causing factors,and the combination of mathematical statistics and machine learning models,the probability of geological disasters in different areas within the study area can be predicted,i.e.,the evaluation of geological disaster susceptibility.However,the evaluation results considering only the major disaster-causing factors cannot adapt to the constantly changing ground surface conditions.This paper monitors the ground deformation of Xingguo County based on time-series InSAR technology,analyzes the deformation causes,and obtains the deformation characteristics of typical disaster points.At the same time,time-series InSAR monitoring data is used as an index of ground stability to revise the susceptibility evaluation results considering only disaster-causing factors,increasing the rationality and applicability of susceptibility evaluation results and achieving continuous updates of susceptibility evaluation results based on time-series InSAR technology.The main work of this paper is as follows:(1)The application of time-series InSAR technique to monitor surface deformation in Xingguo County and evaluate the quality of monitoring results.Sentinel-1A images of Xingguo County from March 2017 to December 2021 were processed by using typical time-series InSAR technology(PS and SBAS)to monitor surface deformation in Xingguo County during the past five years.The two InSAR techniques show good consistency in deformation trend and deformation rate monitoring,which proves that the deformation monitoring results are reliable.At the same time,SBAS-InSAR technology successfully monitored the deformation characteristics of typical geological disasters.In terms of space,obvious subsidence areas were monitored.In terms of temporal evolution,continuous subsidence and abrupt change of the surface in rainy season were monitored,which showed the ability of temporal InSAR technology to monitor the deformation of small geological disasters.(2)Analysis of influencing factors of surface deformation in Xingguo County based on SBAS-InSAR monitoring results.Based on the SBAS-InSAR deformation monitoring results,the causes of typical surface deformation areas in Xingguo County are analyzed from two aspects: natural factors and human activities.In terms of natural factors,precipitation and river erosion have a significant impact on the surface deformation of Xingguo County;in terms of human activities,road construction in mountainous areas,mining,and land cultivation are the main causes of surface deformation.Human activities destroy vegetation coverage and slope structure,which are then affected by precipitation and erosion,resulting in surface deformation and fostering geological disasters.(3)Evaluation of ground disaster susceptibility in Xingguo County based on SBAS-InSAR.Based on the analysis of the causes of geological disasters and the screening of major disaster factors in the study area,the regional geological disaster susceptibility was evaluated by the single information model and the logistic regression model based on the information of impact factors,and the SBAS-InSAR monitoring results were used as the surface stability index to revise the evaluation results.The results show that the two models have higher evaluation accuracy,and the coupled model is more reasonable while the accuracy is improved.Based on the revised evaluation results of SBAS-InSAR monitoring results,the surface stability characteristics reflected by surface deformation in a period of time can be taken into account while considering the influence of disaster factors.For regions with low susceptibility rating but poor surface stability during the monitoring period,the susceptibility rating should be improved accordingly,so as to improve the rationality of the evaluation results and make the evaluation results more timeliness.The monitoring of surface deformation and susceptibility assessment of geological disasters in Xingguo County based on time-series InSAR technology can provide scientific data support for geological disaster monitoring and prevention work in Xingguo County,and has important practical significance for local social construction,economic development and people’s life. |
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