Research On Identification Of Hidden Geological Hazards In Tonghua County,Jilin Province Based On Multi-Source Remote Sensing Data

With the intensification of human activities such as large-scale engineering construction and resource development,geological disasters such as landslides,mudslides,ground subsidence and ground fissures occur frequently,and with the additional influence of climate and environment,regional mass disasters are intensified,and the forms of geological disaster prevention and control are becoming more and more severe,which has become one of the hot issues in domestic and foreign research.In mountainous areas with complex geological environment conditions,highway and railway projects are seriously threatened by geological disasters,so it is of great practical significance to carry out quantitative risk assessment of geological disasters,which is also an important way to effectively reduce the harm.This study relies on the "Tonghua County Natural Resources Bureau’s First National Disaster Risk Survey(1:50000)Project" undertaken by Tonghua County Natural Resources Bureau.By collecting the exist data of geological disasters in Tonghua County,Jilin Province and the related research data at home and abroad,the comprehensive remote sensing technology is applied to identify the hidden dangers of geological disasters in the study area,providing support for the follow-up disaster prevention and control.Tonghua County,Jilin Province is mountainous and hilly,and the complex geological conditions lead to frequent geological disasters,which are not easy to be investigated on the spot.In this study,the advantages are complemented by the combination of In SAR technology and optical remote sensing technology,and the key technical problems in the process of applying remote sensing technology to identify potential hazards are successfully solved.This method can not only obtain the surface deformation information of geological hazard points,but also decipher the morphological characteristics of surface elements,which can effectively overcome various adverse effects such as complex terrain,poor spatial coherence and high vegetation coverage in mountainous and hilly areas,and avoid problems of false detection and missed detection in the process of identifying geological hazard points.Firstly,the basic geological data of the study area,GF-1 optical image and Sentinel-1A radar data are collected through the results of previous work.The annual average deformation rate map of the study area is obtained by SBAS-In SAR technology,and the key deformation areas in the study area are circled with the help of DEM data and previous experience summary.On this basis,combined with optical characteristics and geological background,the distribution characteristics of geological hazards are determined by visual interpretation method of GF-1 high ground resolution optical image.The main results of this study are as follows:(1)Using Sentinel-1A radar data,the distribution map of annual average deformation rate in the LOS direction of the study area is obtained,and the deformation rate ranges from-170.187mm/a to 197.804 mm/a.(2)With the absolute value of the deformation rate in the LOS direction greater than 60mm/a as the threshold,find out the positions where at least four CT points coexist to delineate the key deformation areas,and finally extract 62 key deformation areas of geological disasters.(3)Through SBAS-InSAR and optical remote sensing technology,there are 70 remote sensing interpretation points in the working area,including 51 collapses,11 landslides and 8 mudslides.The total number of disaster points identified after field investigation is 70,including 56 collapses identified in the field.Collapse is the main disaster type in this area,accounting for 80% of the total number of disaster points identified in the field.Six landslides were confirmed,accounting for 8.57% of the total number of confirmed disaster points in the field.The above results show that it is feasible to identify hidden dangers of geological disasters in mountainous and hilly areas by using multi-source remote sensing data.This study lays the foundation for the follow-up disaster prevention and mitigation work in Tonghua County,Jilin Province,and also provides reference for the identification methods of large-scale hidden dangers of geological disasters in other mountainous and hilly areas,which proves that multi-source remote sensing data has great prospects in the study of hidden dangers of geological disasters.