| In recent years,a series of landslides represented by the Baige landslide on the Jinsha River and the Xinmocun landslide in Maoxian County,Sichuan have the characteristics of suddenness,high position,and concealment.Traditional investigations alone cannot identify hidden landslide hazards that these people cannot reach.This study combines InSAR technology with optical remote sensing,combining deformation information with map information,and complementing each other,exploring a comprehensive remote sensing landslide hazard identification method suitable for high mountain and valley-canyon areas,and identifying landslide hazards to the greatest extent.The Gongjue section of the Jinsha River is located in the Jinsha River fault zone,where geological tectonic activities are intense and landslide disasters occur frequently.This paper comprehensively considers the topography and geomorphology characteristics of the Gongjue section of the Jinsha River and the advantages and disadvantages of the InSAR technology.The Sentinel-1 data is selected and the Stacking InSAR technology is used to obtain the annual average surface deformation rate of the radar line of sight in the study area;combined with surface deformation information,optical Remote sensing visual interpretation has realized the identification of hidden hazards of landslides in the Gongjue section of the Jinsha River,and the validity and reliability of the identification results of hidden hazards of landslides have been verified through field investigations.The main results of the paper are as follows:(1)Using Sentinel-1 ascending data to obtain the average annual deformation rate in the line of sight of the radar covering the study area,the maximum deformation rate is 0.404m/a and the minimum deformation rate is 0.010m/a.The Sentinel-1derailment data obtains a maximum transmission rate of 0.086m/a and a minimum transmission rate of 0.067m/a.(2)Taking the absolute value of the deformation rate in the LOS direction of0.01m/a as the threshold,the annual average deformation results based on the ascending orbit data delineated 41 obvious deformation areas,of which the ascending orbit data delineated 16 large deformation areas,and the descending orbit The data detected 26 large deformation areas,of which 1 large deformation area was detected by the SAR images of the two orbits.The Sentinel-1 data of the two types of tracks were used to identify the hidden dangers of landslides in the study area to a certain extent to compensate for each other.(3)Geological interpretation of 41 delineated large deformation areas was carried out to determine the hidden danger points of landslides.Through discriminant analysis,30 deformation areas can be identified as hidden dangers of landslides.The identification verification rate of hidden dangers of landslides is 73.18%.The remaining 11 deformations are caused by water erosion,avalanches,glacier movement and ground subsidence,and they are not hidden dangers of landslides.(4)InSAR and optical remote sensing technology have identified 44 hidden landslide hazards within the study area,30 of which were identified by the deformation area obtained by InSAR technology and visual interpretation of optical images,and 24 were identified by optical remote sensing visual interpretation,Of which 10 InSAR and optical remote sensing are all identified.There are 15 hidden landslide hazards in the study area that have the risk of blocking the main stream of the Jinsha River,and 7 hidden hazards threaten human engineering activities(arable land and residential areas).The characteristics of boundary,scale,activity,and threat objects have been determined and the Jinsha River tribute has been compiled.Distribution map of hidden dangers of Jue Duan landslide.24 hidden hazards of landslides were verified in the field,and the accuracy rate of hazard identification reached 87.5%.The above research results prove the feasibility of using integrated remote sensing technology to identify landslide hazards in alpine and valley-canyon areas.This case study can lay a foundation for disaster prevention and mitigation,and at the same time provide a reference for the identification of landslide hazards in a wide range of alpine and valley-canyon areas.Great development and application prospects. |
