Early Identification And Susceptibility Of Landslides In The Upper Reaches Of Jinsha River Based On Time Series InSAR Technology

The Jinsha River Basin is a high-incidence area of geological disasters in my country.Its unique topography,geomorphology and hydrogeological conditions lead to frequent occurrence of landslide disasters along its coast,which has a great impact on the sustainable development of society and economy and the construction of ecological environment.Synthetic Aperture Interferometry(InSAR)has been widely used in the monitoring of geological disasters such as earthquakes,landslides,and surface subsidence due to its large monitoring range,high temporal and spatial resolution,and non-contact.This paper takes the upper reaches of the Jinsha River as the research area,based on the Sentinel-1A lifting rail data,uses the time series InSAR technology to identify and monitor the active landslides in the study area,constructs the landslide sliding surface coordinate system to analyze the typical landslide development characteristics,and introduces the lifting rail deformation.The landslide susceptibility study in the study area was carried out using the rate as an evaluation factor.The main research contents and conclusions are as follows:(1)Using SBAS-InSAR technology to process the data of 286 orbit-ascend images and291 orbit-descend images covering the study area,and combine visibility masks to eliminate unreliable areas,and obtain the study area from July 2019 to 2021 Surface deformation rate in July.By setting deformation thresholds and combining optical images and terrain factors to identify and catalogue active landslides in the study area,a total of 117 potential landslide hazards were identified,of which 80 were identified by the ascend mode,and landslides were identified by the descend mode.66 hidden dangers.Among all identified active landslide hazards,79 are historical landslide hazards,and 38 new landslide hazards are newly added.The landslide identification results can update the landslide database in the upper reaches of the Jinsha River and provide the main basis for regional landslide disaster prevention and control.(2)The IPTA method is used to obtain the high-precision deformation results of the landslide,and the coordinate system of the landslide sliding surface is constructed in combination with the DEM data.On the basis of ignoring the deformation in the vertical sliding direction,the sliding direction along the slope and the vertical slope are obtained through the observation of the lifting rail.For normal deformation,the development law and deformation mode of two typical landslides in the study area were analyzed.The results show that geological tectonic movement and water erosion of the Jinsha River are the main driving forces for the development of landslides in the study area.(3)Combined with the historical landslide hazard data in the study area,a landslide hazard database in the study area was constructed.Two susceptibility evaluation factors,which directly characterize the deformation level and developmental pattern,are introduced into the rail deformation rate,and the information model is used to classify the landslide susceptibility in the study area.The results show that the landslide high-risk areas in the study area are generally linearly distributed along the Jinsha River,and river erosion is the main factor affecting the distribution of landslide hazards in the study area.East-west or nearly east-west is the dominant combination of landslide development in the study area.