Early Identification And Vulnerability Assessment Of High-level Slope Disasters In Lixian Based On Multi-source Remote Sensing Data

High-level slope disasters are generally covered by vegetation,with high-level and concealed characteristics.Traditional manual investigation and group monitoring and group prevention have been powerless in the face of such disasters,and it is difficult to find hidden hazards of such disasters in advance.Li County is located in the dry and warm valley area of the upper Minjiang River and belongs to the Longmen Mountain fault zone.The rock mass in the area is relatively broken,the lithology is complex,and high slope disasters occur frequently.This article,with the support of the National Natural Science Foundation of China(fund number:41572291)and relying on the“High-level Geological Hazards Detailed Investigation and Demonstration Project in the Alpine Gorge Region(Li County)”,carried out the integration of multi-source remote sensing data in the early slope of Lixian high-level geological disasters Identification and susceptibility evaluation.Vulnerability assessment is one of the important contents of geological disaster research.This paper uses remote sensing interpretation and on-site drone review SBAS-In SAR technology to extract the high-level deformation area to determine the high-level slope disaster point in the study area as the study area susceptibility evaluation Based on the sample data,the susceptibility of high-level slope disasters in the study area is evaluated by information method.The main results of this paper are as follows:(1)High-level slope deformation area extraction and disaster recognition based on spaceborne remote sensing technology.Combined with SBAS-In SAR technology,189 high-level deformation zones were finally delineated under the conditions of displacement rate,number of deformation points,slope gradient,and relative height difference.Geogle Earth satellite remote sensing images were used to superimpose the image data and the deformation area,and 189 high-level deformation areas were remotely interpreted to determine 122 high-level geological disasters,including 98high-level collapses and 24 high-level landslides.The interpretation is effective The recognition rate is 64%.(2)Adopt drones to review high slope disasters.Establish high-level slope geological disasters(landslides,collapses)UAV remote sensing interpretation signs,interpret the remote sensing images acquired by the UAV,and review the deformation area.Finally,189 high-level slope disaster points were determined from the extracted189 high-level deformation zones,including 150 high-level slope disaster points in the hidden danger points existing in Li County,and 19"missing net fish"that were repeatedly inspected and detailed in the previous period,SBAS-In SAR technology's high slope disaster point determination rate is 89.42%.(3)Distribution characteristics of geological disasters on high slopes in Li County.The high-level slope geological disasters in the area are well developed,and the main characteristics are as follows:(1)Mainly distributed in the valley valley slopes along the Zangnao River(National Highway 317)and its tributaries Mengtungou(Xuemeng Line),Thoruo Gully,Xiaogou,etc.The area is discontinuous and strip-shaped;(2)High-level slope disasters are mainly developed in high mountainous areas with an elevation of 1500-2100m;(3)High-level landslides with gravel and silty clay in the landslide body are most developed,sandstone and phyllite strata The number of high-level collapses developed in the middle accounts for 96.92%of the total;(4)High-level slope disasters are also mostly distributed in Xuecheng S-type structures along the Xuecheng and Lixian counties,as well as the northwest-facing structures of Malkang along the Miyaluo and Gulgou areas.(4)Analysis and impact assessment of high-level slope disasters in the study area.Using quantitative research methods,the relationship between high-level slope disasters and susceptibility assessment factors was analyzed in detail.Slope,aspect,elevation,distance to river,stratum lithology,slope structure,distance to highway,and distance to fault were selected.A total of 8 factors are used as the evaluation factors of high slope disaster susceptibility.The area of Lixian's high slope disasters with extremely low risk area,low risk area,middle risk area,and high risk area estimated by information model is 1600.54km~2,1586.51km~2,734.74km~2,and 400.72km~2,respectively.37.03%,36.70%,17.00%,and 9.27%of the county area;high-prone areas with high slope disasters are mainly distributed on the high and steep slopes on both sides of the Zagunao River,distributed in stripes,and the middle-prone areas are irregularly distributed,mostly in patches shape.