Debris Flow Extraction And Susceptibility Assessment Of The Gaiz River Basin Based On Sentinel-2B

The Gezi River Basin is adjacent to the main range of Tianshan Mountain in the north,the Karakorum Mountain in the south,the Pamir Plateau in the west,and the Tarim Basin in the east.The highway runs up the Gazi River.Debris flow disasters along the China-Pakistan highway which runs upstream along the Gezi river seriously threaten the safety of the highway.Due to the complex causes and diverse forms of debris flow,it is still difficult to extract debris flow information by remote sensing.In current research.,how to apply highresolution optical remote sensing to monitor and extract debris flow disaster information is a hot and difficult issue.Based on the Sentinel-2 remote sensing images in the ESA Copernicus satellite series,a rule-based object-oriented classification method is used to integrate the pop features,geometric features,terrain features and texture features to the debris flow in the Gezi River Basin.Disaster information extraction is studied,and the susceptibility of debris flow to the basin is classified according to the extraction results.The main conclusions are as follows:(1)Based on sentinel-2 image and using object oriented classification method,the optimal segmentation scale of debris flow information in Gezi river basin is 45 and the combined scale is 65.(2)Rule-based object-oriented classification method can obtain high-quality interpretation results in the remote sensing information extraction of debris flow geological hazards.Based on the object-oriented classification method,the Normalized Difference Vegetation Index(NDVI),Modified Normalized Difference Water Index(MNDWI),and Normalized Difference Snow Index(NDSI),Band4 / 11 spectral mean and Elongation are used.Based on the establishment of debris flow extraction rules,preliminary interpretation of debris flow information,post-processing to get 98 debris flow disasters in the study area.By comparing with the debris flow disaster accuracy verification data,the interpretation accuracy rate is 73.6%.(3)Based on the weight evidence analysis model,According to the susceptibility assessment,44.37% of the areas in the Gezi River Basin are extremely vulnerable to debris flow disasters,accounting for 74.89% of the total number of debris flow disaster points in the basin.mainly distributed on both sides of the Gezi River and Kushan River,,especially along the China-Pakistan Highway.This study can provide support for debris flow monitoring and early warning in the Gezi River Basin,and provide a method and technical reference for the investigation of geological disasters in the China-Pakistan Economic Corridor.It has certain scientific value and practical significance.