Research On Remote Sensing Information Extraction And Risk Assessment Of Debris Flow Disasters In Deqin County

The use of remote sensing and geographic information technology to extract information and risk assessment of debris flow disasters can not only provide data support for disaster prevention and mitigation work,but also provide auxiliary decision-making services.It also plays an important role in regional economic development and people's living standards.The geographical environment and geological environment in Deqin County are complex,and the geological disasters in the county are strongly developed.The frequency of debris flow disasters is high and the drainage area is wide,which seriously threatens the lives and property of the people and restricts the local economic development.Based on the above background,this paper uses remote sensing and geographic information technology,combined with three-dimensional visualization technology to quickly extract debris flow disaster information,and uses the information method to improve the analytic hierarchy process to evaluate the debris flow risk in Deqin County.Through research and analysis,the conclusions are following:(1)Analyzing the morphological characteristics and image characteristics of debris flow in Deqin County,and establishing a interpretation mark of debrics flow.The Landsat8 image is used as the data source,and different land types are selected as training samples.The maximum likelihood method and support vector machine method are used to extract the debris source in Deqin County.The accuracy vector is used to find the support vector machine method in extracting debris source information,which is better than the maximum likelihood method.(2)Using DEM data and Landsat8 image data,which make a three-dimensional remote sensing image map in the study area,observe the debris flow disaster in Deqin County from multiple angles,and perform visual interpretation.94 field debris flow disasters in Deqin County were determined by field verification,including 75 gullytype debris flows and 19 slope-type debris flows,and further information on the water system,drainage area and disaster area of the debris flow,and the debris flow in Deqin County was established with uniform standards.The disaster spatial database provides data support for debris flow characteristics analysis and impact factor analysis.(3)Through the analysis of debris flow characteristics in the study area,it is found that the debris flow disasters in Deqin County have obvious clustering in spatial distribution,and 28.72% of the debris flow disaster points are distributed in Benzilan Town.Similarly,it is found that the debris flow basin in Deqin County is mainly distributed in elevations of 3400~4200m,slope 30~45°,precipitation 800~1000mm,low vegetation coverage,engineering geological rock group is weak rock group,and distance fault,water systems,roads and areas where residents gather closer.(4)Selecting elevation,slope,vegetation coverage,engineering geological rock group,distance from fault,annual average precipitation,distance from river,distance from resident gathering place,and distance from road to highway,using information level analysis quantitative debris flow risk assessment was carried out for each basin unit in Deqin County,which was divided into light danger zone,moderate danger zone,high risk zone and severe danger zone.The severely dangerous areas are mainly located in Shengping Town,Benzilan Town and Tuoding Township;the high-risk main areas are located in Foshan Township and Yunling Township;the moderate-risk areas are scattered and distributed in all towns and villages;the light-risk areas are mostly distributed in Yangla Township,Xia Ruo Township.