Landslide Susceptibility Evaluation In Zhouqu County Based On Comprehensive Index Model

Zhouqu County is located on the eastern edge of the Qinghai-Tibet Plateau,where the west wing of the West Qinling Mountains meets the Minshan Mountains.The complex and changeable geological environment conditions and the precipitation characteristics of frequent rainstorms determine the development of landslide disasters in Zhouqu County,which seriously affects the local economic development and the safety of people's lives and property.Carrying out the evaluation of regional landslide disasters is of great significance to the economic development of Zhouqu County and can provide a reference for the prevention and control of geological disasters in Zhouqu County in the future.This study is based on the field geological hazard investigation in Zhouqu County,collates 67 landslide disaster points in the Statistics Department,comprehensively analyzes the development characteristics and gestation process of landslide disasters in the region,constructs a comprehensive index model with the help of Arc GIS software to evaluate the vulnerability of landslides in Zhouqu County,and uses the ROC curve to test the evaluation results,verifies the evaluation results,and obtains the susceptibility zoning map of landslide disasters in Zhouqu County.The main work of this paper is as follows:(1)The geological background of Zhouqu County is briefly described,and the distribution of landslide disasters in the region is summarized.Through the analysis and study of landslide points in the study area,and combined with previous research data,eight evaluation factors such as elevation,slope,aspect,plane curvature,section curvature,stratum lithology,distance from river and road are selected to construct the evaluation system of landslide susceptibility in Zhouqu County,and the grid unit is determined as the mapping unit of the study area.(2)The weights of eight evaluation factors such as elevation are obtained by Analytic hierarchy process,and then the vulnerability index of landslide disaster in Zhouqu County is calculated by using the comprehensive index model,and the study area is divided into five zones by using the natural breakpoint method in Arc GIS software.Among them,the area of the extremely high-risk area is 408.87km~2,accounting for13.5%of the total area of the county;the area of the high-risk area is 712.73 km~2,accounting for 23.5%of the total area of the county;the area of the easy middle area is854.72 km~2,accounting for 28.2%of the total area of the county;the area of the low easy area is 737.49 km~2,accounting for 24.3%of the total area of the county;and the area of the non-easy area is 315.98 km~2,accounting for 10.4%of the total area of the county.(3)The receiver operating characteristic curve(ROC curve)is used to test the evaluation results,and the area AUC under the ROC curve is 0.8033,indicating that the evaluation result is better and the selected evaluation model is better.It shows that the evaluation model,combined with the analytic hierarchy process and the comprehensive index model is suitable for the vulnerability assessment of landslide disasters in Zhouqu County.