Research On Landslide Hazard Assessment And Prevention Zones In Xiangcheng County Based On Random Forest Model

Xiangcheng County is located in the Ganzi Prefecture,west of Sichuan Province of China.The terrain in the area is higher in north than it in the south.The landslides caused in rural counties for various and complicated reasons,which bring great losses to the lives and property of the community.Therefore,it is of great significance to evaluate the landslide hazard and propose relevant prevention and control measures for reducing the loss caused by landslide disaster,and it can also provide important decision support and scientific basis for local economic development,territorial space planning,disaster prevention and reduction.Taking the whole Xiangcheng County as the case area,in view of the landslide disaster within the area,in combination with field investigation and historical data of landslides,we aimed to investigate the landslide development and distribution characteristics,as well as evaluate its landslide hazard level by using the random forest model combined with GIS technology.According to the result of evaluation and prevention and control of partitions,the specific countermeasures are put forward.The primary research findings of thesis listing as follows(1)The development and distribution characteristics of landslides in Xiangcheng County were analyzed based on the collected basic data such as the detailed investigation report on geological disasters in Xiangcheng County,the management system for filling and reporting basic geological environment data,and the investigation report on potential geological disasters in Xiangcheng County,scale,development type,and shape are expounded,and the distribution characteristics of landslides are analyzed from two aspects of time and space.(2)Select 8 influencing factors: elevation,slope,slope aspect,distance from water system,rainfall,engineering rock group,distance from fault,and distance from road to establish a landslide hazard evaluation index system.Moreover,use variance expansion test(VIF)and Information gain(IG)to test the correlation of evaluation factors,and the results showed that each factor is independent and reliable.(3)The landslide hazard zoning map of rural and urban counties was obtained based on the random forest model and GIS,and divided it into five grades of extremely high,high,medium,low,and extremely low area with natural breakpoint method.The proportion of each zone was 5.98%,8.50%,13.37%,17.46%,and54.69%,respectively.ROC curve was applied to test the effectiveness of the random forest model with its value was 0.922,indicating that the prediction accuracy of the model was level I.(4)According to the hazard zoning map and the social and economic development of the county,we divided it into four key control areas,three sub-key control areas,and one general control area.In addition,the corresponding control countermeasures were put forward to each important hazard zones.