Evaluation Of Landslide Susceptibility And Rainfall Threshold Research For Pubei County,Guangxi Province

Landslide is the main part of the geological disaster in Guangxi Province,it will not only bring threats to people and property,but also affects the progress of society.Landslide disasters occurred frequently in Pubei County,Guangxi province.Therefore,it is necessary to study the inducing factors of landslide in Pubei County,divide the landslide prone areas,count the rainfall information of landslide,and explore the regional rainfall threshold.The main contents of this paper are as follows:(1)On the basis of collecting the landslide disaster data and investigating the comprehensive study of the landslide hazard-formative environments,eight conditioning factors including slope,aspect,landform,water system,geological structure,lithology,engineering slope cutting intensity and annual rainfall average were selected as evaluation indexes.The analytic hierarchy process model were constructed to calculate the weight of evaluation factors.(2)Then the information quantity model combined with Arc GIS software was used to calculate the grading information value of each index.Finally the landslide disaster susceptibility of Pubei County was assessed and the resulted susceptibility map was classified into five classes by the weighted information value,including very low,low,moderate,high and very high susceptibility,which accounted for 13.8%,39.6%,24.2%,18.5%and 3.9%of the research area respectively.The examination result of the area below the ROC curve was71%,indicating that he results of susceptibility assessment are reasonable.(3)In order to study the relationship between landslide disaster and rainfall in Pubei County,59 rainfall type landslides were selected from historical landslide disasters in Pubei County.The TRMM satellite rainfall data is corrected by using the surface rainfall station data,and then the rainfall data is extracted by interpolation,and the effective rainfall that led to landslide disaster was calculated.The rainfall threshold model was established,and the rainfall threshold curves of extremely high,high and medium prone areas were drawn respectively according to the landslide prone degree:I(28)72.523D^-0.907?I(28)93.274D^-0.934?I(28)44.767D^-0.959,so as to calculate the rainfall threshold which leads to landslide disaster,among them,the effective rainfall of landslide disaster in extremely high risk area is the lowest.