Changsha County,Hunan Province Based On Information Quantity Method Evaluation Of The Susceptibility Of Geological Disasters

Changsha County is located in the central part of Changsha City,Hunan Province,with mostly hilly landforms.In recent years,with the increase of human engineering activities such as building houses,road construction,mining,and the occurrence of seasonal heavy rainfall,a large number of geological disasters have been induced,threatening the safety of people’s lives and property.On the basis of fully collecting relevant data and field investigation,this paper conducts systematic research on Changsha County,and summarizes the types and developmental characteristics of landslides and collapses.The formation conditions for the development of geological disasters are discussed,and 9 main influencing factors are selected.The weight of each evaluation factor was determined by the information measurement method,and the assignment and superposition calculations were carried out to obtain the regional planning map of the geological disaster susceptibility of Changsha County.Using the analytic hierarchy method as a comparative reference,the ROC curve verifies the accuracy of the susceptibility evaluation model based on the information quantity method.The following are the main research contents and results:(1)Based on the data analysis,storage and extraction functions of GIS technology,the geological data and DEM data obtained from field research are processed,and the 9 influencing factors of rainfall,landform,elevation,slope,engineering geological rock formation,fault,vegetation coverage,human engineering activities and water system are selected,and the database is established in combination with landslide and collapse disaster points.The development characteristics and distribution rules of landslide and collapse disasters in the study area were analyzed from the number and density of disasters in different grading ranges of each impact factor.(2)The weight of each evaluation factor is determined by the information quantity method,the weight of each factor is assigned to the raster layer for overlay calculation,and the calculated vulnerability index layer is classified by the natural break point classification method,and finally the geological disaster vulnerability partition result based on the information quantity method is obtained.Among them,the main scope of the high-prone area is in the high hills and low-mountainous landforms at the northern edge of the middle of the study area and the south-east end,as well as the junction of Ansha Town,Lukou Town and Guoyuan Town in the central part.(3)The analytic hierarchy method was selected as the comparison reference,and the accuracy rate test and comparison of the two methods obtained by the AUC value of the ROC curve were verified,which verified that the geological disaster vulnerability evaluation results based on the information quantity method were more accurate and effective.Where disaster point data are detailed and the impact factors are similar,geological hazard vulnerability assessments can be generalized to other regions.