| Assessment of collapse hazards (karst collapse and mining collapse) on the nation wide scale is very important in government decision making. In this paper, the author describes the analytical and assessment methods which use GIS function, such as buffer analysis, overlay analysis, and spatial analysis. The influencing factors considered include carbonate rock type, geomorphic type, hydrogeological condition, human activities and land use. Human activities consist of urbanization, mining, highway and railway. All of these factors were digitized as corresponding layers and assigned values based on the distribution probability of collapses. In order to determine the weight of each factor to the hazard, AHP (The Analytic Hierarchy Process) was used. The assessment result is divided into five levels, i.e., very high risk, high risk, medium risk, low risk, and very low risk. It is shown that the very high risk and high risk areas are mainly distributed in Guangxi, Guizhou, Yunnan, followed by Hubei, Hunan, Chongqing, Sichuan, and Shaanxi. |