Regional landslide risk assessment based on GIS and contributing weight model — A case study of Wenchuan County

Geological disaster risk assessment is a process, which indicates a quantitative description of the occurrence probability of geological hazard and the extent of the harm to human society. The degree of geological disaster risk mainly depends on the dynamic conditions of geological disaster activities and the human social economic vulnerability. With the transformation of contribution rate and weight, contribution rate methods obtain the intra-weight and inter-weight of assessment factors from the contributing weight model. The geological disaster risk zoning can be achieved by integrating the results of vulnerability and hazard which results from composing the two weights and index value. Taking the landslide disaster risk assessment in Wenchuan County as an example, formation lithology, elevation, topographic relief, slope aspect, slope gradient, profile curvature, and plane curvature were selected as the landslide disaster hazard assessment factors, meanwhile population density, forest density, cultivated density, landslide disaster density, residential density and road network density were selected as the landslide disaster vulnerability assessment factors. This paper discusses the regional landslide risk assessment theory and method based on contributing weight model. It is revealed that areas of high, medium, and low risks are respectively 2.39%, 15.82%, and 81.79% of the entire research area.