Study on the risk assessment of geological disasters in alpine valley area: A case study in Aba County, Sichuan Province

The geological hazard assessment was carried out by the evaluation train thought the study area of multiple disaster species coupling , which has a complete range of disasters such as collapse, landslide and debris flow. The evaluate unit of collapse, landslide and other slopes are grids and the debris flow disasters evaluate units are watershed, Based on the information model and analytic hierarchy process, the risk assessment is carried out respectively, then, the comprehensive geological disaster risk evaluation results of the study area were obtained by taking the method of large value. In the study area, the area of extremely high and high risk area of comprehensive geological disaster is obviously larger than that of the evaluation results of single hazard. The extremely high and high risk area is mainly located in the cataclastic rock area with relatively developed collapse and landslide and extremely prone debris flow basin. In view of the risk assessment of geological disasters in high mountains and valleys, the idea of dividing first and combining later can more reasonably reflect the morphological and spatial differences of different disaster types in the process of risk assessment, and obtain more accurate risk assessment results.