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As a natural disaster prone to occur in mountainous areas, geological hazards cause serious economic losses to China every year. In order to reveal the factors influencing of geological hazards susceptibility in typical mountain valley, this paper takes Changdu City as the study area.Firstly, we analyze the spatial distribution of geological hazards, and then divides it into three major watersheds based on the differences of disaster-inducing environments in the study area, selects 10 indicators such as elevation, slope and terrain relief to build a evaluation index system of geological hazard susceptibility , and the weights of index determined based on the Random Forest. The spatial distribution of geological hazards in each watershed of Changdu City is obtained by overlaying with GIS, and it is found that: (1) The types of geological hazards in Changdu City are mainly small disasters, while the distribution of large disasters is relatively small but the hazards are huge and the danger level is high. (2) In general, the factors influencing geological hazards are more or less the same in each basin, but there are still some differences, with the factor of medium altitude and road being more prominent in the Jinsha River basin, the factor of density of settlements being more prominent in the Lancang River basin, and the factor of road being more prominent in the Nujiang River basin.(3) The Jinsha River basin has the largest area of low susceptibility, and the Lancang and Nujiang River basins have the largest area of medium susceptibility; all three basins have the smallest area of high susceptibility, but they are distributed in the whole basin, and mainly in areas with strong human activities and soft lithology.

The high mountain and gorge area is an typically area, where geological disasters happen frequently. Especially landslide is one of the most serious geological disasters. Recently relative researches on geological disasters showed that landslides had an increasing trends due to the impacts of both climate change and human activities. In this study, Jiangda County in Tibet Autonomous region was selected as our study area, which located in the high mountain and gorge area of the Hengduan Mountain Region. In addition, using the landslide data for 85 sites based on field survey, choosing Slope, River density, Geomorphic type, Precipitation, the distance from the fault, Road density, the ground motion peak acceleration and Lithology as 8 influencing factors on landslide, and then employing the Geodetector model to analyze the impact of various variables on landslide stability. The results showed that 1) according to the volume of landslide, medium and small landslides are main types in Jiangda County; According to its stability, more than 50% of the landslide is in a stable state; according to the danger level, they are mainly divided into Ⅲ, Ⅳ. In space, it is mainly along rivers and roads in Jiangda County, which caused by the limitations of the field survey besides physical factors. Because all 85 landslide survey sites located near rivers, and more than 71% sites are distributed on both sides of the road. 2) The geomorphic type, River density, Road density and the distance from the fault are major factors to affect the stability of the landslide in Jiangda County, its contribution rate are 0.501, 0.477, 0.465 and 0.332, respectively. When the influence factors interact in pairs, the explanatory power of factors is always greater than that of a single factor to the stability of landslides. In other words, when the two influencing factors interact, they always promote the instability of landslides.