Evaluation Of Geological Hazards Susceptibility In Northwestern Of Hengduan Mountain Area

With the intensification of global climate change and the increasing of human activities,the frequency and scale of geological disasters are increasing.As one of the countries most seriously affected by geological disasters,our country is greatly affected by geological disasters every year and suffers serious economic losses.Therefore,this paper makes use of the Arc GIS spatial analysis to analyze the spatial distribution characteristics of geological disasters in the northwestern Hengduan Mountain area,and divides it into three basins based on the disaster-generating environment to analyze the spatial distribution and the influencing factors of the potential property losses and the susceptibility of geological hazards based on the stochastic forest model,and constructs the prevention paradigm for geological disasters in the basin,and obtains the following conclusions:(1)The spatial distribution of geological hazards shows a tendency of decreasing the proportion of debris flow hazards and increasing the proportion of landslides and collapses with the increase of elevation and gradient of slope.The geologic hazards are mainly developed in undulating mountainous landform,mainly developed in cinnamon soil,gray cinnamon soil,black felt soil and other soil types,within 150 m from the road distance within 500 m from the river and in a zonal distribution state.(2)On the whole,the factors affecting the occurrence of geological disasters are almost the same.Firstly,the distribution of lithology and active faults are the preconditions for the occurrence of geological disasters.Secondly,the road density,vegetation coverage,density of residential areas,river density,precipitation and other factors provide the preconditions and triggering conditions for the occurrence of geological disasters.Most of the areas prone to geological disasters in each basin account for the largest proportion of medium and low areas prone to geological disasters,while high areas prone to geological disasters account for a smaller proportion but are distributed throughout the country.(3)The bodies of geological disasters are basically the same in all river basins,with the largest proportion of residential buildings,roads and other infrastructure,followed by grassland and woodland,and the smallest contribution of arable land to potential property losses.The main potential property losses in all river basins are 5 to50 million.The maximum potential loss range of Jinsha River basin and Nu jiang River basin is 50 to 100 million,mainly distributed in Gangtuo Town of Jiang da County,near Jiangda Town,Bianba Town,west of Caoka Town,south of Mawu Town,south of Exi Township of Luolong County,north of Zhongyi Town,south of Shuodu Town and southwest of Zituo Town.The maximum potential property losses range of Lancang River basin is 100 million,mainly in Chengguan Town of Karuo District.(4)By comprehensively considering the spatial distribution characteristics of geological disasters in each basin,the influencing factors of geological disasters,the evaluation results of geological disasters and the spatial distribution results of potential property losses in the northwest of Hengduan Mountain Area.A defense model featuring the prevention and control of the Jinsha River Basin,the flexible construction of the Lancang River Basin and the combination of prevention and resistance of the Nu Chiang River Basin shall be established.