| China is one of the most serious country influenced by geo-hazards in the world, losses caused by geological disasters reached several billions every year, and caused serious impact to the people in the stricken region. Therefore, it is necessary to proceeding hazard assessment, in order to provide scientific basis and reference for disaster prevention.Taking Bailongjiang River Basin of Gansu segment as the study area in this paper, according to the1:50000field details of geo-hazards investigation and basic geological data information from Gansu Province Department of Land Resources, the influence factors including landform, geological structure, human activity, climate and hydraulic in the study area are counted and analyzed,9evaluation indexes such as slope, elevation, lithology, fault, earthquake, road, landuse types, river and annual rainfall have been chosen, and made sure the evaluation factors’weight by combing the methods of information and AHP, and finally the geo-hazards assessment has been implemented in study area by the function of superposition, raster calculation and reclassification of GIS technology. The following conclusions can be reached:(1) Landslides, debris flows and collapses are the mainly geological disasters in the study area and most of them are middle and large scale types geological disasters. And the geo-hazards are mainly distributed along with main stream of Bailongjiang River and its branches Baishui River, Min River and Gongba River et al, and also along with roads such as state road212et al, where the density of population and human activity are the most.(2) Geological hazards occurred in the study area is the result of interaction of many factors, and especially for the human activity influence on the occurrence of geological disasters is the largest in the study area.(3) The zoning result indicated that extremely low, low, moderate, large, and extremely large dangerous zones’acreage is3683.07km2,7280.75km2,6822.72km2,3823.76km2, and1936.06km2, account for15.64%,30.92%,28.98%,16.24%,8.22% of the total area of the study area, occurred5,73,542,752,1260geo-hazards and the geo-hazards density is0.14/102km2,1/102km2,7.94/102km2,19.67/102km2,65.08/102km2, respectively. The geo-hazards quantity and density are increasing with the dangerous level; the validation results showed satisfactory agreement between the hazard map and the existing geo-hazards’distribution. |
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