Evaluation Of Geological Disaster Liability Partition

In recent years, with the implementing of the Western Development Strategy, people’s activities become more and more active, which has substantially influence on the geological environment of the Weihe River Basin, where the natural disasters happen frequently, such as landslide, collapse, debris flow. Taking the upper reaches of Weihe River as an example, the paper herein establishes a spatial database of geological disasters by the Geographic Information Platform and obtains the controlling factors, triggering factors and human activities influencing the disasters’ types and characteristics using the spatial database, the accessible information of geology and disaster points, and the MapGIS and ArcGIS Software. Based on the Analytic Hierarchy Process(AHP) and the Information Computation method, the paper herein puts forward with a weighted information method to analyze the geological disaster of the upper reaches of Weihe River. The works are as the following:(1)The tectonic map, terrain unit map and the water system diagram of the upper reaches of Weihe River are obtained through the geographic information system platform and the basic geological information. Besides the spatial database of geological disasters is established according the maps above and the corresponding geological disaster data.(2)Statistical data of the geological disasters on the upper reaches of Weihe River show that there are 2457 disaster points in all in this area. And there are 1501 landslides, taking account of 61%; 234 collapse disasters, making up 9%, and 717 debris flow, making up 29%. There are little ground fissure in this area.(3)The factors influencing the types and distribution of geological disasters are including controlling factors and natural factors. Controlling factors includes stratigraphic lithology, topography and river development and so on. Natural factors include average annual rainfall and plant coverage. Acting as internal and external factors relatively, the controlling factors and natural factors influence the distribution and development of geological disasters.(4) The geological disaster liability partition map is obtained using the combined AHP and the Information Computation method. The evaluation factors include slope angle, slope type, stratigraphic lithology, river distribution, annual rainfall, plant coverage and the distance from residents. The area of low liability of disasters is 10042km~2, making up 27% of the total area. The middle disaster prone area in 15791km~2, making up of 41%. And the high disaster prone area is 12,339km~2, making up of 32%.