The Study On Geographical Hazard Evaluation Of Baota District In Yan'an City

Loess Plateau is one of places where the geological hazard is serious in our country. It is influence on ecological environment and developing society that loess landslide brings. On the basis of results and experience of pioneers, combination of geographical hazards in the study area of the field survey data, with the foundation of topographic information of 1:50000 DEM, and evaluation unit is slope, the core of geographical hazards (hazard evaluation) is researched by using Information value method and Fuzzy comprehensive evaluation. Evaluation results in accord with the actual situation.The main researches are following:(1) Geographical hazards of the study area were evaluated respectively with Information value method and Fuzzy comprehensive evaluation, we have divided the evaluation results into high-hazardous areas, middling-hazardous areas, low-hazardous areas and non-hazardous areas. The hazardous zoning plans have b een obtained by two methods are closer. High-hazardous areas are mainly located in the central part of Baota District and the northern region, non-hazardous areas concentrated in the southern Baota District Fen River Basin. This nonlinear theory in practice have been applied successfully.(2) With the natural geological environment of Baota District, the technical route, methods and working flow of local geographical hazard evaluation are formed, the steps is data acquisition→data analysis→building index system→decomposing computation units→evaluation analysis→determination of result.(3) The extraction of evaluation index and the division of slope unit have been implemented based on DEM data. We have choosed disaster points density, slope gradient, slope height, slope aspect, slope shape, vegetation and human engineering activities, which seven geological hazard factors as evaluation indexs. Study area has been divided into 893 slopes units.(4) In the studying, it is fully applying the spatial analysis of GIS. It summarizes the method of making use of the function of spatial overlay analysis of grid data to evaluate the geological hazard.