Abstract:

To improve the accuracy of the evaluation of the regional geological hazard in a large scale，this paper focuses on the question that what kind of spatial resolution can be used to raster-based data on these quantify factors that is more appropriate to the accurate evaluation process, and analyzes the factors which affect choosing spatial resolution. With slope unit as an object of study, it develops a suitable new method for accurate evaluation which a study area can be automatically divided in to units using geographical information system (GIS) and hydrological analysis tools. Large parts of the study area, which is in Huangling county, Shaanxi Province， are classified into 6 258 evaluation modules, with a model of geological hazard accuracy contribution scoring to measure the distribution of degreeprone for each evaluation unit. The effectiveness of the proposed method has been tested in a practical application to a geo-hazard susceptibility evaluation in Huangling County of Yan’an City. Evaluating results show that Huangling county is divided into five level according to different geological hazard accuracy region. High accuracy areas account for 9.94% and are mainly situated in vaueies of Luohe River, Juhe River and Koujia River, which are the important areas for prevention and treatment of geological disaster in the future.

Key words: susceptibility evaluation, grid size, geographic information systems, evaluation unit