GEO-HAZARDS RISK ASSESSMENT IN LOESS AREA: A CASE STUDY OF ROUYUAN TOWNSHIP IN HUACHI COUNTY,GANSU PROVINCE,CHINA

Loess plateau is one of the most serious geo-hazard areas in China. Frequent hazard brings large damage to the local human life and property and impedes the progress of county urbanization. In this paper, in the case of Rouyuan Township in Huachi County, Gansu Province, research findings that the best unite size of average relief is 65m65m in loess area in large scale, using the curve fitting and the mean change point method. The hazard assessment model of Rouyuan was established by the factors of history hazard intensity and potential hazard, including hazard surface density, formation lithology, the thickness of the loess, elevation, slope, aspect, relief, the distance to gully, NDVI,the distance to road, the distance to building, the weight of factors above were obtained by AHP. The vulnerability assessment was completed according to the difference between landcover after field survey and remote sensing interpretation. The risk assessment map was got from hazard assessment and vulnerability assessment by raster overlaying tool in ArcGIS. The study area was divided into high risk, middle risk, low risk, very low risk area, which covers 4.6%, 11.7%, 30.2%, 53.5% of total area, the result identifies with disaster and vulnerability of hazard-affected body, it can provide suitable suggestion to Rouyuan urbanization.