CASE STUDY OF VULNERABILITY EVALUATION FOR GEO-HAZARDS BEARING CAPACITY OF A REGION

Geological hazards lead to great threatens in China. The vulnerability of geo-hazards bearing capacity directly determines the severe of geological disasters. Its corresponding quantitative assessment of vulnerability is very importance. This paper presents the index system of the vulnerability for geo-hazards bearing capacity. The system includes four indexes and nineteen sub-indexes. The four indexes are life index, material index, ecological environment index and social economy index. A case study is performed in Qingchuan County, China. The township units and administrative village units are used as the basic unit in GIS. Both TOPSIS model and Weighted Sum model are adopted to evaluate the vulnerability of geo-hazards bearing capacity in this area. Five vulnerability levels are classified and include high vulnerability level, relatively high vulnerability level, moderate vulnerability level, relatively low vulnerability level, and low vulnerability level. Comparative study of these two models indicates that the results derived from the two models are consistent as a whole. 73 percent of the area has the same vulnerability level. The rest 27 percent area differs with a gap of one vulnerability level. In the areas of high, low vulnerability levels derived by the two models are quite consistent with each other. The agreements between two models in relatively high and medium level are 86% and 73%respectively, while in relatively low vulnerability level was slightly worse(54%). An evaluated comparison of township unit and administrative village unit presents the good consistency at the whole. Approximately above half level of vulnerability of two units are exact the same or general same. The evaluation results of administrative villages are apparently more accurate. The reason is that there are obvious differences among various administrative villages in their index values, while the township standard eliminates the differences among administrative villages.