LANDSLIDE SUSCEPTIBILITY EVALUATION AND MAPPING ALONG A RIVER VALLEY IN CHINA

Landslide susceptibility evaluation at regional scale is commonly performed based dominantly on the analysis of geological and geomorphological conditions of historical landslide cases. This analysis mainly involves identifying key casual factors, their critical groupings and relative importances. Our study demonstrates application of this concept to a 90 km long segment of Jinshajing River valley in China. Correlations of landslide occurrences with potential causative factors are derived from field investigations. Lithology, orientation of bedding planes, slope angle, stream action, rainfall, and earthquake intensity are recognized as identifiable/measurable causative factors to establish a factor domain. Grades of membership, to the susceptibility classes, for field values of quantitative factors are determined based on fuzzy sets theory, while those of descriptive factors are assigned from a fuzzy score table. The analytic hierarchy process (AHP) is adopted for assigning weights to individual factors. Subsequently, the evaluation procedure is implemented in a GIS software IDRISI, leading to identification and delineation of four classes of landslide susceptibility in the area. The proposed approach is consistent with the nature and availability of information for evaluating landslide susceptibility at regional scale, and provides an effective means of identifying risky areas and developing management strategies for land use.