Terrain-based mapping of landslide susceptibility using a geographical information system: a case study

This paper deals with the development of a technique for mapping landslide susceptibility using a geographical information system (GIS), with particular reference to landslides on natural terrain. The method has been applied to Lantau Island, the largest outlying island within the territory of Hong Kong. Landslide susceptibility in the study area is related to a number of terrain variables, viz., lithology, slope gradient, slope aspect, elevation, land cover, and distance to drainage line. Multiple correspondence analysis (MCA) was carried out to generate the principal axes that are linear combinations of these terrain variables using occurrence data of landslides and terrain variables. A GIS is used to project the values of the principal axes, and subsequently to relate these principal axes to landslide susceptibility by logistic regression modeling. The spatial landslide susceptibility response in the study area can then be obtained by applying this logistic regression model to the study area. The results from this study indicate that such a GIS-based model is useful and suitable for the scale adopted in this study.