Spatial databases and GIS as tools for regional landslide susceptibility modeling

摘要

Summary. This study presents a regional landslide susceptibility model for the Federal State of Lower Saxony in the NW part of Central Europe. On the basis of a landslide database and a Geographical Information System (GIS), a modified information value approach is developed, which uses bivariate statistics to predict the spatial distribution and probability of mass movements. The input data of the susceptibility model include a spatial inventory of about 900 landslides and different data sets of geomorphometry, lithology and land use. A regional perspective puts specific requirements on the modeling, which is considered by a reformulation of the weighting function. The model estimates that about 2% of the Lower Saxon territory shows a predisposition to landslides. Most part of this land is concentrated on three key areas in the Lower Saxon Uplands. The spatial pattern of landslide susceptibility is directly correlated with the regional relief configuration and is characterized by specific clusters. In addition to slope gradient between 21° and 49°, Mesozoic sedimentary rock, especially sequences of lime- and claystone, are identified to be the most relevant predisposing factors. Like lithology, land use can be of stabilizing or destabilizing influence, but its significance, however, is less important. A special focus is on the identification of potential infrastructure exposure to landslides. This assessment reveals that in the Lower Saxon Uplands about 1% of the urban area and up to 4% of the road network is located in zones of significant hazard. Although the model is proven to be of good predictive power and high spatial accuracy, the study clarifies that susceptibility modeling often faces methodological shortcomings and a lack of plausibility. Some of these problems are discussed in this paper in detail.