Mapping landslide susceptibility at national scale by spatial multi-criteria evaluation

The representation of terrain propensity to generate landslides, meaning the mapping of landslide susceptibility, represents a first step in the assessment of the risk induced by these geomorphological hazards. Results of the numerous studies differ according to the available input data, the applied methodology, the level of detail or the scale of analysis. The main goal of the present study is to provide a new landslide susceptibility map for the national territory of Romania. The application of the European Landslide Susceptibility (ELSUS) mapping methodology, based on the analytical hierarchy process (AHP), using more accurate and higher spatial resolution input data, led to the achievement of a landslide susceptibility map within individual climate-physiographic zones across the country. The landslide susceptibility is computed by combining the information regarding landslide frequency with a Spatial Multi-Criteria Evaluation (SMCE) model based on three predictors (slope angle, lithology and land cover). The continuous landslide susceptibility model was validated by receiver operating characteristic (ROC) analysis, which indicated a better performance in the plateau, hilly and plain areas (AUC = 0.750) compared to the mountain area. Also, an independent sample validation was performed for testing the consistency of the landslide susceptibility classes. The classified susceptibility map shows patterns that are in agreement with terrain reality.