Assessment of shallow landslide hazard by using a physically-based model of hyllslope stability.

A model for the simulation of shallow landsliding triggered by heavy rainstorms is analysed and discussed here. The model, which focuses on the topographic influence on shallow landsliding, is composed of two parts: a steady-state model for shallow sub-surface runoff and an infinite-slope Coulomb failure model. The model is applied in two mountainous catchments in the Dolomites: the Cordon catchment (5 km2) and the Vauz catchment (1.9 km2), where field surveys provided a description of hydraulic and geotechnical properties of soils and an inventory of landslide scars is available. The comparison of the landslides observed in the study basins with model predictions shows that the distribution of critical rainfall obtained from the model provides a surrogate for failure initiation probability as a function of topographic location.