Influence of geological, morphological and climatic factors in the initiation of shallow landslides in North Western Italy

Landslides are recurrent geomorphic processes in Italy and represent a serious economic and societal problem. Historical catalogues report thousands of landslide casualties since the 9th Century. The importance to predict landslide occurrence is particularly evident to prevent the effects of rapid mass movements. The mitigation of landslide-related risk needs the improvement of prediction skills, obtained with a better understanding of triggering mechanisms, which are peculiar of the specific geological and environmental settings. The prominent role of rainfall in mass movement activations is widely recognised in the scientific community and several authors all over the world have long attempted to define the critical values responsible for landslide initiation. In Italy, the National Department for Civil Protection (DPC) is funding a CNR-IRPI (National Research Council-Research Institute for Hydro-geological Protection) research, aiming at the definition of regional rainfall thresholds for shallow landslides for the entire national territory. In this study, we investigated the role of geological, morphological and climatic factors on the initiation of rainfall-induced slope failures in the Piedmont, the Aosta Valley and the Lombardy regions (NW Italy).