Modelling of the initiation of rainfall-induced debris flows in the Cardoso basin (Apuan Alps, Italy)

A case study is being carried out in relation to the event of June 19, 1996, when an intense rainstorm hit the Cardoso area in the Apuan Alps, Italy. The catastrophe triggered several gravitational movements, mainly characterized by soil slip-debris flows. A dataset coming from field and laboratory surveys allowed a complete parameterization of the event, and consequently the realization of a physically based dynamic model related to the initiation of the rainfall-induced landslides. The aim of the study is to analyze the processes involved in the light of the modelling results and to assess the spatio-temporal activity of the landslides, both in terms of location of the triggering sites and of determination of the critical rainfall conditions. The critical rainfall input thresholds, obtained with a deterministic approach, are then compared with the thresholds obtained by an empirical analysis of the main rainfall events occurred in the southern Apuan area in the period from 1975 to 2002.