Post-failure analysis of the Maierato landslide using the material point method

The 15 February 2010 Maierato landslide has become the symbol of the hydrogeological instability of the Calabria region (Southern Italy). It occurred after a long period of rain in an area prone to landslides. Some videos filmed during the event documented the high velocity and the flow-like character of this landslide after the slope failure. Several studies focused on the pre-failure and failure stages of the Maierato landslide in order to interpret its failure mechanism and to establish the main factors of triggering. However, none of these studies analysed the post-failure stage of this landslide. In the present study, the Material Point Method (MPM) is used to simulate the run-out process of the Maierato landslide and provide a possible explanation of this process. Different scenarios are considered and for each of them the simulated post-failure configuration of the displaced material is compared to that detected after the event. Numerical results match fairly well the observed ones when a severe reduction in the shear strength of the involved soil is accounted for in the analysis. This strength reduction is attributed herein to the high excess pore water pressures generated by the large distortions of the moving soil mass. Moreover, the back-calculated post-failure strength is consistent with that found in several case histories of slope failures involving liquefied materials.