Geomechanical modelling of 1999 Cervinara debris avalanche propagation (Southern Italy)

Debris avalanches occur in triangular source areas where initial slides turn into avalanches through further failures and/or eventual soil entrainment. This paper deals with the numerical modeling of the propagation stage which provides information such as the propagation pattern of the mobilized material, its velocity, thickness and run-out distance. The “GeoFlow_SPH” depth-integrated model is used which allows: (i) adequately taking into account the irregular topography of real slopes which greatly affect the propagation stage and (ii) using a less time consuming model than fully 3D approaches. In this work the behavior of debris avalanches is analyzed with special emphasis on the apical angle, one of the main features of this type of landslide, in relation to soil rheology, hillslope geometry and features of triggering area. An important case study of Campania region (Italy) is analyzed related to pyroclastic soils coming from the eruptive products of Vesusius volcano. The achieved results outline the key role played by the erosion on the whole propagation stage of debris avalanches and well reproduce the in situ evidence. .