Geomechanical models for shallow rainfall-induced landslides at the catchment scale built in feedback-loop from geological-geomorphological investigation

The 1997 winter season recorded prolonged and intense rainfalls all over the Campania region in Italy. As a result, a large number of extremely rapid debris-earth flow-like landslides were triggered. These phenomena occurred in the late Quaternary volcanoclastic deposits, mantling the carbonate slopes of Campania region. The Sorrento Peninsula- Lattari Mts. was the most affected area by this catastrophic event: some hundreds of shallow mass movements took place during January 1997. These phenomena have been studied and monitored for several years since then, and many models have been proposed to explain the mechanisms of slope failures. Several field cam- paigns and investigations have been conducted in order to gain information about the strati- graphical setting of the areas affected by the slope instabilities and laboratory tests have been performed in order to characterize the hydro-mechanical behavior of the soils involved in the landslides. The aim of this work is to build reliable physically-based numerical models for a number of landslides events recognized from the past geological surveys. These models were built and validated against well characterized slope failures and, therefore, used to investigate the geo- metrical factors making the slopes more prone to failure. Potential geo-physical methods to characterize the slope geometry and their practical implementations are finally discussed.