Numerical modelling of Plio-Quaternary slope evolution based on geological constraints: a case study from the Caramanico Valley (Central Apennines, Italy).

Evidence of deep-seated gravitational slope deformations (DSGSD) and of large prehistoric landslides is fairly widespread within the Central Apennines (Italy). These gravityinduced processes accompanied the intense Plio-Quaternary uplift phases that affected the mountain chain. In this study a multidisciplinary approach has been adopted in order to better constrain the relationship between the tectonic evolution and the gravitational morphogenesis of a typical Apennine morphostructure, such as the Caramanico Valley. For this purpose a conceptual model of the morphostructural evolution of the area has been reconstructed, on the basis of geological constraints derived by the integration of detailed geological-structural and geomorphological surveys with available literature data. Based on this evolutionary model, a multistage numerical modelling using the finite difference method code FLAC 6.0 has been performed in order to: (i) evaluate the effect of the uplift-related morphological changes of the valley-slope system; and (ii) assess the role of the horizontal/vertical stress ratio variations due to geodynamic regime shifts. The results of the numerical model show a good fit with the actual geomorphical evidence and also confirm the presence during some evolutionary stages of stress-strain conditions compatible with those necessary to produce the massive rock slope failures testified by the presence of large palaeo-landslide deposits.