Replay of the 1987 Val Pola Landslide, Italian Alps

The 1987 Val Pola Landslide was the most destructive and costly natural disaster that occurred in Italy during the last two decades. The disaster response and monitoring system, along with related construction activities for this single landslide event amounts to nearly half of the annual landslide prevention budget in Italy. It is also one of the few cases of landslide study for which a large amount of quantitative data have been gathered. The Val Pola landslide thus provides an invaluable benchmark for geotechnical modelling and model calibrations due to its fully three-dimensional features and significant multi-directional impact in space. In this paper, the entire runout process including the reactivation of the landslide has been numerically replayed using a (quasi) three-dimensional finite element method in the Lagrangian reference frame, based on Voellmy rheology and high-precision basal topography available in a GIS database. Comparison between the results of the present analysis and the available field observations is remarkable, demonstrating the capability of the present methodology in tackling large-scale landslides of complex nature. The technique is thus of value in land use zoning and the study of geomorphologic features. It also provides a powerful and handy tool in studying possible scenarios of future landform processes.