Application of a Geomorphologic-Heuristic Model to Estimate the Landslides Reactivation Likelihood in the Emilia-Romagna Region (Italy)

Abstract

In many Italian regions and, in particular, in Emilia Romagna (RER), most land-use policies are based on Landslide Inventory Maps and on the landslide’s observed state of activity, that has riskily poor forecast significance. In this work we tried to realize a geomorphologic-heuristic model aiming at estimating the dormant landslides reactivation likelihood. The model is only focused on the spatial forecast as no correlation with rainfalls or return period are considered. Based on the typical reactivation process, three different landslide issues have been considered: (1) the shallow landslide initiation susceptibility in the areas upwards the mapped landslides (starting from the results of another model we developed in 2006); (2) the “push and undrained loading” effect of active landslides on the dormant accumulations, evaluated through a GIS-based geometric analysis; (3) The presence of documented past reactivations in the RER’s Historical Landslide Database. Combining these different topics we obtained a new classification of those landslides mapped as dormant, that can be very useful to overcome the actual planning practice forecast weaknesses.