Is there Predictive Power in Hydrological Catchment Information for Regional Landslide Hazard Assessment?

Regional landslide hazard assessment is often carried out by means of empirical meteorological thresholds, which reliability is sometimes limited by the lack of information about the hydrological processes which lead to landslide triggering in slopes. Hence, in this paper the inclusion of hydrological information at catchment scale in the definition of landslide triggering thresholds is applied to a catchment in the northern Apennines (Italy). In particular, an hydro-meteorological threshold based on event precipitation and catchment specific storage (H-S threshold) is proposed. The performance of the proposed threshold is compared with the one of the usually adopted precipitation Intensity-Duration (I-D) threshold. Although most of the landslide recorded in the observed period (2002-2013) were triggered by short and intense precipitation events with little influence of the slope conditions prior the precipitation, the H-Sthreshold performs slightly better than the I-D threshold.