Definition of Rainfall Thresholds Triggering Landslides in Slovenia

In this paper the definition of rainfall thresholds for rainfall-induced landslides in Slovenia is presented. The thresholds have been calculated by collecting approximately 900 landslide data and the relative rainfall amounts, which have been collected from 41 rain gauges all over the country. The thresholds have been defined by the use of an existing procedure, developed for a test site with very different geological and climatic characteristics (Tuscany, central Italy). A single national threshold has been firstly defined, subsequently the country was divided into four zones, on the basis of major the river basins and a single threshold has been calculated for each of them. The effectiveness of the thresholds has been verified by the use of several statistical parameters and it resulted in quite good performances, even if with some uncertainties, probably due to the quality of the available data. Beside the setting of a threshold system, usable for civil protection purposes at national scale, an additional outcome of this work was the possibility of applying, with good results, a methodology defined for another region, therefore testing its degree of exportability in different settings.