Maps of Empirical Rainfall Threshold for shallow landslide initiation based on multivariate geostatistical tools

An Empirical Rainfall Threshold for shallow landslide initiation represents a boundary curve between rainfall duration D and cumulated E pairs that can be responsible or not for triggering shallow landslides. Since the 1980s, both deterministic and probabilistic methods have been employed to reduce the ERT’s large uncertainties due to their dependence on both hydrological and geomorphological variables. In this research, such an attempt has been accomplished by (1) to drawing maps of E and D constrained by the territorial parameters and (2) deriving lower and upper value maps of E and D threshold values based on the Multi-Collocated Co-kriging. This method has been applied to the Adriatic portion of the Abruzzo Region (Italy), where 62 shallow landslides have been collected. The reliability of E and D maps have been accounted for: it definitively depends on the number of the shallow landslide collected.