Calibration of rainfall thresholds for landslide early warning purposes: Applying the EDuMaP method to the system deployed in Campania region (Italy)

The paper investigates the technical performance of a landslide early warning system operating, at regional scale, in Campania region (Italy). The system is managed by the regional civil protection, it covers an area of about 13.600 km(2) divided into eight warning zones, it sets the municipality as the minimum territorial unit for warning purposes and it employs four warning levels. Warnings are activated by rain gauge specific rainfall thresholds defined by means of statistical analyses on historical series of rainfalls. The system performance analysis is conducted applying the EDuMaP method which is based on the computation of a duration matrix reporting the time associated with the occurrence of landslide events in relation to warning events, in their respective classes. The dataset used to this purpose refers to landslides recorded within one warning zone from 2010 to 2013 and rainfall data from three rain gauges belonging to different municipalities. Moreover, the rainfall thresholds associated to one of these rain gauges are calibrated by maximizing the performance indicators derived from a set of duration matrices, each one associated to a warning scenario derived from the original one.