Earthquake-induced landslides in Italy: from the distribution of effects to the hazard mapping

Abstract

Earthquake-induced landslides should be viewed, in the perspective of natural risk, like “domino effects” since they represent hazardous phenomena induced by independent triggering events. In this sense, the probability of an earthquake-induced landslide occurrence is lower with respect to that related to the earthquake itself. However, at the same time, the induced damage become much more intense thus increasing the related risk. Italy takes advantage from one of the most ancient and complete historical databases of earthquake-induced ground effects that was collected recently in the CEDIT (Italian Catalogue of Earthquake-inDuced ground failures in ITaly) catalogue (an open access database available at the http://www.ceri.uniroma1.it/cn/gis.jsp website). The last updating of the catalogue was performed on 2017 after the seismic sequence in the Central Apennines that started with the 24/08/2016 Mw 6.0 Amatrice earthquake, culminated with the 30/10/2016 Mw 6.5 Norcia earthquake and included the 18/01/2017 Mw 5.5 Capitignano earthquake. The maximun expected distances for the earthquake-induced effects of this seismic sequence are in very goodagreement with the CEDIT-derived curves of maximum distance vs. magnitude, so demonstrating the reliability of the Italian inventory to constrain areas potentially involved in earthquake-induced effects. The inventoried data prove that almost 56% of the earthquake-induced ground effects are due to landslides. The space-time distribution of earthquake-induced landslides in the Italian territory solicited new solutions for mapping the related hazard at a Municipality scale to depict scenarios of earthquake-induced ground effect also in the frame of seismic micro-zonation studies. In this way, a virtuous scientific path can be followed starting from evidences of the Past, collecting them for constrain studies in the Present and applying technical methodologies to the establishment of a prevention strategy for the Future ranging from land-use management to natural risk mitigation.