Landslides' susceptibility on large surfaces triggered by rain histories

A fast landslides' susceptibility evaluation capability has become, nowadays, an important issue when dealing with large land surfaces. Many disciplines such as the territorial planning, environmental impact and risk evaluation, have the need to address properly this specific field of interest. The usual approaches, based on slope stability analyses in plane-stress/strain, are practically unsuitable over an outsized land context. In the full paper the Authors shall outline a computational procedure which allows assessing the soil mass sensitivity to sliding, in relation to actions of rain histories. This is a combination of a hydrological and geotechnical simulation models, both kept as simple as possible in order to be used on a large scale. The procedure is implemented on a GIS platform and, provided the availability/distribution of the relevant geotechnical-hydrological parameters, a rather fast susceptibility analysis can be performed on the area of interest, thanks to a 3D tessellation of the total loose soils' volume into pixel units. Other issues had been relevant to pinpoint related aspects of this research, which is characterized by a particular interdisciplinary connotation. For instance, geophysical logging and interpretation of the soils' response to ambient noise had been found very effective, in order to recognize the local bedrock depth at many spots: this technique is very quick and affordable when applied on large surfaces, with respect to the usual boreholes. The computational procedure has been tested on two specific sites, set within the Ligurian Appennines in northern Italy, and the promising results obtained in these instances shall be briefly summarized in the full paper.