A new approach for landslide modelling: applications to the 1783 Scilla event and to potential Marsili volcano collapses

In this study, we present a new 2D numerical model (UBO-Inter) capable to simulate the motion of a landslide down generic surfaces. The body is represented by N point masses that can be seen as the projection on the sliding surface of the center of mass of the elements the system is discretized into. The masses are strictly adherent to the surface and interact with each other by means of inner forces that involve pairs of point masses. The inner force pattern can be schematized by a mass grid where the grid nodes are the point masses and the pairs of interacting masses are connected through edges. The external forces acting on the point masses are: gravity, which is the driving force, the reaction force of the surface, basal friction and drag exerted by the environmental fluid. We test the UBO-Inter model on the 1783 Scilla tsunamigenic landslide, a historical case that serves as a benchmark due to the abundance of coeval data and recent observations on the onshore detachment niche, run-out distance and offshore deposits. Eventually, we investigate three scenarios of mass movements down the eastern flanks of the Marsili submarine volcano (located in the southern Tyrrhenian Sea). They are relevant because cover a broad range of slide volume, from small to huge, and different types of movements. We outline that this is the first time that slope instabilities of Marsili are given specific attention. Though in this thesis we do not address the tsunami generation and propagation problem, Marsili mass failures have the potential to be tsunamigenic and hence our study may be also seen as a significant contribution to tsunami hazard assessment in a broad area of the Tyrrhenian region.