Tsunamigenic Landslides In The Western Corinth Gulf: Numerical Scenarios

The western Corinth Gulf, central Greece, is characterized by steep slopes and large sediment river discharge, that are factors increasing the occurrence probability of underwater landslides. Thus the generation of tsunamis from submarine movements is expected to be frequent in this region, and this is confirmed in the historical tsunami catalogues, where reports of tsunamis related to landslides exist either triggered by earthquakes or by gravitational load. In this work we concentrate on the numerical simulation of submarine landslides and of the propagation of the ensuing tsunamis. We elaborate different scenarios basing on recent swath-bathymetry and seismic profiling surveys performed by the Hellenic Centre for Marine Research (HCMR). The most prominent potentially unstable bodies are found in three different regions: one is placed in the area off the city of Aigion, the second is located close to the Psathopyrgos fault, and the third occupies an elongated area off Eratini on the northern side of the gulf. All considered landslides are characterized by relatively small volumes (in the order ranging from 105-107 m3). For each scenario, the slide motion is simulated by means of a Lagrangian block model, implemented in the numerical code UBO-BLOCK1, developed by the Tsunami Research Team (TRT) of the University of Bologna, Italy. The tsunami generation and propagation modelling is carried out through the finiteelement code UBO-TSUFE, developed by the same research team, solving the Navier- Stokes equation in the shallow water approximation on a triangular-element mesh. We will show how landslide-induced sunamis propagate inside the western Corinth Gulf, the amplitude and period of the tsunami waves at some selected coastal points, and the spatial distribution of the extreme wave heights along the coast.