An approach to explore the tsunamigenic potential of flank collapses of Tyrrhenian seamounts, Italy

Abstract:

The about 60 seamounts of the Tyrrhenian Sea Basin (Italy) exhibit peculiar geomorphological features reflecting the widespread occurrence of gravity instability processes ranging from seafloor sliding to partial collapses. Gravity instability may be related to volcanism, earthquakes, deep hydrothermal alteration, and oversteepening. Therefore, submarine volcanic edifices may be affected by periodic mass movements able to generate tsunami waves whose height is generally an increasing function of the volume of the dislocated mass and a decreasing function of the depth at which the failures occur. Here, we analyze the tsunamigenic potential of the main Tyrrhenian Sea seamounts elevating up to 3000 m from the seafloor and present a series of numerical scenarios of flank collapses on the Vavilov, Marsili, and Palinuro volcanic complexes. Our results clearly show the need for a systematic assessment of the hazard related to landslide-triggered tsunamis for the peri-Tyrrhenian coasts. At present, the available data do not allow us to perform a robust analysis of the slope stability for all the Tyrrhenian seamounts, which requires a better-focused research. However, our results show the potential hazard related to possible, future sliding episodes and associated tsunami.