Geohazard features of the Central-Southern Tyrrhenian seamounts

The Tyrrhenian Sea is the youngest back-arc basin in the Mediterranean. Its formation is related to the extension and crustal thinning which followed the subduction of the Ionian oceanic lithosphere beneath the Calabrian Arc. During Pliocene, production of oceanic crust is located in the Vavilov back-arc basin, where the homonymous Vavilov Volcano develops. Subsequently, the minimum stress direction changed to ESE and production of oceanic crust migrated eastwards forming the Marsili back-arc basin (1.9-1.7 Ma) and the Marsili Volcano (<0.73 Ma), originating the present day arc and back-arc configuration of the southern Tyrrhenian. In this context, the Palinuro volcanic complex also developed at ~350 ka BP. The large back-arc volcanoes occupy an axial position in the Vavilov and Marsili basins, and, in the case of Palinuro, at the margin between the continental and oceanic crusts. The development of the Tyrrhenian took place in a setting in which the lithosphere in subduction was rapidly sinking and characterized by fast rollback. Geohazards related to the Tyrrhenian seamounts have been investigated mainly in terms of the tsunamigenic potential of large landslides generated by the sector collapses of the volcano flanks and the associated seismic or volcanic trigger mechanisms (Gallotti et al., 2020, 2021; Tinti et al., 2018). Results show that tsunamis produced by landslides with substantial volumes (in the order of 2-7 Km 3 ) are realistic and could powerfully impact neighbouring coastal areas.