Continental margins as a source of tsunami hazard: The 1977 Gioia Tauro (Italy) landslide-tsunami investigated through numerical modeling

Slides along continental margins represent a considerable source of hazard, especially when occurring in shallow water close to a densely populated coast. Among the known landslide-tsunamis affecting harbors or coastal infrastructures, the 1977 event that hit the harbor of Gioia Tauro (SE Tyrrhenian Sea, Italy) is one of the less studied. According to historical reports, 5 m waves hit the western dock, provoking relevant damages on port facilities. Post-event bathymetric surveys found a lack of mass of more than 5 million m3 at the head of the Gioia Tauro canyon, that starts just outside the harbor. After having considered two possible sliding bodies, the respective landslide motion and generated tsunami are calculated here through numerical in-house developed numerical codes, in order to assess their effects on the coast and validate the hypothesis of a landslide source for the 1977 event. Tsunami features inside the harbor basin are characterized as well, evidencing the importance of assessing the consequence of such small-scale events, not involving large areas but posing a relevant threat for coastal communities and infrastructures.