GNGTS 2017 - 36° Convegno Nazionale

modifications of the sea bottom due to the sliding motion; these are filtered through a transfer function depending on the depth, resulting into a time-dependent sea surface elevation. The code UBO-TSUFD, then, accounts for the wave propagation over the computational domain, solving the non-linear hydrodynamic equations in the shallow-water approximation, allowing to compute land inundation. The nested grid technique is also implemented, enabling one to zoom on area of special interest with higher-resolution computational grids (Tinti and Tonini, 2013). In this work some improvements of the previous investigation reported in Zaniboni et al. (2016) are presented. First of all, an alternative hypothesis for the landslide is explored, considering the observed morphological continuation of the scar also in the underwater portion of the Mt. Pacì. Therefore, a subaerial-submarine initial sliding body is assumed as an alternative to the purely subaerial one, and the peculiar features of the respective generated tsunamis are evaluated. Comparison with observations are used to get hints on which option turns out to be more plausible. Second, the tsunami computational domain is extended to cover a wider area of the Calabrian coast, and Sicily from Capo Peloro to Messina in the attempt to reproduce the reported effects not only in the source region but also at some distance from it. The numerical simulation of the tsunami provides also significant clues on the energy propagation pattern. Since the tsunami wave propagation is mainly driven by the sea depth, we can expect that the computed features of the energy pattern depend more on the geographical position of the landslide than by its dynamics. Therefore, exploring numerical scenarios of the Scilla tsunami provides very precious indications of the coastal stretches that are most exposed to a tsunami attack, and this can be used by authorities to set up the most suitable countermeasures to minimize consequences to people and coastal facilities. References Bosman A., Bozzano F., Chiocci F.L., Mazzanti P.; 2006: The 1783 Scilla tsunami: evidences of a submarine landslide as a possible (con?)cause. Geophys Res Abstr 8:10558. Graziani L., Maramai A., Tinti S.; 2006: A revision of the 1783–1784 Calabrian (southern Italy) tsunamis. Nat Hazards Earth Syst Sci 6:1053–1060. Guidoboni E., Ferrari G., Mariotti D., Comastri A., Tarabusi G., Valensise G.; 2007: CFTI4Med, Catalogue of strong earthquakes in Italy (461 B.C.-1997) and Mediterranean area (760 B.C.-1500). INGV-SGA. http://storing.ingv. it/cfti4med/ Jacques E., Monaco C., Tapponnier P., Tortorici L., Winter T.; 2001:, Faulting and earthquake triggering during the 1783 Calabria seismic sequence. Geophysical Journal International, Volume 147, Issue 3, Pages 499–516, https:// doi.org/10.1046/j.0956-540x.2001.01518.x. Mazzanti P., Bozzano F.; 2011: Revisiting the February 6th 1783 Scilla (Calabria, Italy) landslide and tsunami by numerical simulation. Mar Geophys Res 32:273–286. doi:10.1007/s11001-011-9117-1. Rovida A., Camassi R., Gasperini P., Stucchi M. (eds); 2011: CPTI11, the 2011 version of the parametric catalogue of Italian earthquakes. Istituto Nazionale di Geofisica e Vulcanologia, Milano, http://doi.org/10.6092/INGV.IT- CPTI11. Tinti S., Tonini R.; 2013: The UBO-TSUFD tsunami inundation model: validation and application to a tsunami case study focused on the city of Catania, Italy, Nat Hazards Earth Syst Sci, 13, 1795–1816, www.nat-hazards-earth- syst-sci.net/13/1795/2013/. doi: 10.5194/nhess-13-1795-2013. Tinti S., Bortolucci E., Vannini C.; 1997: A block-based theoretical model suited to gravitational sliding. Nat Hazards 16:1–28. Zaniboni F., Armigliato A., Tinti S.; 2016: A numerical investigation of the 1783 landslide-induced catastrophic tsunami in Scilla, Italy. Nat Hazards (2016) 84:S455–S470. doi: 10.1007/s11069-016-2461-3. 270 GNGTS 2017 S essione 2.1