The BIG’95 Submarine Landslide–Generated Tsunami: A Numerical Simulation
EstadísticasView Usage Statistics
Full recordShow full item record
AuthorIglesias Cerdeira, Olaia; Lastras Membrive, Galderic; Canals Artigas, Miquel; Olabarrieta Lizaso, Maitane; González Rodríguez, Ernesto Mauricio; Aniel-Quiroga Zorrilla, Íñigo; Otero, Luis; Durán Gallego, Ruth; Amblàs Novellas, David; Casamor Bermúdez, José Luis; Tahchi, Elias; Tinti, Stefano; De Mol, Ben
Abstract: This article presents a reasonable present-day, sea-level highstand numerical simulation and scenario for a potential
tsunami generated by a landslide with the characteristics of the BIG’95 debris flow, which occurred on the Ebro
margin in the western Mediterranean Sea in prehistoric times (11,500 cal yr BP). The submarine landslide deposit
covers an area of 2200 km2 of the slope and base of slope (200–1800-m water depth), involving a volume of 26 km3.
A leapfrog finite difference model, COMCOT (Cornell multigrid coupled tsunami model), is used to simulate the
propagation of the debris-flow-generated tsunami and its associated impact on the nearby Balearic Islands and Iberian
coastlines. As a requisite of the model, reconstruction of the bathymetry before the landslide occurrence and seafloor
variation during landsliding have been developed based on the conceptual and numerical model of Lastras et al. (2005).
We have also taken into account all available multibeam bathymetry of the area and high-resolution seismic profiles
of the debris flow deposit. The results of the numerical simulation are displayed using plots of snapshots at consecutive
times, marigrams of synthetic stations, maximum amplitude plots, and spectral analyses. The obtained outputs show
that the nearest shoreline, the Iberian coast, would not be the first one hit by the tsunami. The eastward, outgoing
wave would arrive at Eivissa Island 18 min after the triggering of the slide and at Mallorca Island 9 min later, whereas
the westward-spreading wave would hit the Iberian Peninsula 54 min after the slide was triggered. This noticeable
delay in the arrival times at the peninsula is produced by the asymmetric bathymetry of the Catalano-Balearic Sea
and the shoaling effect due to the presence of the wide Ebro continental shelf, which in addition significantly amplifies
the tsunami wave (19 m). The wave amplitudes attain 8 m in Eivissa, and waves up to 3 m high would arrive to
Palma Bay. Resonance effects produced in the narrow Santa Ponc¸a Bay in Mallorca Island could produce waves up
to 9 m high. A similar event occurring today would have catastrophic consequences, especially in summer when human use of these tourist coasts increases significantly.