Numerical Simulation of the BIG’95 Debris Flow and of the Generated Tsunami

Underwater mass movements along continental margins constitute a relevant threat for coastal communities. In the Mediterranean Sea this issue is particularly critical, both for the concentration of potential sources and for the density of population living along the coast. One of the biggest event recently mapped by submarine geophysical surveys, named BIG’95, is located in the Balearic Sea, between the homonymous islands and the Eastern coast of Spain: it occurred around 11 kyrs BP, involving a volume of around 26 km3 over an area of 2,200 km2, from 200 m depth down to 1,600 m and over: the looser fraction of the mass was driven along the Valencia Channel, NE-ward, more than 110 km far from the source area. The BIG’95 event is here simulated through numerical codes, adopting some reasonable simplifications on the slide morphology and dynamics. The tsunamigenic impulse is then evaluated and the propagation of the wave simulated over a computational domain covering the Western Mediterranean Sea. Results show that an event of these characteristics can generate catastrophic tsunami along the coasts of the Balearic Sea, reaching also North Africa, Corsica and Sardinia coasts with relevant waves.