A Double Benioff Zone in the Tyrrhenian-Ionian subduction?
De Gori P., Amato A., Chiarabba C.
IV - Geofisica e fisica dell'ambiente
Aula 32C-1 - Giovedì 20 h 16:30 - 19:00
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We investigate the seismicity in the southern Tyrrhenian subduction zone, where the Ionian oceanic lithosphere is slowly subducting beneath the Calabrian arc. We use high-precision three-dimensional earthquake locations in order to verify the existence of a double Benioff zone (DBZ). Studies revealing the presence of a DBZ have been focused on the main subduction zones of the world, mainly located around the Pacific plate, where the boundary plate dimensions and the rates of subduction are larger than those observed in the Ionian slab, while the age of the subducting lithosphere is on average younger. The double plane of seismicity has been explained as due to dehydration processes and related fluid flow that occur at upper mantle depths in the descending plate. The presence of a DBZ in the Tyrrhenian slab could demonstrate that the DSZ is a general feature of all the subduction zones, independently of both the plate age and the internal deformation processes occurring within the slabs.