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Abstract

The Marsili Seamount (MS) is a 70 x 20 km extended, NNW-SSE elongated volcanic complex rising 3200 m from the seafloor of the Southern Tyrrhenian Sea (Italy) and with the top at ca. 500 m b.s.l.. MS represents the inflated spreading ridge of the 2 Ma old Marsili back-arc basin (BAB) formed in the last 1 Ma on a 10 to 12 km thick oceanic crust and associated to the Ionian Sea subduction below the Calabrian Arc. MS last erupted 2-3 ka BP, and it is now characterized by shallow seismicity and hydrothermal activity. In a previous study of a 25 x 25 m Digital Bathymetric Model (DBM) of MS, some authors have identified signs of seafloor failures and coexisting central-type and fissural volcanoes with prevailing passive magma ascent mechanisms mainly controlled by tectonics. Here we present a morphometric and morphological analysis of a high resolution (5 m x 5 m) DBM of the Marsili seamount in order to: (a) identify its detailed morphological and geological features and (b) better understand how volcanoes, overlapping and/or segmented spreading centres, and faults interact and control the growth and evolution of BAB ridges. Our results emphasize the importance of high-resolution bathymetry data in deciphering the geodynamic evolution of BAB. The results may also help to individuate sites of hydrothermalism and identify areas where landslides or flank/sector collapses occurred in the past and, eventually, could develop in the future.