Seafloor characterisation of the offshore sector around Scoglio d’Affrica islet (Tuscan Archipelago, northern Tyrrhenian sea)

We present a very high-resolution bathy-morphological map of the offshore sector around the Scoglio d’Affrica islet (northern Tyrrhenian Sea, Italy). The study area covers a sector of 45 km2, between 3 and 85 m depth. Its central part, i.e. the apex of the Ridge, is characterised by a flat or gently sloping seafloor, where three mud volcanoes, and 250 pockmarks are recognised. Differently, the western and eastern Ridge flanks are steeper and characterised by 60 quasi-rectilinear escarpments and small ridges, more than 20 morphological highs, and elongated channels occasionally floored by bedforms. The seafloor shallower than 40 m is covered by Posidonia oceanica, forming compact and continuous or fragmented meadows intermingled with sandy patches. The main map represents the bathy-morphological setting of the area, which is largely affected by fluid seepage, providing insights for habitat mapping and preliminary marine geohazard assessment due to the violent gas outburst from mud volcanoes.</p

Geohazard features of the north-western Sicily and Pantelleria

We present maps of geohazard features identified across north-western Sicily and Pantelleria in the framework of the Magic project (MArine Geohazard along Italian Coasts), which involved Italian marine geological researchers in 2007-2013. These seafloor features were recognized using high-resolution bathymetry data and rely on the morphological expression of the seafloor and shallow sub-surface processes. The north-western Sicily is a complex continental margin, affected by morphodynamic, depositional, and tectonic processes. The Egadi offshore is controlled by fault escarpments and alternating retreating and progradational processes. Ustica and Pantelleria submerged edifices show the effect of volcanic activity. The Ustica seafloor is interested in volcanic, tectonic, and gravitational instability processes, while the Pantelleria offshore underwent erosive-depositional processes and the effect of bottom currents. Two levels of interpretation are represented: the physiographic domain at a scale of 1:250.000 and the morphological units and morpho-bathymetric elements at a 1:100.000 scale.</p