Geological evolution of the Ischia volcanic complex (Naples Bay, Tyrrhenian sea) based on submarine seismic reflection profiles

The geological evolution of the Ischia volcanic complex has been reconstructed based on recently acquired submarine seismic reflection data. Implications on submarine slope stability both in northern and western submerged flanks of the island, characterized by thick submarine slide deposits and in southern flank of the island, characterized by active erosion of the coastal systems due to submarine canyons, will be discussed. The classification of volcanic landforms has been recently improved taking into account the complexity in the generation of volcanic structures and their control factors, such as the magmatic systems, the styles of eruption and erupted materials. The Ischia offshore is characterized by alkali-potassic volcanic rocks (trachytes, latites, alkali-basalts) and pertains to a volcanic complex emplaced during the last 55 ky. Four main phases have been distinguished in the eruptive activity of the Ischia volcanic complex from 150 ky B.P. and 1302 A.D. The geologic interpretation of marine DEM and Sparker data has allowed the identification of important submarine instability processes, both catastrophic (debris avalanches) and continuous (creep and accelerated erosion along canyons).