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

摘要

The geological evolution of the Ischia volcanic complex has been reconstructed based on recentlyrnacquired submarine seismic reflection data. Implications on submarine slope stability both in northern andrnwestern submerged flanks of the island, characterized by thick submarine slide deposits and in southern flank ofrnthe island, characterized by active erosion of the coastal systems due to submarine canyons, will be discussed.rnThe classification of volcanic landforms has been recently improved taking into account the complexity in therngeneration of volcanic structures and their control factors, such as the magmatic systems, the styles of eruptionrnand erupted materials. The Ischia offshore is characterized by alkali-potassic volcanic rocks (trachytes, latites,rnalkali-basalts) and pertains to a volcanic complex emplaced during the last 55 ky. Four main phases have beenrndistinguished in the eruptive activity of the Ischia volcanic complex from 150 ky B.P. and 1302A.D. The geologicrninterpretation of marine DEM and Sparker data has allowed the identification of important submarine instabilityrnprocesses, both catastrophic (debris avalanches) and continuous (creep and accelerated erosion along canyons).rnThe present paper has been prepared in the frame of the scientific activities of the TESSA-OTTIMA researchrnproject, dealing with the operational oceanography of Southern Italy.