Volcanic islands: the tip of large submerged volcanoes that only marine geology may reveal (examples from WPontine Archipelago, Ischia, Stromboli and Pantelleria).

Submarine portions of volcanic islands are several times (up to an order of magnitude) larger than subaerial ones but very poorly known. Their knowledge about them is essential for the reconstruction of eruptive history and volcano-tectonic evolution,which are more difficult to be fully witnessed on-land. The offshore investigation of a number of Italian volcanic islands led to the identification of key outcomes, such as the widespread occurrence of mass-wasting features ranging across different scalesand occurrence frequency. Large-scale features (i.e. debris avalanche deposits) occur vboth at Stromboli and Ischia islands, whereas morphologies and deposits related tominor slides and density flows (e.g. debris flows, grain flows, and turbidity flows) are very common in all the study areas. Moreover, several primary volcanic features have been identified, such as volcanic cones, eruptive fissures and lava fields. The resultshighlight the complex evolution of volcanic edifices, through the alternation of constructive phases, due to magma emission, and destructive processes, with mass wasting at different scales, including flank collapse. Thus, the achieved scientific results also provide a relevant contribution to the instability hazard assessment.