Structural framework of Stromboli Volcano, lateral collapses and the dyke system

We describe the geological-structural framework of the Stromboli volcano, focusing on lateral collapses and sheet intrusions, by synthesizing the most relevant results obtained from field investigations coupled with numerical modelling. The Stromboli evolution was characterized by building phases, with extrusive products and sheet intrusion, alternating with destructive events, represented by Late Pleistocene summit caldera collapses and Holocene nested flank and sector collapses towards the n-w. The intrusive pattern is characterized by both a main n-e-trending weakness zone crossing the island, and a horseshoe-shaped arrangement of sheets on the n-w flank, resulting from the interaction between regional tectonics, a stationary magma level and morphostructural changes associated to lateral collapses. Flank stability analyses and stress-strain numerical modelling explored the critical conditions necessary to generate large instability and failure of the edifice, by simulating the building and collapse history of the volcano, and evaluating the role of dynamic perturbations and magma pressure in the feeding system.