Revisiting the last major eruptions at stromboli volcano: Inferences on the role of volatiles during magma storage and decompression

We have revisited the available data on the last two major eruptions at Stromboli volcano and concentrated our analysis on the 2007 eruption. First, we further analysed petrological-geochemical data to assess equilibrium conditions by using standard thermobarometry; then we used a grid of selected reactions which involve solid-melt-fluid equilibria to better constrain the P-T regimes that adequately describe our system. Pure extensional regimes and recent geophysical data suggest the existence of a prolate ellipsoidal magma chamber below Stromboli. To constrain its volume we estimated the magma volumes associated with SO2 degassing (during the 2007 major eruption) by applying a refined petrological model that allowed us to estimate the magma fluxes in the subvolcanic region (i.e., the magma flux entering the degassing zone).