title: Volcano seismicity and ground deformation unveil the gravity-driven magma discharge dynamics of a volcanic eruption.
abstract: Effusive eruptions are explained as the mechanism by which volcanoes restore the equilibrium perturbed by magma rising in a chamber deep in the crust. Seismic, ground deformation and topographic measurements are compared with effusion rate during the 2007 Stromboli eruption, drawing an eruptive scenario that shifts our attention from the interior of the crust to the surface. The eruption is modelled as a gravity-driven drainage of magma stored in the volcanic edifice with a minor contribution of magma supplied at a steady rate from a deep reservoir. Here we show that the discharge rate can be predicted by the contraction of the volcano edifice and that the very-long-period seismicity migrates downwards, tracking the residual volume of magma in the shallow reservoir. Gravity-driven magma discharge dynamics explain the initially high discharge rates observed during eruptive crises and greatly influence our ability to predict the evolution of effusive eruptions.
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ripepe
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Dario Delle
authors.initials: DD
authors.lastname: Donne
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Genco
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maggio
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Marco
authors.identifier: http://orcid.org/0000-0002-5096-3708
authors.initials: M
authors.lastname: Pistolesi
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Marchetti
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Lacanna
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Firenze 50121, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Ulivieri
authors.affiliation: Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Firenze 50121, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Poggi