Infuence of permeability on the hydrothermal system at Vulcano Island (Italy): inferences from numerical simulations

Volcano-hydrothermal systems are governed by complex interactions between fuid transport, and geochemical and mechanical processes. Evidence of this close interplay has been testifed by distinct spatial and temporal correlations in geochemical and geophysical observations at Vulcano Island (Italy). To understand the interaction between fuid circulation and the geochemical and geophysical manifestations, we perform a parametric study to explore diferent scenarios by implementing a hydro-geophysical model based on the equations for heat and mass transfer in a porous medium and thermo-poroelastic theory. Numerical simulations allow us to defne the controlling role of permeability distribution on the diferent modeled parameters as well as on the geophysical observables. Changes in the permeability within the highly fractured crater area could be responsible for the fuctuations in gas emission and temperature recorded during the crisis periods, which are accompanied by shallow volcano-seismicity in the absence of signifcant deformation and gravity variations. Despite the general medium permeability of the volcanic edifce, the presence of more highly permeable pathways, which allow the gas to rapidly escape, as testifed by the presence of a well-developed fumarolic feld, prevents the pressure buildup at shallow depths.