GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 1.3 193 and resonance of the circulation of fluids inside the fumarolic ducts. Once the inflating process settled in, the negative recorded deformations have been interpreted as a “balloon-like” model, depressurizing the shallower magmatic reservoirs until the complete settlement of the feeding system. This, still active, mechanism is monitored through the GPS network and is producing the subsidence evidenced before. In order to have a complete view of the recorded data, we have estimated the thermal contribution of gaseous phases, comparing two different periods. The heat flow in a normal regime period has an average corresponding energy of 2.8 x 10 11 J/d; conversely, the unrest period, characterized by an increase of more than the 100%, reaches a total value of 5.6 x 10 11 J/d. The increase in total heat flux has been triggered by a major input of magmatic gases released by the deepest magmatic body, a phenomenon in turn triggered by regional tectonics that led to the geochemical and geophysical unrest phase. This model evidences how an unrest phase could be triggered by regional tectonics, producing a reaction chain allowing fluids to ascend through the volcanic system and reactivating the shallower, fluid empty reservoirs. Acknowledgements. I would like to express my very great appreciation to Professor Marco Viccaro for his valuable and constructive suggestions during the development of this work. References Alparone S., BonforteA., Gambino S., Guglielmino F., Obrizzo F. and Velardita R.; 2018: Dynamics of Vulcano Island (Tyrrhenian Sea, Italy) investigated by long-term (40 years) geophysical data , Earth Sci. Rev., 190 , 521-535. Cannata A., Diliberto I.S., Alparone S., Gambino S., Gresta S., Liotta M., Madonia P., Milluzzo V., Aliotta M. and Montalto P.; 2012; Multiparametric Approach in Investigating Volcano-Hydrothermal Systems: the Case Study of Vulcano (Aeolian Islands, Italy) , Pure Appl. Geophys, 169 , 167-182. Cintorrino A., Palano M. and Viccaro M.; 2019: Magmatic and tectonic sources at Vulcano (Aeolian Islands, Southern Italy): a geodetic model based on two decades of GPS observations. Chiodini G., Cioni R., Marini L. and Panichi C.; 1995: Origin of the fumarolic fluids of Vulcano Island, Italy and implication for volcanic surveillance , Bull. Volcanol, 57 , 99-110. De Astis G., La Volpe G., Peccerillo A. and Civetta L.; 1997: Volcanological and petrological evolution of Vulcano island (Aeolian Arc, Southern Tyrrhenian Sea) . J. Geophys. Res., 102 , 8021-8050. De Astis G., Lucchi F., Dellino P, La Volpe R., Tranne C.A., Frezzotti M.L. and Peccerillo A.; 2013: Geology, volcanic history and petrology of Vulcano (central Aeolian archipelago) Geological Society, London, Memoirs 2013, 37 , 281-349. Diliberto I.S.; 2013 : Time series analysis of high temperature fumaroles monitored on the island of Vulcano (Aeolian Archipelago, Italy) , J. Volcanol. Geotherm. Res. 264 , 150–163. Diliberto I.S.; 2017: Long-term monitoring on a closed-conduit volcano: A 25 year long time-series of temperatures recorded at La Fossa cone (Vulcano Island, Italy), ranging from 250 °C to 520 °C, J. Volcanol. Geotherm. Res., 346 , 151–160. Mandarano M., Paonita A, Martelli M., Viccaro M., Nicotra E. and Millar I.L.; 2016: Revealing magma degassing below closed-conduit active volcanoes: Geochemical features of volcanic rocks versus fumarolic fluids at Vulcano (Aeolian Islands, Italy) , Lithos, 248–251 , 272–287. Nicotra E., Giuffrida M., Viccaro M., Donato P., D’Oriano C., Paonita A. and De Rosa R.; 2018; Timescales of pre- eruptive magmatic processes at Vulcano (Aeolian Islands, Italy) during the last 1000 years , Lithos, 316–317 , 347–365. Peccerillo A., Frezzotti M.L., De Astis G. and Ventura G.; 2006: Modeling the magma plumbing system of Vulcano (Aeolian Islands, Italy) by integrated fluid-inclusion geobarometry, petrology, and geophysics , Geology, 34 , 17– 20. Tamburello G., Kantzas E.P., McGonigle A.J.S., Aiuppa A. and Giudice G.; 2011: UV camera measurements of fumarole field degassing (La Fossa crater, Vulcano Island) , J. Volcanol. Geotherm. Res, 199 , 47–52.