GNGTS 2015 - Atti del 34° Convegno Nazionale

system are recognized comparing geochemical and geophysical signals. The physical numerical modelling of such episodes, together with several other independent observations, indicates that the large amount of steam involved in the process is currently heating the hydrothermal system through condensation. This heating process, which for the first time is documented to occur with so many details during a caldera unrest, may be one of the main causes of the current deformation phase of CFc. The input of magmatic steam into geothermal systems is potentially a very efficient way both for heating and for deforming the rocks to such an extent that steam injection is used is used in oil industry for heavy oil exploitation (e.g. Dusseault and Collins, 2008; Dusseault, 2011). Acknowledgments. This study has benefited from funding provided by the MEDiterranean SUpersite Volcanoes FP7 project (grant number 308665) and by the “Precursori d’eruzione” project (funded by DPC, Italian Presidenza del Consiglio dei Ministri – Dipartimento della Pro-tezione Civile). This paper does not necessarily represent DPC official opinion and policies. References Acocella V., Di Lorenzo R., Newhall C., and Scandone R.; 2015: An overview of recent (1988 to 2014) caldera unrest: Knowledge and perspectives . Rev. Geophys., article in Press, doi: 10.1002/2015RG000492 Afanasyev A., Costa, A. and Chiodini G.; 2015; Investigation of hydrothermal activity at Campi Flegrei caldera using 3D numerical simulations: Extension to high temperature processes . J. Volcanol. Geotherm. Res., 299 , 68-77, doi:10.1016/j.jvolgeores.2015.04.004 Aiuppa A., G. Tamburello, R. Di Napoli, C. Cardellini, G. Chiodini, G. Giudice, F. Grassa and M. Pedone; 2013: First observations of the fumarolic gas output from a restless caldera: Implications for the current period of unrest (2005–2013) at Campi Flegrei. Geochem. Geophys. Geosys., doi:10.1002/ggge.20261. Amoruso A., Crescentini L. and Sabbetta I.; 2014: Paired deformation sources of the Campi Flegrei caldera (Italy) required by recent (1980-2010) deformation history . J. Geophys Res. 119 , doi:10.1002/2013JB010392 Caliro S., Chiodini G. and Paonita A.; 2014: Geochemical evidences of magma dynamics at Campi Flegrei (Italy). Geochim. Cosmochim. Acta 132 , 1-15 Caliro S., Chiodini G., Moretti R., Avino R., Granieri D., Russo M. and Fiebig, J.; 2007: The origin of the fumaroles of La Solfatara (Campi Flegrei, South Italy). Geochim. Cosmochim. Acta, 71 (12), 3040-3055 Chiodini, G.; 2009: CO 2 /CH 4 ratio in fumaroles a powerful tool to detect magma degassing episodes at quiescent volcanoes . Geophys. Res. Lett., 36 , L02302, doi:10.1029/2008GL036347. Chiodini G. and Marini, L.; 1998: Hydrothermal gas equilibria; the H 2 O–H 2 –CO 2 –CO–CH 4 system. Geochim. Cosmochim. Acta, 62 , 15, 2673–2687. Chiodini G., Caliro S., Cardellini C., Granieri D., Avino R., Baldini A., Donnini M. and Minopoli C.; 2010: Long-term variations of the Campi Flegrei, Italy, volcanic system as revealed by the monitoring of hydrothermal activity. J. Geophys Res., 115, 3, B03205 Chiodini G., Caliro S., De Martino P., Avino R. and Gherardi F.; 2012; Early signals of new volcanic unrest at Campi Flegrei caldera? Insights from geochemical data and physical simulations . Geology, 40 , 943–946. Chiodini G., Vandemeulebrouck J., Caliro S., D’Auria L., De Martino P., Mangiacapra A. and Petrillo Z.; 2015: Evidence of thermal driven processes triggering the 2005-2014 unrest at Campi Flegrei caldera . Earth Planet. Sci. Lett. , 414 , 58–67. Del Gaudio C., Aquino I., Ricciardi G. P., Ricco C. and Scandone R.; 2010: Unrest episodes at Campi Flegrei: A reconstruction of vertical ground movements during 1905– 2009 . J. Volcanol. Geotherm. Res., 195 , 48–56, doi: 10.1016/j.jvolgeores.2010.05.014. De Martino P., Tammaro U. and Obrizo F.; 2014: GPS time series at Campi Flegrei caldera (2000-2013). Ann. Geophys., 57 , 2, 2014, S0213; doi: 10.4401/ag-6431 De Siena L., Del Pezzo E. and Bianco F.; 2010: Seismic attenuation imaging of Campi Flegrei: Evidence of gas reservoirs, hydrothermal basins, and feeding systems. J Geophys Res, 115 , 1–18. Di Vito M. A., Isaia R., Orsi G., Southon J., De Vita S., D’Antonio M., Pappalardo L. and Piochi M.; 1999; Volcanism and deformation since 12000 years at the Campi Flegrei caldera (Italy). J. Volcanol. Geotherm. Res., 91 , 221– 246. Dusseault M.B.; 2011: Geomechanical Challenges in Petroleum Reservoir Exploitation . KSCE Journal of Civil Engineering 15 , 4, 669-678, doi: 10.1007/s12205-011-0007-5. Dusseault M.B. and Collins P.M.; 2008: Geomechanics Effects in Thermal Processes. CSEG Recorder, June 2008, 20-23. Dvorak J. J. and Mastrolorenzo G.; 1991: The mechanisms of recent vertical crustal movements in Campi Flegrei Caldera, southern Italy . Spec. Pap. Geol. Soc. Am., 263 , 47 GNGTS 2015 S essione 1.3 175