GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 1.3 251 References Caliro, S., Chiodini, G., Paonita, A., 2014. �� Geochemical evidences of magma dynamics at Campi Flegrei (Italy). Geochim. Cosmochim. Acta 132, 1-15, doi:10.1016/j.gca.2014.01.021. Chiodini, G., Marini, L., 1998. �� Hydrothermal gas equilibria: The H 2 O-H 2 -CO 2 -CO-CH 4 system. �� Geochim. Cosmochim. Acta 62, 2673-2687. Chiodini, G., Avino, R., Caliro, S., Minopoli, C., 2011. �� Temperature and pressure gas geoindicators at the Solfatara fumaroles (Campi Flegrei). Ann. Geophys. �� 54, doi: 10.4401/ag-5002. Chiodini, G., Vandemeulebrouck, J., Caliro, S., D’Auria, L., De Martino, P., Mangiacapra, A., Petrillo, Z., 2015. Evidence of thermal driven processes triggering the 2005-2014 unrest at Campi Flegrei caldera. Earth Planet. Sci. Lett. 414, 58-67, doi:10.1016/j.epsl.2015.01.012. D’Amore, F., and Panichi, C., 1980. Evaluation of deep temperatures in hydrothermal systems by new gas geothermometer, Geochim. Cosmochim. Acta, 44, 549-556. De Martino, P., Tammaro, U., Obrizo, F., 2014. �� GPS time series at Campi Flegrei caldera (2000-2013). Annals of Geophysics 57, S0213, doi:10.4401/ag-6431. Heat flux monitoring of steam heated grounds on two active volcanoes I.S. Diliberto, E. Gagliano Candela, M. Longo Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Italy Introduction. The output temperature of Fumarole fluids is strongly related to the upward flux of magmatic volatiles. �� Some previous works, dealing with long term monitoring data, showed that �� the thermal anomalies associated to fumaroles output are strictly related to �� transients occurring in the volcanogenic vapor, �� responding to changes either of seismic and/or volcanic activity (Diliberto, 2013; �� Madonia et al. , 2013a, 2013b; Cannata et al. , 2012� �� ; Milluzzo et al. , 2010; �� Aubert et al. , 2008). Some examples of heat flux monitoring from two very different volcanic areas, showed in figure 1 (Vulcano Island, Mount Etna) are presented here, and the results are compared to other observational data. The monitoring method here applied, worked properly to follow time variations of surface heat flux in particular field conditions, where a simplified equation can be applied to the surface heat balance. The key parameter for this simple and cheap monitoring method is the temperature gradient in the ground, measured on the main heat flow direction in an area where an active fracture network is interested by steam up-flow. In a porous ground profile, the temperature gradient allows to properly evaluate the time variations of heat flux within the range of about 30-300 w · m -2 (Aubert et al. , 1999), but the main conditions are that, within the monitored soil profile, the radiative and convective components of the heat transfers can be considered null. The discussed datasets widely demonstrated the direct link between temperature anomalies monitored on surface and transient state changes of the volcanic system, confirmed on a multidisciplinary basis. The presented data came from a close conduit volcano (La Fossa active cone, Aeolian Islands) during a quiescent period (since 1990, but particularly in 2004-2007); but also from an active erupting volcano, that is Mount Etna, during the eruptive cycle which produced the New South East Cone (2009 to 2012). Results about temperature monitoring on Vulcano island are shown in Figs. 2b, 2c, 2d. Results about temperature monitoring carried out on M.t Etna are shown in Figs. 3b, 3c, 3d. Methods and sites descriptions. Soil temperatures were acquired hourly at four depths on a short vertical profile into the ground, by automated stations, based on Onset Microstation four- channel data loggers, each connected to two 12-bit digital temperature smart sensors from the