GNGTS 2015 - Atti del 34° Convegno Nazionale

162 GNGTS 2015 S essione 1.3 Our data is in agreement with this model and we can conclude that, as an enhanced magmatic input causes higher fluid emissions and consequently chemical and physical changes, a chemical variation occurs also in the soil gases (in particular H 2 , CO 2 , H 2 S, CO and CH 4 ) and a temperature rise in the whole area. The observed H 2 /T positive correlation in our work shows us a very shallow system (actually very first meters below ground surface) of multi-equilibrium reactions described by Eqs. 1, 2 and 4, in which near-surface f H 2 variations justify enrichment in CO, CH 4 and H 2 S. Results of our study shows up the feasibility of a new approach in monitoring Solfatara gas emissions: the high frequency micro-gaschromatography (Sortino et al. , ��������������� Interpretations on rise up of volcanic fluids through high-frequency gas analysis by micro gas-cromatograph�, oral presentation at GNGTS Meeting, Trieste 2015), a newly experimented setup of classical gaschromatography, which could be installed at Solfatara in more easily accessible sites and under less aggressive environmental conditions than the fumarolic sites. References Barberi F., Corrado G., Innocenti F., Luongo G., (1984). Phlegraean Fields 1982-1984: Brief Chronicle of a Volcano Emegency in a Densely Populated Area . ����� ���������� ��� ����� �������� Bull. Volcanol., Vol 47-2. 175-185. Barberi F., Navarro J.M., Rosi M., Santacroce R., Sbrana A., (1988). Explosive interaction of magma with ground water: insight from xenoliths and geothermal drillings . ���������� ����� ������� �������� �� ����������� � Rendiconti della società italiana di Mineralogia e Petrologia, 1988, Vol. 43, pp. 901-926. Caliro S., Chiodini G., Moretti R., Avino R., Granieri D., Russo M., Fiebig J. (2007) The origin of the fumaroles of La Solfatara (Campi Flegrei, South Italy). Geochimica et Cosmochimica Acta 71 (2007) 3040–3055 Carapezza M.L,, Barberi F., Ranaldi M., Ricci T., Tarchini L.,. Barrancos J., Fischer C., Perez N., Weber K. , Di Piazza A., Gattuso A. (2011). Diffuse CO 2 soil degassing and CO 2 and H 2 S concentrations in air and related hazards at Vulcano Island (Aeolian arc, Italy). Journal of Volcanology and Geothermal Research 207 (2011) 130–144 Fig. 3 – Binary plot of: a) CH 4 /H 2 vs CO 2 /H 2 ; b) H 2 S/H 2 vs CH 4 /H 2 ; both plots are relative to the 7 points transect at different depths (0.3, 0.5,0.8, 1 m) compared with fumaroles values (BG; BN) c) Scatter plot of CH 4 vs H 2 S at 0.5 m depth of the 50 points grid inside Solfatara crater. d) Variation of soil (CO) as a function of soil temperature.