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Fiordilino, E.
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Fiordilino, E.
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- PublicationRestrictedCO2 degassing at La Solfatara volcano (Phlegrean Fields): Processes affecting d13C and d18O of soil CO2(2010)
; ; ; ; ; ; ; ;Federico, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Corso, P. P.; Dipartimento di Scienze Fisiche e Astronomiche, Universita` di Palermo.Italy ;Fiordilino, E.; Dipartimento di Scienze Fisiche e Astronomiche, Universita` di Palermo,Italy ;Cardellini, C.; Dipartimento di Scienze della Terra, Universita` di Perugia,Italy ;Chiodini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Parello, E.; Dipartimento CFTA, Universita` degli Studi di Palermo, Italy ;Pisciotta, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; ; ; ; ; ; The soil CO2 degassing is affected by processes of isotope exchange and fractionation during transport across the soil, which can deeply modify the pristine isotope composition. This has been observed in the Solfatara volcano, upon a field survey of 110 points, where the CO2 flux was measured, together with temperature, CO2 concentration and oxygen and carbon isotopes within the soil. Furthermore, in some selected sites, the measurements were made at different depths, in order to analyze vertical gradients. Oxygen isotope composition appears controlled by exchange with soil water (either meteoric or fumarolic condensate), due to the fast kinetic of the isotopic equilibrium between CO2 and water. Carbon isotope composition is reliably controlled by transport-driven fractionation, due to the differences in diffusion coefficients between 13C16O2 and 12C16O2. We model the processes affecting CO2 transport across the soil in La Solfatara volcano by means of the Dusty Gas Model applied to a multicomponent system, to evaluate the reciprocal effect on diffusion of involved gases, i.e. 12C16O2, 13C16O2, N2 and O2 in our case. Both numerical and simplified analytical solutions of the equations based on the Dusty Gas Model are given. The modeling results fit well with the experimental data and put in evidence an isotope fractionation of carbon up to about þ4:4& with respect to the source value in the soil gas. This fractionation is independent from the entity of the CO2 flux, and occurs as long as a concentration gradient exists within the soil. On these grounds, the Dusty Gas Model can be applied to whichever diffusing gas mixture to evaluate the extent of chemical and/or isotopic fractionation that can affect ascending gases upon diffusion in any geothermal, volcanic or tectonic area.591 76 - PublicationRestrictedTime variability of low-temperature fumaroles at Stromboli island (Italy) and its application to volcano monitoring(2013-12)
; ; ;Madonia, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Fiordilino, E.; Università di Palermo, Dipartimento di Fisica e Chimica; The constant and mild activity of Stromboli volcano (Italy) is occasionally interrupted by effusive events and/or more energetic explosions, referred to as major explosions and paroxysms, which are potentially dangerous for the human community. Although several premonitory signals for effusive phases have been identified, precursors of major explosions and paroxysms still remain poorly understood. With the aim of contributing to the identification of possible precursors of energetic events, this work discusses soil temperature data acquired in low-temperature fumaroles at Stromboli in the period 2006–2010. Data analysis revealed that short-term anomalies recorded in the thermal signal are potentially useful in predicting state changes of the volcano. In particular, sudden changes in fumarole temperatures and their hourly gradients were observed from several days to a few hours prior to fracturing and paroxysmal events, heralded by peculiar waveforms of the recorded signals. The qualitative interpretation is supported by a quantitative, theoretical treatment that uses circuit theory to explain the time dependence of the short-period temperature variations, showing a good agreement between theoretical and observational data.121 22