Geochemical characterization of the Lake “Specchio di Venere”, Pantelleria island, Italy.

Trace metal modelling of groundwater–gas–rock interactions in a volcanic aquifer: Mount Vesuvius

CO2 flux measurements in volcanic areas using the dynamic concentration method: the influence of the soil permeability.

In order to evaluate the influence of soil permeability on soil CO2 flux measurements performed with the dynamic concentration method, several tests were carried out using soils characterized by different permeability values and flow rates. A special device was assembled in the laboratory to create a one-dimensional gas flow through a soil of known permeability. Using the advective-diffusion theory, a physical model to predict soil concentration gradients was also developed. The calculated values of CO2 concentrations at different depths were compared with those measured during the tests and a good agreement was found. Four soils with different gas permeability (3.6 x 10(-2) to 1.23 x 10(2)…

Plume chemistry provides insights into the mechanisms of sulfur and halogen degassing at basaltic volcanoes,

This paper deals with sulfur, chlorine and fluorine abundances in the eruptive volcanic plume of the huge October 2002-January 2003 eruption of Mount Etna, aiming at relating the relevant compositional variations observed throughout with changes in eruption dynamics and degassing mechanisms. The recurrent sampling of plume acidic volatiles by filter-pack methodology revealed that, during the study period, S/Cl and Cl/F ratios ranged from 0.1-6.8 and 0.9-5.6, respectively. Plume S/Cl ratios increased by a factor of ∼10 as volcanic activity drifted from paroxysmal lava fountaining (mid- and late November) to passive degassing and minor effusion (early January), and then decreased to the low v…

Soil and groundwater discharge of magmatic CO2 and He on south western Ischia Island (Central Italy)

In situ permeability measurements based on radial gas advection model: relationship between soil permeability and diffuse CO2 degassing in volcanic areas.

Hydrothermal buffering of the SO2/H2S ratio in volcanic gases: Evidence from La Fossa crater fumarolic field, Vulcano Island.

Emission of Bromine and Iodine from Mt. Etna volcano

Constraining fluxes of volcanic bromine and iodine to the atmosphere is important given the significant role these species play in ozone depletion. However, very few such measurements have been made hitherto, such that global volcanic fluxes are poorly constrained. Here we extend the data set of volcanic Br and I degassing by reporting the first measurements of bromine and iodine emissions from Mount Etna. These data were obtained using filter packs and contemporaneous ultraviolet spectroscopic SO2 flux measurements, resulting in time-averaged emission rates of 0.7 kt yr(-1) and 0.01 kt yr(-1) for Br and I, respectively, from April to October 2004, from which we estimate global Br and I flu…

Real-time detection of volcanic plume H2O, CO2 and SO2 as a precursor to 2006 Mt. Etna eruptions

Mount Etna, in southern Italy, is well known for its uninterrupted open-vent degassing activity from the summit craters, making the volcano the largest point source of volcanogenic volatiles on Earth. Notwithstanding a substantial improvement of our understanding of degassing rates and mechanisms over the past two decades, analytical limitations still hamper the quantitative evaluation of the total volatile budget from the volcano. In contrast with the routine sensing of volcanic SO2 by UV-spectroscopy (Allard, 1997; Caltabiano et al., 2004), only a few spot determinations of CO2 emissions from Mount Etna have been reported to date (Allard et al., 1991; Aiuppa et al., 2006), while H2O emiss…

Variation of H2O/CO2 and CO2/SO2 ratios of volcanic gases discharged by continuous degassing of Mount Etna volcano, Italy

A PTFE membrane for the in situ extraction of dissolved gases in natural waters: Theory and applications

A new method for extracting dissolved gases in natural waters has been developed and tested, both in the laboratory and in the field. The sampling device consists of a polytetrafluroethylene (PTFE) tube (waterproof and gas permeable) sealed at one end and connected to a glass sample holder at the other end. The device is pre-evacuated and subsequently dipped in water, where the dissolved gases permeate through the PTFE tube until the pressure inside the system reaches equilibrium. A theoretical model describing the time variation in partial gas pressure inside a sampling device has been elaborated, combining the mass balance and "Solution-Diffusion Model" (which describes the gas permeation…

High Carbon dioxiede emissions at Capo Calavà promontory (north easytern Sicily, Italy) Relationships between soil degassing and tectonics