Article ID Journal Published Year Pages File Type
8966182 Journal of Volcanology and Geothermal Research 2018 48 Pages PDF
Abstract
In the period July 2005-October 2006 several soil gas prospections were performed on the island of Pantelleria, an active volcanic/geothermal system at present in a quiescent state. Measured parameters were CO2 concentrations and 220Rn and 222Rn activities at 50 cm depth and CO2 fluxes from the soil. The whole island was covered with a measurement density of 3.5 points/km2 for CO2 (flux and concentration) and 1.6 points/km2 for Rn. Further three main and seven minor areas of previously ascertained or expected exhalative activity were covered with a measurement density up to 100 points/km2. The obtained results ranged from 0.038 to 95%vol for CO2 concentration, from 10 Bq/m3 to 164,000 Bq/m3 from 10 Bq/m3 to 750,000 Bq/m3 for 220Rn and 222Rn activities, respectively and from <0.1 to 4700 g/m2 day for CO2 fluxes. Probability plots evidenced for all measured parameters the presence of three populations (background, mixed and hydrothermal). All anomalous values were found in the central part of the island within the youngest caldera. Flux data allowed us to estimate a total CO2 output of the volcanic/geothermal system of Pantelleria in 24.2 tons per day. Some new exhaling area, significantly contributing to the total output and characterised by stunted or absent vegetation, were evidenced on the southern flank of Mt. Grande. At one of these areas the relationships between the measured parameters and vegetation cover were studied in detail along a 140 m long transect of 15 points. Finally, a first evaluation of the gas hazard related to the geogenic degassing evidenced some high risk area at the mofette along the shores of the Lake Specchio di Venere (CO2) and in the village of Rekale (CO2 and Rn).
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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