Search results for "Volcanic gas"
showing 10 items of 96 documents
Helium isotope systematics of volcanic gases and thermal waters of Guadeloupe Island, Lesser Antilles
2014
Abstract The island of Guadeloupe is located in the middle of the 850 km long Lesser Antilles island arc. Present-day volcanic and geothermal activity is concentrated in two systems both located in the southwestern part of the island (Basse Terre): the La Soufriere volcanic complex and the Bouillante hydrothermal system, some 20 km to the northwest of the volcano. We report here the largest isotopic data set for helium isotopes in hydrothermal gases and waters from both systems, acquired between 1980 and 2012. 3 He/ 4 He ratios in the fumarolic gases of La Soufriere volcano have been quite homogeneous and stable over the last thirty years. The average ratio of 8.2 ± 0.2 R a confirms that th…
Volcanogenic fluorine in rainwater around active degassing volcanoes: Mt. Etna and Stromboli Island, Italy
2002
Many studies have assessed the strong influence of volcanic activity on the surrounding environment. This is particularly true for strong gas emitters such as Mt. Etna and Stromboli volcanoes. Among volcanic gases, fluorine compounds are potentially very harmful. Fluorine cycling through rainwater in the above volcanic areas was studied analysing more than 400 monthly bulk samples. Data indicate that only approximately 1% of fluorine emission through the plume is deposited on the two volcanic areas by meteoric precipitations. Although measured bulk rainwater fluorine fluxes are comparable to and sometimes higher than in heavily polluted areas, their influence on the surrounding vegetation i…
Dissolved major and trace elements in meteoric depositions on the flanks of Mt. Etna (Italy): the impact of volcanic activity on the environment
2019
In the framework of the “Save the Etna World” research project, which investigates the impact of the volcanic activity on the surrounding environment, three bulk collectors were deployed on the flank of the Mt. Etna volcano to collect the meteoric depositions. The sampling sites were at distances between 5.5 and 13 km from the summit vents of the volcano on its eastern flank, that is the most exposed to the volcanic plume due to the high-altitude prevailing winds direction. The sites were selected in order to have a gradient of exposition with respect to the volcanic emissions, the most exposed being CIT, the intermediate ILI and the least NIC. Samples were collected monthly from July 2017 …
Protocols for UV camera volcanic SO2 measurements
2010
Abstract Ultraviolet camera technology offers considerable promise for enabling 1 Hz timescale acquisitions of volcanic degassing phenomena, providing two orders of magnitude improvements on sampling frequencies from conventionally applied scanning spectrometer systems. This could, for instance enable unprecedented insights into rapid processes, such as strombolian explosions, and non-aliased corroboration with volcano geophysical data. The uptake of this technology has involved disparate methodological approaches, hitherto. As a means of expediting the further proliferation of such systems, we here study these diverse protocols, with the aim of suggesting those we consider optimal. In part…
Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring.
2016
Abstract Eruptive activity at Turrialba Volcano (Costa Rica) has escalated significantly since 2014, causing airport and school closures in the capital city of San José. Whether or not new magma is involved in the current unrest seems probable but remains a matter of debate as ash deposits are dominated by hydrothermal material. Here we use high‐frequency gas monitoring to track the behavior of the volcano between 2014 and 2015 and to decipher magmatic versus hydrothermal contributions to the eruptions. Pulses of deeply derived CO2‐rich gas (CO2/Stotal > 4.5) precede explosive activity, providing a clear precursor to eruptive periods that occurs up to 2 weeks before eruptions, which are acc…
Gas Leakage From Shallow Ponding Magma and Trapdoor Faulting at Sierra Negra Volcano (Isabela Island, Galápagos)
2022
We report on new volcanic gas composition results acquired in October 2017 at Minas de Azufre, a persistent fumarolic field topping the resurgent Sierra Negra caldera, in the Galápagos archipelago. Our results indicate that the Minas de Azufre fumaroles are moderately hydrous (52–64 mol.% H2O) and rich in CO2 (35–46 mol.%), with total sulfur (ST) being 21–35 times less abundant than CO2. SO2, the most abundant S species, is released at an average rate of 19 ± 9 tons/day. Using a volatile saturation model that provides the composition of magmatic gases at equilibrium with western Galápagos basaltic melt (48 wt. % SiO2) in the 400–0.1 MPa pressure range, we infer that Minas de Azufre fumaroli…
Magmatic gas flux emissions from Gorelyi volcano, Kamchatka, and implications for volatile recycling in the NW Pacific
2012
The Kamchatka peninsula, in the north-western part of the Pacific ’Ring of Fire’, is one of the most active volcanic realms on Earth, with 29 historically erupting volcanoes along its 700 km-long Eastern Volcanic Belt (EVB). This notwithstanding, volatile input and output fluxes along this arc sector have remained poorly characterised until very recently. We here report on the very first assessment of volatile flux emissions from Gorelyi, a large (25 km3, 1830 m high) and most active shield-like Holocene volcano located on the southern segment of the Kamchatka EVB. By combing results from a variety of in situ and remote sensing techniques (MultiGAS, filter packs, and UV camera), we determine the…
Geothermal mercury output at Nisyros Volcano (Greece)
2019
Nisyros (Greece) is an active volcano in the eastern part of the South Aegean Active Volcanic Arc (SAAVA), hosting a high-enthalpy geothermal system. On June 2013, an extensive survey on Hg concentrations in different types of matrices (fumarolic fluids, atmosphere, soils and plants) was carried out at Lakki plain, an area affected by widespread soil degassing and fumarolic manifestations. To investigate the spatial distribution of mercury emission and its possible relationships with diffuse degassing of hydrothermal fluids, Hg concentrations in soils were related to their physicochemical parameters (e.g. temperature, soil-pH, hydrothermal gases and elemental C, N and S concentrations). Fur…
The precious treasure of Mariano Valenza: The history of Ludovico Sicardi and the birth of geochemical volcano monitoring
2020
I was lucky enough to meet Mariano Valenza in September 1995. I was hitchhiking on the highway that leads from Cefalu to Palermo to go back home. I had spent my summer holidays in the beautiful and wild Madonie mountains. An off-road vehicle (a Land Rover Defender) stopped and a refined gentleman with a curious and charismatic gaze offered me a ride. During our journey, we chatted pleasantly and he told he was originally from that area. When I told him, I was a Geology student, he smiled at me and said Then we will meet again soon, I am going to be your Teacher of Geochemistry!. After a few weeks the lessons began and I met again Professor Valenza in Via Archirafi 36, at the University of P…
Influence of volcanic activity on the quality of water collected in roof water catchment systems at Stromboli Island (Italy)
2013
Abstract With the aim of detailing the interaction between volcanic emissions and water harvesting by Roof Water Catchment Systems (RWCSs), the present work illustrates the results of a study carried out at Stromboli Island, a small but densely populated active volcanic area in the South of Italy. Concentrations of major and trace elements determined in RWCS waters and sediments revealed clear clues of a contamination with gases and suspended particles of volcanic origin, even if the values of those contaminants considered by the World Health Organization as dangerous for human health are always below the Maximum Admitted Concentration (MAC). In particular, cistern water showed a compositio…