Search results for "volcanic gase"
showing 10 items of 79 documents
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…
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…
Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone
2017
Abstract Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO 2 flux of 15.3 ± 2.3 kg s − 1 (1325-ton day − 1 ) at Sabancaya and of 11.4 ± 3.9 kg s − 1 (988-ton day − 1 ) at Ubinas using scanning ultraviolet spectr…
Conduit dynamics and post explosion degassing on Stromboli: A combined UV camera and numerical modeling treatment.
2016
Abstract Recent gas flux measurements have shown that Strombolian explosions are often followed by periods of elevated flux, or “gas codas,” with durations of order a minute. Here we present UV camera data from 200 events recorded at Stromboli volcano to constrain the nature of these codas for the first time, providing estimates for combined explosion plus coda SO2 masses of ≈18–225 kg. Numerical simulations of gas slug ascent show that substantial proportions of the initial gas mass can be distributed into a train of “daughter bubbles” released from the base of the slug, which we suggest, generate the codas, on bursting at the surface. This process could also cause transitioning of slugs i…
Geochemical constraints on volatile sources and subsurface conditions at Mount Martin, Mount Mageik, and Trident Volcanoes, Katmai Volcanic Cluster, …
2017
Abstract We use the chemical and isotopic composition of volcanic gases and steam condensate, in situ measurements of plume composition and remote measurements of SO2 flux to constrain volatile sources and characterize subvolcanic conditions at three persistently degassing and seismically active volcanoes within the Katmai Volcanic Cluster (KVC), Alaska: Mount Martin, Mount Mageik and Trident. In situ plume measurements of gas composition were collected at all three volcanoes using MultiGAS instruments to calculate gas ratios (e.g. CO2/H2S, SO2/H2S and H2O/H2S), and remote measurements of SO2 column density were collected from Mount Martin and Mount Mageik by ultraviolet spectrometer system…
Mercury and halogen emissions from Masaya and Telica volcanoes, Nicaragua
2008
We report measurements of Hg, SO2, and halogens (HCl, HBr, HI) in volcanic gases from Masaya volcano, Nicaragua, and gaseous SO2 and halogens from Telica volcano, Nicaragua. Mercury measurements were made with a Lumex 915+ portable mercury vapor analyzer and gold traps, while halogens, CO2 and S species were monitored with a portable multi gas sensor and filter packs. Lumex Hg concentrations in the plume were consistently above background and ranged up to 350 ng m-3. Hg/SO2 mass ratios measured with the real-time instruments ranged from 1.1 × 10-7 to 3.5 × 10-5 (mean 2 × 10-5). Total gaseous mercury (TGM) concentrations measured by gold trap ranged from 100 to 225 ng m-3. Reactive gaseous m…
Ratiocalc: Software for processing data from multicomponent volcanic gas analyzers
2015
Portable gas analyzers have become a powerful tool for the real-time monitoring of volcanic gas composition over the last decade. Gas analyzers make it possible to retrieve in real-time the chemical composition of a fumarole system or a plume in an open-conduit volcano via periodic field-deployments or at permanent stations. The core of a multicomponent volcanic gas analyzer (MultiGAS) consists of spectroscopic and electrochemical sensors that are used to determine the concentrations of the most abundant volcanic gases (H2O, CO2, SO2, H2S, H2, CO and HCl) in a diluted plume and their mutual molar ratios. Processing such data is often difficult due to the high sensitivity of the sensors to e…
Scavenging of sulphur, halogens and trace metals by volcanic ash: The 2010 Eyjafjallajökull eruption
2013
The Eyjafjallajökull volcanic eruption in 2010 released considerable amounts of ash into the high troposphere-low stratosphere, leading to unprecedented disruption of air traffic over Europe. The role of such fine-grained tephra in adsorbing, and therefore rapidly scavenging, volcanogenic volatile elements such as sulphur and halogens, is explored here. We report on results (major to trace element chemistry) of leaching experiments carried out on 20 volcanic ash samples, taken from the deposits of the main phases of the eruption (March–April 2010), or directly while falling (5–9 May 2010). Ash leachate solutions from Eyjafjallajökull are dominated – among cations – by Ca and Na, and display…