Search results for "Volcanic gase"
showing 10 items of 79 documents
UV camera measurement at a dormant volcano
2010
The UV camera is now becoming a new important tool in the armory of volcano geochemists for high rate SO2 flux measurements. The high spatial resolution of the camera is particularly useful for exploring multiple-source SO2 gas emissions, as the large composite fumarolic systems topping most quiescent volcanoes. We report here on the first SO2 flux measurements from individual fumaroles of the fumarolic field of La Fossa crater (Vulcano island, Aeolian island), which we performed using a UV camera in two field campaigns on November 12, 2009 and February 4, 2010. Making advantage of the high temporal and spatial resolution of the UV camera, we derived ~0.5 Hz SO2 flux time-series for the mai…
A golden era for volcanic gas geochemistry?
2022
The exsolution, rise, expansion, and separation of volatiles from magma provide the driving force behind both effusive and explosive volcanic eruptions. The field of volcanic gas geochemistry therefore plays a key role in understanding volcanism. In this article, we summarize the most important findings of the past few decades and how these shape today’s understanding of volcanic degassing. We argue that the recent advent of automated, continuous geochemical monitoring at volcanoes now allows us to track activity from unrest to eruption, thus providing valuable insights into the behavior of volatiles throughout the entire sequence. In the next 10 years, the volcanological community stands t…
Genesis of fumarolic emissions as inferred by isotope mass balances: CO 2 and water at Vulcano Island, Italy
2002
We have developed a quantitative model of CO2 and H2O isotopic mixing between magmatic and hydrothermal gases for the fumarolic emissions of the La Fossa crater (Vulcano Island, Italy). On the basis of isotope balance equations, the model takes into account the isotope equilibrium between H2O and CO2 and extends the recent model of chemical and energy two-end-member mixing by Nuccio et al. (1999). As a result, the H2O and CO2 content and the δD, δ18O, and δ13C isotope compositions for both magmatic and hydrothermal end-members have been assessed. Low contributions of meteoric steam, added at a shallow depth, have been also recognized and quantified in the fumaroles throughout the period fro…
Gas emissions from five volcanoes in northern Chile and implications for the volatiles budget of the Central Volcanic Zone
2014
This study performed the first assessment of the volcanic gas output from the Central Volcanic Zone (CVZ) of northern Chile. We present the fluxes and compositions of volcanic gases (H2O, CO2, H2, HCl, HF, and HBr) from five of the most actively degassing volcanoes in this region—Lascar, Lastarria, Putana, Ollague, and San Pedro—obtained during field campaigns in 2012 and 2013. The inferred gas plume compositions for Lascar and Lastarria (CO2/Stot = 0.9–2.2; Stot/HCl = 1.4–3.4) are similar to those obtained in the Southern Volcanic Zone of Chile, suggesting uniform magmatic gas fingerprint throughout the Chilean arc. Combining these compositions with our own UV spectroscopy measurements of …
Forecasting Etna eruptions by real-time observation of volcanic gas composition
2007
It is generally accepted, but not experimentally proven, that a quantitative prediction of volcanic eruptions is possible from the evaluation of volcanic gas data. By discussing the results of two years of real-time observation of H2O, CO2, and SO2 in volcanic gases from Mount Etna volcano, we unambiguously demonstrate that increasing CO2/SO2 ratios can allow detection of the pre-eruptive degassing of rising magmas. Quantitative modeling by the use of a saturation model allows us to relate the pre-eruptive increases of the CO2/SO2 ratio to the refilling of Etna's shallow conduits with CO2-rich deep-reservoir magmas, leading to pressurization and triggering of eruption. The advent of real-ti…
Geochemistry and isotope composition (Sr, Pb, δ66Zn) of Vulcano fumaroles (Aeolian Islands, Italy)
2018
We present and discuss temperatures, major and trace element gas geochemistry, radiogenic isotopes (Pb, Sr) and the first Zn isotope data of fumarole condensates and altered rocks from the Vulcano fumarolic field. The fumaroles of the La Fossa cone, sampled on 5th May 2015, have temperatures ranging between 233 and 427 °C. They plot compositionally on the mixing trend between the magmatic and hydrothermal end-members defined by previous studies, but are strongly displaced towards the hydrothermal component. Correlations of radiogenic (Sr, Pb) and stable isotopes of Zn with δ13CCO2 and several trace elements of the fumarolic acid condensates support mixing between the above mentioned distinc…
Isotopically (δ13C and δ18O) heavy volcanic plumes from Central Andean volcanoes: a field study
2017
International audience; Stable isotopes of carbon and oxygen in volcanic gases are key tracers of volatile transfer between Earth's interior and atmosphere. Although important, these data are available for few volcanoes because they have traditionally been difficult to obtain and are usually measured on gas samples collected from fumaroles. We present new field measurements of bulk plume composition and stable isotopes (δ13CCO2 and δ18OH2O+CO2) carried out at three northern Chilean volcanoes using MultiGAS and isotope ratio infrared spectroscopy. Carbon and oxygen in magmatic gas plumes of Lastarria and Isluga volcanoes have δ13C in CO2 of +0.76‰ to +0.77‰ (VPDB), similar to slab carbonate;…
First determination of magma-derived gas emissions from Bromo volcano, eastern Java (Indonesia)
2015
The composition and fluxes of volcanic gases released by persistent open-vent degassing at Bromo Volcano, east Java (Indonesia), were characterised in September 2014 from both in-situ Multi-GAS analysis and remote spectroscopic (dual UV camera) measurements of volcanic plume emissions. Our results demonstrate that Bromo volcanic gas is water-rich (H2O/SO2 ratios of 56-160) and has CO2/SO2 (4.1 +/- 0.7) and CO2/S-tot (3.2 +/- 0.7) ratios within the compositional range of other high-temperature magma-derived gases in Indonesia. H-2/H2O and H2S/SO2 ratios constrain a magmatic gas source with minimal temperature of 700 degrees C and oxygen fugacity of 10(-17)-10(-18) bars. UV camera sensing on …
Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring
2016
OVSICORI 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…
Terminal Strombolian activity at Etna's central craters during summer 2012: The most CO2-rich volcanic gas ever recorded at Mount Etna
2016
By using a permanent network of multi-component gas analyzer systems (Multi-GAS), we report for the first time the H2O-CO2-SO2 composition of the volcanic gases emitted prior to, during, and after terminal Strombolian activity at Mount Etna's central craters (CCs). We show that the summer 2012 Strombolian episodes of the Bocca Nuova crater (BNC), the largest of Etna's CCs, are associated with the emission of the most CO2-rich gas measured at the volcano thus far. The BNC plume was particularly CO2-rich with CO2/SO2 up to 100, H2O/CO2 1 prevailed at the BNC and at other degassing vents such as Voragine and Northeast craters during Strombolian eruptions. Based on the results of numerical simu…