scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Forecasting Etna eruptions by real-time observation of volcanic gas composition

TL;DR: In this article, the results of two years of real-time observation of H2O, CO2, and SO2 in volcanic gases from Mount Etna volcano were unambiguously demonstrated that increasing CO2/SO2 ratios can allow detection of pre-eruptive degassing of rising magmas.
Abstract: 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-time observations of H2O, CO2, and SO2, combined with well-constrained models of degassing, represents a step forward in eruption forecasting.
Citations
More filters
Journal ArticleDOI
TL;DR: The role of CO2 degassing from the Earth is clearly fundamental to the stability of the climate, and therefore to life on Earth as discussed by the authors, but the uncertainty in our knowledge of this critical input into the geological carbon cycle led Berner and Lagasa (1989) to state that it is the most vexing problem facing us in understanding that cycle.
Abstract: Over long periods of time (~Ma), we may consider the oceans, atmosphere and biosphere as a single exospheric reservoir for CO2. The geological carbon cycle describes the inputs to this exosphere from mantle degassing, metamorphism of subducted carbonates and outputs from weathering of aluminosilicate rocks (Walker et al. 1981). A feedback mechanism relates the weathering rate with the amount of CO2 in the atmosphere via the greenhouse effect (e.g., Wang et al. 1976). An increase in atmospheric CO2 concentrations induces higher temperatures, leading to higher rates of weathering, which draw down atmospheric CO2 concentrations (Berner 1991). Atmospheric CO2 concentrations are therefore stabilized over long timescales by this feedback mechanism (Zeebe and Caldeira 2008). This process may have played a role (Feulner et al. 2012) in stabilizing temperatures on Earth while solar radiation steadily increased due to stellar evolution (Bahcall et al. 2001). In this context the role of CO2 degassing from the Earth is clearly fundamental to the stability of the climate, and therefore to life on Earth. Notwithstanding this importance, the flux of CO2 from the Earth is poorly constrained. The uncertainty in our knowledge of this critical input into the geological carbon cycle led Berner and Lagasa (1989) to state that it is the most vexing problem facing us in understanding that cycle. Notwithstanding the uncertainties in our understanding of CO2 degassing from Earth, it is clear that these natural emissions were recently dwarfed by anthropogenic emissions, which have rapidly increased since industrialization began on a large scale in the 18th century, leading to a rapid increase in atmospheric CO2 concentrations. While atmospheric CO2 concentrations have varied between 190–280 ppm for the last 400,000 years (Zeebe and Caldeira 2008), human activity has produced a remarkable increase …

309 citations


Cites methods from "Forecasting Etna eruptions by real-..."

  • ...The MultiGas approach (Shinohara 2005) has greatly simplified the measurement of volcanic CO2/SO2 ratios, allowing automatic, unattended analysis of volcanic plumes for extended periods of time (Aiuppa et al. 2007)....

    [...]

Journal ArticleDOI
TL;DR: In this article, the authors present some of the current petrological techniques that can be used for studying eruptive products and for constraining key magmatic variables such as pressure, temperature, and volatile content.
Abstract: Explosive volcanic eruptions constitute a major class of natural hazard with potentially profound economic and societal consequences. Although such eruptions cannot be prevented and only rarely may be anticipated with any degree of accuracy, better understanding of how explosive volcanoes work will lead to improved volcano monitoring and disaster mitigation. A major goal of modern volcanology is linking of surface-monitored signals from active volcanoes, such as seismicity, ground deformation and gas chemistry, to the subterranean processes that generate them. Because sub-volcanic systems cannot be accessed directly, most of what we know about these systems comes from studies of erupted products. Such studies shed light on what happens underground prior to and during eruptions, thereby providing an interpretative framework for post hoc evaluation of monitoring data. The aim of this review is to present some of the current petrological techniques that can be used for studying eruptive products and for constraining key magmatic variables such as pressure, temperature, and volatile content. We first review analytical techniques, paying particular attention to pitfalls and strategies for analyzing volcanic samples. We then examine commonly used geothermometry schemes, evaluating each by comparison with experimental data not used in the original geothermometer calibrations. As there are few mineral-based geobarometers applicable to magma storage regions, we review other methods used to determine pre-eruptive magma equilibration pressures. We then demonstrate how petrologically-constrained parameters can be compared to the contemporaneous monitoring record. These examples are drawn largely from Mount St. Helens volcano, for which there are abundant petrological and monitoring data. However, we emphasize that our approaches can be applied to any number of active volcanoes worldwide. Finally, we illustrate the application of these techniques to two different types of magmatic systems—large silicic magma chambers and small intermediate-composition magma storage regions—with particular focus on the combined evolution of melt …

301 citations


Cites background from "Forecasting Etna eruptions by real-..."

  • ...To date such measurements have been confined to persistently degassing basaltic volcanoes (e.g., Burton et al. 2000; Aiuppa et al. 2007)....

    [...]

Journal ArticleDOI
TL;DR: The major magmatic volatile components (H2O, CO2, S, Cl, and F) play an important role in the formation, evolution, and eruption of magma as mentioned in this paper.
Abstract: The major magmatic volatile components—H2O, CO2, S, Cl, and F— play an important role in the formation, evolution, and eruption of magma. Knowledge of magmatic concentrations and fluxes of these volatiles is thus important for understanding explosive eruptive behavior of volcanoes, recycling of volatiles in subduction zones, formation of magmatic-hydrothermal ore deposits, fluxes of volcanic gases to Earth’s atmosphere, and potential climatic impacts of large volcanic eruptions. Over the past 30 years, new analytical techniques for measuring volatiles in melt inclusions and glasses from volcanic rocks and new developments in remote sensing technology used for quantifying volcanic emissions have led to major advances in our understanding of volatiles in magmatic systems and their fluxes from Earth’s mantle to the crust and hydrosphere. Sulfur plays a particularly important role in many of the processes noted above because it affects partitioning of metals into sulfide phases or vapor in magmas during crustal storage, and when released to the atmosphere, it forms sulfuric acid aerosol droplets that catalyze ozone destruction, influences other aspects of atmospheric chemistry, and blocks incoming solar radiation. In addition, S may play a role in causing oxidation of the mantle wedge above subduction zones (Kelley and Cottrell 2009). In silicate melts, the solubility behavior, activity-composition relations, and vapor-melt partitioning of S are complex due to multiple valence states and species (S2−, S6+ in melt; H2S, S2, SO2, SO3 in vapor) and the occurrence of non-volatile S-rich phases (immiscible Fe-S-O liquid, pyrrhotite, monosulfide and intermediate solid solutions, anhydrite). Sulfur dioxide (SO2) is the easiest of the main magmatic volatiles to measure in volcanic plumes using ground- and satellite-based remote sensing techniques because of its relatively high concentration in volcanic plumes relative to background values. More …

237 citations

Journal ArticleDOI
TL;DR: This article used ion-microprobe data on H2O, CO2, Be, B, Li and Sc in melt inclusions from the 1980-1986 eruptions of Mount St. Helens.

202 citations

Journal ArticleDOI
TL;DR: A review of the current state of the field can be found in this paper, starting with an analysis of what is, and what is not, known about the distribution of halogens in Earth's interior reservoirs, and the principal controls on their behaviour during partial melting, crystallisation and degassing.

191 citations

References
More filters
Journal ArticleDOI
TL;DR: A time-averaged inventory of subaerial volcanic sulfur (S) emissions was compiled primarily for the use of global S and sulfate modelers as discussed by the authors, which relies upon the 25-year history of S, primarily sulfur dioxide (SO2), measurements at volcanoes.
Abstract: A time-averaged inventory of subaerial volcanic sulfur (S) emissions was compiled primarily for the use of global S and sulfate modelers. This inventory relies upon the 25-year history of S, primarily sulfur dioxide (SO2), measurements at volcanoes. Subaerial volcanic SO2 emissions indicate a 13 Tg/a SO2 time-averaged flux, based upon an early 1970s to 1997 time frame. When considering other S species present in volcanic emissions, a time-averaged inventory of subaerial volcanic S fluxes is 10.4 Tg/a S. These time-averaged fluxes are conservative minimum fluxes since they rely upon actual measurements. The temporal, spatial, and chemical inhomogeneities inherent to this system gave higher S fluxes in specific years. Despite its relatively small proportion in the atmospheric S cycle, the temporal and spatial distribution of volcanic S emissions provide disproportionate effects at local, regional, and global scales. This work contributes to the Global Emissions Inventory Activity.

594 citations

Journal ArticleDOI
30 May 1991-Nature
TL;DR: In this article, the authors used data collected from 1975 to 1987 to estimate carbon dioxide emissions from the summit craters and the upper flanks of the volcano and found that the average output of CO2 from summit crater degassing is 13±3 Tg yr−1, an order of magnitude higher than the annual CO2 output from Kilauea, Hawaii, and representative arc volcanoes.
Abstract: MOUNT Etna, in Sicily, is one of the world's most actively degassing volcanoes1. Here we use data collected from 1975 to 1987 to estimate carbon dioxide emissions from the summit craters and the upper flanks of the volcano. By combining measurements of the SO2 flux in the plume (refs 1–6 and this paper) with measurements of the CO2/SO2 ratio of the plume gases, we find that the average output of CO2 from summit crater degassing is 13±3 Tg yr−1. This is an order of magnitude higher than the annual CO2 output from Kilauea7,8, Hawaii, and representative arc volcanoes9,10. Furthermore, we find that diffuse emissions of CO2 from the upper flanks of Etna are magma-derived and are of a similar magnitude to those emitted from the crater plume. This observation, as well as others11–14, verifies the idea15 that extensive diffuse release of magmatic CO2 may occur in volcanically active regions—a process that needs to be taken into account when evaluating the volatile budget of subaerial volcanism. Such degassing may be of use for monitoring volcanic activity, could provide a means for radiocarbon dating of eruptions, and may be a mechanism by which CO2 is injected into crater lakes.

474 citations

Book ChapterDOI
01 Jan 1996
TL;DR: The composition of gases released from volcanoes is a function of deep processes, such as vapor-melt separation during the generation and rise of the magmas, and shallow processes, active within the volcanic structures themselves as discussed by the authors.
Abstract: The composition of gases released from volcanoes is a function of deep processes, such as vapor-melt separation during the generation and rise of the magmas, and shallow processes, active within the volcanic structures themselves. Of the three major types of volcanic systems, those associated with andesitic magmatism are the most suitable to the application of geochemical surveillance and monitoring techniques. Volatile contents of andesitic magmas, largely representing fluids released from the subducted slab, are likely to be high enough to allow a separate, volatile-rich phase to be present during all stages of magma generation and migration. In spite of highly variable solubilities in magmatic melts, the proportions of volatiles present in the vapors discharged from volcanic fumaroles resemble closely those acquired at depth suggesting that the vapor-melt systems have attained steady-state and that the overall process active during the rise of the volatiles is effectively nonfractionating.

424 citations

Journal ArticleDOI
TL;DR: In this article, the authors decipher the origin and mechanisms of the second eruption from the composition and volatile (H2O, CO2, S, Cl) content of olivine-hosted melt inclusions in explosive products from its south flank vents.
Abstract: [1] Two unusual, highly explosive flank eruptions succeeded on Mount Etna in July August 2001 and in October 2002 to January 2003, raising the possibility of changing magmatic conditions. Here we decipher the origin and mechanisms of the second eruption from the composition and volatile (H2O, CO2, S, Cl) content of olivine-hosted melt inclusions in explosive products from its south flank vents. Our results demonstrate that powerful lava fountains and ash columns at the eruption onset were sustained by closed system ascent of a batch of primitive, volatile-rich (≥4 wt %) basaltic magma that rose from ≥10 km depth below sea level (bsl) and suddenly extruded through 2001 fractures maintained opened by eastward flank spreading. This magma, the most primitive for 240 years, probably represents the alkali-rich parental end-member responsible for Etna lavas' evolution since the early 1970s. Few of it was directly extruded at the eruption onset, but its input likely pressurized the shallow plumbing system several weeks before the eruption. This latter was subsequently fed by the extrusion and degassing of larger amounts of the same, but slightly more evolved, magma that were ponding at 6–4 km bsl, in agreement with seismic data and with the lack of preeruptive SO2 accumulation above the initial depth of sulphur exsolution (∼3 km bsl). We find that while ponding, this magma was flushed and dehydrated by a CO2-rich gas phase of deeper derivation, a process that may commonly affect the plumbing system of Etna and other alkali basaltic volcanoes.

310 citations

Journal ArticleDOI
TL;DR: In this scenario, the growth of magma storage areas at a depth of 3-5 km below sea level exerts pressure against those flank sectors prone to displacement, causing them to detach from the stable portions of the volcanic edifice as discussed by the authors.

249 citations