New geochemical insights into volcanic degassing

2008 ◽  
Vol 366 (1885) ◽  
pp. 4559-4579 ◽  
Author(s):  
Marie Edmonds
Keyword(s):  
Gas Flow ◽  
Volcanic Eruptions ◽  
Shear Zones ◽  
High Temporal Resolution ◽  
Volcanic Gases ◽  
Spectroscopic Techniques ◽  
Volcanic Degassing ◽  
Effusive Activity ◽  
Gas Loss ◽  
Melt Segregation

Magma degassing plays a fundamental role in controlling the style of volcanic eruptions. Whether a volcanic eruption is explosive, or effusive, is of crucial importance to approximately 500 million people living in the shadow of hazardous volcanoes worldwide. Studies of how gases exsolve and separate from magma prior to and during eruptions have been given new impetus by the emergence of more accurate and automated methods to measure volatile species both as volcanic gases and dissolved in the glasses of erupted products. The composition of volcanic gases is dependent on a number of factors, the most important being magma composition and the depth of gas–melt segregation prior to eruption; this latter parameter has proved difficult to constrain in the past, yet is arguably the most critical for controlling eruptive style. Spectroscopic techniques operating in the infrared have proved to be of great value in measuring the composition of gases at high temporal resolution. Such methods, when used in tandem with microanalytical geochemical investigations of erupted products, are leading to better constraints on the depth at which gases are generated and separated from magma. A number of recent studies have focused on transitions between explosive and effusive activity and have led to a better understanding of gas–melt segregation at basaltic volcanoes. Other studies have focused on degassing during intermediate and silicic eruptions. Important new results include the recognition of fluxing by deep-derived gases, which buffer the amount of dissolved volatiles in the melt at shallow depths, and the observation of gas flow up permeable conduit wall shear zones, which may be the primary mechanism for gas loss at the cusp of the most explosive and unpredictable volcanic eruptions. In this paper, I review current and future directions in the field of geochemical studies of volcanic degassing processes and illustrate how the new insights are beginning to change the way in which we understand and classify volcanic eruptions.

scholarly journals Long range transport and fate of a stratospheric volcanic cloud from Soufriere Hills volcano, Montserrat

2007 ◽  
Vol 7 (2) ◽  
pp. 4657-4672 ◽  
Author(s):  
A. J. Prata ◽  
S. A. Carn ◽  
A. Stohl ◽  
J. Kerkmann
Keyword(s):  
Volcanic Eruptions ◽  
Particle Dispersion ◽  
Volcanic Gases ◽  
Satellite Measurements ◽  
Radiative Balance ◽  
Soufriere Hills Volcano ◽  
Soufrière Hills Volcano ◽  
Soufriere Hills ◽  
Volcanic Cloud ◽  
The Impact

Abstract. Volcanic eruptions emit gases, ash particles and hydrometeors into the atmosphere, occasionally reaching great heights to reside in the stratospheric overworld where they affect the radiative balance of the atmosphere and the earth's climate. Here we use satellite measurements and a Lagrangian particle dispersion model to determine the mass loadings, vertical penetration, horizontal extent, dispersion and transport of volcanic gases and particles in the stratosphere from the volcanic cloud emitted during the 20 May 2006 eruption of Soufriere Hills volcano, Montserrat, West Indies. Infrared, ultraviolet and microwave radiation measurements from two polar orbiters are used to quantify the gases and particles, and track the movement of the cloud for 23 days, over a distance of ~18 000 km. Approximately, 0.1±0.01 Tg(S) was injected into the stratosphere in the form of SO2: the largest single sulfur input to the stratosphere in 2006. Microwave Limb Sounder measurements indicate an enhanced mass of HCl of ~0.003–0.01 Tg. Geosynchronous satellite data reveal the rapid nature of the stratospheric injection and indicate that the eruption cloud contained ~2 Tg of ice, with very little ash reaching the stratosphere. These new satellite measurements of volcanic gases and particles can be used to test the sensitivity of climate to volcanic forcing and assess the impact of stratospheric sulfates on climate cooling.

scholarly journals Characterisation of the magmatic signature in gas emissions from Turrialba Volcano, Costa Rica

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 1341-1350 ◽  
Author(s):  
Y. Moussallam ◽  
N. Peters ◽  
C. Ramírez ◽  
C. Oppenheimer ◽  
A. Aiuppa ◽  
...  
Keyword(s):  
Hydrothermal System ◽  
Gas Sensing ◽  
Equilibrium Composition ◽  
Volcanic Plume ◽  
Volcanic Gases ◽  
Gas Composition ◽  
So2 Flux ◽  
Summit Region ◽  
Melt Segregation ◽  
Turrialba Volcano

Abstract. The equilibrium composition of volcanic gases with their magma is often overprinted by interaction with a shallow hydrothermal system. Identifying the magmatic signature of volcanic gases is critical to relate their composition to properties of the magma (temperature, fO2, gas-melt segregation depth). We report measurements of the chemical composition and flux of the major gas species emitted from Turrialba Volcano during March 2013. Measurements were made of two vents in the summit region, one of which opened in 2010 and the other in 2012. We determined an average SO2 flux of 5.2 ± 1.9 kg s-1 using scanning ultraviolet spectroscopy, and molar proportions of H2O, CO2, SO2, HCl, CO and H2 gases of 94.16, 4.03, 1.56, 0.23, 0.003 and 0.009% respectively by open-path Fourier transform infrared (FTIR) spectrometry and a multi-species gas-sensing system. Together, these data imply fluxes of 88, 8, 0.44, 5 × 10-3 and 1 × 10-3 kg s-1 for H2O, CO2, HCl, CO and H2 respectively. Although H2S was detected, its concentration could not be resolved. HF was not detected. The chemical signature of the gas from both vents was found to be broadly similar. Following the opening of the 2010 and 2012 vents we found limited to negligible interaction of the magmatic gas with the hydrothermal system has occurred and the gas composition of the volcanic plume is broadly representative of equilibrium with the magma. The time evolution of the gas composition, the continuous emission of large quantities of SO2, and the physical evolution of the summit area with new vent openings and more frequent eruptions all point towards a continuous drying of the hydrothermal system at Turrialba's summit at an apparently increasing rate.

Real time and in-situ analysis of the gas-emissions of the Eastern Carpathians: results and perspectives

2020 ◽  
Author(s):  
Roland Szalay ◽  
Boglárka-Mercédesz Kis ◽  
Szabolcs Harangi ◽  
László Palcsu ◽  
Marcello Bitetto ◽  
...  
Keyword(s):  
Real Time ◽  
Volcanic Eruptions ◽  
Volcanic Area ◽  
Tectonic Structures ◽  
Gas Emissions ◽  
Volcanic Degassing ◽  
Eastern Carpathians ◽  
In Situ Investigation ◽  
Carpathian Flysch

<p>The Carpathian-Pannonian region was dominated by diverse volcanic activity for the last 20 million years, and even 1 million years ago there was precedent for active zones.  Although volcanic eruptions are very uncommon in the region today, however the frequent earthquakes in the Carpathian-bend, the numerous appearance and intense manifestation of gas-emissions in the southeastern areas of the region and many petrochemical and geochemical volcanologic studies as well, indicate that the area is likely not completely inactive. The gas emissions investigated by us may be directly related to these geodynamic processes [1].</p><p>In Romania, the Eastern Carpathian Neogene-Quaternary volcanic chain and it’s neighbouring zones contain most of the carbon dioxide rich gas emissions, which also occur in the form of natural mofettes, bubbling pools and springs. They can appear in frequently populated settlements more often in cellars, which puts the inhabitants in direct danger due the lack of information in the public knowledge.</p><p>The motivation of our work is to gather real time and in-situ information with the help of Multi-Gas instrument about the composition of the gas-emissions across the Eastern Carpathians and to create a high resolution geological map from the measured sites in the mentioned area above. Furthermore, we would like to clarify if there is any relation between the tectonic characteristics of the study area and the manifestation, concentration of gas-emissions.</p><p>In total, 205 gas emissions were investigated for their CO<sub>2 </sub>(0-100%), CH<sub>4 </sub>(0-7%) and H<sub>2</sub>S (0-200 ppm) concentrations. The composition of the different gas-species varied according to the geological context. The <strong>CO<sub>2</sub></strong> concentrations varied between 0.96 and 98.08 %. The highest values were measured in the the Quaternary volcanic area of Ciomad, and also in the neighbouring thrusted and folded area of the Carpathian Flysch which suggests a tectonic control over the appearance of the gas emissions.</p><p>The <strong>CH<sub>4</sub></strong> concentrations ranged between 0.21 and 6.76% and were higher at hydrocarbon-prone areas, such as the sedimentary deposits of the Transylvanian Basin and Carpathian Flysch. In these cases the CO<sub>2</sub> concentrations were low (up to 4.6%).</p><p>The <strong>H<sub>2</sub>S</strong> concentrations varied between 0.21 and 200 ppm, according to our knowledge, these are the first H<sub>2</sub>S in-situ measurements in the gas emissions of the study area. The concentrations of H<sub>2</sub>S were higher at the volcanic area of Ciomad, reaching values above the detection limit (~200 ppm) which are related to volcanic degassing.</p><p>In conclusion, based on the investigated sites, there is a spatial correlation between the appearance of mineral water springs, gas emissions on surface and the neighbouring tectonic structures. The Multi-Gas proved to be a useful tool in the in-situ investigation of gas emissions of the Eastern Carpathians, being efficient especially for the measurement of the H<sub>2</sub>S concentrations that are very sensitive for oxidation processes.</p><p><strong>Bibliography:</strong></p><p>1.Kis B.M., Caracusi, A., Palcsu, L., Baciu, C., Ionescu, A., Futó, I., Sciarra, A., Harangi, Sz., Noble Gas and Carbon Isotope Systematics at the Seemingly Inactive Ciomadul Volcano (Eastern‐Central Europe, Romania): Evidence for Volcanic Degassing, Geochemistry, Geophysics, Geosystems, vol.20, issue 6, 2019, 3019-3043.</p>

Transtensional shear zones controlling volcanic eruptions: the Middle Pleistocene Mt Amiata volcano (inner Northern Apennines, Italy)

Terra Nova ◽  
2010 ◽  
Vol 22 (2) ◽  
pp. 137-146 ◽  
Author(s):  
Andrea Brogi ◽  
Domenico Liotta ◽  
Marco Meccheri ◽  
Lorenzo Fabbrini
Keyword(s):  
Volcanic Eruptions ◽  
Shear Zones ◽  
Northern Apennines ◽  
Middle Pleistocene

scholarly journals Transient conduit permeability controlled by a shift between compactant shear and dilatant rupture at Unzen volcano (Japan)

2021 ◽  
Author(s):  
Yan Lavallée ◽  
Takahiro Miwa ◽  
James D. Ashworth ◽  
Paul A. Wallace ◽  
Jackie E. Kendrick ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Shear Zone ◽  
Damage Zone ◽  
Volcanic Eruptions ◽  
Shear Zones ◽  
Stick Slip ◽  
Anisotropic Permeability ◽  
Unzen Volcano ◽  
Porosity And Permeability ◽  
Low Porosity

Abstract. The permeability of magma in shallow volcanic conduits controls the fluid flow and pore pressure development that regulates gas emissions and the style of volcanic eruptions. The architecture of the permeable porous structure is subject to changes as magma deforms and outgasses during ascent. Here, we present a high-resolution study of the permeability distribution across two conduit shear zones (marginal and central) developed in the dacitic spine that extruded towards the closing stages of the 1991–1995 eruption at Unzen volcano, Japan. The marginal shear zone is approximately 3.2 m wide and exhibits a 2-m wide, moderate shear zone with porosity and permeability similar to the conduit core, transitioning into a ~1-m wide, highly-sheared region with relatively low porosity and permeability, and an outer 20-cm wide cataclastic fault zone. The low porosity, highly-sheared rock further exhibits an anisotropic permeability network with slightly higher permeability along the shear plane (parallel to the conduit margin) and is locally overprinted by oblique dilational Riedel fractures. The central shear zone is defined by a 3-m long by ~9-cm wide fracture ending bluntly and bordered by a 15–40 cm wide damage zone with an increased permeability of ~3 orders of magnitude; directional permeability and resultant anisotropy could not be measured from this exposure. We interpret the permeability and porosity of the marginal shear zone to reflect the evolution of compactional (i.e., ductile) shear during ascent up to the point of rupture, estimated by Umakoshi et al. (2008), at ~500 m depth. At this point the compactional shear zone would have been locally overprinted by brittle rupture, promoting the development of a shear fault and dilational Riedel fractures during repeating phases of increased magma ascent rate, enhancing anisotropic permeability that channels fluid flow into, and along, the conduit margin. In contrast, we interpret the central shear zone as a shallow, late-stage dilational structure, which partially tore the spine core with slight displacement. We explore constraints from monitored seismicity and stick-slip behaviour to evaluate the rheological controls, which accompanied the upward shift from compactional toward dilational shear as magma approached the surface, and discuss their importance in controlling the permeability development of magma evolving from overall ductile to increasingly brittle behaviour during ascent and eruption.

scholarly journals Characterisation of the magmatic signature in gas emissions from Turrialba volcano, Costa Rica

2014 ◽  
Vol 6 (2) ◽  
pp. 2293-2320 ◽  
Author(s):  
Y. Moussallam ◽  
N. Peters ◽  
C. Ramírez ◽  
C. Oppenheimer ◽  
A. Aiuppa ◽  
...  
Keyword(s):  
Hydrothermal System ◽  
Gas Sensing ◽  
Equilibrium Composition ◽  
Volcanic Plume ◽  
Volcanic Gases ◽  
Gas Composition ◽  
So2 Flux ◽  
Summit Region ◽  
Melt Segregation ◽  
Turrialba Volcano

Abstract. The equilibrium composition of volcanic gases with their magma is often overprinted by interaction with a shallow hydrothermal system. Identifying the magmatic signature of volcanic gases is critical to relate their composition to properties of the magma (temperature, fO2, gas-melt segregation depth). We report measurements of the chemical composition and flux of the major gas species emitted from Turrialba volcano during March 2013. Measurements were made of two vents in the summit region; one of which opened in 2010 and the other in 2012. We determined an average SO2 flux of 2.40 ± 0.75 kg s−1 using scanning ultraviolet spectroscopy, and molar proportions of H2O, CO2, SO2, HCl, CO and H2 gases of 94.16, 4.03, 1.56, 0.23, 0.003 and 0.009%, respectively, by open-path Fourier transform infrared (FTIR) spectrometry and a multi-species gas sensing system. Together, these data imply fluxes of 41, 4, 0.2, 2 × 10−3 and 5 × 10–4 kg s−1 for H2O, CO2, HCl, CO and H2 respectively. Although H2S was detected, its concentration could not be resolved. HF was not detected. The chemical signature of the gas from both vents was found to be broadly similar. Following the opening of the 2010 and 2012 vents we found limited to negligible interaction of the magmatic gas with the hydrothermal system has occurred and the gas composition of the volcanic plume is broadly representative of equilibrium with the magma. The time evolution of the gas composition, the continuous emission of large quantities of SO2 and the physical evolution of the summit area with new vent opening and more frequent eruptions all point towards a continuous drying of the hydrothermal system at Turrialba's summit at an apparently increasing rate.

Volcanic degassing along the enigmatic South Sandwich volcanic arc

2020 ◽  
Author(s):  
Emma Liu ◽  
Kieran Wood ◽  
Alessandro Aiuppa ◽  
Gaetano Giudice ◽  
Marcello Bitetto ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Subduction Zones ◽  
Lava Lake ◽  
Volcanic Eruptions ◽  
Geochemical Evolution ◽  
The South ◽  
Aerosol Composition ◽  
Volcanic Arc ◽  
Volcanic Degassing

<p>The South Sandwich Islands (SSI) are a chain of active volcanoes in the Southern Ocean and remain one of the most remote and enigmatic island arcs on Earth. The relatively recent development of the SSI over the past 20 million years has been closely linked with the formation of the Drake Passage, making this one of the youngest known volcanic arcs and therefore one of the most critical for understanding the early stages of arc geochemical evolution. Recent volcanic eruptions in the SSI have had significant impacts on local terrestrial and marine ecosystems, including some of the largest penguin colonies ever observed, through tephra deposition and from sustained volcanic degassing. Rare cloud-free satellite images over the last two decades have indicated that the summit of Mt Michael (Saunders) hosts a sustained lava lake, but until now these observations have not been ground-truthed by in-situ measurements. Long-term persistent passive outgassing at many of these volcanoes, even between eruptive phases, suggests that the SSI volcanic arc could be a significant source of volatiles to our atmosphere, and yet we lack any constraints on the degassing budgets of this volcanic arc. Here, we present novel measurements of gas chemistry, aerosol composition, and carbon isotope signature from along the South Sandwich Island arc. By combining ground-based measurements of SO<sub>2</sub> flux with in-situ samples of plume composition using Unoccupied Aerial Systems (UAS), we present multi-species volatile fluxes for the major along-arc degassing sources. Further, by evaluating the carbon to sulfur ratio (C/S<sub>T</sub>) and carbon isotope composition in emitted gases together with petrological constraints from erupted tephra, we aim to test the hypothesis that carbon is supplied to the SSI by subduction of oceanic carbonated serpentinite, and thus contribute to our understanding of carbon recycling at subduction zones.</p>

scholarly journals Variability of sulfate signal in ice core records based on five replicate cores

2016 ◽  
Vol 12 (1) ◽  
pp. 103-113 ◽  
Author(s):  
E. Gautier ◽  
J. Savarino ◽  
J. Erbland ◽  
A. Lanciki ◽  
P. Possenti
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Flux Measurement ◽  
Volcanic Eruptions ◽  
Local Scale ◽  
High Temporal Resolution ◽  
Polar Regions ◽  
Regional Patterns ◽  
Snow Drift ◽  
Volcanic Events

Abstract. Current volcanic reconstructions based on ice core analysis have significantly improved over the past few decades by incorporating multiple-core analyses with a high temporal resolution from different parts of the polar regions into a composite common volcanic eruption record. Regional patterns of volcanic deposition are based on composite records, built from cores taken at both poles. However, in many cases only a single record at a given site is used for these reconstructions. This assumes that transport and regional meteorological patterns are the only source of the dispersion of the volcanic products. Here we evaluate the local-scale variability of a sulfate profile in a low-accumulation site (Dome C, Antarctica), in order to assess the representativeness of one core for such a reconstruction. We evaluate the variability with depth, statistical occurrence, and sulfate flux deposition variability of volcanic eruptions detected in five ice cores, drilled 1 m apart from each other. Local-scale variability, essentially attributed to snow drift and surface roughness at Dome C, can lead to a non-exhaustive record of volcanic events when a single core is used as the site reference, with a bulk probability of 30 % of missing volcanic events and close to 65 % uncertainty on one volcanic flux measurement (based on the standard deviation obtained from a five-core comparison). Averaging n records reduces the uncertainty of the deposited flux mean significantly (by a factor 1∕ √ n); in the case of five cores, the uncertainty of the mean flux can therefore be reduced to 29 %.

Gas Flow Through Water-Saturated Shear Zones: Field and Laboratory Experiments and Their Interpretation

1997 ◽  
Vol 506 ◽  
Author(s):  
P. Marschall ◽  
J. Croisé ◽  
U. Fischer ◽  
R. Senger ◽  
E. Wyss
Keyword(s):  
Shear Zone ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Gas Permeability ◽  
Numerical Models ◽  
Shear Zones ◽  
Parameter Estimates ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Processes

ABSTRACTGas threshold pressure tests and gas tracer tests have been performed at the Grimsel Test Site to study two-phase flow processes in a shear zone. In addition, capillary pressure and gas permeability measurements were carried out in the laboratory on drillcore samples. The laboratory investigations were complemented by assessing the pore structure of the shear zone material. The interpretation of the field tests with numerical models indicated that the structural and two-phase flow parameters to be determined are highly correlated with one another and, consequently, the parameter estimates can be rather uncertain. The joint interpretation of field and laboratory results, however, led to a more stringent description of the two-phase flow processes, expressed by a better overall fit of the test data and smaller uncertainty ranges of the estimated parameters. The results showed that the gas mobility in the shear zone was very high even at high water saturation and gas flow was limited to the narrow zones of brittle deformation along the shear zone.

scholarly journals Lava Flow Monitoring Using TET-1 Satellite

2015 ◽  
Vol XL-7/W3 ◽  
pp. 877-882
Author(s):  
K. Zakšek ◽  
E. Lorenz ◽  
M. Hort
Keyword(s):  
Lava Flow ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Satellite Monitoring ◽  
High Temporal Resolution ◽  
Stromboli Volcano ◽  
Flow Monitoring ◽  
Effusive Activity ◽  
Spectral Bands

Lava flow monitoring using satellites provides information on the temporal evolution of volcanic activity. It is usually done using metrological satellites because of the lack of more suitable satellites. The advantage of many meteorological satellites is the availability of appropriate spectral bands. For lava flow monitoring are most useful data in spectrum 3–4 μm (MIR) and 9–12 μm (TIR). However, the spatial resolution of meteorological satellites is usually very coarse causing uncertainties in results. Here we present the first long term satellite monitoring of an active lava flow on Stromboli volcano (end of August till the beginning of November 2014) in high spatial resolution (160 m) and relatively high temporal resolution (~3 days). We analysed data from a test satellite TET-1, which is a test satellite developed at DLR. It carries an instrument dedicated to monitoring of high temperature events. MIR band observations are often saturated at the meteorological satellites. This is not the case of TET-1, although their spatial resolution is very fine for a thermal sensor. TET-1 retrieved 27 datasets over Stromboli during its effusive activity. Some of images were cloudy situations, but most of them were very useful for monitoring of the lava flow radiant power.

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