Search results for " gas flux"
showing 9 items of 9 documents
Periodic volcanic degassing behavior: The Mount Etna example
2013
[1] In contrast to the seismic and infrasonic energy released from quiescent and erupting volcanoes, which have long been known to manifest episodes of highly periodic behavior, the spectral properties of volcanic gas flux time series remain poorly constrained, due to a previous lack of hightemporal resolution gas-sensing techniques. Here we report on SO2 flux measurements, performed on Mount Etna with a novel UV imaging technique of unprecedented sampling frequency (0.5Hz), which reveal, for the first time, a rapid periodic structure in degassing from this target. These gas flux modulations have considerable temporal variability in their characteristics and involve two period bands: 40–250…
Non-stationary nature of SO2 degassing at Etna’s North-east crater (Italy).
2012
Investigating Etna’s long-term SO2 flux behaviour has led to important conclusions on the structure of the volcano’s magma feeding system, magma production (and degassing) rates, and causes for the excess degassing behaviour. Nonetheless, our knowledge of the short-term (timescales of seconds to a few hours) behaviour of magmatic volatiles (e.g., bubble coalescence, separate ascent and surface bursting of gas-rich bubbles) in the volcano’s upper feeding conduit system is still fragmentary, and based on indirect evidences (petrologic-textural data, observation of geophysical signals , physical modelling and laboratory experiments). In the past, direct gas flux measurements at Etna have been ta…
Steam and gas emission rate from La Soufriere volcano, Guadeloupe (Lesser Antilles): implications for the magmatic and hydrothermal fluid supply duri…
2014
Since its last magmatic eruption in 1530 AD, La Soufrière andesitic volcano in Guadeloupe has displayed intense hydrothermal activity and six phreatic eruptive crises. Here we report on the first direct quantification of gas plume emissions from its summit vents,which gradually intensified during the past 20 years. Gas fluxes were determined in March 2006 and March 2012 by measuring the horizontal and vertical distributions of volcanic gas concentrations in the air-diluted plume and scaling to the speed of plume transport. Fluxes in 2006 combine realtime measurements of volcanic H2S concentrations and plume parameters with the composition of the hot (108.5 °C) fumarolic fluid at exit. Fluxe…
Strombolian eruptions and dynamics of magma degassing at Yasur Volcano (Vanuatu)
2020
Abstract Open vent basaltic volcanoes account for a substantial portion of the global atmospheric outgassing flux, largely through passive degassing and mild explosive activity. We present volcanic gas flux and composition data from Yasur Volcano, Vanuatu collected in July 2018. The average volcanic plume chemistry is characterised by a mean molar CO2/SO2 ratio of 2.14, H2O/SO2 of 148 and SO2/HCl of 1.02. The measured mean SO2 flux in the period of 6th to 9th July is 4.9 kg s−1. Therefore, the mean fluxes of the other species are 7.5 kg∙s−1 CO2, 208 kg∙s−1 H2O and 4.8 kg∙s−1 HCl. The degassing regime at Yasur volcano ranges from ‘passive’ to ‘active’ styles, with the latter including Stromb…
Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw
2020
Significance Over many millennia, northern peatlands have accumulated large amounts of carbon and nitrogen, thus cooling the global climate. Over shorter timescales, peatland disturbances can trigger losses of peat and release of greenhouses gases. Despite their importance to the global climate, peatlands remain poorly mapped, and the vulnerability of permafrost peatlands to warming is uncertain. This study compiles over 7,000 field observations to present a data-driven map of northern peatlands and their carbon and nitrogen stocks. We use these maps to model the impact of permafrost thaw on peatlands and find that warming will likely shift the greenhouse gas balance of northern peatlands. …
First gas flux measurements of conduit permeability decrease prior to Strombolian eruption at Stromboli volcano (Italy)
2016
Strombolian eruptions can be described in terms of growth, coalescence, and rise of a gas pocket (aka slug) bursting at the surface of a vent. This model overlooks that the transition to explosive regimes is mostly controlled by the permeability in the upper part of a volcanic conduit. We report here on the first gas flux measurements of Strombolian explosions from a vent that exhibited a significant decrease of passive degassing tens of second prior to the onset of the explosion. This particular explosive activity took place during the July 2014 lava overflows, when the magma level inside the conduit rose up to the crater terrace. The amount of gas that accumulated before the eruption is i…
Plume composition and volatile flux of Nyamulagira volcano, Democratic Republic of Congo, during birth and evolution of the lava lake, 2014-2015
2017
Very little is known about the volatile element makeup of the gaseous emissions of Nyamulagira volcano. This paper tries to fill this gap by reporting the first gas composition measurements of Nyamulagira’s volcanic plume since the onset of its lava lake activity at the end of 2014. Two field surveys were carried out on 1 November 2014, and 13–15 October 2015. We applied a broad toolbox of volcanic gas composition measurement techniques in order to geochemically characterize Nyamulagira’s plume. Nyamulagira is a significant emitter of SO2, and our measurements confirm this, as we recorded SO2 emissions of up to ~ 14 kt/d during the studied period. In contrast to neighbouring Nyiragongo volc…
CO2 flux emissions from the Earth's most actively degassing volcanoes, 2005-2015
2019
AbstractThe global carbon dioxide (CO2) flux from subaerial volcanoes remains poorly quantified, limiting our understanding of the deep carbon cycle during geologic time and in modern Earth. Past attempts to extrapolate the global volcanic CO2 flux have been biased by observations being available for a relatively small number of accessible volcanoes. Here, we propose that the strong, but yet unmeasured, CO2 emissions from several remote degassing volcanoes worldwide can be predicted using regional/global relationships between the CO2/ST ratio of volcanic gases and whole-rock trace element compositions (e.g., Ba/La). From these globally linked gas/rock compositions, we predict the CO2/ST gas…
New Techniques for real-time volcanic gas measurements: the UV camera
2012
In this study, I take advantage of a novel technique - the UV camera - to image SO2 emissions from the Italian volcanoes with improved high temporal resolution. Here, this technique has been updated to a new configuration (dual-camera system), which combines higher temporal resolution (0.5-1.2 Hz) and improved accuracy relative to the single-camera setup. The methodology has been extensively tested and improved, whilst developing a user-friendly control software (Vulcamera) and a calibration technique (in tandem DOAS-SO2 quartz cells calibration), which simplify instrument deployment, acquisition and data analysis. A first application was focused on SO2 gas flux measurements at individual fuma…