Volcanic Gas Emissions and Geochemical Dynamics

Volcanic gases, predominantly water vapour, carbon dioxide and sulphur species, are critical conveyors of deep‐Earth processes to the surface environment. Their fluxes and compositions provide direct insights into magma ascent, redox state and magma‐hydrothermal interactions. Gas emissions regulate volcanic explosivity, drive phreatic and magmatic eruptions, and influence atmospheric chemistry, climate forcing and air quality on regional to global scales. Advances in remote sensing, in‐situ analysis and geochemical modelling have revealed complex controls on gas‐melt separation, shallow‐level storage and pressure cycling within conduits. High‐resolution spectroscopic measurements and satellite retrievals now resolve rapid changes in gas ratios that presage eruptive transitions. Integrative approaches spanning gas flux inventories, experimental photochemistry and field observation are unravelling the cascading effects of volcanic degassing on aerosol formation, tropospheric ozone budgets and the long‐term carbon cycle.

Research from Nature Portfolio

Recent studies have captured time‐resolved gas release during pulsatory lava fountaining at a basaltic vent, revealing sequential degassing of CO₂ at depth followed by shallow H₂O–SO₂ separation. This work elucidates how cyclical pressure buildup in a near‐surface magma chamber governs fountain intermittency and supports broader models of magma–gas interaction. Over decadal timescales, global satellite measurements of SO₂ emissions have been synthesised into a comprehensive inventory of passive volcanic degassing, quantifying average fluxes of ~23 Tg yr⁻¹ and identifying regional trends in increasing outputs. Complementary assessments of CO₂ flux from the most actively degassing subaerial volcanoes have combined gas‐rock compositional correlations with satellite SO₂ data to constrain a total CO₂ output of ~39 Mt yr⁻¹. These integrative inventories underpin refined estimates of volcanic contributions to the modern carbon cycle and highlight significant unmeasured degassing at remote systems.

Volcanic Gas Emissions and Geochemical Dynamics publication trend

The graph below shows the total number of articles in volcanic gas emissions and geochemical dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Degassing: Release of volatiles from magma during ascent or storage.

Passive degassing: Continuous gas emission in the absence of eruptive activity.

Phreatic eruption: Steam‐driven explosion caused by heating of groundwater by magma or hot gases.

Sulphur dioxide (SO₂) flux: Rate of SO₂ mass released per unit time, critical for atmospheric and climate impact assessment.

Remote sensing: Measurement of gas concentrations and fluxes from a distance using satellites or ground‐based spectrometers.

Vacuum ultraviolet photodissociation: Photon‐driven cleavage of molecular bonds at wavelengths below 200 nm, generating reactive species.

Back‐trajectory analysis: Modelling approach to trace the transport pathways of emitted gases from source to sampling location.

References

1. Near-surface magma flow instability drives cyclic lava fountaining at Fagradalsfjall, Iceland. Nature Communications (2023).
2. A decade of global volcanic SO2 emissions measured from space. Scientific Reports (2017).
3. CO2 flux emissions from the Earth’s most actively degassing volcanoes, 2005–2015. Scientific Reports (2019).
4. Vacuum ultraviolet photodissociation of sulfur dioxide and its implications for oxygen production in the early Earth's atmosphere. Chemical Science (2023).
5. Satellite derived SO2 emissions from the relatively low-intensity, effusive 2021 eruption of Fagradalsfjall, Iceland. Earth and Planetary Science Letters (2023).
6. Implementation of electrochemical, optical and denuder-based sensors and sampling techniques on UAV for volcanic gas measurements: examples from Masaya, Turrialba and Stromboli volcanoes. Atmospheric Measurement Techniques (2018).