Quantification of low-temperature gas emissions reveals CO<sub>2</sub> flux underestimates at Soufrière Hills volcano, Montserrat.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40173220.
- Also identified by DOI 10.1126/sciadv.ads8864 and PMC identifier 11963986.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
We performed helicopter-borne optical MultiGAS measurements of volcanic gas emissions from Soufrière Hills Volcano, Montserrat, revealing distinct spikes in SO<sub>2</sub> and HCl concentrations within a larger CO<sub>2</sub>-rich plume. Acid-rich concentration spikes matched the distribution of high-temperature fumaroles, whereas CO<sub>2</sub> is emitted broadly from high- and low-temperature fumaroles. The CO<sub>2</sub> flux was 15 to 41 kilograms per second from hot fumaroles and 61 to 131 kilograms per second for the overall plume. The typical CO<sub>2</sub> flux calculation of multiplying CO<sub>2</sub>/SO<sub>2</sub> ratio with SO<sub>2</sub> flux underestimates total CO<sub>2</sub> flux by at least threefold. We quantified substantial magmatic gas scrubbing by the hydrothermal system, with 56 to 79% of initial HCl and 33 to 68% of initial SO<sub>2</sub> lost. This study highlights the importance of precise acid-gas measurements for detecting heterogeneous degassing and suggests that traditional CO<sub>2</sub> flux measurements may substantially underestimate contributions from cold CO<sub>2</sub> degassing, leading to underestimated global volcanic fluxes.