Direct observation of degassing during decompression of basaltic magma
Year: 2024
Type: article
Abstract: Transitions in eruptive style during volcanic eruptions strongly depend on how easily gas and magma decouple during ascent. Stronger gas-melt coupling favors highly explosive eruptions, whereas weaker coupling promotes lava fountaining and lava flows. The mechanisms producing these transitions are still poorly understood because of a lack of direct observations of bubble dynamics under natural magmatic conditions. Here, we combine x-ray radiography with a novel high-pressure/high-temperature apparatus to observe and quantify in real-time bubble growth and coalescence in basaltic magmas from 100 megapascals to surface. For low-viscosity magmas, bubbles coalesce and recover a spherical shape within 3 seconds, implying that, for lava fountaining activity, gas and melt remain coupled during the ascent up to the last hundred meters of the conduit. For higher-viscosity magmas, recovery times become longer, promoting connected bubble pathways. This apparatus opens frontiers in unraveling magmatic/volcanic processes, leading to improved hazard assessment and risk mitigation.
Source: Science Advances
Institutions: University of Manchester, Università di Camerino, Istituto Nazionale di Geofisica e Vulcanologia, INGV Osservatorio Etneo, Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Institut Néel, Université Grenoble Alpes, University of Bristol, Diamond Light Source, University College London, Rutherford Appleton Laboratory, Research Complex at Harwell
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,500
OpenAlex ID: W4401633660