Explosive-effusive volcanic eruption transitions caused by sintering

Wadsworth, Fabian B.; Llewellin, Edward W.; Vasseur, Jérémie; Gardner, James E.; Tuffen, Hugh

Abstract

Silicic volcanic activity has long been framed as either violently explosive or gently effusive. However, recent observations demonstrate that explosive and effusive behavior can occur simultaneously. Here, we propose that rhyolitic magma feeding subaerial eruptions generally fragments during ascent through the upper crust and that effusive eruptions result from conduit blockage and sintering of the pyroclastic products of deeper cryptic fragmentation. Our proposal is supported by (i) rhyolitic lavas are volatile depleted; (ii) textural evidence supports a pyroclastic origin for effusive products; (iii) numerical models show that small ash particles ≲10−5 m can diffusively degas, stick, and sinter to low porosity, in the time available between fragmentation and the surface; and (iv) inferred ascent rates from both explosive and apparently effusive eruptions can overlap. Our model reconciles previously paradoxical observations and offers a new framework in which to evaluate physical, numerical, and geochemical models of Earth’s most violent volcanic eruptions.

Citation

Wadsworth, F. B., Llewellin, E. W., Vasseur, J., Gardner, J. E., & Tuffen, H. (2020). Explosive-effusive volcanic eruption transitions caused by sintering. Science Advances, 6(39), Article eaba7940. https://doi.org/10.1126/sciadv.aba7940

• Journal Article Type: Article
• Acceptance Date: Jul 22, 2020
• Publication Date: 2020-09
• Deposit Date: Oct 7, 2020
• Publicly Available Date: Oct 7, 2020
• Journal: Science Advances
• Electronic ISSN: 2375-2548
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 6
• Issue: 39
• Article Number: eaba7940
• DOI: https://doi.org/10.1126/sciadv.aba7940
• Public URL: https://durham-repository.worktribe.com/output/1260211