Houghton, B.F. and Tisdale, C.M. and Llewellin, E.W. and Taddeucci, J. and Orr, T.R. and Walker, B.H. and Patrick, M.R. (2021) 'The birth of a Hawaiian fissure eruption.', Journal of geophysical research : solid earth., 126 (1). e2020JB020903.
Abstract
Most basaltic explosive eruptions intensify abruptly, allowing little time to document processes at the start of eruption. One opportunity came with the initiation of activity from fissure 8 (F8) during the 2018 eruption on the lower East Rift Zone of Klauea, Hawaii. F8 erupted in four episodes. We recorded 28 minutes of high-definition video during a 51-minute period, capturing the onset of the second episode on 5 May. From the videos we were able to analyze the following in-flight parameters: frequency and duration of explosions; ejecta heights; pyroclast exit velocities; in-flight total mass and estimated mass eruption rates; and the in-flight total grain size distributions. Videos record a transition from initial pulsating outgassing, via spaced, but increasingly rapid, discrete explosions, to quasi-sustained, unsteady fountaining. This transition accompanied waxing intensity (mass flux) of the F8 eruption. We infer that all activity was driven by a combination of the ascent of a coupled mixture of small bubbles and melt, and the buoyant rise of decoupled gas slugs and/or pockets. The balance between these two types of concurrent flow determined the exact form of the eruptive activity at any point in time, and changes to their relative contributions drove the transition we observed at early F8. Qualitative observations of other Hawaiian fountains at Klauea suggest that this physical model may apply more generally. This study demonstrates the value of in-flight parameters derived from high resolution videos, which offer a rapid and highly time-sensitive alternative to measurements based on sampling of deposits post-eruption.
Item Type: | Article |
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Full text: | (AM) Accepted Manuscript Download PDF (8475Kb) |
Status: | Peer-reviewed |
Publisher Web site: | https://doi.org/10.1029/2020JB020903 |
Publisher statement: | This is the peer reviewed version of the following article: Houghton, B.F., Tisdale, C.M., Llewellin, E.W., Taddeucci, J., Orr, T.R., Walker, B.H. & Patrick, M.R. (2021). The Birth of a Hawaiian Fissure Eruption. Journal of Geophysical Research: Solid Earth 126(1): e2020JB020903., which has been published in final form at https://doi.org/10.1029/2020JB020903. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Date accepted: | 01 December 2020 |
Date deposited: | 03 June 2021 |
Date of first online publication: | 04 December 2020 |
Date first made open access: | 04 December 2021 |
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