Valve-like dynamics of gas flow through a packed crystal mush and cyclic strombolian explosions

Barth, Anna and Edmonds, Marie and Woods, Andrew W. (2019) Valve-like dynamics of gas flow through a packed crystal mush and cyclic strombolian explosions. Scientific Reports, 9 (1). ISSN 2045-2322 DOI https://doi.org/10.1038/s41598-018-37013-8

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Official URL: https://doi.org/10.1038/s41598-018-37013-8

Abstract

Strombolian volcanic explosions are commonly attributed to the rise and burst of conduit-filling gas slugs. The magmas associated with strombolian activity, however, are typically not only volatile-rich but also highly crystalline, with mush regions in the shallow plumbing system, where an exsolved volatile phase may also be abundant. Through analogue experiments, we explore a new mechanism to form gas slugs and strombolian explosions. A steady flux of gas is supplied to the base of a particle-rich liquid layer, generating a localised gas intrusion, which initially grows through plastic deformation. Once the pressure in the intrusion overcomes the effective tensile strength of the particle pack, a localised channel opens, allowing gas to propagate upwards. As the pressure in the intrusion falls, the gas pocket collapses. The continued supply of gas leads to the formation of a new intrusion, and the cycle repeats. With higher gas fluxes, continuous channelised gas flow occurs. Highly crystalline shallow portions of basaltic conduits may act as a flow valve, transforming a steady gas flux into a series of discrete gas slugs which cause explosions.

Item Type: Article
Uncontrolled Keywords: 2018AREP; IA74
Subjects: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Divisions: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
06 - Part-III Projects
07 - Gold Open Access
Journal or Publication Title: Scientific Reports
Volume: 9
Identification Number: https://doi.org/10.1038/s41598-018-37013-8
Depositing User: Sarah Humbert
Date Deposited: 01 Feb 2019 12:50
Last Modified: 01 Feb 2019 12:50
URI: http://eprints.esc.cam.ac.uk/id/eprint/4408

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