Valve-like dynamics of gas flow through a packed crystal mush and cyclic strombolian explosions.
Nature Publishing Group
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Barth, A., Edmonds, M., & Woods, A. (2019). Valve-like dynamics of gas flow through a packed crystal mush and cyclic strombolian explosions.. Scientific reports, 9 (1), 821. https://doi.org/10.1038/s41598-018-37013-8
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 both volatile-rich but also highly crystalline, with mush regions in the shallow plumbing system, where an exsolved volatile phase is 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, which generates 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.
NERC (via University of Leeds) (RGEVEA100399)
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External DOI: https://doi.org/10.1038/s41598-018-37013-8
This record's URL: https://www.repository.cam.ac.uk/handle/1810/288295
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/