DOI: 10.1016/j.epsl.2020.116658
论文题名: Explosivity of basaltic lava fountains is controlled by magma rheology, ascent rate and outgassing
作者: La Spina G. ; Arzilli F. ; Llewellin E.W. ; Burton M.R. ; Clarke A.B. ; de' Michieli Vitturi M. ; Polacci M. ; Hartley M.E. ; Di Genova D. ; Mader H.M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 553 语种: 英语
中文关键词: basalt
; effusive eruption
; explosive eruption
; fragmentation
; lava fountain
; magma ascent
英文关键词: Basalt
; Explosives
; Reynolds number
; Sensitivity analysis
; Viscosity
; Volcanoes
; Basaltic eruptions
; Effusive eruptions
; Explosive activity
; Explosive eruption
; Lower viscosities
; Numerical results
; Parameter spaces
; Volcanic eruptions
; Fountains
; basalt
; fragmentation
; lava flow
; magma chamber
; numerical model
; plinian eruption
; rheology
; sensitivity analysis
; viscosity
; Catania [Sicily]
; Etna
; Hawaii [(ISL) Hawaiian Islands]
; Hawaii [United States]
; Hawaiian Islands
; Italy
; Kilauea
; Sicily
英文摘要: The dichotomy between explosive volcanic eruptions, which produce pyroclasts, and effusive eruptions, which produce lava, is defined by the presence or absence of fragmentation during magma ascent. For lava fountains the distinction is unclear, since the liquid phase in the rising magma may remain continuous to the vent, fragment in the fountain, then re-weld on deposition to feed rheomorphic lava flows. Here we use a numerical model to constrain the controls on basaltic eruption style, using Kilauea and Etna as case studies. Based on our results, we propose that lava fountaining is a distinct style, separate from effusive and explosive eruption styles, that is produced when magma ascends rapidly and fragments above the vent, rather than within the conduit. Sensitivity analyses of Kilauea and Etna case studies show that high lava fountains (>50 m high) occur when the Reynolds number of the bubbly magma is greater than ∼0.1, the bulk viscosity is less than 106Pas, and the gas is well-coupled to the melt. Explosive eruptions (Plinian and sub-Plinian) are predicted over a wide region of parameter space for higher viscosity basalts, typical of Etna, but over a much narrower region of parameter space for lower viscosity basalts, typical of Kilauea. Numerical results show also that the magma that feeds high lava fountains ascends more rapidly than the magma that feeds explosive eruptions, owing to its lower viscosity. For the Kilauea case study, waning ascent velocity is predicted to produce a progressive evolution from high to weak fountaining, to ultimate effusion; whereas for the Etna case study, small changes in parameter values lead to transitions to and from explosive activity, suggesting that eruption transitions may occur with little warning. © 2020 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165551
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Environmental Sciences, The University of Manchester, Manchester, United Kingdom; Department of Earth Sciences, Durham University, Durham, United Kingdom; School of Earth and Space Exploration, Arizona State University, Tempe, United States; Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Pisa, Italy; Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany; School of Earth Sciences, University of Bristol, Bristol, United Kingdom
Recommended Citation:
La Spina G.,Arzilli F.,Llewellin E.W.,et al. Explosivity of basaltic lava fountains is controlled by magma rheology, ascent rate and outgassing[J]. Earth and Planetary Science Letters,2021-01-01,553