The influence of geometry on the ascent of magma in open fissures

Giberti, G. and Wilson, L. (1990) The influence of geometry on the ascent of magma in open fissures. Bulletin of Volcanology, 52 (7). pp. 515-521. ISSN 0258-8900

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Abstract

During steady eruption, the flow conditions (emitted mass flux, exit velocity and exit pressure) depend on the geometry of the conduit in which the eruption occurs. This dependence is examined for the onedimensional, isothermal ascent of a homogeneous basaltic magma with an aqueous volatile phase and newtonian rheology. By fixing the geometry of the feeding fissure, the mass flux flowing in steady conditions can be determined at any depth, as well the magma pressure and vertical velocity. Flow behaviour is analysed for three fissure shapes: constant width, slowly upward narrowing and lenticular. In all the cases examined the magma arrives at the earth's surface with a pressure greater than atmospheric. The results are compared with those obtained when a lithostatic pressure gradient is assumed for the magma column. Some speculations are made, moreover, about the change in eruption style, if conduit geometry varies during a non-steady phase.

Item Type:
Journal Article
Journal or Publication Title:
Bulletin of Volcanology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1906
Subjects:
ID Code:
148998
Deposited By:
Deposited On:
12 Nov 2020 16:40
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Nov 2020 14:56