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A porous flow model for the geometrical form of volcanoes - Critical commentsA critical evaluation is presented of the assumptions on which the mathematical model for the geometrical form of a volcano arising from the flow of magma in a porous medium of Lacey et al. (1981) is based. The lack of evidence for an equipotential surface or its equivalent in volcanoes prior to eruption is pointed out, and the preference of volcanic eruptions for low ground is attributed to the local stress field produced by topographic loading rather than a rising magma table. Other difficulties with the model involve the neglect of the surface flow of lava under gravity away from the vent, and the use of the Dupuit approximation for unconfined flow and the assumption of essentially horizontal magma flow. Comparisons of model predictions with the shapes of actual volcanoes reveal the model not to fit lava shield volcanoes, for which the cone represents the solidification of small lava flows, and to provide a poor fit to composite central volcanoes.
Document ID
19820044035
Document Type
Reprint (Version printed in journal)
Authors
Wadge, G.
Francis, P.
Date Acquired
August 10, 2013
Publication Date
February 1, 1982
Publication Information
Publication: Earth and Planetary Science Letters
Volume: 57
Issue: 2, Fe
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NASW-3389
Distribution Limits
Public
Copyright
Other