The effect of internal gas pressurization on volcanic edifice stability: Evolution towards a critical state

Mark E. Thomas, Nick Petford, Edward N. Bromhead

    Research output: Contribution to JournalArticle

    Abstract

    Results from simple physical and numerical models investigating the effects of increased internal pore-fluid pressures of a Mohr–Coulomb volcanic edifice are presented. Physical experiments make use of a heap built from angular sand on top of a stiff substrate of variable angle, with the provision for injection of internal fluid (gas) pressures into the base. The resulting failure geometries arising from internal pressurization of the model appear similar to some natural examples of sector collapse. Two-dimensional limit equilibrium models analysing 42 500 possible failure surfaces were run with internal pressures (P0) in the range 5–35 MPa, and show that the potential critical failure surface migrates to increasingly deeper levels with increasing internal pressure. Although internal pressurization alone is unlikely to reduce the factor of safety (FS) below unity, the edifice is driven towards a state of criticality that will render in susceptible to any internal or external perturbations.
    Original languageEnglish
    Pages (from-to)312-317
    Number of pages6
    JournalTerra Nova
    Volume16
    Issue number5
    DOIs
    Publication statusPublished - 5 Nov 2004

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