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Stability of volcanic conduits during explosive eruptions and the influence of conduit geometry.

Aravena Á., de' Michieli Vitturi M. Cioni R., Neri A.
  Venerdì 30/09   09:00 - 12:00   Edificio Psicologia 2 - Aula 2A   IV - Geofisica, Fisica dell'ambiente
Stability of volcanic conduits is a key factor that can affect the dynamics of explosive eruptions. Based on numerical simulations carried out by a two-phase steady-state model, it emerges that conduit stability is mainly controlled by magma rheology and conduit radius. We estimated a minimum magma flux for developing stable conduits, which is consistent with the unsteady character usually observed in low-mass flux events, opposite to mainly stationary eruptions, commonly characterized by high magma fluxes. As instability conditions are not uniform along the conduit, two non-cylindrical geometries have been tested, evidencing major modifications in some eruptive parameters.