Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/2372
AuthorsDiller, K.* 
Clarke, A.* 
Voight, B.* 
Neri, A.* 
TitleMechanisms of conduit plug formation: implications for Vulcanian explosions.
Issue Date2006
Series/Report no./33 (2006)
DOI10.1029/2006GL027391
URIhttp://hdl.handle.net/2122/2372
Keywordsphysical mechanisms
magma
Subject Classification04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous 
04. Solid Earth::04.08. Volcanology::04.08.03. Magmas 
05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous 
AbstractWe explore physical mechanisms controlling formation of a confining conduit plug using 1D, steady-state numerical models of magma ascent. Model results for the welldocumented 1997 Vulcanian explosions at Soufrie`re Hills volcano were compared against subsurface conditions constrained by geophysical and petrologic analysis. We suggest that, if magma is permeable and overpressured and rock surrounding the conduit is permeable, degassing occurs both vertically and through conduit walls. This outgassing creates a region of low-vesicularity, dense magma near the surface (magma plug) which eventually seals the conduit and promotes system overpressure. Driving pressure increases with increasing magma flow rate, hindering volatile exsolution and shifting open-system degassing to shallower levels of the conduit. As a result, increasing magma flow rate for a fixed conduit width creates a vertically thinner plug and increases the magnitude and vertical extent of conduit overpressure. Plug thickness and density are also controlled by magma and edifice permeability
Appears in Collections:Papers Published / Papers in press

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