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SUMMARY:Development of anisotropy of permeability in expanding vesicular m
 agma - Ed Llewellin\, Earth Sciences\, University of Durham
DTSTART:20070608T103000Z
DTEND:20070608T113000Z
UID:TALK7376@talks.cam.ac.uk
CONTACT:Anne Alexander
DESCRIPTION:_The rate of escape of magmatic gases from vesiculating\, expa
 nding magma is key to controlling the explosivity of an eruption.  Permeat
 ing networks of bubbles may develop as magma rises and bubbles grow and im
 pinge on one another.  Geometric analysis shows that permeability develops
  anisotropically in the volcanic conduit: permeability across the conduit 
 is enhanced and permeability along the conduit is hindered.  The higher ra
 te of horizontal gas loss that results has implications for the eruption r
 ate and eruptive style - enhanced lateral degassing facilitates rapid gas 
 escape\, reducing the likelihood of magma fragmentation and mitigating eru
 ption explosivity.  The finding also calls into question the validity of e
 ruption models which assume vertical gas flow\, and paves the way for a ne
 w class of eruption model that resolves permeability throughout the volcan
 ic system._
LOCATION:Open Plan Area\, BP Institute\, Madingley Rise CB3 0EZ
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