HR: 17:05h
AN: V34A-04    [Abstracts]
TI: Volcano Relaxation Following Great Dome Collapses: Impact on Magma Volume Retrievals From Geodetic Monitoring at Soufriere Hills Volcano, Montserrat, West Indies
AU: * Fournier, N
EM: nicofournier@uwiseismic.com
AF: Seismic Research Unit The University of the West Indies, Gordon Street, St Augustine, Trinidad and Tobago
AU: Ryan, G
EM: graham@mvo.ms
AF: Montserrat Volcano Observatory, Flemmings, Montserrat
AU: Ryan, G
EM: graham@mvo.ms
AF: British Geological Survey, Kingsley Dunham Centre Keyworth, Nottingham, NG12 5GG, United Kingdom
AU: Strutt, M
EM: mick@mvo.ms
AF: Montserrat Volcano Observatory, Flemmings, Montserrat
AU: Strutt, M
EM: mick@mvo.ms
AF: British Geological Survey, Kingsley Dunham Centre Keyworth, Nottingham, NG12 5GG, United Kingdom
AB: Large dome collapses can induce a significant stress release on volcanic edifices. We used 3D Finite Element Method (FEM) analysis to assess the effect of the July 12-13, 2003 dome collapse at Montserrat on the edifice (i.e. ground deformation due to elastic relaxation). The edifice geometry was derived from a high-resolution Digital Elevation Model whereas the dome geometry was estimated from recorded observations. We used linear and isotropic elastic properties for the FEM structural analysis of the edifice response and simulated the dome collapse by the cancellation of gravitational body forces in the dome domain. Results of our numerical modelling show that a significant amount of observed ground deformation is due to the edifice elastic relaxation. Direct interpretation of ground deformation as solely due to magma input into the shallow magma chamber and/or overpressurization due to volatile exsolution would therefore be greatly over-estimated. Here we quantify the ground deformation due to the edifice relaxation and discuss our model implications for volcano deformation monitoring and magma volume retrieval.
DE: 1299 General or miscellaneous (1709)
DE: 3225 Numerical approximations and analysis (4260)
DE: 8419 Volcano monitoring (7280)
DE: 8428 Explosive volcanism
DE: 8439 Physics and chemistry of magma bodies
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly