HR: 0800h
AN: V21C-0731    [Abstracts]
TI: Gas slug ascent as a source for very long-period seismicity: a numerical investigation
AU: * O'Brien, G S
EM: gareth.obrien@ucd.ie
AF: School of Geological Sciences, University College Dublin, Belfield, Dublin 4, D4, Ireland
AU: Bean, C
EM: chris.bean@ucd.ie
AF: School of Geological Sciences, University College Dublin, Belfield, Dublin 4, D4, Ireland
AB: Very long period (VLP) signals provide a unique insight into the source process of seismic signals recorded on active or restless volcanoes. This is due to the large wavelengths that may allow the structural heterogeneity to be ignored hence source inversions can be calculated. The source process involved in such events is thought to be related to magma transport, gas slug ascent or dike resonance initiated by a fluid driven process. Numerical modelling of gas slug ascent (constrained by results from published laboratory experiments) shows that this process is capable of generating VLP like signals. Inputting the fluid dynamic derived forces into an elastic medium, with ‘volcano' like topography, VLP-like signals are reproduced. A moment tensor inversion is performed on these synthetic VLP signals. The moment tensor inversion produces a Compensated Linear Vector Dipole (CLVD) source mechanism for a pipe structure.
DE: 7280 Volcano seismology (8419)
DE: 7290 Computational seismology
DE: 8430 Volcanic gases
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting