HR: 0800h
AN: V51D-0782    [Abstracts]
TI: Using the Seismic Amplitude Decay of Low-Frequency Events to Constrain Magma Properties.
AU: * Smith, P J
EM: p.j.smith@see.leeds.ac.uk
AF: The University of Leeds, Institute of Geophysics & Tectonics, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
AU: Neuberg, J W
EM: j.neuberg@see.leeds.ac.uk
AF: The University of Leeds, Institute of Geophysics & Tectonics, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
AB: Low-frequency events are considered a key part of volcanic monitoring, as they are one of the few tools available that can link surface observations directly to internal volcanic processes and properties. Our model for their generation on the Soufrière Hills Volcano, Montserrat, is brittle fracturing of the magma at the conduit walls, providing the seismic trigger mechanism, followed by conduit resonance. The attenuation of seismic waves in a viscous magma is highly dependent on the properties of the attenuating material, in particular the viscous friction, controlled by the melt viscosity, gas content and diffusivity. Therefore we can use the seismicity to gain information on these magma properties. This research uses a two-dimensional viscoelastic finite-difference model, with the attenuative behaviour of the magma parameterised by an array of Standard Linear Solids. By examining the relationship between the amplitude decay of the synthetic low-frequency events, the intrinsic attenuation and the elastic parameter contrast, this research aims to link observables such as amplitude decay of the coda directly to properties such as the magma viscosity.
DE: 5144 Wave attenuation
DE: 7280 Volcano seismology (8419)
DE: 8419 Volcano monitoring (7280)
DE: 8429 Lava rheology and morphology
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting