HR: 11:35h
AN: S42A-06    [Abstracts]
TI: Potential and Pitfalls of Guided Waves at Subduction Zones
AU: * Martin, S
EM: s.martinberlin@web.de
AF: Dept of Earth Sciences University of Liverpool, 4 Brownlow street, Liverpool, L69 3GP United Kingdom
AU: Rietbrock, A
EM: ariet@liv.ac.uk
AF: Dept of Earth Sciences University of Liverpool, 4 Brownlow street, Liverpool, L69 3GP United Kingdom
AB: Seismic guided waves that travel along the surface of subducted slabs provide a means to infer petrology to depth beyond the volcanic arc. It is now possible to retrieve detailed information on the width and velocity contrast of low-velocity layering at the slab surface using guided wave onsets. However, they have to be analyzed carefully accounting for slab geometry and higher-modes to avoid misinterpretation. 2-dimensional finite difference simulations shed light on the potential and dangers of the guided wave method: Different mechanisms of decoupling of guided waves from the slab surface are investigated, and the distribution of guided wave onsets in the forearc region is calculated. Furthermore, simulations of double couple sources show the exceeding effects of source orientation and location on pulse shapes including excitation of higher-modes. The simulations explain the complex wave field caused by low-velocity layers at the top of subducted slabs and show the potential of guided wave observations to narrow down mineralogical interpretations.
DE: 7220 Oceanic crust
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005