Synthetic waveform modelling of SS precursors from anisotropic upper-mantle discontinuities
Synthetic waveform modelling of SS precursors from anisotropic upper-mantle discontinuities
SS precursors are a powerful tool for interrogating upper-mantle discontinuity structure. Some of these discontinuities may be defined fully or partially by a variation in anisotropy with depth. Therefore, a careful evaluation of SS precursor waveform predictions from anisotropic discontinuities is required. Here, we perform synthetic waveform modelling to evaluate the potential for using SS precursors to constrain anisotropic discontinuities. We investigate SS precursor amplitudes from models with azimuthally anisotropic discontinuities with assumed hexagonal symmetry. We demonstrate that SS precursor polarity variations are robust across a wide range of earthquake source polarizations for our anisotropic models. While polarity variations are not unique among all potential two-layer models with anisotropic discontinuities, other observables, such as the relative arrival time of the precursor and tectonic settings, may be used to constrain anisotropic structure. We discuss implications for previous imaging of upper-mantle discontinuities that may be anisotropic, such as the Lehmann discontinuity, and discontinuities in depth range of the lithosphere–asthenosphere boundary beneath the Pacific.
Mantle processes, Body waves, Seismic anisotropy, Wave scattering and diffraction, Pacific Ocean
1694-1705
Rychert, C.A.
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Harmon, N.
10d11a16-b8b0-4132-9354-652e72d8e830
Schmerr, N.
2e1b3c29-1ece-40d0-96ac-05b40353dff0
March 2014
Rychert, C.A.
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Harmon, N.
10d11a16-b8b0-4132-9354-652e72d8e830
Schmerr, N.
2e1b3c29-1ece-40d0-96ac-05b40353dff0
Rychert, C.A., Harmon, N. and Schmerr, N.
(2014)
Synthetic waveform modelling of SS precursors from anisotropic upper-mantle discontinuities.
Geophysical Journal International, 196 (3), .
(doi:10.1093/gji/ggt474).
Abstract
SS precursors are a powerful tool for interrogating upper-mantle discontinuity structure. Some of these discontinuities may be defined fully or partially by a variation in anisotropy with depth. Therefore, a careful evaluation of SS precursor waveform predictions from anisotropic discontinuities is required. Here, we perform synthetic waveform modelling to evaluate the potential for using SS precursors to constrain anisotropic discontinuities. We investigate SS precursor amplitudes from models with azimuthally anisotropic discontinuities with assumed hexagonal symmetry. We demonstrate that SS precursor polarity variations are robust across a wide range of earthquake source polarizations for our anisotropic models. While polarity variations are not unique among all potential two-layer models with anisotropic discontinuities, other observables, such as the relative arrival time of the precursor and tectonic settings, may be used to constrain anisotropic structure. We discuss implications for previous imaging of upper-mantle discontinuities that may be anisotropic, such as the Lehmann discontinuity, and discontinuities in depth range of the lithosphere–asthenosphere boundary beneath the Pacific.
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e-pub ahead of print date: January 2014
Published date: March 2014
Keywords:
Mantle processes, Body waves, Seismic anisotropy, Wave scattering and diffraction, Pacific Ocean
Organisations:
Geology & Geophysics
Identifiers
Local EPrints ID: 361094
URI: http://eprints.soton.ac.uk/id/eprint/361094
ISSN: 0956-540X
PURE UUID: 1332270c-a9eb-4d1a-9717-63e5afc4c836
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Date deposited: 13 Jan 2014 10:09
Last modified: 15 Mar 2024 03:33
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Author:
N. Schmerr
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