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| Titel |
Velocity and attenuation of seismic waves in random media: A spectral function approach |
| VerfasserIn |
Ludovic Margerin, Marie Calvet, Marc Monnereau, Annie Souriau |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074207
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| Zusammenfassung |
| This contribution investigates the scattering of scalar and elastic waves in two-phase materials
and single-mineral-cubic, hexagonal, orthorhombic-polycrystalline aggregates with
randomly oriented grains. Based on the Dyson equation for the mean field, explicit
expressions for the imaginary part of Green’s function in the frequency-wavenumber
domain (Ï,p), also known as the spectral function, are derived. This approach allows
the identification of propagating modes with their relative contribution, and the
computation of both attenuation and phase velocity for each mode. The results should be
valid from the Rayleigh (low-frequency) to the geometrical optics (high-frequency)
regime. Applications of the proposed theory to the structure of the inner core of the
Earth will be presented. In particular, it will be shown that our scattering theory can
explain the striking correlation between velocity and attenuation and the associated
hemispherical variations revealed by PKP waves propagating through the inner
core of the Earth. The implications for inner core dynamics will be summarized. |
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