Data/hora: 05/06/2024 11:28:28

Provedor de dados: | 5
País: | France
Título: | Ray-theoretical modeling of secondary microseism P-waves
Autores: | Farra, V.; Stutzmann, Eleonore; Gualtieri, Lucia; Schimmel, M.; Ardhuin, Fabrice.
Data: | 2016-09
Ano: | 2016
Palavras-chave: | Seismic interferometry; Body waves; Seismic noise; Wave propagation.
Resumo: | Secondary microseism sources are pressure fluctuations close to the ocean surface. They generate acoustic P-waves that propagate in water down to the ocean bottom where they are partly reflected, and partly transmitted into the crust to continue their propagation through the Earth. We present the theory for computing the displacement power spectral density of secondary microseism P-waves recorded by receivers in the far field. In the frequency domain, the P-wave displacement can be modeled as the product of (1) the pressure source, (2) the source site effect that accounts for the constructive interference of multiply reflected P-waves in the ocean, (3) the propagation from the ocean bottom to the stations, (4) the receiver site effect. Secondary microseism P-waves have weak amplitudes, but they can be investigated by beamforming analysis. We validate our approach by analyzing the seismic signals generated by Typhoon Ioke (2006) and recorded by the Southern California Seismic Network. Back projecting the beam onto the ocean surface enables to follow the source motion. The observed beam centroid is in the vicinity of the pressure source derived from the ocean wave model WAVEWATCH IIIR. The pressure source is then used for modeling the beam and a good agreement is obtained between measured and modeled beam amplitude variation over time. This modeling approach can be used to invert P-wave noise data and retrieve the source intensity and lateral extent.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/00344/45509/45063.pdf

DOI:10.1093/gji/ggw242

http://archimer.ifremer.fr/doc/00344/45509/

Editor: | Oxford Univ Press
Formato: | application/pdf
Fonte: | Geophysical Journal International (0956-540X) (Oxford Univ Press), 2016-09 , Vol. 206 , N. 3 , P. 1730-1739

Fonte:

The Authors 2016. Published by Oxford University Press on behalf of The Royal Astronomical Society.

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