Data/hora: 17/06/2024 07:34:10

Provedor de dados: 	5	
País: 	France	
Título: 	Modelling secondary microseismic noise by normal mode summation	
Autores: 	Gualtieri, L.; Stutzmann, E.; Capdeville, Y.; Ardhuin, Fabrice; Schimmel, M.; Mangeney, A.; Morelli, A.	
Data: 	2013-06	
Ano: 	2013	
Palavras-chave: 	Surface waves and free oscillations; Seismic attenuation; Theoretical seismology; Wave propagation.	
Resumo: 	Secondary microseisms recorded by seismic stations are generated in the ocean by the interaction of ocean gravity waves. We present here the theory for modelling secondary microseismic noise by normal mode summation. We show that the noise sources can be modelled by vertical forces and how to derive them from a realistic ocean wave model. We then show how to compute bathymetry excitation effect in a realistic earth model by using normal modes and a comparison with Longuet-Higgins approach. The strongest excitation areas in the oceans depends on the bathymetry and period and are different for each seismic mode. Seismic noise is then modelled by normal mode summation considering varying bathymetry. We derive an attenuation model that enables to fit well the vertical component spectra whatever the station location. We show that the fundamental mode of Rayleigh waves is the dominant signal in seismic noise. There is a discrepancy between real and synthetic spectra on the horizontal components that enables to estimate the amount of Love waves for which a different source mechanism is needed. Finally, we investigate noise generated in all the oceans around Africa and show that most of noise recorded in Algeria (TAM station) is generated in the Northern Atlantic and that there is a seasonal variability of the contribution of each ocean and sea.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/00146/25703/24020.pdf

DOI:10.1093/gji/ggt090	
Editor: 	Oxford Univ Press	
Relação: 	http://archimer.ifremer.fr/doc/00146/25703/	
Formato: 	application/pdf	
Fonte: 	Geophysical Journal International (0956-540X) (Oxford Univ Press), 2013-06 , Vol. 193 , N. 3 , P. 1732-1745	
Fonte: 	2013 The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society