|
|
|
|
|
| Hanafin, Jennifer; Quilfen, Yves; Ardhuin, Fabrice; Sienkiewicz, Joseph; Queffeulou, Pierre; Obrebski, Mathias; Chapron, Bertrand; Reul, Nicolas; Collard, Fabrice; Corman, David; De Azevedo, Eduardo B.; Vandemark, Doug; Stutzmann, Eleonore. |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00094/20538/18197.pdf |
| |
|
|
| Ardhuin, Fabrice; Balanche, Abel; Stutzmann, E.; Obrebski, Mathias. |
| Seismic noise is an indirect source of information on ocean waves. Using a model of noise generation and propagation, seismic stations can be separated into those that are mostly sensitive to local sea states, and those that integrate sources from a large oceanic area. The model also provides a classification of noise-generating sea states into three classes. The analysis of Central California seismic noise data, well correlated with local waves, reveals that class I events dominate in summer, caused by a single wind-sea system, and for which ocean wave spectral levels are proportional to seismic spectral levels to an exponent b similar or equal to 0.9. In winter, noise is dominated by class II generation, for which coastal reflection is important, with a... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00083/19443/17051.pdf |
| |
|
|
| Obrebski, Mathias; Ardhuin, Fabrice; Stutzmann, E.; Schimmel, M.. |
| The location of oceanic sources of the micrometric ground displacement recorded at land stations in the 0.1-0.3 Hz frequency band ("double frequency microseisms") is still poorly known. Here we use one particularly strong noise event in the Pacific to show that small swells from two distant storms can be a strong deep-water source of seismic noise, dominating temporarily the signals recorded at coastal seismic stations. Our interpretation is based on the analysis of noise polarization recorded all around the source, and the good fit achieved for this event and year-round between observed and modeled seismic data. The model further suggests that this is a typical source of these infrequent loud noise bursts, which supports previous inconclusive evidences of... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00085/19625/17262.pdf |
| |
|
| |
|
|
| Obrebski, Mathias; Allen, Richard M.; Zhang, Fengxue; Pan, Jiatie; Wu, Qingju; Hung, Shu-huei. |
| The India-Eurasia collision and the decratonization of the North China Craton have drawn much attention from the scientific community. Here we provide the first large-scale S wave velocity model for China (CH11-S) based on constraints from both teleseismic surface and body waves. We take advantage of the recent deployment of the 140 permanent stations of the Chinese Digital Seismic Network and temporary network deployments to resolve both the lithospheric and deeper mantle structure. Slow velocities are widespread in the crust and upper mantle. Deeply rooted fast anomalies are located beneath the stable Yangtze Craton and the western (Ordos) block of the North China Craton. An upper mantle fast anomaly is observed beneath the eastern block of the North... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00066/17757/15712.pdf |
| |
|
|
| Ardhuin, Fabrice; Lavanant, Thibaut; Obrebski, Mathias; Marie, Louis; Royer, Jean-yves; D'Eu, Jean-francois; Howe, Bruce M.; Lukas, Roger; Aucan, Jerome. |
| The generation of ultra-low frequency acoustic noise (0.1 to 1 Hz) by the nonlinear interaction of ocean surface gravity waves is well established. More controversial are the quantitative theories that attempt to predict the recorded noise levels and their variability. Here a single theoretical framework is used to predict the noise level associated with propagating pseudo-Rayleigh modes and evanescent acoustic-gravity modes. The latter are dominant only within 200 m from the sea surface, in shallow or deep water. At depths larger than 500 m, the comparison of a numerical noise model with hydrophone records from two open-ocean sites near Hawaii and the Kerguelen islands reveal: (a) Deep ocean acoustic noise at frequencies 0.1 to 1 Hz is consistent with the... |
| Tipo: Text |
|
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00176/28748/27211.pdf |
| |
|
| |
|
|
|
