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| Tary, Jean-baptiste; Geli, Louis; Guennou, Claude; Henry, Pierre; Sultan, Nabil; Cagatay, N.; Vidal, V.. |
| Different types of 4-component ocean bottom seismometers (OBS) were deployed for variable durations ranging from 1 week to about 4 months in 2007, over soft sediments covering the seafloor of the Tekirdag Basin (western part of the Sea of Marmara, Turkey). Non-seismic microevents were recorded by the geophones, but generally not by the hydrophones, except when the hydrophone is located less than a few tens of centimetres above the seafloor. The microevents are characterized by short durations of less than 0.8 s, by frequencies ranging between 4 and 30 Hz, and by highly variable amplitudes. In addition, no correlation between OBSs was observed, except for two OBSs, located 10 m apart. Interestingly, a swarm of similar to 400 very similar microevents (based... |
| Tipo: Text |
Palavras-chave: Time series analysis; Gas and hydrate systems; Body waves; Interface waves; Seismic attenuation; Wave propagation. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00089/20012/17825.pdf |
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| Lecoulant, Jean; Guennou, Claude; Guillon, Laurent; Royer, Jean-yves. |
| The low-frequency (4-40 Hz) acoustic waves generated by undersea earthquakes are of great importance to monitor the low-level seismic activity associated with seafloor spreading ridges. To better understand the near-source interaction of seismic waves with the seafloor and the resulting generation of low-frequency acoustic waves, the wave propagation in a solid medium (the Earth's crust) and in the overlaying fluid medium (the ocean) were jointly simulated using a three-dimensional (3D) spectral finite-element code (SPECFEM3D). Due to numerical limitations of 3D simulations, the focus was on simple model configurations with a 1 Hz source located below a Gaussian seamount or ridge. The simulated acoustic waves (0-2.5 Hz) propagate as Rayleigh modes and are... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74914/75768.pdf |
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