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| Lurton, Xavier; Antoine, Loic. |
| The use of acoustical systems in various human activities in the ocean (industry, defence, science) raises the issue of their impact upon marine mammals populations. Several serious accidents linked to the use of naval sonars led the military, industrial and scientific communities to investigate the potential dangers of their own activity. This report aims at identifying the risks for the cetaceans linked to the use of acoustic and seismic systems currently used for oceanographic science. The analysis proposed here stays within the frame of bibliography synthesis and elementary modelling, and brings no new scientific elements on the topic. An overview of the status of cetacean populations is given first, with a summary of the possible acoustical... |
| Tipo: Text |
Palavras-chave: Seismics; Sonar; Acoustics; Oceanography; Acoustical methods; Auditory threshold; Stranding; Acoustical risks; Marine mammals. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/rapport-2390.pdf |
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| Geli, Louis; Cosquer, Emmanuel; Hobbs, R. W.; Klaeschen, D.; Papenberg, C.; Thomas, Yannick; Menesguen, Claire; Hua, Bach-lien. |
| A small volume (117 cu-inch) seismic source producing signal predominantly in the 150-200 Hz frequency window was used during the GO calibration experiment in the Gulf of Cadiz (April-May 2007). The data show the small scale (< 10 m in the z direction) internal structure of the ocean. High-resolution images display seismic reflectors that often appear as distinct, horizontal, short (similar to a few hundred meters to a few km long) segments, lying at different depths, while low-resolution (similar to 20 to 30 Hz) display long, horizontal reflectors (similar to a few tens of km), sometimes linked by short, apparently "dipping" segments. The present data suggest that this apparent dipping effect is due to the insufficient separation power (similar to... |
| Tipo: Text |
Palavras-chave: High resolution; Seismics; Oceanography. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/2009/publication-7297.pdf |
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| Collot, Julien; Geli, Louis; Lafoy, Y; Vially, R; Cluzel, D; Klingelhoefer, Frauke; Nouze, Herve. |
| New, high-quality multichannel seismic reflection data from the western New Caledonia offshore domain allow for the first time the direct, continuous connection of seismic reflectors between the Deep Sea Drilling Project 208 drill hole on the Lord Howe Rise and the New Caledonia Basin. A novel seismic interpretation is hence proposed for the northern New Caledonia Basin stratigraphy, which places the Eocene/Oligocene unconformity deeper than previously thought and revisits the actual thickness of the pre-Oligocene sequences. A causal link is proposed between the obduction of the South Loyalty Basin over New Caledonia (NC) and the tectonic history of the northern New Caledonia Basin. Here it is suggested that as the South Loyalty Basin was being obducted... |
| Tipo: Text |
Palavras-chave: New Caledonia; Seismics; Obduction. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4782.pdf |
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| Gutscher, Marc-andre; Dominguez, Stephane; Mercier De Lepinay, Bernard; Pinheiro, Luis; Gallais, Flora; Babonneau, Nathalie; Cattaneo, Antonio; Le Faou, Yann; Barreca, Giovanni; Micallef, Aaron; Rovere, Marzia. |
| Subduction of a narrow slab of oceanic lithosphere beneath a tightly curved orogenic arc requires the presence of at least one lithospheric scale tear fault. While the Calabrian subduction beneath southern Italy is considered to be the type example of this geodynamic setting, the geometry, kinematics and surface expression of the associated lateral, slab tear fault offshore eastern Sicily remain controversial. Results from a new marine geophysical survey conducted in the Ionian Sea, using high-resolution bathymetry and seismic profiling reveal active faulting at the seafloor within a 140 km long, two-branched fault system near Alfeo Seamount. The previously unidentified 60 km long NW trending North Alfeo Fault system shows primarily strike-slip kinematics... |
| Tipo: Text |
Palavras-chave: Slab tear; Subduction; Mediterranean; Bathymetry; Seismics; Active faults. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00318/42924/42421.pdf |
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