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Registros recuperados: 11 | |
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Savoye, Bruno. |
Sediment instability appears to be important as a part of global sedimentary budget. Among the various types of sedimentary instabilities, submarine slides are probably the most spectacular and the hardest to study and predict, although their consequences on human and industrial marine activities can be dramatic. IFREMER is conducting a research project on this topic. An area off Nice (France) has been particularly studied because of its recent activity. Mapping and instability area detection have been carried out. With the possibility of direct interactive observation and highly accurate submarine in -situ operation, the submersible is an extremely efficient tool for sediment studies, but diving purposes have to be precisely defined to provide useful... |
Tipo: Text |
Palavras-chave: Sediments; Instability; Sedimentology; Sedimentary structures; Ocean floor; Marine technology; Geology; Submersibles; Unmanned vehicles. |
Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1150.pdf |
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Otsuka, K. |
The JAMSTEC/Deep Tow Camera System conducts pre-site-surveys for the manned submersible "SHINKAI 2000". The vehicle is towed by double armored coaxial cable (RG-8/U) of 4500 m length. The color composite video signal is converted to an FM signal with central frequency of 6.15 MHz because it is very difficult to compensate completely for the transmission loss of video frequency through the coaxial cable. The data from the CTD sensors and the altimeter are displayed with date and time on the monitor screen in real time. Temperature data has proved very important in finding hydrothermal anomaly phenomena. Two years ago, our research group found an active chimney at North Fiji Basin during cooperative cruise between France and Japan. Last year, we deployed... |
Tipo: Text |
Palavras-chave: Altimeters; Sensors; Television systems; Underwater cameras; Ocean floor; Unmanned vehicles. |
Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1153.pdf |
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Renard, V. |
The side looking sonars have been developed for greater swath coverage, digital processing of the signals has improved the quality of the images and interferometric techniques have been used to determine the depth of the bottom features. A review of the systems existing today is presented. Documents such as graphs, block diagrams, images, maps, sections, created from data acquired at sea level suffer from a filtering or smoothing effect that restricts the representativity of the measured parameters and therefore limits their interpretation. The greater the depth of the seafloor, the greater the filtering. It is due not only to the nature of the measured phenomenon but also the characteristics of the sensors, to their operation and to the data processing.... |
Tipo: Text |
Palavras-chave: Bathymetry; Cartography; Sensors; Echosounders; Acoustic imagery; Acoustics; Ocean floor; Seafloor mapping. |
Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1147.pdf |
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Muller, R; Sdrolias, M; Gaina, C; Roest, Walter. |
We present four companion digital models of the age, age uncertainty, spreading rates, and spreading asymmetries of the world's ocean basins as geographic and Mercator grids with 2 arc min resolution. The grids include data from all the major ocean basins as well as detailed reconstructions of back-arc basins. The age, spreading rate, and asymmetry at each grid node are determined by linear interpolation between adjacent seafloor isochrons in the direction of spreading. Ages for ocean floor between the oldest identified magnetic anomalies and continental crust are interpolated by geological estimates of the ages of passive continental margin segments. The age uncertainties for grid cells coinciding with marine magnetic anomaly identifications, observed or... |
Tipo: Text |
Palavras-chave: Seafloor spreading; Geodynamic; Plate kinematic; Ocean floor; Digital isochrons. |
Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3900.pdf |
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Greger, B. |
A conceptually new, modularly designed exploration system for the deep sea (600 m) has been constructed and tested. In its base unit, different soil sampling tools can be integrated. These are, for the time being, a drill core barrel with 0 48 mm iD and a length of 500 mm for rocky basements as a box corer for softer soils as well as an orange peel grab. Towed along via a coaxial cable from a research vessel, the system is TV-guided and can be actively positioned by means of 2 thrusters in order to be lowered precisely and horizontally levelled on the seafloor. The total system is operated by the help of an onboard computer and may be controlled by sensor displays and operation messages. Microprocessors control the underwater unit which is partially... |
Tipo: Text |
Palavras-chave: Marine technology; Mineral exploration; Towed vehicles; Research vessels; Geology; Ocean floor. |
Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1158.pdf |
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Domínguez, Juan G.; Gómez, Juan C.; Ricaurte, Constanza; Mayo, Gisela; Orejarena, Jaime; Díaz, Juan M.; Anrdade, Carlos A.. |
Se determinaron las unidades ecológicas submarinas alrededor de un volcán activo de lodo en los bancos de Salmedina, Caribe colombiano, y se cartografiaron mediante video-transectos submarinos georreferenciados, análisis de la batimetría e interpretación de imágenes satelitales. Se describen la distribución, la cobertura relativa y los organismos bentónicos sésiles más representativos de las diferentes unidades ecológicas. La zona somera (0-10 m) de los bancos presenta 60 % de cobertura algal y 10 % de coral vivo; en las zonas más profundas (<10 m) la cobertura de coral vivo varía entre 33 % en los cantiles semiverticales y 55 % en las cimas de los bancos menos elevados; las especies de coral dominantes fueron Siderastrea siderea y Montastraea annularis... |
Tipo: Journal Contribution |
Palavras-chave: Ocean floor; Seafloor mapping. |
Ano: 2010 |
URL: http://hdl.handle.net/1834/3749 |
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Registros recuperados: 11 | |
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