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Bourgeois, J; Renard, V; Michaud, F; Mercier De Lepinay, B. |
The data of the Seamat Cruise indicate that: a) the junction between the East Pacific Rise and the Rivera Fracture Zone is located 165 km seaward the Acapulco Trench axis at 18 degree 30'N latitude and 106 degree 15'W longitude; and b) the East Pacific Rise axial ridge connects the Rivera Transverse Ridge trough an overshot ridge. This situation makes the Rivera Fracture Zone located eastward of the junction progressively inactive and documents a westward jump of the junction. |
Tipo: Text |
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Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37951/36032.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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Pichon, Xle; Renard, V; Cadet, J P. |
Many scientists have participated at these Kaiko cruises. Three legs have been studied. The observations show that the trenches around Japan exhibit a whole range of possible subduction processes. It has been demonstrated that the subduction could fairly "swallow" as sharp-pointed fishbones as volcanoes as Fuji Yama or as big lumps as the palau Kyushu volcanic arc. The subduction then changes into collision and these surveys provide the first indications about the way. The transition from the Nankai trench to the Izu collision takes place. Such transition is accompanied by an oceanic lithosphere overthrust. Last, it appears that scars exhibited by the oceanic lithosphere in the form of fossil rift valleys and faults are reactivated upon the bending of the... |
Tipo: Text |
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Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37955/36036.pdf |
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