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Registros recuperados: 23
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Active thrust faulting offshore Boumerdes, Algeria, and its relations to the 2003 Mw 6.9 earthquake - art. no. L043111 ArchiMer
Deverchere, Jacques; Yelles, K; Domzig, Anne; Mercier De Lepinay, B; Bouillin, J.p.; Gaullier, V; Bracene, R; Calais, E; Savoye, Bruno; Kherroubi, A; Le Roy, P; Pauc, H; Dan, Gabriela.
[1] We investigate the active seismogenic fault system in the area of the 2003 Mw 6.9 Boumerdes earthquake, Algeria, from a high-resolution swath bathymetry and seismic survey. A series of 5 main fault-propagation folds similar to20-35 km long leave prominent cumulative escarpments on the steep slope and in the deep basin. Fault activity creates Plio-Quaternary growth strata within uplifted areas such as a rollover basin on the slope and piggyback basins in the deep ocean. Most thrusts turn to fault-propagation folds at the sub-surface and depict ramp-flat trajectories. We find that the two main slip patches of the 2003 Mw 6.9 Boumerdes earthquake are spatially correlated to two segmented cumulative scarps recognized on the slope and at the foot of the...
Tipo: Text Palavras-chave: Continental margin; Sismicity; Tectonophysics.
Ano: 2005 URL: http://archimer.ifremer.fr/doc/2005/publication-743.pdf
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Des courants de turbidité hyperpycnaux dans la tête du canyon du Var ? Données hydrologiques et observations de terrain ArchiMer
Mulder, T; Savoye, Bruno; Syvitski, Jpm; Parize, O.
The Var River is 120 km long upon entry into the western Mediterranean Sea and drains a 2820 km(2) basin (Fig. 1). A steep submarine canyon connects directly to the river mouth (Fig. 2). The submarine canyon is sinuous and shows typical badland features such as high slopes resulting from erosion (Fig. 3). The average water discharge 152-53 m(3) s(-1); Fig. 4) can be multiplied by tens during spring or fall ''flash floods'', when suspended sediment concentration can reach many tells of kg m(-3). The rating coefficient b corresponding to instantaneous discharges is 1.534 (Eq. (1) and Fig. 5, curve 1), according to data published by Laurent (1971), but might be larger if suspended sediment concentration related to floods occurring after a dry period (Fig. 5,...
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Ano: 1997 URL: http://archimer.ifremer.fr/doc/00093/20421/18088.pdf
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Dimensions and architecture of late Pleistocene submarine lobes off the northern margin of East Corsica ArchiMer
Deptuck, M; Piper, D; Savoye, Bruno; Gervais, A.
Sandy lobe deposits on submarine fans are sensitive recorders of the types of sediment gravity flows supplied to a basin and are economically important as hydrocarbon reservoirs. This study investigates the causes of variability in 20 lobes in small late Pleistocene submarine fans off East Corsica. These lobes were imaged using ultra-high resolution boomer seismic profiles (< 1 m vertical resolution) and sediment type was ground truthed using piston cores published in previous studies. Repeated crossings of the same depositional bodies were used to measure spatial changes in their dimensions and architecture. Most lobes increase abruptly down-slope to a peak thickness of 8 to 42 m, beyond which they show a progressive, typically more gradual, decrease...
Tipo: Text Palavras-chave: Turbidites; Submarine lobes; Pleistocene; Dimensions; Compensation stacking; Architecture.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-4712.pdf
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Direct observation of intense turbidity current activity in the Zaire submarine valley at 4000 m water depth ArchiMer
Khripounoff, Alexis; Vangriesheim, Annick; Babonneau, Nathalie; Crassous, Philippe; Dennielou, Bernard; Savoye, Bruno.
A large turbidity current was detected in the Zaire submarine valley at 4000 m water depth. Current meters, turbidimeter and sediment trap deployed on a mooring located in the channel axis, although they were damaged, recorded the signature of a very high energy event. An average velocity of more than 121 cm s-1 was measured 150 m above the channel floor. Coarse sand and plant debris were collected at 40 m height. The turbidity current clearly overflowed the edges of the valley as demonstrated by the large quantity of turbiditic material (464 mg organic carbon m-2 d-1) found in the sediment trap moored 13 km south from the channel axis.
Tipo: Text Palavras-chave: West equatorial Africa; Particle composition; Particle flux; Zaire channel; Turbidity current.
Ano: 2003 URL: http://archimer.ifremer.fr/doc/2003/publication-1419.pdf
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First observations of deep-sea coral reefs along the Angola margin ArchiMer
Le Guilloux, E.; Olu, Karine; Bourillet, Jean-francois; Savoye, Bruno; Iglesias, S. P.; Sibuet, Myriam.
The West African continental slope is an important theatre for geological survey prospecting and drilling for hydrocarbons but little is known about local deep-sea biological communities at these depths. While shallow-water reefs are common and well-known features in the tropics, only few records of deep-water corals exist at low latitudes, and most of them have been reported by historical oceanographic cruises undertaking circum-navigations of the world. This study, based on a multi-disciplinary approach, presents a description of newly discovered deep-water coral reef communities along the Angola margin. Data from ROV, multibeam bathymetry, side-scan sonar and seismics from a deep-towed acoustic system (SAR) were used to describe the morphology of the...
Tipo: Text Palavras-chave: Lucinids; Habitat mapping; ROV; Lophelia pertusa; Deep sea corals; Angola margin.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-7403.pdf
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Geological overview of the Angola-Congo margin, the Congo deep-sea fan and its submarine valleys ArchiMer
Savoye, Bruno; Babonneau, Nathalie; Dennielou, Bernard; Bez, Martine.
The Congo deep-sea fan is one of the largest fans in the world still affected by presently active turbidity currents. The present activity of deep-sea sedimentary processes is linked to the existence of a direct connection between the Congo River estuary and the Congo canyon head that allows relatively continuous sediment feeding of the deep-sea environment, in spite of a wide continental shelf (150 km). Because of this important activity in terms of sedimentary processes, the deep-sea environment of the Congo-Angola margin presents major interests concerning physical, chemical and biological studies near the seafloor. The main aim of this paper is to present the initial geological context of the BioZaire Program, showing a synthesis of the major results...
Tipo: Text Palavras-chave: Congo Angola margin; Congo channel; Sedimentary deposits; Turbidite.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/00000/11128/7848.pdf
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Instabilites sous-marine etudiees par submersibles ArchiMer
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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Investigation of a possible submarine landslide at the Var delta front (Nice continental slope, southeast France) ArchiMer
Sultan, Nabil; Savoye, Bruno; Jouet, Gwenael; Leynaud, Didier; Cochonat, Pierre; Henry, P.; Stegmann, Sylvia; Kopf, Achim.
The Var prodelta progrades across a straight, narrow shelf (less than 2 km wide) with a very steep continental slope reaching locally more than 30 degrees. Historically, the Var delta front is sadly famous for the 1979 catastrophic submarine landslide that resulted in several casualties and infrastructural damage. Geotechnical and geophysical investigations carried out in late 2007 to the east of the 1979 landslide scar provide evidence for the possible occurrence of a new important sedimentary collapse and submarine landslide. Geophysical data acquired in the area show the presence of several seafloor morphological steps rooted to shallow subsurface seismic reflections. Moreover, in situ piezocone measurements demonstrate the presence of several shear...
Tipo: Text Palavras-chave: CPTu; Gassy soil; Piezocone; Shear zone; Submarine landslides.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00004/11481/8096.pdf
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Le logmètre : un nouvel outil de saisie des descriptions de carottes ArchiMer
Savoye, Bruno; Floch, Gilbert; Kerbrat, Rene; Apprioual, Ronan.
Core description is used extensively by sedimentologists to yield critical information from sediments. It consists of a naturalistic description of the visual and textural characteristics of the sediment. It is generally a manual procedure. However, digital core descriptions are now required re manage data processing. Hand-written description can be keyed into a computer, but it is tedious and time consuming. Moreover, recording and typing errors can occur. A system is presented for digital description of sediment cores using a bar code principle. It can be used in the laboratory as well as on board vessels. It comprises a box inside which the half-core can be placed. A ruler and several sets of bar codes are printed on the inside box top. Bar codes are...
Tipo: Text Palavras-chave: Traitement informatique; Outil; Sédiment; Codes barres; Carotte; Software processing; Measuring board; Sediment; Bar codes; Core.
Ano: 1999 URL: http://archimer.ifremer.fr/doc/1999/publication-838.pdf
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Morphology and sedimentary architecture of a modern volcaniclastic turbidite system: The Cilaos fan, offshore La Reunion Island ArchiMer
Sisavath, Emmanuelle; Babonneau, Nathalie; Saint-ange, Francky; Bachelery, Patrick; Jorry, Stephan; Deplus, Christine; De Voogd, Beatrice; Savoye, Bruno.
Recent oceanographic surveys revealed the existence of five volcaniclastic deep-sea fans off La Reunion Island. The Cilaos fan is a large volcaniclastic submarine fan, connected to rivers that episodically experience torrential floods through a narrow and steep shelf-slope system. New piston cores presented in this study together with echosounder profiles give new insight into the evolution, of this extensive and sand-rich turbidite system. The Cilaos fan extends over 15,000 km(2) on an abyssal plain and is compartmentalized by topographic highs. Located southwest of the island, the sedimentary system consists of a canyon area and a deep sea fan divided into a proximal and a distal fan. The proximal fan is characterized by its wide extent and...
Tipo: Text Palavras-chave: Turbidite; Deep-sea fan; Volcaniclastic; La Reunion Island.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00056/16704/14203.pdf
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Morphology, structure, composition and build-up processes of the active channel-mouth lobe complex of the Congo deep-sea fan with inputs from remotely operated underwater vehicle (ROV) multibeam and video surveys ArchiMer
Dennielou, Bernard; Droz, Laurence; Babonneau, Nathalie; Jacq, Celine; Bonnel, Cedric; Picot, Marie; Le Saout, Morgane; Saout, Yohan; Bez, Martine; Savoye, Bruno; Olu, Karine; Rabouille, Christophe.
The detailed structure and composition of turbiditic channel-mouth lobes is still largely unknown because they commonly lie at abyssal water depths, are very thin and are therefore beyond the resolution of hull-mound acoustic tools. The morphology, structure and composition of the Congo turbiditic channel-mouth lobe complex (90×40 km; 2525 km2) were investigated with hull-mounted swath bathymetry, air gun seismics, 3.5 kHz sub-bottom profiler, sediment piston cores and also with high-resolution multibeam bathymetry and video acquired with a Remote Operating Vehicle (ROV). The lobe complex lies 760 km off the Congo River mouth in the Angola abyssal plain between 4740 and 5030 m deep. It is active and is fed by turbidity currents that deposit several...
Tipo: Text Palavras-chave: Congo deep-sea fan; Lobe; Lobe complex; Channel; Channel-Lobe Transition Zone; Angola basin; Slump; Slide; Debrite; Turbidite; ROV; Bathymetry; Seismic; Sediment core.
Ano: 2017 URL: https://archimer.ifremer.fr/doc/00378/48976/49383.pdf
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Multiscale spatio-temporal variability of sedimentary deposits in the Var turbidite system (North-Western Mediterranean Sea) ArchiMer
Mas, Virginie; Mulder, T.; Dennielou, Bernard; Schmidt, S.; Khripounoff, Alexis; Savoye, Bruno.
The Var turbidite system is a small sandy system located in the Ligurian Basin (Mediterranean Sea). It is active during present sea-level highstand and shows four types of sediment transfer processes: (1) low-density turbidity surges generated by small-scale failures (2) low-magnitude, high-frequency (yearly) hyperpycnal turbid plumes, (3) high-magnitude, less-frequent, hyperpycnal currents and (4) high-magnitude flows generated by large slope failures. These processes have different imprints on the morphology of the system. Inversely, the topography plays a role on the behaviour of these flows. The depositional and erosional architecture of the system has been investigated in detail on the basis of SAR imagery and a set of cores using an interface corer...
Tipo: Text Palavras-chave: Var; France; Gravity processes; Mediterranean; Turbidity current; Hyperpycnal; Flood.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00013/12458/11862.pdf
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New modelling of submarine gravity flows: application to the Nice collapse in 1979. ArchiMer
Hugot, Alexandre; Joseph, Philippe; Savoye, Bruno; Zaleski, Stéphane.
We propose to apply in this note a simple mathematical model for the sedimentation of gravity deposits in deep water. An inverse method has been developed in order to characterize the parameters associated with the submarine flow. This method also provides the initial conditions, which constitute a major uncertainty in geoscience modelling. Application of the inverse method to the 1979 Nice air-port collapse (southern France), constrained by cable breaks and/or deposit thicknesses, leads, for example, to the estimation of the initial volume and/or the physical parameters of the flow (friction coefficient, modified turbulent Schmidt number, etc.). The application of the model to this real case shows that only the simultaneous inversion of dynamic (cable...
Tipo: Text Palavras-chave: France; 1979 Nice airport collapse; Inverse problem; Flow object; Turbidity current; Gravity flow.
Ano: 2001 URL: http://archimer.ifremer.fr/doc/2001/publication-787.pdf
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Quantifying the role of sandy-silty sediments in generating slope failures during earthquakes: example from the Algerian margin ArchiMer
Dan, Gabriela; Sultan, Nabil; Savoye, Bruno; Deverchere, Jacques; Yelles, Karim.
The Algerian margin is a seismically active region, where during the last century, several large magnitude earthquakes took place. This study combines geotechnical and sedimentological data with numerical modelling to quantitatively assess the present-day slope stability of the Algerian margin. Geotechnical laboratory tests, such as cyclic triaxial tests, oedometric tests and vane shear tests were carried out on sediment cores collected on the study area. The liquefaction potential of a sediment column located about 30 km from the BoumerdSs earthquake epicentre of 21st May 2003 was evaluated theoretically for an earthquake of M (w) = 6.8. We show that thin sand and silt beds such as those described on recovered sediment cores are the main cause of sediment...
Tipo: Text Palavras-chave: Earthquakes; Potential of liquefaction; Slope stability; Algerian margin.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6448.pdf
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Searching for the Africa-Eurasia Miocene boundary offshore western Algeria (MARADJA'03 cruise) ArchiMer
Domzig, Anne; Yelles, Karim; Le Roy, Charlotte; Deverchere, Jacques; Bouillin, Jean-pierre; Bracene, Rabah; De Lepinay, Bernard Mercier; Le Roy, Pascal; Calais, Eric; Kherroubi, Abdelaziz; Gaullier, Virginie; Savoye, Bruno; Pauc, Henri.
We present new results from the MARADJA'03 cruise depicting the geological structures offshore central and western Algeria. Using swath bathymetry and seismic reflection data, we map and discuss the offshore limits of the Internal Zones corresponding to relics of the AIKaPeCa domain that drifted and collided the African plate during the Miocene. We identify large reverse faults and folds that reactivate part of these limits and are still active today. The morphology of the westernmost NE-SW margin suggests a former strike-slip activity accommodating a westward block translation responsible for the shift of the Internal Zones towards the Moroccan Rif.
Tipo: Text Palavras-chave: Sismique réflexion; Bathymétrie multifaisceau; Évolution tectonique du Bassin méditerranéen; Néotectonique; Zones Internes; Marge Algérienne; Seismic reflection; Swath bathymetry; Tectonic evolution of the Mediterranean; Internal zones neotectonics; Algerian margin.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-1211.pdf
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Sediment distribution and evolution of sedimentary processes in a small sandy turbidite system (Golo system, Mediterranean Sea): implications for various geometries based on core framework ArchiMer
Gervais, A; Mulder, T; Savoye, Bruno; Gonthier, E.
The Golo Margin in eastern Corsica is dissected by four canyons and two gullies which fed turbidite systems. Study of the dispersal of surficial sediments and flow dynamic in the Golo system is based on Kullenberg and interface cores interpreted in relation to a previously published seismic dataset. Cores were described in detail and interpreted within a sedimentary and stratigraphic framework. During the last 42,000 years, gravity processes which occurred in the large systems with a canyon source were mainly slide-induced, differentiated turbulent surges and hyperpycnal flows. Processes occurring in the small system with a gully source are mainly hyperconcentrated and concentrated flows. Deposits from the Corsican Margin can intercalate with products of...
Tipo: Text
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-3594.pdf
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Seismic imaging of the ocean internal structure: A new tool in physical oceanography? ArchiMer
Géli, Louis; Savoye, Bruno; Carton, Xavier; Stephan, Manuel.
Reflection seismics has been intensively used for the last four decades by marine geologists and geophysicists for imaging Earth structures below the seafloor. Because their subject of interest is below the sea bottom, solid Earth scientists do not usually consider the seismic signal propagating in the water column and most often do not even record it, in order to save data storage space. Two physical oceanographers, Gonella and Michon [1988],first reported internal waves revealed by reflection seismics in the northeastern Atlantic. Only recently, though, has the scientific community realized the importance of this issue, after Holbrook et al. [2003] published reflection seismic sections of the water column off Newfoundland, Canada, showing reflectors...
Tipo: Text
Ano: 2005 URL: http://archimer.ifremer.fr/doc/00451/56259/57828.pdf
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The 1979 Nice harbour catastrophe revisited: Trigger mechanism inferred from geotechnical measurements and numerical modelling ArchiMer
Dan, Gabriela; Sultan, Nabil; Savoye, Bruno.
In 1979, a catastrophic event occurred on the Nice continental slope (French Riviera) generating the lost of human lives and important material damages. Part of the new harbour constructed at the edge of the International Airport of Nice collapsed into the sea. The main aim of this work was 1) to present a review of facts and details related to the 1979 accident and a review of the geological setting, and 2) to evaluate the slope stability before and after the new harbour construction, by taking into account new available data such as sediment cores and piezocone CPTU data. The CPTU data were of great value to understand the origin of the 1979 event. They show the existence of a sensitive clay bed between 30 mbsf and 45 mbsf Under high deviatoric load a...
Tipo: Text Palavras-chave: Finite element method; Trigger mechanism; Slope stability; Nice 1979 event.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-3507.pdf
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The Celtic deep-sea fan: seismic facies, architecture and stratigraphy ArchiMer
Droz, Laurence; Auffret, Gerard; Savoye, Bruno.
Tipo: Text
Ano: 2003 URL: http://archimer.ifremer.fr/doc/00072/18357/15929.pdf
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The Kramis fan offshore western Algeria: the role of sediment waves in turbiditic levee growth ArchiMer
Babonneau, Nathalie; Cattaneo, Antonio; Savoye, Bruno; Barjavel, Guy; Deverchere, Jacques; Yelles, Karim.
The Kramis deep-sea fan extends over 45 km at the base of the western Algerian continental slope between 2000 and 2550 m water depth and covers an area of approximately 1200 km2. The Kramis Fan was initiated after Messinian time, evolved during the Plio-Quaternary, and, is still active, as proved by submarine cable breaks during the 1954 Orléansville earthquake. The Kramis Fan is fed by two perpendicular canyons: the Kramis Canyon and the Khadra Canyon, merging in a single E–W-oriented channel confined at the foot of the slope. It is strongly asymmetric with a super-developed levee on the right-hand side of the channel, the Kramis Ridge. Based on recent multibeam, side-scan sonar, and sediment core data (Maradja, 2003 and 2005, Prisma, 2004, and Prisme,...
Tipo: Text Palavras-chave: Algerian margin; Turbidity currents; Sediment waves; Scours.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00129/24021/21978.pdf
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