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Dano, Alexandre; Praeg, Daniel; Migeon, Sebastien; Augustin, Jean-marie; Ceramicola, Silvia; Ketzer, Joao Marcelo; Augustin, Adolfo Herbert; Ducassou, Emmanuelle; Mascle, Jean. |
The central Nile Deep-Sea Fan contains a broad area of seabed destabilisation in association with fluid seepage: slope-parallel sediment undulations are associated with multibeam high-backscatter patches (HBPs) related to authigenic carbonates. During the 2011 APINIL campaign, a deep-towed sidescan and profiling system (SAR) was used to acquire high-resolution data along three transects across water depths of 1,700-2,650 m. Three seabed domains are distinguished, all developed within stratified sediments overlying mass-transport deposits (MTDs). Upslope of the undulations (<1,950 m), sidescan HBPs record focused fluid seepage via seabed cracks. In the western area of undulations, sidescan HBPs are distinct from intermediate-backscatter patches (IBPs)... |
Tipo: Text |
Palavras-chave: Fluid seepage; Sediment deformation; Backscatter; Gas flares. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00226/33752/37059.pdf |
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Sultan, Nabil; Cattaneo, Antonio; Urgeles, R; Lee, H; Locat, J; Trincardi, F; Berne, Serge; Canals, M; Lafuerza, S. |
This study is among the first to examine the genesis of the seafloor and subsurface undulations on the Adriatic continental shelf by integrating stratigraphic information and in situ and laboratory geotechnical measurements. Interpretation of sediment behavior is based on a 32-m-long borehole crossing ( 1) a possible shear plane and ( 2) a silty clay layer at about 20 m below seafloor (mbsf) on which sediment undulations are rooted and could be interpreted as a potential weak layer succession. Our main results in terms of triggering mechanism for the observed undulations show that under an earthquake, liquefaction and/or failure of the silty-clay sediments ( weak layer) leading to deformation of the upper more cohesive sediments is possible only when such... |
Tipo: Text |
Palavras-chave: Sediment deformation; Shear strength; Earthquake; Adriatic shelf. |
Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4105.pdf |
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