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Gay, Aurelien; Padron Mora, Crelia; Meyer, Solene; Beaufort, Daniel; Oliot, Emilien; Lallemand, Serge E; Marcaillou, Boris; Philippon, Mélody; Cornée, Jean-jacques; Audemard, Franck A; Lebrun, Jean-frédéric; Klingelhoefer, Frauke; Mercier De Lepinay, Bernard; Munch, Philippe; Garrocq, Clément; Boucart, Milton; Laigle, Mireille; Schenini, Laure; The Garanti Cruise Team,. |
Based on an extensive seismic and multibeam dataset, 1-5 km wide giant polygons were identified at the bottom of the Grenada basin, covering a total area of ~55000 km². They represent the top part of an active underlying polygonal fault system due to the volumetric contraction of clay- and smectite-rich sediments during burial. To date, this is the widest area of outcropping polygonal faults ever found on Earth. The seabed polygons are bounded by rectilinear ~1000-1500 m wide and ~10-60 m deep furrows, depending on the location in the basin. They are relatively regular in the north Grenada Basin, whereas they are getting longer and more elongated in the south Grenada Basin. The polygonal faults consist in a set of discrete normal faults affecting... |
Tipo: Text |
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Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00688/79963/82891.pdf |
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De Lepinay, Bernard Mercier; Deschamps, Anne; Klingelhoefer, Frauke; Mazabraud, Yves; Delouis, Bertrand; Clouard, Valerie; Hello, Yann; Crozon, Jacques; Marcaillou, Boris; Graindorge, David; Vallee, Martin; Perrot, Julie; Bouin, Marie-paule; Saurel, Jean-marie; Charvis, Philippe; St-louis, Mildor. |
After the January 12, 2010, Haiti earthquake, we deployed a mainly offshore temporary network of seismologic stations around the damaged area. The distribution of the recorded aftershocks, together with morphotectonic observations and mainshock analysis, allow us to constrain a complex fault pattern in the area. Almost all of the aftershocks have a N-S compressive mechanism, and not the expected left-lateral strike-slip mechanism. A first-order slip model of the mainshock shows a N264 degrees E north-dipping plane, with a major left-lateral component and a strong reverse component. As the aftershock distribution is sub-parallel and close to the Enriquillo fault, we assume that although the cause of the catastrophe was not a rupture along the Enriquillo... |
Tipo: Text |
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Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00054/16557/14071.pdf |
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