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| Escartin, Javier; Leclerc, Frederique; Olive, Jean-arthur; Mevel, Catherine; Cannat, Mathilde; Petersen, Sven; Augustin, Nico; Feuillet, Nathalie; Deplus, Christine; Bezos, Antoine; Bonnemains, Diane; Chavagnac, Valerie; Choi, Yujin; Godard, Marguerite; Haaga, Kristian A.; Hamelin, Cedric; Ildefonse, Benoit; Jamieson, John W.; John, Barbara E.; Leleu, Thomas; Macleod, Christopher J.; Massot-campos, Miguel; Nomikou, Paraskevi; Paquet, Marine; Rommevaux-jestin, Celine; Rothenbeck, Marcel; Steinfuehrer, Anja; Tominaga, Masako; Triebe, Lars; Campos, Ricard; Gracias, Nuno; Garcia, Rafael; Andreani, Muriel; Vilaseca, Geraud. |
| Properly assessing the extent and magnitude of fault ruptures associated with large earthquakes is critical for understanding fault behavior and associated hazard. Submarine faults can trigger tsunamis, whose characteristics are defined by the geometry of seafloor displacement, studied primarily through indirect observations (e.g., seismic event parameters, seismic profiles, shipboard bathymetry, coring) rather than direct ones. Using deep-sea vehicles, we identify for the first time a marker of coseismic slip on a submarine fault plane along the Roseau Fault (Lesser Antilles), and measure its vertical displacement of ∼0.9 m in situ. We also map recent fissuring and faulting of sediments on the hangingwall, along ∼3 km of rupture in close proximity to the... |
| Tipo: Text |
Palavras-chave: Submarine fault; Surface rupture; Earthquake; Fault slip; Neotectonics; Microbathymetry. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00344/45500/45051.pdf |
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| Szitkar, Florent; Dyment, Jerome; Choi, Yujin; Fouquet, Yves. |
| High-resolution magnetic surveys acquired near the seafloor show that active basalt-hosted hydrothermal sites are associated with zones of lower magnetization. This observation may reflect the thermal demagnetization of a hot hydrothermal zone, the alteration of basalt affected by hydrothermal circulation, and/or the presence of thick, nonmagnetic hydrothermal deposits. In order to discriminate among these inferences, we acquired vector magnetic data 50 m above inactive hydrothermal site Krasnov using the Remotely Operated Vehicle (ROV) Victor. This deep hydrothermal site, located 7 km east of the Mid-Atlantic Ridge (MAR) axis at 16°38′N, is dissected by major normal faults and shows no evidence of recent hydrothermal activity. It is therefore a perfect... |
| Tipo: Text |
Palavras-chave: Magnetic anomalies; Hydrothermalism; Alteration; Modeling. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29915/28375.pdf |
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| Szitkar, Florent; Dyment, Jerome; Fouquet, Yves; Choi, Yujin; Honsho, Chie. |
| The analysis of high-resolution vector magnetic data acquired by deep-sea submersibles (DSSs) requires the development of specific approaches adapted to their uneven tracks. We present a method that takes advantage of (1) the varying altitude of the DSS above the seafloor and (2) high-resolution multibeam bathymetric data acquired separately, at higher altitude, by an Autonomous Underwater Vehicle, to estimate the absolute magnetization intensity and the magnetic polarity of the shallow subseafloor along the DSS path. We apply this method to data collected by DSS Nautile on a small active basalt-hosted hydrothermal site. The site is associated with a lack of magnetization, in agreement with previous findings at the same kind of sites: the contrast between... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00252/36300/34829.pdf |
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