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| D'Acremont, Elia; Leroy, Sylvie; Maia, Marcia; Patriat, Philippe; Beslier, Marie-odile; Bellahsen, Nicolas; Fournier, Marc; Gente, Pascal. |
| Magnetic and gravity data gathered during the Encens-Sheba cruise (2000 June) in the eastern Gulf of Aden provide insights on the structural evolution of segmentation from rifted margins to incipient seafloor spreading. In this study, we document the conjugate margins asymmetry, confirm the location of the ocean-continent transition (OCT) previously proposed by seismic data, and describe its deep structure and segmentation. In the OCT, gravity models indicate highly thinned crust while magnetic data indicate presence of non-oceanic high-amplitude magnetic anomalies where syn-rift sediments are not observed. Thus, the OCT could be made of ultra-stretched continental crust intruded by magmatic bodies. However, locally in the north, the nature of the OCT... |
| Tipo: Text |
Palavras-chave: Gulf of Aden; Kinematic evolution; Ocean-continent transition; Passive continental margin; Seafloor spreading; Segmentation. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34561/33314.pdf |
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| Momoh, Ekeabino; Cannat, Mathilde; Leroy, Sylvie. |
| Extensive outcrops of serpentinized peridotite in melt‐starved spreading corridors of the ultraslow easternmost Southwest Indian Ridge are hypothesized to be due to slip on successive long‐offset normal faults that alternate polarity (flip‐flop detachment faults). We investigate the nature of the oceanic crust which forms under these conditions, using seismic reflection data acquired during the SISMOSMOOTH 2014 cruise. Using 3‐D binning, the seismic profiles were binned elastically, while three of the profiles shot closely were merged into one to take advantage of the larger air gun source volume. Using a poststack imaging sequence, we observe several types of reflectors at crustal and infracrustal depths, in the axial valley and off‐axis. Correlating our... |
| Tipo: Text |
Palavras-chave: Detachment faulting; Ultra-slow spreading; Serpentinization. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71124/69429.pdf |
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| Poupardin, Adrien; Calais, Eric; Heinrich, Philippe; Hébert, Hélène; Rodriguez, Mathieu; Leroy, Sylvie; Aochi, Hideo; Douilly, Roby. |
| The devastating Mw 7, 2010, Haiti earthquake was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse component of coseismic ground motion that accompanied this mostly strike-slip event. However, observations of run-up heights up to 2 m along the southern coast of the island at distances up to 100 km from the epicenter, as well as tide gauge and DART buoy records at distances up to 600 km from the epicenter have not yet received an explanation. Here we demonstrate that these observations require a secondary source, most likely a... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00601/71265/69652.pdf |
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| Watremez, L.; Burov, E.; D'Acremont, E.; Leroy, Sylvie; Huet, B.; Lepourhiet, L.; Bellahsen, N.. |
| Physical properties of the mantle lithosphere have a strong influence on the rifting processes and rifted structures. In particular, in context of rifting, two of these properties have been overlooked: (1) Mohr-Coulomb plasticity (localizing pressure dependent) may not be valid at mantle depths as opposed to nonlocalizing pressure-independent plasticity (hereafter, perfect plasticity), and (2) lithosphere buoyancy can vary, depending on the petrological composition of the mantle. Focussing on the Arabian plate, we show that the lithosphere may be negatively buoyant. We use thermomechanical modeling to investigate the importance of mantle rheology and composition on the formation of a passive margin, ocean-continent transition (OCT) and oceanic basin. We... |
| Tipo: Text |
Palavras-chave: Thermomechanical modeling; Rifting; Ocean-continent transition; Plasticity; Lithosphere buoyancy; Gulf of Aden. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00199/31070/29483.pdf |
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| Ahmed, Abdulhakim; Doubre, Cecile; Leroy, Sylvie; Kassim, Mohamed; Keir, Derek; Abayazid, Ahmadine; Julie, Perrot; Laurence, Audin; Vergne, Jerome; Alexandre, Nercessian; Jacques, Eric; Khanbari, Khaled; Sholan, Jamal; Rolandone, Frederique; Al-ganad, Ismael. |
| In November 2010, intense seismic activity including 29 events with a magnitude above 5.0, started in the western part of the Gulf of Aden, where the structure of the oceanic spreading ridge is characterized by a series of N115 degrees-trending slow-spreading segments set within an EW-trending rift. Using signals recorded by permanent and temporary networks in Djibouti and Yemen, we located 1122 earthquakes, with a magnitude ranging from 2.1 to 5.6 from 2010 November 1 to 2011 March 31. By looking in detail at the space-time distribution of the overall seismicity, and both the frequency and the moment tensor of large earthquakes, we re-examine the chronology of this episode. In addition, we also interpret the origin of the activity using high-resolution... |
| Tipo: Text |
Palavras-chave: Earthquake source observations; Seismicity and tectonics; Mid-ocean ridge processes; Transform faults; Submarine tectonics and volcanism; Dynamics: seismotectonics. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00639/75087/75528.pdf |
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