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| Tiberi, C.; Gautier, S; Ebinger, C.; Roecker, S.; Plasman, M.; Albaric, J.; Deverchere, Jacques; Peyrat, S.; Perrot, Julie; Wambura, R. Ferdinand; Msabi, M.; Muzuka, A.; Mulibo, G.; Kianji, G.. |
| We present a joint analysis of newly acquired gravity and teleseismic data in the North Tanzanian Divergence, where the lithospheric break-up is at its earliest stage. The impact of a mantle upwelling in more mature branches of the East African Rift has been extensively studied at a lithospheric scale. However, few studies have been completed that relate the deep-seated mantle anomaly detected in broad regional seismic tomography with the surface deformation observed in the thick Archaean Pan-African suture zone located in North Tanzania. Our joint inversion closes the gap between local and regional geophysical studies, providing velocity and density structures from the surface down to ca. 250 km depth with new details. Our results support the idea of a... |
| Tipo: Text |
Palavras-chave: Gravity anomalies and Earth structure; Africa; Joint inversion; Seismic tomography; Intra-plate processes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74944/76038.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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| Tsang-hin-sun, Eve; Royer, Jean-yves; Perrot, Julie. |
| Volcanic and tectonic events are the main processes involved in the generation of the oceanic crust and responsible for the seismicity associated with seafloor spreading. To monitor this activity, usually not or poorly detected by land-based seismological stations, we deployed from February 2012 to February 2013 a network of autonomous hydrophones to compare the behaviour of the ultraslow-spreading Southwest (SWIR) with that of the intermediate-spreading Southeast Indian ridges (SEIR). The rate of seismicity is similar for both ridges, suggesting that there is no systematic relationship between seismicity and spreading rates. The along-axis distribution of the seismic events, however, does differ, reflecting the rate-dependence of accretion modes.... |
| Tipo: Text |
Palavras-chave: Seismicity and tectonics; Acoustic properties; Mid-ocean ridge processes; Indian Ocean. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00340/45165/44559.pdf |
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| Van Vliet-lanoe, Brigitte; Authemayou, Christine; Molliex, Stephane; Field, Michael Hugh; Frechen, Manfred; Le Roy, Pascal; Perrot, Julie; Andrieu-ponel, Valerie; Gregoire, Gwendoline; Hallegouet, Bernard. |
| The Brittany region of France is located in a low seismicity intraplate zone. Most of the instrumented earthquakes are limited to a shallow crustal depth without surface rupture. A paleoseismological analysis was performed on deposits on the Crozon Peninsula and in the Elorn estuary. We highlight hydroplastic deformations induced by liquefaction leading to clay diapirism, which were likely triggered by past earthquakes. This diapirism seems to be frequent in continental nonconsolidated sediments and to develop on the inherited tectonic structures, when a shallow water table and confining layers exist. Timing of deformation is dated using paleoenvironmental data, and electron spin resonance and infrared-stimulated luminescence dating methods. Two seismic... |
| Tipo: Text |
Palavras-chave: Clay diapirism; Liquefaction; Earthquake; Saprolite; Brittany; Variscan structures; Paleoseismology; Intraplate; Middle Pleistocene. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74955/76029.pdf |
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| Kaub, C; Geoffroy, Laurent; Bollinger, L; Perrot, Julie; Le Roy, Pascal; Authemayou, C. |
| The ∼M6 1799 Bouin earthquake is considered as one of the largest earthquakes to have struck Western France. However, the seismogenic source potentially responsible for this event remain marginally documented. We present results from a focused offshore-onshore multidisciplinary survey in its meizoseismal area in order to identify the fault segments that potentially ruptured during this earthquake. Based on macroseismic data and the geology, we focused our study on the so-called Machecoul Fault as a potential source of the 1799 Bouin event. Our survey includes extensive high-resolution seismic reflection, high resolution bathymetry and a one-year seismological survey. These data were combined with existing topography, onshore gravity data and drill data to... |
| Tipo: Text |
Palavras-chave: Intra-plate processes; Seismicity and tectonics; Marine geophysics; Geomorphology; Europe. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79394/81927.pdf |
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