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| Registros recuperados: 12 | |
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| Mazzullo, Alessandro; Stutzmann, Eleonore; Montagner, Jean-paul; Kiselev, Sergey; Maurya, Satish; Barruol, Guilhem; Sigloch, Karin. |
| In the western Indian Ocean, the Reunion hot spot is one of the most active volcanoes on Earth. Temporal interactions between ridges and plumes have shaped the structure of the zone. This study investigates the mantle structure using data from the Reunion Hotspot and Upper Mantle-Reunions Unterer Mantel (RHUM-RUM) project, which significantly increased the seismic coverage of the western part of the Indian Ocean. For more than 1year, 57 ocean bottom seismometer stations and 23 temporary land stations were deployed over this area. For each earthquake station path, the Rayleigh wave fundamental mode phase velocities were measured for the periods from 30s to 300s and group velocities for the period from 16s to 250s. A three-dimensional model of the shear... |
| Tipo: Text |
Palavras-chave: Tomography; Indian Ocean; Seismic anisotropy; Hot spot ridge; Upper mantle. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00600/71180/69533.pdf |
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| Hable, Sarah; Sigloch, Karin; Barruol, Guilhem; Staehler, Simon C.; Hadziioannou, Celine. |
| Many applications in seismology rely on the accurate absolute timing of seismograms. However, both seismological land stations and ocean bottom seismometers (OBSs) can be affected by clock errors, which cause the absolute timing of seismograms to deviate from a highly accurate reference time signal, usually provided by GPS satellites. Timing problems can occur in land stations when synchronization with a GPS signal is temporarily or permanently lost. This can give rise to complicated, time-dependent clock drifts relative to GPS time, due to varying environmental conditions. Seismometers at the ocean bottom cannot receive GPS satellite signals, but operate in more stable ambient conditions than land stations. The standard protocol is to synchronize an OBS... |
| Tipo: Text |
Palavras-chave: Time-series analysis; Seismic instruments; Seismic interferometry; Seismic noise. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00444/55599/57230.pdf |
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| Fontaine, Fabrice R.; Barruol, Guilhem; Tkalcic, Hrvoje; Woelbern, Ingo; Ruempker, Georg; Bodin, Thomas; Haugmard, Meric. |
| The Piton de la Fournaise basaltic volcano, on La Réunion Island in the western Indian Ocean, is one of the most active volcanoes in the world. This volcano is classically considered as the surface expression of an upwelling mantle plume and its activity is continuously monitored, providing detailed information on its superficial dynamics and on the edifice structure. Deeper crustal and upper mantle structure under La Réunion Island is surprisingly poorly constrained, motivating this study. We used receiver function techniques to determine a shear wave velocity profile through the crust and uppermost mantle beneath La Réunion, but also at other seismic stations located on the hotspot track, to investigate the plume and lithosphere interaction and its... |
| Tipo: Text |
Palavras-chave: Surface waves and free oscillations; Oceanic hotspots and intraplate volcanism; Hotspots; Crustal structure; Indian Ocean. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00287/39830/38352.pdf |
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| Bousquet, Olivier; Barruol, Guilhem; Cordier, Emmanuel; Barthe, Christelle; Bielli, Soline; Calmer, Radiance; Rindraharisaona, Elisa; Roberts, Gregory; Tulet, Pierre; Amelie, Vincent; Fleischer-dogley, Frauke; Mavume, Alberto; Zucule, Jonas; Zakariasy, Lova; Razafindradina, Bruno; Bonnardot, François; Singh, Manvendra; Lees, Edouard; Durand, Jonathan; Mekies, Dominique; Claeys, Marine; Pianezze, Joris; Thompson, Callum; Tsai, Chia-lun; Husson, Romain; Mouche, Alexis; Ciccione, Stephane; Cattiaux, Julien; Chauvin, Fabrice; Marquestaut, Nicolas. |
| The international research program “ReNovRisk-CYCLONE” (RNR-CYC, 2017–2021) directly involves 20 partners from 5 countries of the south-west Indian-Ocean. It aims at improving the observation and modelling of tropical cyclones in the south-west Indian Ocean, as well as to foster regional cooperation and improve public policies adapted to present and future tropical cyclones risk in this cyclonic basin. This paper describes the structure and main objectives of this ambitious research project, with emphasis on its observing components, which allowed integrating numbers of innovative atmospheric and oceanic observations (sea-turtle borne and seismic data, unmanned airborne system, ocean gliders), as well as combining standard and original methods... |
| Tipo: Text |
Palavras-chave: Tropical cyclone; South-west Indian Ocean; Gliders; Unmanned airborne system; Biologging; Sea turtles; Global satellite navigation system; ReNovRisk; Numerical modelling; Climate modelling; Austral and cyclonic swells; Seismic data. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00691/80281/83366.pdf |
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| Barruol, Guilhem; Sigloch, Karin. |
| Whether volcanic intraplate hot spots are underlain by deep mantle plumes continues to be debated 40 years after the hypothesis was proposed by Morgan [1972]. Arrivals of buoyant plume heads may have been among the most disruptive agents in Earth's history, initiating continental breakup, altering global climate, and triggering mass extinctions. Further, with the temporary shutdown of European air traffic in 2010 caused by the eruption of Eyjafjallajökull, a geologically routine eruption in the tail end of the presumed Iceland plume, the world witnessed an intrusion of hot spot activity into modern-day life. |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00273/38465/36874.pdf |
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| Bouffaut, Lea; Dreo, Richard; Labat, Valerie; Boudraa, Abdel-o.; Barruol, Guilhem. |
| As a first step to Antarctic blue whale (ABW) monitoring using passive acoustics, a method based on the stochastic matched filter (SMF) is proposed. Derived from the matched filter (MF), this filter-based denoising method enhances stochastic signals embedded in an additive colored noise by maximizing its output signal to noise ratio (SNR). These assumptions are well adapted to the passive detection of ABW calls where emitted signals are modified by the unknown impulse response of the propagation channel. A filter bank is computed and stored offline based on a priori knowledge of the signal second order statistics and simulated colored sea-noise. Then, the detection relies on online background noise and SNR estimation, realized using time-frequency... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00600/71179/69530.pdf |
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| Pratt, Martin J.; Wysession, Michael E.; Aleqabi, Ghassan; Wiens, Douglas A.; Nyblade, Andrew A.; Shore, Patrick; Rambolamanana, Gerard; Andriampenomanana, Fenitra; Rakotondraibe, Tsiriandrimanana; Tucker, Robert D.; Barruol, Guilhem; Rindraharisaona, Elisa. |
| The crust and upper mantle of the Madagascar continental fragment remained largely unexplored until a series of recent broadband seismic experiments. An island-wide deployment of broadband seismic instruments has allowed the first study of phase velocity variations, derived from surface waves, across the entire island. Late Cenozoic alkaline intraplate volcanism has occurred in three separate regions of Madagascar (north, central and southwest), with the north and central volcanism active until <1 Ma, but the sources of which remains uncertain. Combined analysis of three complementary surface wave methods (ambient noise, Rayleigh wave cross-correlations, and two-plane-wave) illuminate the upper mantle down to depths of 150 km. The phase-velocity... |
| Tipo: Text |
Palavras-chave: Surface wave; Ambient noise; Tomography; Madagascar; Intraplate volcanism. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00600/71182/69528.pdf |
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| Fontaine, Fabrice R.; Roult, Genevieve; Michon, Laurent; Barruol, Guilhem; Di Muro, Andrea. |
| Seismic records from La Réunion Island very broadband Geoscope station are investigated to constrain the link between the 2007 eruptive sequence and the related caldera collapse of the Piton de la Fournaise volcano. Tilt estimated from seismic records reveals that the three 2007 eruptions belong to a single inflation-deflation cycle. Tilt trend indicates that the small-volume summit eruption of 18 February occurred during a phase of continuous inflation that started in January 2007. Inflation decelerated 24 days before a second short-lived, small-volume eruption on 30 March, almost simultaneous with a sudden, large-scale deflation of the volcano. Deflation rate, which had stabilized at relatively low level, increased anew on 1 April while no magma was... |
| Tipo: Text |
Palavras-chave: Piton de la Fournaise; Caldera collapse; Broadband seismometer; Tilt; Tidal correction; Deep magma injection. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00287/39823/38326.pdf |
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| Hable, Sarah; Sigloch, Karin; Stutzmann, Eleonore; Kiselev, Sergey; Barruol, Guilhem. |
| We use seismic noise cross-correlations to obtain a 3-D tomography model of SV-wave velocities beneath the western Indian Ocean, in the depth range of the oceanic crust and uppermost mantle. The study area covers 2000×2000 km2 between Madagascar and the three spreading ridges of the Indian Ocean, centred on the volcanic hotspot of La Réunion. We use seismograms from 38 ocean bottom seismometers (OBSs) deployed by the RHUM-RUM project and 10 island stations on La Réunion, Madagascar, Mauritius, Rodrigues, and Tromelin. Phase cross-correlations are calculated for 1119 OBS-to-OBS, land-to-OBS, and land-to-land station pairs, and a phase-weighted stacking algorithm yields robust group velocity measurements in the period range of 3-50 s. We demonstrate that OBS... |
| Tipo: Text |
Palavras-chave: Crustal imaging; Seismic instruments; Seismic interferometry; Seismic noise; Seismic tomography. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00508/61988/66099.pdf |
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| Registros recuperados: 12 | |
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