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1. Large seafloor rupture caused by the 1956 Amorgos tsunamigenic earthquake, Greece

Author

Frédérique Leclerc, Sylvain Palagonia, Nathalie Feuillet, Paraskevi Nomikou, Danai Lampridou, Paul Barrière, Alexandre Dano, Eduardo Ochoa, Nuno Gracias, and Javier Escartin

Subjects
Geology, QE1-996.5, Environmental sciences, GE1-350
Abstract

Abstract In the Mediterranean Sea, the probability that a large earthquake-triggered tsunami will occur in the coming decades is high. Historical tsunami database informs us on their geographical occurrence but their sources, i.e., the faults that slipped during earthquakes and displaced the seafloor to generate tsunamis, are often unknown. Here we identify the submarine rupture of the Amorgos earthquake that on July 9, 1956, triggered the largest mediterranean tsunami in the past two centuries. Using submarines, we explored major normal faults in the epicentral area, and discovered a large surface rupture along the 75-km long Amorgos fault. The 9.8-16.8-m large seafloor offset is compatible with a Mw7.5 event. This finding prompts a reassessment of the largest (≥20 m) tsunami wave origin, previously attributed to earthquake-triggered submarine mass-wasting. It demonstrates that tsunami source can be determined several decades after an event, a key information to better assess future seismic and tsunami hazards.

Published
2024
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2. Tectonic, Topographic, Geologic, and Hydroclimatic Influence on Crack Formation During the 2021 Haiti Earthquake

Author

Newdeskarl Saint Fleur, Joseph E. Dessable, Germain Saint‐Preux, Éric Calais, Nathalie Feuillet, Dominique Boisson, Jean‐Bernard deChabalier, and Yann Klinger

Subjects
crack, Enriquillo‐Plantain Garden Fault, partitioning, interference, thrust, Geophysics. Cosmic physics, QC801-809, Geology, QE1-996.5
Abstract

Abstract The 14 August 2021 Haiti earthquake mainly portrayed reverse motion to the east near L’Asile town and left‐lateral strike‐slip motion to the west near Camp‐Perrin town. To map the rupture and infer its segmentation, we conducted the first post‐seismic field reconnaissance along the left‐lateral strike‐slip Enriquillo fault from L’Asile to Macaya mountain. We identified 98 linear, minor cracks that are not representative of primary fault surface rupture. Analyzing the topographic slope distribution, we detected that the cracks were often located in areas that are prone to topographic instability. About 60% of the cracks are located in Quaternary alluvium and Middle‐Miocene continental marls, indicating a preference for soft sediments. The rivers also have an impact, as crack lengths and openings negatively correlate with their distance to neighboring rivers. In addition, the earthquake occurred in a rainy region with up to 2,479.34 mm of rainfall in 2021, increasing soil instability. Above all, we found a contrast and asymmetry between the eastern and the western parts of the rupture. By dividing the 60‐km long rupture into two equal parts, we observed 57 cracks to the west against 41 to the east. The longest and the widest cracks are to the west. Analyzing their orientation, the cracks mainly oriented as left‐lateral strike‐slip faults to the west and mainly thrusts to the east. This configuration appears to be influenced by the slip pattern of the 2021 Haiti earthquake and consistent with the regional stress field.

Published
2024
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3. Seafloor earthquake ruptures and mass wasting from the 2004 Mw 6.3 Les Saintes submarine earthquake

Author

Alex Hughes, Javier Escartín, Jeremy Billant, Frédérique Leclerc, Muriel Andreani, Jean-Arthur Olive, Aurélien Arnaubec, Alexandre Dano, Arthur Delorme, Christine Deplus, Nathalie Feuillet, Caroline Gini, Nuno Gracias, Cédric Hamelin, Klemen Istenič, Jean-Christophe Komorowski, Anne Le Friant, Claire Marchand, Catherine Mével, Solveig Lie Onstad, and Xavier Quidelleur

Subjects
Geology, QE1-996.5, Environmental sciences, GE1-350
Abstract

Abstract The seismic hazard posed by submarine faults and the capacity of submarine earthquakes to trigger mass wasting are poorly understood because we lack detailed characterizations of coseismic ruptures at the seafloor. Here, we present comprehensive mapping of a seafloor rupture caused by the 2004 M w 6.3 Les Saintes earthquake on the Roseau normal fault in the Lesser Antilles. We report the visual characteristics, displacement profile, and note pronounced asymmetry of the rupture that bears similarities with well-studied subaerial normal fault ruptures. We also identify footwall-derived mass wasted debris that locally cover the coseismic rupture, and show that ground accelerations of 0.1–0.2 g can trigger submarine mass wasting events in well consolidated bedrock along unstable, over-steepened, scarps. Our study demonstrates the potential of underwater vehicles for detailed mapping of seafloor ruptures and hints at a key role for earthquakes in shaping submarine bedrock landscapes by triggering mass wasting events.

Published
2023
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5. Coexistence of Adjacent Siliciclastic, Carbonate, and Mixed Sedimentary Systems: An Example From Seafloor Morphology in the Northern Lesser Antilles Forearc

Author

Pierre Morena, Gueorgui Ratzov, Antonio Cattaneo, Frauke Klingelhoefer, Christian Beck, Chloé Seibert, Boris Marcaillou, and Nathalie Feuillet

Subjects
sediment pathways, mixed turbidite system, subduction zone, submarine canyon, plunge-pool, active tectonics, Science
Abstract

Three main types of factors commonly control the nature of the clasts, the arrangement of the distinctive lithologies, and the general architecture of turbidite systems: sedimentation rate and carbonate production; climates and glacio-eustatism; and morphology and tectonics. The coexistence of adjacent systems of distinctive nature is, however, scarcely documented, and the relative influence of each factor needs better constrain. In the Northern Lesser Antilles Segment (NLAS), carbonate and siliciclastic sediment sources coexist within a 150 km lateral distance, with carbonate platforms lying onto a volcanic substratum, and by a succession of spurs and triangular valleys that are bounded by active normal faulting. To better understand the factors controlling sedimentary processes from the carbonate platform sources to the deep-sea sinks, we used backscatter, bathymetry, multichannel seismic, and sub-bottom profiles. Sedimentary systems are dominated by siliciclastic input (by retrogressive erosion of confined canyons affecting the volcanic slope), carbonate input (by carbonate sediment transported by oceanic- and wind-driven submarine currents beyond the leeward edges of carbonates platforms), or both. In the mixed systems, the retrogressive erosion of the canyon head determines the nature of the source (volcanic on the slope, carbonate when the canyons reach the shelf edge). Glacio-eustatism has a key role in carbonate availability on the platform, as attested by the presence of drowned platforms. The main contribution of this study is the identification of the major role that tectonic activity plays in the short-distance coexistence of the distinctive sedimentary systems since fault-bounded V-shaped valleys in map view offer alternating leeward and windward edges favoring carbonate or mixed systems. Additionally, the steep slope gradient induced by normal faults and regional subsidence seems to be the main factor controlling sediment dispersal. It causes multiple line sources and the dispersion of gravity-driven currents under the effect of hydraulic jumps, thus preventing the formation of a channelized system. Our study provides a modern analog of adjacent systems dominated by distinctive lithologies in a tectonically active area. The results appear particularly appropriate to decipher the nature of ancient source-to-sink systems dominated by complex tectonics, paleo-bathymetry, and sediment routings.

Published
2022
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8. Active Tectonics in Southern Haiti and Surface Rupture of the 14 August 2021 Earthquake

Author

Newdeskarl Saint Fleur, Yann Klinger, Joseph Emmanuel Dessable, Germain Saint-Preux, Nathalie Feuillet, Dominique Boisson, Eric Calais, and Jean-Bernard de Chabalier

Abstract

The 14 August 2021 earthquake occurred along the southern peninsula of Haiti only 11 years after the 12 January 2010 devastating earthquake. According to seismological and geodetic data, the events are both complex involving more than one fault. The 2021 rupture mainly portrayed reverse motion to the east near L’Asile town and left-lateral strike-slip motion to the west near Camp-Perrin town and Macaya mountain. A few days after the 2021 event, we conducted the first post-seismic field reconnaissance along the left-lateral Enriquillo-Plantain Garden Fault (EPGF) zone from L’Asile to Macaya mountain. We found numerous fresh cracks and landslides along that fault zone. The 111 cracks are mainly E-W-striking, some are oriented WNW-ESE, consistent with fault orientation in the area. In addition, the biggest cracks are mostly located to the west of the rupture zone, some of them may be potential fault surface rupture as revealed by seismological data. Furthermore, our observations along the northern coast of the southern peninsula revealed no significant coseismic coastal uplift as also suggested by InSAR data. Besides that field reconnaissance, we revisited the fault map around the epicentral area using high-resolution LiDAR data, Pléiades imagery and aerial photographs. We identified several left-lateral offsets of tens of meters corresponding to successive slips along the EPGF from L’Asile to Macaya mountain. In addition to the strike-slip deformation, we identified numerous geomorphic features related to long-term tectonic uplift to the north of the EPGF surface trace near the eastern part of the 2021 rupture. Those features are strikingly rare to the south. Such a pattern may indicate that the EPGF is north-dipping in the area. The 14 August 2021 rupture offers a new opportunity to constrain the kinematics and geometry of the EPGF system in southern Haiti.

Published
2023
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10. Hurricane Irma: an unprecedented event over the last 3700 years? Geomorphological changes and sedimentological record in Codrington Lagoon, Barbuda

Author

Maude Biguenet, Eric Chaumillon, Pierre Sabatier, Antoine Bastien, Emeline Geba, Fabien Arnaud, Thibault Coulombier, and Nathalie Feuillet

Abstract

Low-lying coasts and small islands, such as in the Lesser Antilles, are particularly vulnerable to hurricane-induced marine floods. In September 2017, Category 5 Hurricane Irma, with winds up to 360 km/h, hit the northern Caribbean islands and caused the destruction of 95 % of the structures on Barbuda Island. We investigated the geomorphological impacts and the sedimentological record of this hurricane in Barbuda’s Codrington Lagoon. Following Hurricane Irma, two wide inlets developed across the Codrington sandy barrier. One of these inlets enlarged and was still opened four years later. From available data, it seems that this barrier remained continuous for the last 250 years before Hurricane Irma. At a longer time scale, very high-resolution seismic exploration combined with sediment cores sampled in Codrington Lagoon were used to investigate Irma deposit and environmental changes for the last 3700 years. The evolution from a low-energy small and shallow lagoon to the modern wide and high-energy lagoon recorded by the lagoon sediment-fill was related to both long-term sea-level rise and subsidence. The top of the lagoon fill consists of a thick and extensive sand sheet recording an abrupt increase in energy. Given its location at the top of the cores, its very recent age supported by short-lived radionuclides data, together with large inlets opening and barrier erosion after Irma implying a large sand supply to the lagoon, this sand sheet was attributed to Hurricane Irma. From our cores, it appears that this deposit is unique over more than 3700 years. Both the opening of a new inlet and the thick upper sand sheet support the exceptional character of Irma at the scale of centuries to millennia. Our study reinforces the idea that Hurricane Irma was exceptional in terms of intensity and may be associated with global warming.

Published
2023

11. Volcano-tectonic structures of Mayotte’s upper submarine slope: insights from high-resolution bathymetry and in-situ imagery from a deep-towed camera

Author

Valentine Puzenat, Nathalie Feuillet, Jean-Christophe Komorowski, Javier Escartín, Christine Deplus, Patrick Bachèlery, Carole Berthod, Lucia Gurioli, Carla Scalabrin, Cécile Cathalot, Emmanuel Rinnert, Benoît Loubrieu, Delphine Pierre, Mathilde Pitel-Roudaut, Nina Tanguy, Yves Fouquet, Stephan J. Jorry, Elodie Lebas, Fabien Paquet, Isabelle Thinon, Institut de Physique du Globe de Paris (IPG Paris), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, In-situ imagery, [SDU]Sciences of the Universe [physics], Geological mapping, Mayotte, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, General Earth and Planetary Sciences, Submarine volcanism, High-resolution bathymetry, General Environmental Science
Abstract

International audience; Unlike subaerial volcanic activity, deep submarine eruptions are difficult to detect, observe and monitor. The objective of this paper is to describe a large and complex volcanic region, named the Horseshoe area, recently discovered at 1500 m below sea level on the eastern upper submarine slope of Mayotte Island. The area is crucial because, since 2018, it has experienced an exceptionally deep seismic activity associated with the ongoing submarine eruption that formed a new volcanic edifice, Fani Maoré, about 40 km to the east. We present the results of a multiscale study, based on high-resolution bathymetry and in-situ seafloor observations carried out with autonomous underwater vehicles (AUVs) and deep-towed camera systems. In-situ imagery provides ground-truth for the geological interpretation of seafloor textures mapped with the bathymetry. The combination of both datasets allows us to discuss the nature of the volcanic structures and to propose a relative chronology of previous eruptive events in the Horseshoe area. Based on our analyses, we propose the following chronology: (a) the emplacement of a large explosive volcanic cone, the Horseshoe edifice, (b) the later collapse of this edifice that resulted in the formation of an elongated, 2 km wide horseshoe-shaped depression, crosscutting older hummocky lava flows, (c) the development of an E–W eruptive fissure associated with numerous explosive craters, east of the Horseshoe edifice, and (d) late volcanism emanating from the rim of the horseshoe-shaped depression that fed elongated thin lava flows both towards and away from the depression. While all volcanic features mapped at the Horseshoe area were emplaced prior to the 2018 eruption, our study shows that this region has still been volcanically active in the recent past. Our results thus document a complex geological history at small spatial scales involved in the construction of major submarine edifices, and that are controlled by volcano-tectonic processes at larger scales.

Published
2023
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12. Volcanisme et tectonique découverts le long de l’archipel des Comores entre l’Afrique et Madagascar

Author

Isabelle Thinon, Anne Lemoine, Sylvie Leroy, Fabien Paquet, Carole Berthod, Sébastien Zaragosi, Vincent Famin, Nathalie Feuillet, Pierre Boymond, Charles Masquelet, Nicolas Mercury, Anaïs Rusquet, Carla Scalabrin, Jérôme Van der Woerd, Julien Bernard, Julie Bignon, Valérie Clouard, Cécile Doubre, Eric Jacques, Stephan J. Jorry, Frédérique Rolandone, Nicolas Chamot-Rooke, Matthias Delescluse, Dieter Franke, Louise Watremez, Patrick Bachèlery, Laurent Michon, Daniel Sauter, Stéphane Bujan, Albane Canva, Emilie Dassie, Vincent Roche, Said Ali, Abdoul Hamid Sitti Allaouia, Christine Deplus, Setareh Rad, Ludivine Sadeski, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire GéoSciences Réunion (LGSR), Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Ecole et Observatoire des Sciences de la Terre (EOST), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Faculté des Sciences et Techniques - Université des Comores, CNDRS, and ANR-19-CE31-0018,COYOTES,COmores & maYotte : vOlcanisme, TEctonique et Sismicité(2019)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Comoros Archipelago, Active tectonics, NorthernMozambique Channel, Volcanic province, Northern Mozambique Channel, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Backscatter, Bathymetry, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, General Earth and Planetary Sciences, Incipient plate boundary, General Environmental Science
Abstract

Geophysical and geological data from the North Mozambique Channel acquired during the 2020–2021 SISMAORE oceanographic cruise reveal a corridor of recent volcanic and tectonic features 200 km wide and 600 km long within and north of Comoros Archipelago. Here we identify and describe two major submarine tectono-volcanic fields: the N’Droundé province oriented N160°E north of Grande-Comore Island, and the Mwezi province oriented N130°E north of Anjouan and Mayotte Islands. The presence of popping basaltic rocks sampled in the Mwezi province suggests post-Pleistocene volcanic activity. The geometry and distribution of recent structures observed on the seafloor are consistent with a current regional dextral transtensional context. Their orientations change progressively from west to east (N160°E, N130°E, EW). The volcanism in the western part appears to be influenced by the pre-existing structural fabric of the Mesozoic crust. The 200 km-wide and 600 km-long tectono-volcanic corridor underlines the incipient Somalia–Lwandle dextral lithospheric plate boundary between the East-African Rift System and Madagascar., Des données géophysiques et géologiques ont été acquises lors de la campagne océanographique SISMAORE (2020–2021). Deux grands champs tectono-volcaniques sous-marins ont été découverts tout le long et principalement au nord de l’archipel des Comores : la province N’Droundé orientée N160°E au nord de Grande-Comore, et la province Mwezi orientée N130°E au nord d’Anjouan-Mayotte où des roches basaltiques de type popping-rocks suggèrent une activité volcanique possiblement actuelle à pléistocène. La géométrie et la distribution des structures récentes sont cohérentes avec un contexte régional actuel transtensif dextre. Leurs orientations évoluent d’Ouest en Est (N160°E, N130°E, EW), suggérant pour la partie occidentale, une mise en place du volcanisme influencée par la structuration crustale préexistante. Le corridor tectono-volcanique de 200 km de large et de 600 km de long dessine une limite de plaque lithosphérique Somalie-Lwandle immature en décrochante dextre entre le système du rift est-africain et Madagascar.

Published
2022
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13. Mayotte seismic crisis: building knowledge in near real-time by combining land and ocean-bottom seismometers, first results

Author

Jérôme Vergne, Jean Battaglia, Louis Géli, Stephan J. Jorry, Jérôme Van der Woerd, Anthony Dofal, Jean-Marie Saurel, Hélène Jund, Marie Paule Bouin, Arnaud Gaillot, Alison Colombain, Ronan Apprioual, Nicolas Mercury, Sophie Lambotte, Valérie Ferrazzini, Cécile Doubre, Yves Fouquet, Philippe Kowalski, Simon Besançon, Océane Foix, Cyprien Griot, Céleste Broucke, Mickaël Roudaut, Claudio Satriano, Grégoire Dectot, Isabelle Thinon, Rémi Dretzen, Lise Retailleau, Tom Dumouche, Nicolas Desfete, Félix Léger, Pierre Guyavarch, Didier Bertil, Aude Lavayssière, Philippe Fernagu, Aline Peltier, Fabrice R. Fontaine, Frédéric Lauret, Arnaud Lemarchand, Emmanuel Rinnert, Chastity Aiken, Pascal Pelleau, Wayne C Crawford, Marc Grunberg, Frédéric Tronel, Roser Hoste-Colomer, Soumya Bodihar, Emmanuel Maros, Christophe Brunet, R. Daniel, Eric Jacques, Kevin Canjamale, Emre Güzel, Patrice Boissier, Anne Lemoine, Agathe Roullé, Philippe Catherine, Maxime Bes de Berc, Nathalie Feuillet, Angèle Laurent, Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Observatoire Volcanologique du Piton de la Fournaise (OVPF), Institut de Physique du Globe de Paris (IPG Paris), Laboratoire GéoSciences Réunion (LGSR), Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Faculty of Electrical and Electronics Engineering [Istanbul], and Istanbul Technical University (ITÜ)

Subjects
Volcano monitoring, Seismometer, 010504 meteorology & atmospheric sciences, Population, Magnitude (mathematics), Context (language use), Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Remote sensing of volcanoes, Geochemistry and Petrology, education, Indian Ocean, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, education.field_of_study, geography, geography.geographical_feature_category, Volcano seismology, Geophysics, Volcano, Africa, Submarine pipeline, Geology, Seismology, Channel (geography)
Abstract

SUMMARYThe brutal onset of seismicity offshore Mayotte island North of the Mozambique Channel, Indian Ocean, that occurred in May 2018 caught the population, authorities and scientific community off guard. Around 20 potentially felt earthquakes were recorded in the first 5 d, up to magnitude Mw 5.9. The scientific community had little pre-existing knowledge of the seismic activity in the region due to poor seismic network coverage. During 2018 and 2019, the MAYOBS/REVOSIMA seismology group was progressively built between four French research institutions to improve instrumentation and data sets to monitor what we know now as an on-going exceptional submarine basaltic eruption. After the addition of 3 medium-band stations on Mayotte island and 1 on Grande Glorieuse island in early 2019, the data recovered from the Ocean Bottom Seismometers were regularly processed by the group to improve the location of the earthquakes detected daily by the land network. We first built a new local 1-D velocity model and established specific data processing procedures. The local 1.66 low VP/VS ratio we estimated is compatible with a volcanic island context. We manually picked about 125 000 P and S phases on land and sea bottom stations to locate more than 5000 events between February 2019 and May 2020. The earthquakes outline two separate seismic clusters offshore that we named Proximal and Distal. The Proximal cluster, located 10 km offshore Mayotte eastern coastlines, is 20–50 km deep and has a cylindrical shape. The Distal cluster start 5 km to the east of the Proximal cluster and extends below Mayotte's new volcanic edifice, from 50 to 25 km depth. The two clusters appear seismically separated, however our data set is insufficient to firmly demonstrate this.

Published
2021
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14. A Significant Increase in Interplate Seismicity near Major Historical Earthquakes Offshore Martinique (FWI)

Author

Valérie Clouard, Nathalie Feuillet, Fabrice R. Fontaine, O’Leary Gonzalez, Jean-Marie Saurel, Anne‐Marie Lejeune, Jordane Corbeau, Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Observatoire volcanologique et sismologique de martinique (OVSM), Institut de Physique du Globe de Paris, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), CENAIS Santiago de Cuba, Institut des Sciences de la Terre de Paris (iSTeP), and Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, [SDU]Sciences of the Universe [physics], Geochemistry and Petrology, Submarine pipeline, Martinique, Geology, Seismology, 0105 earth and related environmental sciences
Abstract

Understanding the processes that may be at the origin of major earthquakes in subduction zones is highly challenging, especially in the case of slowly converging areas such as the Lesser Antilles subduction zone. Our study reveals a recorded increase in seismicity rate and cumulative seismic moment over the last two decades offshore Martinique island and, particularly, in the presumed rupture area of the major historical 1839 earthquake. This sustained seismicity is shared between extensive intermediate depth activity since the 2007 Mw 7.4 earthquake that occurred about 20 km north of Martinique and a compressive seismic cluster located in the seismogenic zone of the subduction zone. We also observe a downward migration of the seismicity along the plate interface up to a 60–65 km depth and a recorded increase in the magnitudes of the earthquakes. All these observations may indicate ongoing changes along the plate boundary interface near the area of the historical major rupture of 1839, although more detailed statistical studies and additional data are necessary to confirm this trend.

Published
2021
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16. Initial results from a hydroacoustic network to monitor submarine lava flows near Mayotte Island

Author

Sara Bazin, Jean-Yves Royer, Flavie Dubost, Fabien Paquet, Benoît Loubrieu, Aude Lavayssière, Christine Deplus, Nathalie Feuillet, Éric Jacques, Emmanuel Rinnert, Isabelle Thinon, Élodie Lebas, Delphine Pierre, Lise Retailleau, Jean-Marie Saurel, Alexey Sukhovich, Robin Bonnet, and null the REVOSIMA group

Subjects
Submarine lava flow, Geophysics, Volcan sous-marin, General Earth and Planetary Sciences, Underwater volcano, Hydroacoustic, Seismo-volcanic monitoring, Hydroacoustique, Géophysique, Coulée de lave, General Environmental Science, Surveillance sismo-volcanique
Abstract

In 2019, a new underwater volcano was discovered at 3500 m below sea level (b.s.l.), 50 km east ofMayotte Island in the northern part of theMozambique Channel. In January 2021, the submarine eruption was still going on and the volcanic activity, along with the intense seismicity that accompanies this crisis, was monitored by the recently created REVOSIMA (MAyotte VOlcano and Seismic Monitoring) network. In this framework, four hydrophones were moored in the SOFAR channel in October 2020. Surrounding the volcano, they monitor sounds generated by the volcanic activity and the lava flows. The first year of hydroacoustic data evidenced many earthquakes, underwater landslides, large marine mammal calls, along with anthropogenic noise. Of particular interest are impulsive signals that we relate to steam bursts during lava flow emplacement. A preliminary analysis of these impulsive signals (ten days in a year, and only one day in full detail) reveals that lava emplacementwas active when our monitoring started, but faded out during the first year of the experiment. A systematic and robust detection of these specific signalswould hence contribute to monitor active submarine eruptions in the absence of seafloor deep-towimaging or swath-bathymetry surveys of the active area., En 2019, un nouveau volcan sous-marin a été découvert par 3500 m de profondeur, à 50 km à l’est de l’île de Mayotte dans la partie Nord du Canal du Mozambique. Le RÉseau de surveillance VOlcanologique et SIsmologique de MAyotte (REVOSIMA) a été mis en place pour surveiller l’activité sous-marine de ce nouveau volcan ainsi que l’intense crise sismique qui a débuté en Mai 2018 et qui est toujours en cours. Dans ce cadre, quatre mouillages équipés d’hydrophones ont été déployés en octobre 2020 autour du volcan, à la profondeur du canal SOFAR. L’objectif est, entre autres, d’enregistrer les sons générés par l’activité volcanique sous-marine, notamment par l’éruption de coulées de lave. Plusieurs sources d’ondes hydroacoustiques ont été identifiées pendant la première année d’écoute : séismes, glissements de terrain sous-marins, cris de mammifères marins de différentes espèces et bruit anthropogénique. Parmi ces sons, des signaux impulsionnels ont retenu notre attention. Nous les associons à des formations de vapeur liées à l’épanchement de coulées volcaniques. L’analyse préliminaire de ces signaux (10 jours répartis sur la première année, dont 24 h dépouillées finement) révèle que la forte activité éruptive observée à 10 km au NW du nouveau volcan au début de la surveillance hydroacoustique a fortement diminué pendant la première année d’enregistrement. Une détection systématique robuste de ces signaux offrirait la possibilité de dater et localiser l’activité éruptive, en l’absence de levés bathymétriques et d’imagerie répétée de la zone active.

Published
2022

17. 20th-century strain accumulation on the Lesser Antilles megathrust based on coral microatolls

Author

Belle Philibosian, Nathalie Feuillet, Jennifer Weil-Accardo, Eric Jacques, Abel Guihou, Anne-Sophie Mériaux, André Anglade, Jean-Marie Saurel, Sébastien Deroussi, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Newcastle University [Newcastle]

Subjects
Caribbean, Lesser Antilles, tectonic deformation, Geophysics, Space and Planetary Science, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], earthquake, Earth and Planetary Sciences (miscellaneous), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, coral microatoll, subduction
Abstract

International audience; The seismic potential of the Lesser Antilles megathrust remains poorly known, despite the potential hazard it poses to numerous island populations and its proximity to the Americas. As it has not produced any large earthquakes in the instrumental era, the megathrust is often assumed to be aseismic. However, historical records of great earthquakes in the 19th century and earlier, which were most likely megathrust ruptures, demonstrate that the subduction is not entirely aseismic. Recent occurrences of giant earthquakes in areas where such events were previously thought to be improbable have illustrated the importance of critically evaluating the seismic potential of other "low-hazard" subduction zones, such as the Lesser Antilles. Using the method of coral microatoll paleogeodesy developed in Sumatra, we examine 20th-century vertical deformation on the forearc islands of the Lesser Antilles and model the underlying strain accumulation on the megathrust. Our data indicate that the eastern coasts of the forearc islands have been subsiding by up to ∼8 mm/yr relative to sites closer to the arc, suggesting that on the time scale of the 20th century, a portion of the megathrust just east of the forearc islands has been locked. Our findings are in contrast to recent models based on satellite geodesy that suggest little or no strain accumulation anywhere along the Lesser Antilles megathrust. This discrepancy is potentially explained by the different time scales of measurement, as recent studies elsewhere have indicated that interseismic coupling patterns may vary on decadal time scales and that century-scale or longer records are required to fully assess seismic potential. The accumulated strain we have detected will likely be released in future megathrust earthquakes, uplifting previously subsiding areas and potentially causing widespread damage from strong ground motion and tsunami waves.

Published
2022
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18. Offshore Mayotte volcanic plumbing revealed by local passive tomography

Author

Mayobs, Isabelle Thinon, Emmanuel Rinnert, Chastity Aiken, Océane Foix, Stephan J. Jorry, Revosima Seismology Team, Jean-Marie Saurel, Nathalie Feuillet, Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)

Subjects
Active volcano, Magma chamber, 010504 meteorology & atmospheric sciences, Earthquake tomography, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Comoros archipelago, Geochemistry and Petrology, Lithosphere, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Submarine volcano, Indian Ocean, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Volcano seismology, Fracture zone, Subsidence, Geophysics, Volcano, 13. Climate action, [SDU]Sciences of the Universe [physics], Magma, Submarine pipeline, Seismology, Geology
Abstract

International audience; A new submarine volcano has been discovered offshore Mayotte, a part of the Comoros volcanic archipelago located between Africa and Madagascar. The edifice arose from the sea-floor following a seismo-volcanic crisis that started in May 2018. This seismo-volcanic activity highlights very deep magma reservoirs and dykes in the East Mayotte volcanic system. Since the crisis, the region has experienced >2000 earthquakes with magnitude ≥3.5 and activity continues today (August 17, 2021). The earthquakes are unusually deep and distributed into two swarms: one 5–15 km east of Petite-Terre at 25–55 km depth and a second 25 km away at 30–50 km depth. Significant subsidence of Mayotte to the East has been assigned to the drainage of a deep magma chamber, inferred to be located 30 km from the coast. However, at present, the earthquake locations and geodetic observations have not been sufficient to image entirely the structure of the volcanic plumbing system. In this study, we construct Vp, Vs, dVp, dVs and Vp/Vs 3D velocity models to assess the deeper structure of the young volcano plumbing system, offshore and East of Mayotte. Using >3000 earthquakes from an ongoing monitoring effort, and a 1D velocity model determined onboard, we jointly inverted for velocity structures, earthquake locations, origin times, and station corrections using LOTOS software. The calculated 3D velocity models highlight a complex volcanic system down to 40 km depth. Specifically, we image 3 interpreted reservoirs, more or less consolidated/old. The main reservoir is located at about 30 km depth and deeper, making it one of the deepest magmatic chamber imaged. The reservoirs are connected by several old crystallized conduits, whose existence could have been influenced by the presence of an old fracture zone, globally oriented N130°, due to a regional strike-slip motion of the lithosphere. Moreover, gas-saturated rock may be present below the currently degassing Horse Shoe structure. We were unable to image connections between the new volcanic edifice and reservoirs or conduits due to a lack of resolution in that part of the study area.

Published
2021
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19. The 2018-ongoing Mayotte submarine eruption: magma migration imaged by petrological monitoring

Author

Christine Deplus, Etienne Médard, Isabelle Thinon, Patrick Bachèlery, Jean-Luc Devidal, Aline Peltier, Pascale Besson, Jean-Christophe Komorowski, Georges Boudon, Mhammed Benbakkar, Samia Hidalgo, Lucia Gurioli, Pierre Burckel, Manon Bickert, S. Nowak, Stephan J. Jorry, Nathalie Feuillet, Andrea Di Muro, Anne Le Friant, Melanie Kaliwoda, Estelle Rose-Koga, Jessica Langlade, Yves Fouquet, Carole Berthod, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Physique du Globe de Paris (IPG Paris), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique du Globe de Paris, Observatoire Volcanologique du Piton de la Fournaise (OVPF), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), BRGM – French Geological Survey, 45060 Orléans, France, Ludwig-Maximilians-Universität München (LMU), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), and Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)

Subjects
010504 meteorology & atmospheric sciences, mantle reservoirs, Geochemistry, Mayotte, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, engineering.material, petrological model, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Effusive eruption, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), dredges, 14. Life underwater, submarine eruption, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Olivine, multiple storage zone, Submarine eruption, Geophysics, Volcano, 13. Climate action, Space and Planetary Science, Ridge, [SDU]Sciences of the Universe [physics], Magma, engineering, Submarine pipeline, Geology
Abstract

Co-auteur étranger; International audience; Deep-sea submarine eruptions are the least known type of volcanic activity, due to the difficulty of detecting, monitoring, and sampling them. Following an intense seismic crisis in May 2018, a large submarine effusive eruption offshore the island of Mayotte (Indian Ocean) has extruded at least 6.5 km3 of magma to date, making it the largest monitored submarine eruption as well as the largest effusive eruption on Earth since Iceland's 1783 Laki eruption. This volcano is located along a WNW-ESE volcanic ridge, extending from the island of Petite Terre (east side of Mayotte) to about 3,500 m of water depth. We present a detailed petrological and geochemical description of the erupted lavas sampled by the MAYOBS 1, 2, and 4 cruises between May and July 2019 and use these to infer characteristics and changes through time for the whole magmatic system and its dynamics from the source to the surface. These cruises provide an exceptional time-series of bathymetric, textural, petrological, and geochemical data for the 2018-2019 eruptive period, and hence bring an invaluable opportunity to better constrain the evolution of magma storage and transfer processes during a long-lived submarine eruption. Integrating the petrological signatures of dredged lavas with geophysical data, we show that the crystal-poor and gas-rich evolved basanitic magma was stored at mantle depth (>37 km) in a large (≥10 km3) reservoir and that the eruption was tectonically triggered. As the eruption proceeded, a decrease in ascent rate and/or a pathway change resulted in the incorporation of preexisting differentiated magma stored at a shallower level. Magma transfer from the deep mantle reservoir is syn-eruptive, as indicated by transfer times estimated from diffusion in zoned olivine crystals that are much shorter than the total eruption duration. Our petrological model has important hazard implications concerning the rapid and stealthy awakening of a deep gas-rich magma reservoirs that can produce unusually high output rates and long-lived eruption. Sudden tapping of large crystal poor reservoirs may be the trigger mechanism for other rarely witnessed high-volume (>1 km3) effusive events.

Published
2021
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20. Birth of a large volcanic edifice offshore Mayotte via lithosphere-scale dyke intrusion

Author

Angèle Laurent, Philippe Kowalski, R. Daniel, Eric Jacques, Patrick Bachèlery, Raphaël Grandin, Manuel A. Moreira, Aline Peltier, Valérie Ballu, Nathalie Feuillet, François Beauducel, Jean-Pierre Donval, Arnaud Gaillot, Didier Bertil, Yves Fouquet, Vivien Guyader, Fabien Paquet, Arnaud Lemarchand, Cecile Cathalot, Simon Besançon, Emmanuel Rinnert, Chastity Aiken, Carla Scalabrin, Wayne C Crawford, Isabelle Thinon, Jean Marie Saurel, Océane Foix, Anne Lemoine, Pascal Pelleau, Christine Deplus, Louis Géli, Stephan J. Jorry, J. Gomez, Claudio Satriano, Pascal Bernard, Jérôme Van der Woerd, Institut de Physique du Globe de Paris (IPG Paris), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), French Ministries of Environment, Research and Overseas under a research project to N.F. (proposal INSU-CT3 TELLUS SISMAYOTTE2019)., Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Institut national des sciences de l'Univers (INSU - CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Institut de physique du globe de Strasbourg (IPGS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Lava, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Seafloor spreading, Submarine eruption, Volcano, [SDU]Sciences of the Universe [physics], Lithosphere, Asthenosphere, Magma, General Earth and Planetary Sciences, Caldera, 14. Life underwater, Petrology, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Volcanic eruptions shape Earth’s surface and provide a window into deep Earth processes. How the primary asthenosphericmelts form, pond and ascend through the lithosphere is, however, still poorly understood. Since 10 May 2018, magmaticactivity has occurred offshore eastern Mayotte (North Mozambique channel), associated with large surface displacements,very-low-frequency earthquakes and exceptionally deep earthquake swarms. Here we present geophysical and marine datafrom the MAYOBS1 cruise, which reveal that by May 2019, this activity formed an 820-m-tall, ~5 km³ volcanic edifice on the seafloor.This is the largest active submarine eruption ever documented. Seismic and deformation data indicate that deep (>55 kmdepth) magma reservoirs were rapidly drained through dykes that intruded the entire lithosphere and that pre-existing subverticalfaults in the mantle were reactivated beneath an ancient caldera structure. We locate the new volcanic edifice at the tip ofa 50-km-long ridge composed of many other recent edifices and lava flows. This volcanic ridge is an extensional feature insidea wide transtensional boundary that transfers strain between the East African and Madagascar rifts. We propose that the massiveeruption originated from hot asthenosphere at the base of a thick, old, damaged lithosphere.

Published
2021
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21. Birth of a large volcanic edifice through lithosphere-scale dyking offshore Mayotte (Indian Ocean)

Author

Nathalie Feuillet, Stephan Jorry, Wayne Crawford, Christine Deplus, Isabelle Thinon, Eric Jacques, Jean-Marie Saurel, Anne Lemoine, Fabien Paquet, Claudio Satriano, Chastity Aiken, Océane Foix, Philippe Kowalski, Angèle Laurent, Emmanuel. Rinnert, Cecile Cathalot, Jean.Pierre Donval, Vivien Guyader, Arnaud Gaillot, carla scalabrin, Manuel Moreira, Aline Peltier, François Beauducel, Raphaël Grandin, Valérie Ballu, Romuald Daniel, Pascal Pelleau, Simon Besancon, Louis Geli, Pascal Bernard, Patrick Bachelery, Yves Fouquet, Didier Bertil, Arnaud Lemarchand, and Jerôme Van der Woerd

Published
2021
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22. Mantle xenolith-bearing phonolites and basanites feed the active volcanic ridge of Mayotte (Comoros archipelago, SW Indian Ocean)

Author

Etienne Médard, Stephan J. Jorry, Yves Fouquet, Samia Hidalgo, Anne Le Friant, Christine Deplus, Mhammed Benbakkar, S. Nowak, Pierre Burckel, Catherine Chauvel, Lucia Gurioli, Andrea Di Muro, Theo Hassen Ali, Nathalie Feuillet, Jean-Luc Devidal, Isabelle Thinon, Carole Berthod, Jean-Christophe Komorowski, Patrick Bachèlery, Aline Peltier, Pascale Besson, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Observatoire Volcanologique du Piton de la Fournaise (OVPF), Institut de Physique du Globe de Paris (IPG Paris), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Anorthoclase, magmatic system, Geochemistry, Mayotte, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, phonolite, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Magmatic system, Geochemistry and Petrology, Fractional crystallization, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Xenolith, 14. Life underwater, 0105 earth and related environmental sciences, fractional crystallization, Phonolite, Basanite, geography, geography.geographical_feature_category, Fractional crystallization (geology), Geophysics, Volcano, 13. Climate action, Magma, engineering, Geology
Abstract

International audience; Since 2018, the submarine east flank of Mayotte Island (Comoros archipelago) is the site of a major eruption located at 3.5 km depth bsl on a WNW-ESE volcanic ridge. Samples brought by oceanographic cruises carried out to monitor this seismo-volcanic crisis indicate that this volcanic ridge is built by a bimodal sodic alkaline magmatic series that includes basanites and phonolites. A petrological study of dredged samples allowed us to image the magmatic system feeding the volcanic ridge and to determine the link between basanitic and phonolitic magmas. The magmatic system feeding the volcanic ridge comprises multiple levels of magma storage. Basanitic magmas generated at 80–100 km mantle depth are stored in two or more deep reservoirs (≥ 37 km) and then in shallower basanitic and phonolitic lenses located close to the Moho interface before rising the surface. This study identifies three possible scenarios: (1) the deep basanitic magma rises directly and quickly to the surface from the deep mantle reservoir (as is currently happening 60 km offshore), (2) the basanitic magma stalls in a shallower reservoir near the Moho before resuming its ascent toward the surface and erupting as porphyritic basanite, (3) the basanitic magma stops and evolves to phonolite in these sub-crustal reservoirs. The phonolitic lavas are produced by approximately 80% fractional crystallization (34% clinopyroxene, 30% anorthoclase feldspar, 15.5% magnetite, 12.5% olivine, 5% apatite and 4% ilmenite) of a hydrous basanitic magma at mantle depths (P > 0.6 GPa) under reduced oxygen fugacity (~ FMQ-1). In this third scenario, the phonolitic magma might be reactivated by the arrival of a new batch of deeper basanitic magma.

Published
2021
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24. Simulation of the 2004 tsunami of Les Saintes in Guadeloupe (Lesser Antilles) using new source constraints

Author

Audrey Gailler, Nathalie Feuillet, Louise Cordrie, Philippe Heinrich, Javier Escartín, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE03-0006,CARQUAKES,grands séismes et tsunamis dans les petites Antilles: impact sur la sédimentation côtière et profonde, sur les coraux et l'installation humaine(2017), and ANR-17-CE31-0020,SerSurF,Rupture Sismique des Faille Normales Sous-marines(2017)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 021110 strategic, defence & security studies, Atmospheric Science, 010504 meteorology & atmospheric sciences, Subduction, 0211 other engineering and technologies, Landslide, 02 engineering and technology, Slip (materials science), 01 natural sciences, Seafloor spreading, Tectonics, 13. Climate action, Oceanic crust, [SDU]Sciences of the Universe [physics], Natural hazard, Earth and Planetary Sciences (miscellaneous), Bathymetry, 14. Life underwater, [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

The arc of the Lesser Antilles is associated with a significant tectonic activity due to the subduction of the Atlantic oceanic plate under the Caribbean plate. Earthquakes in this context have the potential to trigger landslides and tsunamis due to the important vertical seafloor displacement. The historical tsunamigenic earthquakes in this region are rare, but the damages they may have generated before along the coasts show that they pose a considerable threat to the closest inhabited islands. The most recent tsunamigenic earthquake occurred in 2004 in the area of Les Saintes, along a normal fault system located in the back-arc of the subduction. This $$M_{w}=6.3$$ earthquake generated small waves with 2 m of run-up in several bays of Les Saintes, a group of islands in the South of Guadeloupe. A recent survey conducted in the source area using deep-sea vehicles revealed for the first time an important coseismic slip on the Roseau fault plane, attributed to the 2004 event, which had not been predicted in the seismic inversion models. This event and the dataset on the Roseau fault gives the opportunity to model precisely the earthquake, to compare the simulation results with the observations and to evaluate the impact of the rupture heterogeneity and rupture shallowness on the height of the tsunami waves. Extending our earlier work (Cordrie et al. in OCEANS 2019—Marseille, Jun 2019, Marseille, France, pp 1–9, 2019. https://doi.org/10.1109/OCEANSE.2019.8867447 ) and in order to avoid a loss of quality from the dataset in the modeling of the initial sea-surface deformation especially in shallow depth and near field context, a transfer function of the deformation from the seafloor to the sea surface and different numerical schemes were used. Results on the tsunami height distribution indicate some local tsunami amplification phenomena linked to the bathymetry or the coastline geometry and highlight the most endangered areas of the islands. The simulations give additional constraints on the source, show the impact of the slip heterogeneities on the tsunami and finally provide a complementary estimation of the 2004 coseismic slip intensity.

Published
2020
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25. Birth of a large volcanic edifice offshore Mayotte (Comoros Island, Western Indian Ocean)

Author

Jérôme Van der Woerd, Didier Bertil, Arnaud Gaillot, Jean-Marie Saurel, Nathalie Feuillet, Claudio Satriano, Vivien Guyader, Louis Géli, François Beauducel, Stephan J. Jorry, Philippe Kowalski, J. Gomez, Patrice Pelleau, Valérie Ballu, Isabelle Thinon, Pascal Bernard, Chastity Aiken, Jean-Pierre Donval, Emmanuel Rinnert, Yves Fouquet, Wayne C Crawford, Manuel A. Moreira, Anne Lemoine, Fabien Paquet, Angèle Laurent, Cecile Cathalot, Carla Scalabrin, R. Daniel, Eric Jacques, Christine Deplus, Raphaël Grandin, Patrick Bachèlery, Aline Peltier, Océane Foix, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
Indian ocean, geography, Oceanography, geography.geographical_feature_category, Volcano, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], 13. Climate action, Submarine pipeline, ComputingMilieux_MISCELLANEOUS, Geology
Abstract

Volcanic eruptions are foundational events shaping the Earth’s surface and providing a window into deep Earth processes. We document here an ongoing magmatic event offshore Mayotte island (Western Indian Ocean) unprecedented in terms of emitted volume of lava and duration of the seismic crisis.This event gave birth to a deep-sea volcanic edifice 820m tall and ~ 5 km3 in volume, located 50 km from Mayotte. A plume with distinct chemical signatures compared to open-ocean seawater emanated from the edifice, generating an exceptional 1900m-high vertical acoustic anomaly in the water column. Noble gas analyses in the vesicles from a popping rock dredged on the flank of the edifice, indicate rapid magma transfer from the asthenosphere. The edifice is located at the tip of a WNW-ESE–striking volcanic ridge composed of many other edifices, cones and lava flows constructed by past eruptions. Starting in May 2018 thousand of earthquakes were triggered by the magmatic event. The space-time distribution of the seismicity suggests that magma below the center of the ridge was transported to the new edifice over a few weeks in dikes that penetrated the brittle mantle a result of a lithosphere-scale extensional episode accommodating motion along a transfer zone between the East-African rifts and Madagascar. Since the eruption’s onset, the seismicity is mostly concentrated closer to the island, in an exceptionally deep zone (25-50 km) overlain by a zone of enigmatic, very low frequency, tremors.

Published
2020
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26. Main active structures in the Barbados accretionary wedge of the Lesser Antilles Subduction: implications for slip partitioning

Author

Helene Carton, T. Pichot, Gaëlle Bénâtre, Eric Jacques, and Nathalie Feuillet

Subjects
Accretionary wedge, Subduction, Slip (materials science), Petrology, Geology
Abstract

At the Lesser Antilles Subduction Zone (LASZ), the American plates subduct under the Caribbean plate at a slow rate of ~2 cm/yr. No major subduction megathrust earthquakes have occurred in the area since the 1839 and 1843 historical events, and the LASZ is typically considered weakly coupled. At the front of the LASZ, the Barbados accretionary wedge (BAW) is one of the largest accretionary wedges in the world. The width of the BAW decreases northward, owing to the increasing distance to the sediment source (Orinoco river) and the presence of several aseismic oceanic ridges, in particular the Tiburon ridge, that stops sediment progression. Marine geophysical studies conducted to date over the northern part of the BAW (Guadeloupe-Martinique sector) have mostly focused on resolving the geometry of the backstop. However, the structure of the wedge and the mechanical behavior of the subduction interface remain poorly known. Our study aims to describe the geometry of the BAW by a detailed morpho-tectonic analysis in order to place constraints on present and past dynamic interactions between the subducting and overriding plates.New high-resolution bathymetric data (gridded at 50 meters), CHIRP data and 48-channels seismic reflection profiles were acquired over the BAW in the Guadeloupe-Martinique sector during the CASEIS cruise (10.17600/16001800) conducted in 2016 with the IFREMER vessel N/O Pourquoi Pas? We present results from the analysis of these new data, complemented by existing bathymetry and seismic reflection data acquired by several previous cruises, with an emphasis on the inner wedge domain. The data reveal a 180 km-long linear structure between 15°15’N and 16°45’N latitude, imaged as a positive flower structure on several CASEIS seismic reflection profiles. We interpret this structure as a strike-slip fault and name it the Seraphine fault. The identification of a horse-tail structure linked to an eastward bend of the fault trace at its northern end, as well as left-stepping en échelon folds west of the Seraphine fault, allow to determine the kinematics of the fault as left-lateral strike-slip. The Seraphine fault could root at the toe of the backstop (at least in its central portion). CHIRP data show evidence of folding of recent sedimentary units that are linked to the Seraphine fault, supporting the idea of recent activity. While at odds with the low obliquity of the convergence in this area, the Seraphine fault could be the expression of slip partitioning, similarly to the Bunce fault observed father north along the LASZ where obliquity is much stronger.

Published
2020
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27. Connecting seismicity, gravity-driven erosion and deposition at submarine normal faults: Insights from mapping of the 2004 Mw 6.3 Les Saintes earthquake rupture (French Antilles)

Author

Jean-Arthur Olive, Javier Escartín, Nathalie Feuillet, Nuno Gracias, Frédérique Leclerc, Rafael Garcia, Klemen Istenic, Christine Deplus, Jérémy Billant, and Aurélien Arnaubec

Subjects
Gravity (chemistry), Erosion, Submarine, Earthquake rupture, Induced seismicity, Deposition (chemistry), Seismology, Geology
Abstract

During the ODEMAR 2013 and SUBSAINTES 2017 cruises we mapped the full extent of the seafloor rupture associated with the 2004 Mw 6.3 Les Saintes extensional earthquake. Near-bottom bathymetry acquired both with ROVs and AUVs along the Roseau Fault reveal a normal fault scarp developing in an extensional graben within the Caribbean volcanic arc, between the islands of Guadeloupe and Dominica. Optical inspection during ROV dives along the scarp’s base, where fault mirrors are well-preserved, allowed us to identify and characterize the coseismic fault rupture, and measure the coseismic displacements using both laser calipers and measurements performed on video-derived, textured 3D models, with accuracies better than 1 cm. The 2004 rupture extends ~20 km along the Roseau Fault, with a vertical displacement exceeding 2.5 m at its center, and tapering towards its ends. Local variations in apparent fault slip within a single 3D model (fault lengths of ~10 to 300 m) document local deposition of gravity debris cones at the base of the scarp, extending laterally between a few to tens of m, and covering the coseismic markers. Gullies eroding the footwall and depositing debris cones on the hanging wall do not show any significant displacement. Fault scarps on either side of the gully mouth instead record significant displacements, suggesting that either erosion or deposition along the gully bottom efficiently obliterated markers of coseismic deformation. We inspected all overlapping seafloor imagery acquired in December 2013 and April 2017, >10 years after the 2004 Les Saintes earthquake, extending laterally over >3 km of the Roseau Fault rupture. Neither the bed of gullies crossing the rupture, nor the debris and rubble at the base of the fault scarp show any noticeable seafloor change indicating mass wasting and transport, and only changes in mobile sediment (e.g., ripples) can be detected between both image sets. We identified a single area, ~2m wide, with apparent deposition of pebbles during these 3.25 years period, and associated with a local mass-wasting event. These observations point towards a systematic triggering of mass-wasting during seismic events, with deposition of rubble and rocks both at dejection cones at the mouth of gullies, or at the base of fault scarp sections displaying fault mirrors, covering or obliterating the coseismic markers. Therefore, long-term erosion and deposition processes here are gravity-driven and triggered by the history and magnitude of seismic events. Similar seismic controls may enable denudation of exposed oceanic lithosphere at fault scarps developing along and flanking mid-ocean ridges.

Published
2020
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28. Frontal accretionary wedge structure from seismic reflection imaging in the Lesser Antilles, Guadeloupe-Antigua sector

Author

Hélène Carton, Nathalie Feuillet, Lianjun Li, Gaëlle Bénâtre, and Yaocen Pan

Subjects
Accretionary wedge, Reflection (physics), Geology, Seismology
Abstract

The Lesser Antilles Subduction Zone (LASZ), forming the plate boundary between North and South American plates and the Caribbean plate, has not produced any recent large instrumentally recorded thrust earthquake. The 1843 earthquake event (~Mw 8.5) located offshore Guadeloupe is possibly subduction thrust related. Previous studies in the north-central LASZ based on active source seismic data have examined the overall configuration of the forearc domain, especially the geometry of the backstop and effect of subducted oceanic ridges. However, the detailed architecture of the accretionary wedge is still poorly known, as are wedge structures like splay faults that may host slip during future megathrust ruptures. In this study, we use selected re-processed deep multichannel seismic (MCS) profiles from the SISMANTILLES surveys (2001, 2007) and higher-resolution MCS profiles from the CASEIS survey (2016) complemented by a bathymetric data compilation. Analysis of this combined dataset yields a more comprehensive characterization of the accretionary wedge offshore Guadeloupe and reveals features that had not been previously described in this area.The time-domain seismic data processing sequences was performed on selected MCS profiles from the SISMANTILLES surveys (profiles H, I and K) to mitigate the strong background noises and the ringy effect from the single-bubble air-gun source. The reprocessed images clearly show the presence of arcward-dipping splay faults extending from décollement to the seafloor. The most prominent one roughly delineates a boundary between the more topographically elevated inner wedge and the less-elevated frontal domain of the accretionary wedge. We estimate an along-strike (N-S) extent of ~168 km for the identified splay faults, between 16°12′N and 17°21′N; their northward continuation is then disturbed by the subducting Barracuda Ridge. In the vicinity of the northern flank of the Barracuda Ridge, landward of the deformation front, we observe a duplex-type structure above the décollement. Its geometry is reminiscent of the initial stage of the development of underplating duplexes as observed in analog models. We suggest that the evolution of such underplating basal duplex may result from the increase in friction due to the subduction of Barracuda Ridge and the increase in sedimentary loading on its northern flank. This observation highlights the complex role played by the Barracuda Ridge on the shaping and deformation of the frontal prism.

Published
2020
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29. Quantifying submarine mass-wasting and links to seismicity along the Roseau normal fault, Lesser Antilles

Author

Nathalie Feuillet, Frédérique Leclerc, Alex Hughes, Luca C. Malatesta, Christine Deplus, Jérémy Billant, Jean-Arthur Olive, and Javier Escartín

Subjects
Submarine, Mass wasting, Induced seismicity, Normal fault, Seismology, Geology
Abstract

At the scale of individual faults, few studies have investigated fundamental interactions between active faulting, erosion, and deposition in submarine landscapes dominated by magmatic and volcaniclastic deposits with thin sedimentary cover. Such landscapes comprise a high percentage of the global seafloor. Therefore, there is a significant gap in our understanding of first-order processes of erosion and deposition for a large portion of the Earth’s surface. The paucity of studies derives mainly from challenges involved in the acquisition of high-resolution bathymetry and seafloor data in a deep-marine environment. In this study, we use bathymetry data obtained with autonomous deep-sea vehicles and processed to obtain a 1-m resolution digital elevation model along the active Roseau normal fault, in the Lesser Antilles volcanic arc. The Roseau fault was the source of the 2004 Mw6.3 Les Saintes earthquake, and Mw 5-6 events are thought to occur on the Roseau fault every few thousand years. Building on the work of Vilaseca (MSc Thesis, 2015), we quantify the height, slope, and volume eroded from a well-defined fault scarp created by the Roseau fault and calculate volumes for a series of erosional footwall catchments developed in the scarp. We also quantify the volume and morphology of a series of dejection cones in the hanging wall of the Roseau fault to facilitate mass-balancing between the hanging wall and footwall of the scarp. Mass-balancing indicates that in isolated basins, where the primary supply of sediment is from the adjacent footwall scarp, dejection cone volumes are around half of the total volume of material eroded from the individual footwall catchments. Geomorphological analyses show that dejection cones have surface slopes as high as 30°and form as radial depositional features adjacent to catchment outlets. The results of the mass-balancing, the high slope values for the cone surface, and the identification of >1 m sized blocks of eroded material present on the cone surfaces indicate that dejection cones form through episodic, coseismic and/or post-seismic, gravitationally driven mass-wasting of the uplifting footwall scarp. Preliminary morphometric analysis of the Roseau fault scarp potentially indicates that erosion of normal fault scarps in volcaniclastic and magmatic deposits may primarily occur beyond a threshold in fault scarp height between ~40­­–70 m. Above ~40–70 m height, erosional catchments may begin to develop on the footwall scarp and average scarp slope decreases with increasing scarp height until average slope values reach an equilibrium of ~35°. The quantitative survey of the Roseau fault scarp in this study demonstrates that episodic earthquake-related mass-wasting is a key erosional process for volcanic and sedimentary deposits in submarine landscapes. Furthermore, the results presented here will be used as first-order inputs to develop models of seafloor erosion and apply them to understand submarine landscape evolution of the oceanic lithosphere.

Published
2020
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30. Early development of a deep sea volcano offshore Mayotte revealed by seafloor mapping : first results from the MAYOBS cruises

Author

Charline Guerin, Delphine Pierre, Fabien Paquet, Anne Le Friant, Mathilde Pitel-Roudaut, Isabelle Thinon, Sylvain Bermell, Patrick Bachèlery, Christine Deplus, Manon Bickert, Arnaud Gaillot, Florian Besson, Stephan J. Jorry, Yves Fouquet, and Nathalie Feuillet

Subjects
Seafloor mapping, geography, geography.geographical_feature_category, Oceanography, Volcano, Submarine pipeline, Deep sea, Geology
Abstract

The early development and growth of seamounts are poorly known as the birth of a volcano on the sea bottom has been rarely observed. The on-going Mayotte seismo-volcanic crisis is associated with the formation of a new seafloor volcano at a water depth of 3300 m and provides the opportunity to study its early development.Four oceanographic cruises, MAYOBS 1 to 4, were carried out between May and July 2019 aboard the French R/V Marion Dufresne. High resolution bathymetry and backscatter data as well as sub-bottom profiler, gravity and magnetic profiles were collected during each cruise. A dense network of profiles has been achieved over the new volcano at different epochs, allowing to assess its detailed morphology and the evolution through time. During MAYOBS4, a deep-towed underwater camera provided sea bottom videos and photos on the volcano.First results indicate that the new volcano is still growing at the end of July 2019. Repetitive surveys in May, June and July 2019 allow to document the morphological evolution of the volcano, to estimate the volume of material emplaced between each epoch and to discuss the emitted lava rate.The new volcano has a starfish shape and is now 820 m high. Steep slopes are observed close to the summit and several radial ridges developed from its central part, displaying hummocky morphology similar to the ones observed along mid oceanic axial volcanic ridges. At the bottom, flat areas with high backscatter could indicate channelized lava flows emplaced at higher effusion rates. The morphological analysis combined with video imagery brings constraints to the eruptive processes yielding to the formation of a nascent volcano.

Published
2020
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31. The 2018 unrest phase at La Soufrière of Guadeloupe (French West Indies) andesitic volcano: Scrutiny of a failed but prodromal phreatic eruption

Author

Jean-Marie Saurel, Thierry Kitou, Sébastien Deroussi, David Jessop, Arnaud Lemarchand, V. Robert, Nathalie Feuillet, P. Allard, Jean-Bernard de Chabalier, Giancarlo Tamburello, Martin Vallée, Dominique Gibert, Tara Shreve, François Beauducel, Roberto Moretti, Séverine Moune, Arnaud Burtin, Tristan Didier, Marina Rosas-Carbajal, Marc Chaussidon, G. Ucciani, Anne Le Friant, Pierre Agrinier, Magali Bonifacie, Jean-Christophe Komorowski, Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG), Institut de Physique du Globe de Paris, Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire Magmas et Volcans (LMV), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement et la société-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Jean Monnet [Saint-Étienne] (UJM), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Bologna (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique, Agence Nationale de la Recherche, Ministère de la Transition écologique et Solidaire, Precursory Research for Embryonic Science and Technology, Observatoires Volcanologiques et Sismologiques, Institut de Physique du Globe de Paris (IPG Paris), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), ANR-18-IDEX-0001,Université de Paris,Université de Paris(2018), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Moretti, R., Komorowski, J. -C., Ucciani, G., Moune, S., Jessop, D., de Chabalier, J. -B., Beauducel, F., Bonifacie, M., Burtin, A., Vallee, M., Deroussi, S., Robert, V., Gibert, D., Didier, T., Kitou, T., Feuillet, N., Allard, P., Tamburello, G., Shreve, T., Saurel, J. -M., Lemarchand, A., Rosas-Carbajal, M., Agrinier, P., Le Friant, A., and Chaussidon, M.

Subjects
010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Hydrothermal system, Hydrothermal systems, Geochemistry and Petrology, Degassing, Hydrofracturing and hydroshearing, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Petrology, Volcanic unrest, Phreatic, 0105 earth and related environmental sciences, West indies, geography, geography.geographical_feature_category, Andesite, Unrest, Phreatic eruption, Geophysics, Volcano, 13. Climate action, Phreatic eruptions, Geology
Abstract

After 25 years of gradual increase, volcanic unrest at La Soufriere of Guadeloupe reached its highest seismic energy level on 27 April 2018, with the largest felt volcano-tectonic (VT) earthquake (M-L 4.1 or M-W 3.7) recorded since the 1976-1977 phreatic eruptive crisis. This event marked the onset of a seismic swarm (180 events, 2 felt) occurring after three previous swarms on 3-6 January (70 events), 1 st February (30 events, 1 felt) and 16-17 April (140 events, 1 felt). Many events were hybrid VI's with long-period codas, located 2-4 km below the volcano summit and clustered within 2 km along a regional NW-SE fault cross-cutting La Soufriere. Elastic energy release increased with each swarm whereas inter-event time shortened. At the same time, summit fractures continued to open and thermal anomalies to extend. Summit fumarolic activity increased significantly until 20 April, with a maximum temperature of 111.4 degrees C and gas exit velocity of 80 m/s, before declining to similar to 95 degrees C and similar to 33 m/s on 25 April. Gas compositions revealed increasing C/S and CO2/CH4 ratios and indicate hydrothermal P-T conditions that reached the critical point of pure water. Repeated MultiGAS analysis of fumarolic plumes showed increased CO2/H2S ratios and SO2 contents associated with the reactivation of degassing fractures (T = 93 degrees C, H2S/SO2 approximate to 1). While no direct evidence of upward magma migration was detected, we attribute the above phenomena to an increased supply of deep magmatic fluids that heated and pressurized the La Soufriere hydrothermal system, triggering seismogenic hydro-fracturing, and probable changes in deep hydraulic properties (permeability) and drainage pathways, which ultimately allowed the fumarolic fluxes to lower. Although this magmatic fluid injection was modulated by the hydrothermal system, the unprecedented seismic energy release and the critical point conditions of hydrothermal fluids suggest that the 2018 sequence of events can be regarded as a failed phreatic eruption. Should a similar sequence repeat, we warn that phreatic explosive activity could result from disruption of the shallow hydrothermal system that is currently responsible for 3-9 mm/y of nearly radial horizontal displacements within 1 km from the dome. Another potential hazard is partial collapse of the dome's SW flank, already affected by basal spreading above a detachment surface inherited from past collapses. Finally, the increased magmatic fluid supply evidenced by geochemical indicators in 2018 is compatible with magma replenishment of the 6-7 km deep crustal reservoir feeding La Soufriere and, therefore, with a potential evolution of the volcano's activity towards magmatic conditions.

Published
2020
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32. Relative Sea‐Level Changes Over the Past Centuries in the Central Ryukyu Arc Inferred From Coral Microatolls

Author

Kenji Satake, Noelynna T. Ramos, Tomoko Goto, Chuan-Chou Shen, Shaw Chen Liu, Tomoya Harada, Jean-Marie Saurel, Hajime Kayanne, Mamoru Nakamura, Tsai-Luen Yu, J. Weil‐Accardo, Kohki Sowa, Kazuhisa Goto, Nathalie Feuillet, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), The University of Tokyo (UTokyo), Institut de Physique du Globe de Paris, Tohoku University [Sendai], University of the Ryukyus [Okinawa], University of the Philippines Diliman (UP Diliman), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), National Taiwan University [Taiwan] (NTU), and Institut de Physique du Globe de Paris (IPG Paris)

Subjects
010504 meteorology & atmospheric sciences, Subduction, Coral, Microatoll, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Slip (materials science), 01 natural sciences, Arc (geometry), Tectonics, Paleontology, Geophysics, Space and Planetary Science, Geochemistry and Petrology, Transition zone, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Sea level, Geology, 0105 earth and related environmental sciences
Abstract

International audience; This study focuses on Okinawa and Yoron islands, in order to better understand tectonics in the Ryukyu Arc related to the subduction zone. We used coral microatolls-known for their centimetric accuracy in the record of relative sea-level (RSL) changes-to reconstruct RSL changes over the last century from living microatolls. A fossil microatoll in Yoron was used to discuss possible RSL changes beyond the last century. The signal consists of emergence whose rate varies through time, interrupted by decadal to multidecadal periods of sudden and/or gradual submergence and by interannual sea-level falls. Comparison with other existing RSL records in the arc highlights RSL variability along the arc. This pattern contrasts with the homogeneous and linear absolute regional sea-level rise, implying that this latter signal cannot fully explain our observations and that an additional process is required. We suggest the subduction zone as a possible source for generating centimetric scale RSL changes observed in coral microatolls. We tested how the Ryukyu megathrust could explain our observations with elastic dislocation modeling. The emergence trend could be explained by interseismic loading on the plate interface with a minimum coupling rate of 25%, which is higher than previous estimates based on short instrumental records. As for the submergence events that occurred regularly in the coral record, we show that they could be explained by slow slip events on the shallower part of the megathrust or in the transition zone. Such process could accommodate a significant part of the total convergence.

Published
2020
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33. Complex deformation at shallow depth during the 30 October 2016 Mw6.5 Norcia earthquake: interference between tectonic and gravity processes?

Author

Eric Jacques, Yann Klinger, Yu Morishita, Marc Pierrot-Deseilligny, Arthur Delorme, Nathalie Feuillet, Ewelina Rupnik, Raphaël Grandin, Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire sciences et technologies de l'information géographique (LaSTIG), Ecole des Ingénieurs de la Ville de Paris (EIVP)-École nationale des sciences géographiques (ENSG), Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Université Gustave Eiffel-Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Université Gustave Eiffel, University of Leeds, Institut de Physique du Globe de Paris, Laboratoire des Sciences et Technologies de l'Information Géographique (LaSTIG), École nationale des sciences géographiques (ENSG), and Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Institut National de l'Information Géographique et Forestière [IGN] (IGN)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Geodetic datum, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Tectonics, Geophysics, 13. Climate action, Geochemistry and Petrology, Gps data, Interferometric synthetic aperture radar, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience; The relation between slip at the near surface and at depth during earthquakes is still not fully resolved at the moment. This deficiency leads to large uncertainties in the evaluation of the magnitude of past earthquakes based on surface observations, which is the only accessible evidence for such events. A better knowledge of the way slip distributes over distinct rupture strands within the first few kilometers from the surface would contribute greatly to reduce these uncertainties. The 30 October 2016 Mw6.5 Norcia earthquake has been captured by a variety of geodetic techniques, which provide access to the slip distribution both at depth and at the ground surface, with an unprecedented level of detail for a normal‐faulting earthquake. We first present coseismic surface offset measurements from correlation of optical satellite images of submetric resolution, which are compared to field observations made shortly after the earthquake. Based on a joint inversion of optical data together with InSAR and GPS data, we then propose a rupture model that explains the observations both at far‐field and near‐field scales. Finally, we explore different rupture geometries at shallow depth, in an attempt to better explain the near‐field deformation (i.e., within the first hundreds of meters around the fault) observed at the surface. Despite the fact that the solution is not unique, several lines of evidence suggest that gravity processes could be locally involved, which interfere with the dominant tectonic processes.

Published
2020
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34. Regional chronostratigraphy in the eastern Lesser Antilles quaternary fore-arc and accretionary wedge sediments: Relative paleointensity, oxygen isotopes and reversals

Author

E. Moreno, Nathalie Feuillet, Julie Carlut, A. Bieber, Guillaume St-Onge, E. Michel, Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Variabilité de l'Océan et de la Glace de mer (VOG), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), ANR-17-CE03-0006,CARQUAKES,grands séismes et tsunamis dans les petites Antilles: impact sur la sédimentation côtière et profonde, sur les coraux et l'installation humaine(2017), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
010506 paleontology, Paleomagnetism, Accretionary wedge, Natural remanent magnetization, Stratigraphy, Lesser antilles, 010502 geochemistry & geophysics, 01 natural sciences, Isotopes of oxygen, Geomagnetic reversals, Quaternary, Paleontology, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Chronostratigraphy, Tephra, 0105 earth and related environmental sciences, Geology, Relative paleointensity, [SDU]Sciences of the Universe [physics], 13. Climate action, Oxygen isotopes, Sediment
Abstract

International audience; Paleomagnetism is a powerful tool for establishing an almost continuous chronostratigraphy for an entire region. When combined with other dating methods, absolute or relative, it can be used to develop a regional reference chronostratigraphic framework. During the summer of 2016, several piston cores were collected along the Atlantic side of the Lesser Antilles onboard the R/V Pourquoi pas? as part of the CASEIS Expedition. Core CAS16-24 PC was devoted to chronostratigraphic analysis and allowed development of a quasi-continuous Quaternary record. In this study, after identifying and removing rapidly deposited layers such as turbidites and tephra layers, we reconstructed the relative paleointensity (RPI) variations by normalizing the natural remanent magnetization with the laboratory induced anhysteretic remanent magnetization. An age model was developed by comparing our RPI record with the PISO-1500 stack and paleomagnetic axial dipole moment model for the past 2 Myr (PADM-2M) and the planktic oxygen isotopic record (δ18O) for core CAS16-24 PC with the LR04 benthic stack. By combining the δ18O stratigraphy with paleomagnetic analyses, we established an age model covering the Brunhes/Matuyama boundary and Jaramillo Subchron back to ∼1.15 Ma with a mean sedimentation rate of 1.7 cm/kyr. This age model complements the paleomagnetic data from IODP campaigns and volcanic records, and offers almost complete inclination, declination and RPI records as a local reference.

Published
2021
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35. Extreme waves in the British Virgin Islands during the last centuries before 1500 CE

Author

Yuki Sawai, Jean Roger, Z. Fuentes, Michaela Spiske, R. B. Halley, Carlos Nuñez, Uri S. ten Brink, Eduard G. Reinhardt, Jennifer Weil-Accardo, Anna Lisa Cescon, Yong Wei, Nathalie Feuillet, Brian F. Atwater, and Martitia P. Tuttle

Subjects
Shore, geography, geography.geographical_feature_category, Diploria strigosa, 010504 meteorology & atmospheric sciences, biology, Stratigraphy, Coral, Fringing reef, Geology, 010502 geochemistry & geophysics, biology.organism_classification, 01 natural sciences, Paleontology, Oceanography, Brain coral, Acropora, Reef, Sea level, 0105 earth and related environmental sciences
Abstract

Extraordinary marine inundation scattered clasts southward on the island of Anegada, 120 km south of the Puerto Rico Trench, sometime between 1200 and 1480 calibrated years (cal yr) CE. Many of these clasts were likely derived from a fringing reef and from the sandy flat that separates the reef from the island’s north shore. The scattered clasts include no fewer than 200 coral boulders, mapped herein for the first time and mainly found hundreds of meters inland. Many of these are complete colonies of the brain coral Diploria strigosa . Other coral species represented include Orbicella (formerly Montastraea ) annu­laris , Porites astreoides , and Acropora palmata . Associated bioclastic carbonate sand locally contains articulated cobble-size valves of the lucine Codakia orbicularis and entire conch shells of Strombus gigas , mollusks that still inhabit the sandy shallows between the island’s north shore and a fringing reef beyond. Imbricated limestone slabs are clustered near some of the coral boulders. In addition, fields of scattered limestone boulders and cobbles near sea level extend mainly southward from limestone sources as much as 1 km inland. Radiocarbon ages have been obtained from 27 coral clasts, 8 lucine valves, and 3 conch shells. All these additional ages predate 1500 cal yr CE, all but 2 are in the range 1000–1500 cal yr CE, and 16 of 22 brain coral ages cluster in the range 1200–1480 cal yr CE. The event marked by these coral and mollusk clasts likely occurred in the last centuries before Columbus (before 1492 CE). The pre-Columbian deposits surpass Anegada’s previously reported evidence for extreme waves in post-Columbian time. The coarsest of the modern storm deposits consist of coral rubble that lines the north shore and sandy fans on the south shore; neither of these storm deposits extends more than 50 m inland. More extensive overwash, perhaps by the 1755 Lisbon tsunami, is marked primarily by a sheet of sand and shells found mainly below sea level beneath the floors of modern salt ponds. This sheet extends more than 1 km southward from the north shore and dates to the interval 1650–1800 cal yr CE. Unlike the pre-Columbian deposits, it lacks coarse clasts from the reef or reef flat; its shell assemblage is instead dominated by cerithid gastropods that were merely stirred up from a marine pond in the island’s interior. In their inland extent and clustered pre-Columbian ages, the coral clasts and associated deposits suggest extreme waves unrivaled in recent millennia at Anegada. Bioclastic sand coats limestone 4 m above sea level in areas 0.7 and 1.3 km from the north shore. A coral boulder of nearly 1 m 3 is 3 km from the north shore by way of an unvegetated path near sea level. As currently understood, the extreme flooding evidenced by these and other clasts represents either an extraordinary storm or a tsunami of nearby origin. The storm would need to have produced tsunami-like bores similar to those of 2013 Typhoon Haiyan in the Philippines. Normal faults and a thrust fault provide nearby tsunami sources along the eastern Puerto Rico Trench.

Published
2017
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36. Active tectonics along the Cul-de-Sac – Enriquillo plain and seismic hazard for Port-au-Prince, Haiti

Author

Newdeskarl Saint Fleur, Nathalie Feuillet, Yann Klinger, and Université de Paris (UP)

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Drainage basin, Active fault, Massif, Fold (geology), 010502 geochemistry & geophysics, 01 natural sciences, Bathymetric chart, Tectonics, Geophysics, Seismic hazard, 13. Climate action, [SDU]Sciences of the Universe [physics], Thrust fault, Geology, Seismology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

The active faults in Haiti were not well known and no detailed mapping of active fault traces was available before the 2010, M7.0 earthquake. The lack of detailed fault mapping hindered the interpretation of the event and the seismic hazard assessment. Here, using high-resolution LIDAR topography, aerial photographs, bathymetric charts, together with geological data complemented with field observations, we carried out a morphotectonic analysis at a variety of scales. We analyzed the drainage network at the northern front of the Massif de la Selle – Sierra de Bahoruco (MSB) by mapping the fans of the main rivers and their associated drainage basins. We found that the areas of all the fans were compatible with the sizes of their drainage basins, except the paleofan of Port-au-Prince. We interpret that this paleofan has been offset by 7.9 ± 0.3 km across the main strike-slip Enriquillo-Plantain Garden Fault (EPGF) and we estimate a minimum horizontal slip rate of ∼3 mm/yr over the Pleistocene. Moreover, in the Cul-de-Sac – Enriquillo plain, within which the capital city of Port-au-Prince is located, we mapped numerous NW-SE to WNW-ESE-striking Quaternary folds and thrust faults. Some of the thrust faults are north-dipping and located to the southern front of the Matheux-Neiba Lower Miocene fold. Other thrusts, such as those near Ganthier, Jacquet, Nan Cadastre, and Port-au-Prince, are south-dipping and located along the northern front of the MSB Lower Miocene fold. Previously, Saint Fleur et al. (2015) showed that the 2010 Haiti earthquake activated both one of the young thrusts (Lamentin) and the EPGF, consistent with oblique convergence between the Caribbean and the North American plates.

Published
2019
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37. Quaternary coral reef complexes as powerful markers of long-term subsidence related to deep processes at subduction zones: Insights from Les Saintes [Guadeloupe, French West Indies]

Author

Frédérique Leclerc and Nathalie Feuillet

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, Stratigraphy, Geology, Subsidence, Coral reef, 010502 geochemistry & geophysics, 01 natural sciences, Term (time), Oceanography, 14. Life underwater, Quaternary, 0105 earth and related environmental sciences, West indies
Abstract

Geodetic measurements reveal modern rates of tectonic deformation along subduction zones, but the kinematics of long-term deformation are typically poorly constrained. We explore the use of submarine coral reefs as a record of long-term coastal vertical motion in order to determine deformation rate and discuss its origins. The Lesser Antilles arc results from the subduction of the American plates beneath the Caribbean plate and undergoes regional vertical deformation. Uplifted reefs along forearc islands are markers of the interplay between tectonics and sea-level variations since the late Pleistocene. We compared results from a numerical model of reef-island profile development to high-resolution marine geophysical measurements of Les Saintes reef plateau (Guadeloupe, French West Indies), a ∼20-km-wide, 250-m-thick submerged platform that lies at 45 m below sea level along the volcanic arc, to constrain its vertical deformation history. Models explore different scenarios over wide parameter domains including start time, basement morphology, sea level variations, reef growth rate, subaerial erosion rate, and vertical motion history. The major features of the plateau (its depth, internal structure, unusual double-barrier) is only reproduced in a context of subsidence, with a constant rate of −0.3 to −0.45 mm/yr since the late Pleistocene, or in a context of increasing subsidence, presently of ∼–0.2 mm/yr. Discussed in the framework of the forearc vertical deformation history, this result indicates subsidence is promoted by local faulting, volcanic, and deep subduction processes. Coseismic deformation accumulation could be a mechanism by which deformation builds up in the long-term. We show that subduction can drive long-term subsidence of a volcanic arc, and demonstrate that submarine reefs are powerful markers of long-term vertical motion.

Published
2019

38. Simulation of the 2004 tsunami of Les Saintes in Guadeloupe (Lesser Antilles)

Author

Louise Cordrie, Philippe Heinrich, Nathalie Feuillet, Javier Escartín, Audrey Gailler, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire Paul Painlevé - UMR 8524 (LPP), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Paul Painlevé (LPP), and Centre National de la Recherche Scientifique (CNRS)-Université de Lille

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Context (language use), Fault (geology), Induced seismicity, 010502 geochemistry & geophysics, Megathrust earthquake, Fault scarp, 01 natural sciences, Tectonics, 13. Climate action, [SDU]Sciences of the Universe [physics], 14. Life underwater, Seismogram, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Subduction zones are areas with significant tectonic activity, complex fault systems, volcanic edifices and growth of islands. Earthquakes in this context are associated with sudden subsidence or uplift of the sea floor with the potential to trigger landslides and tsunamis. A tsunami initiated by a megathrust earthquake can generate strong currents, and is able to carry massive quantities of sediments. The inhabited islands and coasts near subduction areas are threatened by those destructive earthquakes and tsunamis. The arc of the Lesser Antilles which formed due to the plunge of the Atlantic oceanic plate under the Caribean plate, is one of them. The tsunamigenic earthquakes in this region are rare, poorly documented and the only available data are qualitative (observations of coseismic displacement, intensity of the damages). Quantitative data is lacking as no seismograms or tide-gauge were set up before 1968. This lack of data increases the uncertainty on the existent fault models and the shortness of the catalog of seismicity does not enable a good analysis of the recurence cycle of the megathrust earthquakes. The most recent tsunamigenic earthquake occured in 2004 in the area of Les Saintes normal fault system. This Mw6.3 earthquake generated small waves with 2m of run-up in several bays of Les Saintes, a group of island in the South of Guadeloupe. A recent survey done on the fault scarp revealed important coseismic displacement at the surface which had not been predicted in the seismic source models resulting from the joint inversion of teleseismic and GPS data. Tsunami simulations of those different models of fault enable the calculation of the associated time arrivals and water heights of the waves. Compared to the reported observation, those results give complementary informations and additional constrains on the source parameters.

Published
2019
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39. Publisher Correction: A database of the coseismic effects following the 30 October 2016 Norcia earthquake in central Italy (Scientific Data, (2018) 5, 10.1038/sdata.2018.49)

Author

Fabio, Villani, Riccardo, Civico, Stefano, Pucci, Luca, Pizzimenti, Rosa, Nappi, Paolo Marco De Martini, Agosta, Fabrizio, Giuliana, Alessio, Lucilla, Alfonsi, Marco, Amanti, Amoroso, S., Aringoli, Domenico, Auciello, E., Raffaele, Azzaro, Stéphane, Baize, Bello, S., Lucilla, Benedetti, Antonella, Bertagnini, Giulia, Binda, Bisson, M., Anna Maria Blumetti, Bonadeo, L., Paolo, Boncio, Philipp, Bornemann, Branca, S., Braun, Thomas R., Francesco, Brozzetti, Carlo Alberto Brunori, Pierfrancesco, Burrato, Marco, Caciagli, Campobasso, C., Carafa, Michele M. C., Francesca Romana Cinti, Domenico, Cirillo, Valerio, Comerci, Luigi, Cucci, Riccardo De Ritis, Graziella, Deiana, Paola Del Carlo, Luis Mercader del Río, Alain, Delorme, Pio Di Manna, Deborah Di Naccio, Laurel, Falconi, Emanuela, Falcucci, Farabollini, Piero, Joanna Faure Walker, Ferrarini, F., Ferrario, M. F., Matthieu, Ferry, Nathalie, Feuillet, Jules, Fleury, Umberto, Fracassi, Chiara, Frigerio, Frank, Galluzzo, Gambillara, R., Gaetano, Gaudiosi, Hollis, Goodall, Gori, S, Gregory, Laura C., Luca, Guerrieri, Salomon, Hailemikael, James, Hollingsworth, Francesca, Iezzi, Invernizzi, Maria Chiara, Jablonska, Danica, Evouna, Jacques, Hervé, Jomard, Vanja, Kastelic, Yann, Klinger, Giusy, Lavecchia, Frederique, Leclerc, Francesca, Liberi, Arianna, Lisi, Franz, Livio, Lorenzo Lo Sardo, Malet, J. P., Maria Teresa Mariucci, Materazzi, Marco, Maubant, L., Francesco, Mazzarini, Mccaffrey, K. J. W., Michetti, Alessandro Maria, Mildon, Z. K., Paola, Montone, Marco, Moro, Rosella, Nave, Marielle, Odin, Bruno, Pace, Sherman, Paggi, Nicola Mauro Pagliuca, Pambianchi, Gilberto, Daniela, Pantosti, Antonio, Patera, Eugénie, Pérouse, Giuseppe, Pezzo, Luigi, Piccardi, Pierantoni, Pietro Paolo, Maurizio, Pignone, Pinzi, S., Pistolesi, Eugenio, Point, J., Pousse, L., Alessia, Pozzi, Marco, Proposito, Puglisi, C., Puliti, I., Tullio, Ricci, Licia, Ripamonti, Magali, Rizza, Roberts, Gerald P., Roncoroni, M., Vincenzo, Sapia, Michele, Saroli, Alessandra, Sciarra, Oona, Scotti, Grzegorz, Skupinski, Smedile, A., Anne, Socquet, Gabriele, Tarabusi, Simone, Tarquini, Terrana, S., Jim, Tesson, Tondi, Emanuele, Alessio, Valentini, Roberta, Vallone, van der Woerd, J., Paola, Vannoli, Venuti, A., Eutizio, Vittori, Volatili, Tiziano, Wedmore, L. N. J., Max, E Wilkinson, and Melba, Zambrano

Published
2019

40. A 1600 year-long sedimentary record of tsunamis and hurricanes in the Lesser Antilles (Scrub Island, Anguilla)

Author

Louise Cordrie, Fayçal Soufi, Nathalie Feuillet, Anne-Lise Develle, Thibault Coulombier, Catherine Chagué, Frans Jorissen, Eric Chaumillon, Emeline Geba, Maude Biguenet, Fabien Arnaud, Pierre Sabatier, Emilie Chalmin, Pierre Vacher, Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), University of New South Wales [Sydney] (UNSW), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire SYstèmes et Matériaux pour la MEcatronique (SYMME), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])

Subjects
Return period, 010506 paleontology, Coastal hazards, [SDE.MCG]Environmental Sciences/Global Changes, Stratigraphy, Geology, Storm, 010502 geochemistry & geophysics, 01 natural sciences, Oceanography, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 13. Climate action, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Sedimentary rock, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Spatial extent, 0105 earth and related environmental sciences
Abstract

International audience; The Lesser Antilles are a densely populated region where local populations and industrial facilities are concentrated at the coastlines, and are therefore exposed to many rapid-onset hazards such as hurricanes and tsunamis. However, the historical catalog of these events is too short to allow risk assessment and return period estimations, and it needs to be completed with long-term records of washover deposits in coastal sedimentary environments such as lagoons. In this study, two sediment cores were taken in March 2018 in a small coastal lagoon on Scrub Island (northeastern Caribbean). Sedimentological, geochemical, microfaunal and chronological analyses enabled us to identify 25 sandy layers resulting from high-energy-marine floods. Two of these layers were interpreted as tsunami deposits based on sedimentological (rip-up clast of the underlying cohesive substrate and internal mud laminae), and geochemical evidence. The most recent deposit is associated with the transatlantic tsunami triggered by the 1755 CE Lisbon earthquake. The older one is the thickest sandy layer recorded in the lagoon, with an age range of 1364-1469 cal. CE, as determined using 14 C dating. This event was recorded in sedimentary archives of both the northern and the southern part of the Caribbean, with its large spatial extent, supporting a distant tsunamigenic origin. The 23 remaining sandy layers were interpreted as storm deposits, based on sedimentological and chronological data, with the three most recent layers being correlated with historical hurricanes. This new 1600 year-long record displays similarities with that of the Bahamas, with the periods of intense hurricane activity being in antiphase with those of the northeastern US coast. This regional comparison may provide evidence for a latitudinal forcing of hurricane tracks through time in relation to climate fluctuations.

Published
2021
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41. Two hundred thirty years of relative sea level changes due to climate and megathrust tectonics recorded in coral microatolls of Martinique (French West Indies)

Author

Nathalie Feuillet, François Beauducel, Jennifer Weil-Accardo, John Galetzka, Eric Jacques, Guy Cabioch, Jean-Marie Saurel, Paul Tapponnier, and Pierre Deschamps

Subjects
Tectonic subsidence, 010504 meteorology & atmospheric sciences, Coral, Fringing reef, Subsidence, Paleoseismology, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Oceanography, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Tide gauge, 14. Life underwater, Martinique, Sea level, Geology, 0105 earth and related environmental sciences
Abstract

We sampled six coral microatolls that recorded the relative sea level changes over the last 230 years east of Martinique, on fringing reefs in protected bays. The microatolls are cup-shaped, which is characteristic of corals that have been experiencing submergence. X-ray analysis of coral slices and reconstructions of the highest level of survival (HLS) curves show that they have submerged at rates of a few millimeters per year. Their morphology reveals changes in submergence rate around 1829 ± 11, 1895, and 1950. Tide gauges available in the region indicate a regional sea level rise at a constant mean rate of 1.1 ± 0.8 mm/yr, which contrasts with our coral record, implying additional tectonic subsidence. Comparing our coral morphology with that of synthetic corals generated with Matlab by using the Key West tide gauge record (Florida), we show that their growth was controlled by tectonics and that a sudden relative sea level increase drowned them around 1950. Simple elastic models show that this sudden submergence probably occurred during the 21 May 1946 earthquake, which ruptured the plate interface in front of Martinique, in the mantle wedge, in an area of sustained seismic activity. The 1839 M8+ earthquake probably occurred in the same area. Long-term subsidence of microatolls indicates that this deep portion of the megathrust is probably locked down to 60 km depth during the interseismic period. Our oldest coral recorded a long-lasting period (50 years) of stable relative sea level after the 1839 earthquake, indicating that transient interseismic strain rate variations may occur in the Lesser Antilles.

Published
2016
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42. Reservoir Ages in the Western Tropical North Atlantic from One Coral off Martinique Island (Lesser Antilles)

Author

Eric Douville, Elsa Cortijo, Dominique Blamart, Lucile Bonneau, Edwige Pons-Branchu, Martine Paterne, Nathalie Feuillet, Christophe Colin, Jennifer Weill-Accardo, Guy Cabioch, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNRS - ORSTOM Paléohydrologie, Paléoclimatique Continentales, Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Paléocéanographie (PALEOCEAN), Nanyang Technological University [Singapour], Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Universität Heidelberg [Heidelberg], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Universität Heidelberg [Heidelberg] = Heidelberg University, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique du Globe de Paris ( IPGP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -IPG PARIS-Université Paris Diderot - Paris 7 ( UPD7 ) -Université de la Réunion ( UR ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques ( LOCEAN ), Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Centre National de la Recherche Scientifique ( CNRS ), Centre de Recherches Pétrographiques et Géochimiques ( CRPG ), Université de Lorraine ( UL ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre de Paris ( iSTeP ), and Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
[ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, 010506 paleontology, Archeology, Lesser Antilles, 010504 meteorology & atmospheric sciences, δ18O, Coral, location.country, stable isotopes, 01 natural sciences, law.invention, volcanic effects, location, marine reservoir ages, law, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Martinique, 14. Life underwater, Radiocarbon dating, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, coral, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, biology, Volcanic arc, biology.organism_classification, Oceanography, Volcano, 13. Climate action, Martinique island, General Earth and Planetary Sciences, Siderastrea siderea, Geology
Abstract

Sea surface reservoir ages (R) are reported from radiocarbon (14C) measurements of the annual growth bands of coral Siderastrea siderea collected on the Atlantic coast off Martinique Island, in the Lesser Antilles volcanic arc. Mean values of R are similar between 1835 and 1845 during pre-anthropogenic times at 385±30 yr and between 1895 and 1905 at 382±20 yr when there was a huge eruption from the Montagne Pelée volcano in 1902–1903. Limited 14C aging of sea surface (~40 yr) may be due to enhanced volcanic activity. Variability of R is slightly greater during 1835–1845 than during 1895–1905. It is linked to a moderate increase of ∆14C of 5‰, strengthened by a clear increase of δ18O of 0.4‰. This is attributed to a decrease of the northward advection of the South Atlantic Waters into the western tropical North Atlantic and Caribbean Sea and relative enhanced westward flux of the tropical North Atlantic surface waters, the southern waters having lower values of 14C and δ18O than the North Atlantic ones. From 1835 to 1845, the fraction of the South Atlantic Waters transported up to Martinique Island was reduced from 25% to 15%.

Published
2018
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43. The 2011-2012 unrest at Santorini rift: Stress interaction between active faulting and volcanism

Author

Nathalie Feuillet

Subjects
geography, geography.geographical_feature_category, Rift, North Anatolian Fault, Unrest, Fault (geology), Stress field, Geophysics, Volcano, General Earth and Planetary Sciences, Caldera, Echelon formation, Seismology, Geology
Abstract

[1] At Santorini, active normal faulting controls the emission of volcanic products. Such geometry has implication on seismic activity around the plumbing system during unrest. Static Coulomb stress changes induced by the 2011–2012 inflation within a preexisting NW-SE extensional regional stress field, compatible with fault geometry, increased by more than 0.5 MPa in an ellipsoid-shaped zone beneath the Minoan caldera where almost all earthquakes (96%) have occurred since beginning of unrest. Magmatic processes perturb the regional stress in the caldera where strike-slip rather than normal faulting along NE-SW striking planes are expected. The inflation may have also promoted more distant moderate earthquakes on neighboring faults as the M > 5 January 2012, south of Christiania. Santorini belongs to a set of en echelon NE-SW striking rifts (Milos, Nysiros) oblique to the Aegean arc that may have initiated in the Quaternary due to propagation of the North Anatolian fault into the Southern Aegean Sea.

Published
2013
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44. Relative sea-level changes during the last century recorded by coral microatolls in Belloc, Haiti

Author

S. Demeza, Kaustubh Thirumalai, Eric Jacques, Jean-Marie Saurel, Pierre Deschamps, Jennifer Weil-Accardo, Nathalie Feuillet, D. Anglade, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Global and Planetary Change, geography, Caribbean island, Diploria strigosa, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, biology, Coral, Context (language use), 010502 geochemistry & geophysics, Oceanography, biology.organism_classification, 01 natural sciences, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Tide gauge, 14. Life underwater, Reef, Geology, Siderastrea siderea, Sea level, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We present here the first study of coral microatolls in the Caribbean. An exceptional site (Belloc reef) where dozens of microatolls were growing was uplifted and exposed during the 12 January 2010 Mw 7 Haiti earthquake. Total station measurements of the old pre-earthquake and the new post-earthquake coral highest level of survival (HLS) on two generations of Siderastrea siderea corals allowed us to estimate a value of 45 ± 14 cm for the coseismic uplift. In this small 90 m × 70 m reef, microatolls of different shapes (cups, hats or flats) coexist, indicating long term submergence, emergence or stable relative sea-level. This variability in coral shape is uncommon. Two slices of microatolls, one cup-shaped (B8) and one hat-shaped (B10) were sampled with a chain saw and X-rayed to study their stratigraphy. B10 recorded a mean relative sea-level decrease of about − 1 mm/yr over the last five decades, whereas B8 has grown in a context of relative sea-level rise at a rate of about 1 mm/yr over nine decades. Several sudden and temporary die downs simultaneously disrupted the growth of both corals in 1940 ± 2, 1963 ± 2, 1983 ± 2, 1992 ± 1, 2001 ± 1 and 2009 and may be caused by oceanographic/climatic phenomena occurring in the tropical North Atlantic. The last one, in 2009, was associated with a clear sea-level height decrease (about 10 cm) in the satellite data. B10 was strongly affected by these events and records die downs of systematically larger amplitude, which tended to delay its upward growth compared to B8. This makes B10 less reliable for the evaluation of the relative sea-level trend, its emergence rate being only an apparent estimate due to die downs. Fossil coral microatolls of Diploria strigosa which died between 1958 and 1966 (according to U/Th dating), probably during one of the strongest hurricane reported in Haiti (Flora, 1963), display a cup shape attesting for submergence. Their HLS is 1 cm below the HLS of the S. siderea killed in 2010. The record of B8, the diversity in shape of the S. siderea microatolls and the position of fossil D. strigosa corals overall indicate stable to slightly increasing relative sea-level (about 1 mm/yr). This is on the same order of magnitude, although slightly lower, as the rate we determined over the last 74 years by using eight tide gauge records around Hispaniola (1.63 ± 0.20 mm/yr) and the mean rate of sea-level rise previously published (2.0 ± 0.5 mm/yr) in the area. This study demonstrates that coral microatolls can be used to infer relative sea-level changes over the last decades or centuries in the Caribbean, where tide gauge records are often sparse, incomplete or nonexistent. This is of prime importance for the numerous small and flat Caribbean islands, highly vulnerable to the threat of global sea-level rise.

Published
2016
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45. Identification of deep subaqueous co-seismic scarps through specific coeval sedimentation in Lesser Antilles: implication for seismic hazard

Author

Christine Deplus, C. Vidal, François Beauducel, A. Nercessian, Georges Boudon, J. L. Reyss, A. Le Friant, Nathalie Feuillet, T. Pichot, Frédérique Leclerc, Martine Paterne, E. Moreno, L. Barrier, N. Gallou, V. Clement, C. Beck, J-F Lebrun, Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Océan et Interfaces (OCEANIS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de tectonique, mécanique de la lithosphère (LTML (UMR_7578)), Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Vert-Pré, Laboratoire de Recherche en Géosciences et Energies [UR2_1] (LARGE), Université des Antilles (UA), Géochrononologie Traceurs Archéométrie (GEOTRAC), Laboratoire de Géodynamique et Géophysique (LGG), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de tectonique, mécanique de la lithosphère (LTML), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS, Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Université des Antilles et de la Guyane (UAG), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géodynamique et de Géophysique (LGG), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Laboratoire de Recherche en Géosciences et Energies (LARGE), Laboratoire de Géodynamique et Géophysique, Institut des Sciences de la Terre [2011-2015] (ISTerre [2011-2015]), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sciences de la Terre, and Muséum national d'Histoire naturelle (MNHN)

Subjects
Redonda, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Fault (geology), 010502 geochemistry & geophysics, Fault scarp, 01 natural sciences, lcsh:TD1-1066, lcsh:Environmental technology. Sanitary engineering, Geomorphology, lcsh:Environmental sciences, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, lcsh:GE1-350, geography, geography.geographical_feature_category, Volcanic arc, biology, lcsh:QE1-996.5, lcsh:Geography. Anthropology. Recreation, Aseismic creep, biology.organism_classification, lcsh:Geology, Seismic hazard, lcsh:G, 13. Climate action, General Earth and Planetary Sciences, Sedimentary rock, Quaternary, Geology
Abstract

During the GWADASEIS cruise (Lesser Antilles volcanic arc, February–March 2009) a very high resolution (VHR) seismic-reflection survey was performed in order to constrain Late Quaternary to Present faulting. The profiles we obtained evidence frequent "ponding" of reworked sediments in the deepest areas, similar to the deposition of Mediterranean "homogenites". These bodies are acoustically transparent (few ms t.w.t. thick) and are often deposited on the hanging walls of dominantly normal faults, at the base of scarps. Their thickness appears sufficient to compensate (i.e. bury) co-seismic scarps between successive earthquakes, resulting in a flat and horizontal sea floor through time. In a selected area (offshore Montserrat and Nevis islands), piston coring (4 to 7 m long) was dedicated to a sedimentological analysis of the most recent of these particular layers. It corresponds to non-stratified homogenous calcareous silty sand (reworked calcareous plankton and minor volcanoclastics). This layer can be up to 2 m thick, and overlies fine-grained hemipelagites. The upper centimeters of the latter represent the normal RedOx water/sediment interface. 210Pb and 137Cs activities lack in the massive sands, while a normal profile of unsupported 210Pb decrease is observed in the hemipelagite below, together with a 137Cs peak corresponding to the Atmospheric Nuclear Experiments (1962). The RedOx level was thus capped by a recent instantaneous major sedimentary event considered as post-1970 AD; candidate seismic events to explain this sedimentary deposits are either the 16 March 1985 earthquake or the 8 October 1974 one (Mw = 6.3 and Mw = 7.4, respectively). This leads to consider that the syntectonic sedimentation in this area is not continuous but results from accumulation of thick homogenites deposited after the earthquakes (as observed in the following weeks after Haiti January 2010 event, McHugh et al., 2011). The existence of such deposits suggests that, in the area of study, vertical throw likely results from cumulated effects of separated earthquakes rather than from aseismic creep. Examination of VHR profiles shows that all major co-seismic offsets are recorded in the fault growth sequence and that co-seismic offsets can be precisely estimated. By using a sedimentation rate deduced from 210Pb decrease curve (0.5 mm yr−1) and taking into account minor reworking events detected in cores, we show that the Redonda system may have been responsible for five >M6 events during the last 34 000 yr. The approach presented in this work differs from fault activity analyses using displaced sets of isochronous surfaces and postulating co-seismic offsets. Combining VHR seismic imagery and coring we can decipher co-seismic vs. slow continuous displacement, and thus actually estimate the amplitude and the time distribution of major co-seismic offsets.

Published
2012
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46. The 2004–2005 Les Saintes (French West Indies) seismic aftershock sequence observed with ocean bottom seismometers

Author

Sara Bazin, Satish C. Singh, A. Nercessian, Wayne C Crawford, Nathalie Feuillet, Mendy Bengoubou-Valerius, C. Duclos, François Beauducel, Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), and Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)

Subjects
Seismometer, Lesser Antilles, Local earthquake tomography, 010504 meteorology & atmospheric sciences, Fault (geology), 010502 geochemistry & geophysics, Fault scarp, 01 natural sciences, Aftershock sequence, 14. Life underwater, Aftershock, 0105 earth and related environmental sciences, Earth-Surface Processes, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Fault-fluid interactions, Keywords: Ocean bottom seismometer, Graben, Tectonics, Geophysics, Normal-fault earthquake, Archipelago, Intraplate earthquake, Seismology, Geology, Les Saintes
Abstract

International audience; On November 21, 2004 an Mw6.3 intraplate earthquake occurred at sea in the French Caribbean. The aftershock sequence continues to this day and is the most extensive sequence in a French territory in more than a century. We recorded aftershocks from day 25 to day 66 of this sequence, using a rapidly-deployed temporary array of ocean bottom seismometers (OBS). We invert P- and S-wave arrivals for a tomographic velocity model and improve aftershock locations. The velocity model shows anomalies related to tectonic and geologic structures beneath the Les Saintes graben. 3D relocated aftershocks outline faults whose scarps were identified as active in recent high-resolution marine data. The aftershocks distribution suggests that both the main November 21 event and its principal aftershock, on February 14, 2005, ruptured Roseau fault, which is the largest of the graben, extending from Dominica Island to the Les Saintes archipelago. Aftershocks cluster in the lower part of the Roseau fault plane (between 8 and 12.6 km depth) that did not rupture during the main event. Shallower aftershocks occur in the Roseau fault footwall, probably along smaller antithetic faults. We calculate a strong negative Vp anomaly, between 4 and 8 km depth, within the graben, along the Roseau fault plane. This low Vp anomaly is associated with a high Vp/Vs ratio and may reflect a strongly fracturated body filled with fluids. We infer from several types of observation that fault lubrication is the driving mechanism for this long-lasting aftershock sequence.

Published
2010
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47. Seismotectonics of southern Haiti: A new faulting model for the 12 January 2010 M 7.0 earthquake

Author

Yann Klinger, Raphaël Grandin, Nathalie Feuillet, Newdeskarl Saint Fleur, Eric Jacques, and Jennifer Weil-Accardo

Subjects
geography, Geophysics, geography.geographical_feature_category, Seismic hazard, Field data, Seismotectonics, General Earth and Planetary Sciences, Bathymetry, Submarine pipeline, Fault (geology), Urban area, Seismology, Geology
Abstract

The prevailing consensus is that the 2010 Mw7.0 Haiti earthquake left the Enriquillo–Plantain Garden strike-slip Fault (EPGF) unruptured but broke unmapped blind north-dipping thrusts. Using high-resolution topography, aerial images, bathymetry and geology we identified previously unrecognized south-dipping NW-SE-striking active thrusts in southern Haiti. One of them, Lamentin thrust (LT), cuts across the crowded city of Carrefour, extends offshore into Port-au-Prince Bay and connects at depth with the EPGF. We propose that both faults broke in 2010. The rupture likely initiated on the thrust and propagated further along the EPGF due to unclamping. This scenario is consistent with geodetic, seismological and field data. The 2010 earthquake increased the stress toward failure on the unruptured segments of the EPGF and on neighboring thrusts, significantly increasing the seismic hazard in the Port-au-Prince urban area. The numerous active thrusts recognized in that area must be considered for future evaluation of the seismic hazard.

Published
2015
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48. The reef platform of Martinique: Interplay between eustasy, tectonic subsidence and volcanism since Late Pleistocene

Author

Nathalie Feuillet, Guy Cabioch, Frédérique Leclerc, Jean-Marie Saurel, Sara Bazin, Jean-Frédéric Lebrun, Marie Perret, Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Norwegian Geotechnical Institute (NGI), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL)

Subjects
Reef stratigraphy, Lesser Antilles, 010504 meteorology & atmospheric sciences, Carbonate platform, Fringing reef, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Paleontology, Volcanism, Geochemistry and Petrology, 14. Life underwater, Reef, Sea level, 0105 earth and related environmental sciences, Reef morphology, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, Tectonic subsidence, geography.geographical_feature_category, Volcanic arc, Seismic profiles, Geology, Interglacial, Martinique submarine carbonate platform, Martinique, Drowned reefs
Abstract

International audience; Reef positions record the interaction between eustasy and tectonics, and have been used worldwide to characterize vertical deformations of upper-plates at different time-scales and constrain the seismic behavior of megathrusts. Along the Lesser Antilles volcanic arc, high-resolution marine geophysical data were collected on the 2–20 km wide eastern Martinique reef platform to reconstruct its stratigraphic and morphologic history, and understand the influence of local normal faulting, volcanism and plate-scale subduction processes on Holocene and Late Pleistocene reef development. The subsiding Martinique platform's stratigraphy is composed of multiple superimposed sea-level highstand deposits separated by subaerial exposure surfaces of sea-level low stands. The carbonate platform consists of two laterally-extensive carbonate units (unit U2 overlying unit U3) that extend to the platform edge to a depth of − 95 m MSL (mean sea level), and form two morphologic terraces, M2 and M3 respectively. The landward portion of unit U2 is partially overlain between 0 and − 60 m MSL by the living reef tract U1. The current reef is composed of a landward fringing reef, a lagoon and a seaward barrier reef, the latter forming a double-bank barrier around the Caravelle Peninsula. In near-shore multi-channel seismic profiles, a distinct reflector at ~− 35 m MSL, probably a subaerial exposure surface E1, separates the reef sequence formed during the last transgression from a Pleistocene fossil reef tract forming unit U2. Offshore of Mount Pelée volcano (Late Pleistocene), the Holocene reef did not develop above unit U2, whose upper surface is incised by channels and apparent sinkholes. During the Holocene transgression, the possibility of excessive turbidity due to volcanic activity may have inhibited reef development in this area. The un-dated unit U2 probably developed 120–130 ka ago during the last interglacial (MIS 5.5) + 6 m MSL highstand as thick, extensive reefs deposited all along the Lesser Antilles arc. Due to subsidence, MIS 5.5 reefs are not represented by onshore facies, except along the southern Sainte Anne Peninsula where normal faulting and uplift balances island-scale subsidence. Based on unit U2's present elevation and assuming an MIS 5.5 age and + 6 m MSL sea level, Martinique has subsided at maximum 0.3 m/ky, likely due to subduction processes that question the coupling state of the megathrust.

Published
2015
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49. Submarine record of volcanic island construction and collapse in the Lesser Antilles arc: First scientific drilling of submarine volcanic island landslides by IODPExpedition 340

Author

Georges Boudon, Sebastian F. L. Watt, N. Stroncik, A. Le Friant, Fukashi Maeno, Michael Martínez-Colón, Benoît Villemant, Sara Lafuerza, Kyoko S. Kataoka, Christine Deplus, Osamu Ishizuka, Christoph Breitkreuz, Martin R. Palmer, M. Brunet, D. Endo, Yoshihiko Tamura, A. Stinton, Akihiko Fujinawa, Nathalie Feuillet, Robert G. Hatfield, Michael Manga, Fei Wang, Molly C. McCanta, A.J. Fraas, Benoit Caron, K.S.V. Subramanyam, Mohammed Aljahdali, Elodie Lebas, Sally Morgan, Maya Coussens, Martin Jutzeler, Angela L. Slagle, Matthew J. Hornbach, Deborah Wall-Palmer, T. Adachi, Malcolm B. Hart, Barry Voight, Jean-Christophe Komorowski, Jessica Trofimovs, Stephen Sparks, Peter J. Talling, Takeshi Saito, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Geological Survey of Japan, Institute of Advanced Science and Technology, Ocean and Earth Science [Southampton], University of Southampton-National Oceanography Centre (NOC), National Oceanography Center, University of Southampton, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Graduate School of Science and Engineering [Yamagata], Yamagata University, Department of Palaeontology - Institute for Geology, Technishe Universität Bergakademie Freiberg (TU Bergakademie Freiberg), Department of Earth, Ocean and Atmospheric Science [Tallahassee] (FSU | EOAS), Florida State University [Tallahassee] (FSU), Earth Evolution Sciences Department [Tsukuba], Université de Tsukuba = University of Tsukuba, Department of Geosciences, University of Massachusetts [Amherst] (UMass Amherst), University of Massachusetts System (UMASS)-University of Massachusetts System (UMASS), College of Earth, Ocean and Atmospheric Sciences [Corvallis] (CEOAS), Oregon State University (OSU), Department of Environmental Sciences, Ibaraki University, Centre for Research in Earth Sciences [Plymouth] (CRES), Plymouth University, Huffington Department of Earth Sciences [SMU Dallas], Southern Methodist University (SMU), Research Institute for Natural Hazards and Disaster Recovery [Niigata], Niigata University, Earthquake Research Institute, The University of Tokyo (UTokyo), Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), College of Marine Science [St Petersburg, FL], University of South Florida [Tampa] (USF), Geology Department, Tufts University [Medford], Department of Geology [Leicester], University of Leicester, International Researchers Empowerment Center, Shinshu University, Borehole Research Group (BRG), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York]-Columbia University [New York], School of Earth Sciences [Bristol], University of Bristol [Bristol], Montserrat Volcano Observatory (MVO), Institut für Erd‐ und Umweltwissenschaften, University of Potsdam = Universität Potsdam, Geochemistry Division, National Geophysical Research Institute [India], Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Queensland University of Technology [Brisbane] (QUT), Pennsylvania State University (Penn State), Penn State System-Penn State System, School of Geography, Earth and Environmental Sciences [Plymouth] (SoGEES), Institute of Geology and Geophysics [Beijing] (IGG), Chinese Academy of Sciences [Beijing] (CAS), School of Geography, Earth and Environmental Sciences [Birmingham], University of Birmingham [Birmingham], Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Geology and Paleontology [Freiberg], Technishe Universität Bergakademie Freiberg, Department of Earth, Ocean and Atmospheric Science [Tallahassee] (EOAS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), University of Tsukuba, CEOAS, The University of Tokyo, University of California [Berkeley], University of California-University of California, University of South Florida (USF), Universität Potsdam, Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Scienze della Terra [Pisa], University of Pisa - Università di Pisa, Département des sciences de la Terre, and Université Paris-Sud - Paris 11 (UP11)

Subjects
landslide, Geochemistry & Geophysics, Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, IODP, Geochemistry and Petrology, 14. Life underwater, Geomorphology, ComputingMilieux_MISCELLANEOUS, geography, geography.geographical_feature_category, debris avalanche, Scientific drilling, Landslide, Debris, seafloor sediment failure, Seafloor spreading, Geophysics, Volcano, [SDU]Sciences of the Universe [physics], Subaerial, Physical Sciences, Earth Sciences, Submarine pipeline, Institut für Geowissenschaften, tsunami, volcanic island, Martinique, Geology
Abstract

IODP Expedition 340 successfully drilled a series of sites offshore Montserrat, Martinique and Dominica in the Lesser Antilles from March to April 2012. These are among the few drill sites gathered around volcanic islands, and the first scientific drilling of large and likely tsunamigenic volcanic island-arc landslide deposits. These cores provide evidence and tests of previous hypotheses for the composition and origin of those deposits. Sites U1394, U1399, and U1400 that penetrated landslide deposits recovered exclusively seafloor-sediment, comprising mainly turbidites and hemipelagic deposits, and lacked debris avalanche deposits. This supports the concepts that i/ volcanic debris avalanches tend to stop at the slope break, and ii/ widespread and voluminous failures of pre-existing low-gradient seafloor sediment can be triggered by initial emplacement of material from the volcano. Offshore Martinique (U1399 and 1400), the landslide deposits comprised blocks of parallel strata that were tilted or micro-faulted, sometimes separated by intervals of homogenized sediment (intense shearing), while Site U1394 offshore Montserrat penetrated a flat-lying block of intact strata. The most likely mechanism for generating these large-scale seafloor-sediment failures appears to be propagation of a decollement from proximal areas loaded and incised by a volcanic debris avalanche. These results have implications for the magnitude of tsunami generation. Under some conditions, volcanic island landslide deposits comprised of mainly seafloor sediment will tend to form smaller magnitude tsunamis than equivalent volumes of subaerial block-rich mass flows rapidly entering water. Expedition 340 also successfully drilled sites to access the undisturbed record of eruption fallout layers intercalated with marine sediment which provide an outstanding high-resolution dataset to analyze eruption and landslides cycles, improve understanding of magmatic evolution as well as offshore sedimentation processes. This article is protected by copyright. All rights reserved.

Published
2014
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50. The Holocene drowned reef of Les Saintes plateau as witness of a long-term tectonic subsidence along the Lesser Antilles volcanic arc in Guadeloupe

Author

L. De Min, Frédérique Leclerc, D. Melezan, François Beauducel, Jean-Frédéric Lebrun, A. Lefriant, Christine Deplus, Guy Cabioch, Sara Bazin, Nathalie Feuillet, Georges Boudon, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Recherche en Géosciences et Energies (LARGE), Université des Antilles (UA), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Recherche en Géosciences et Energies [UR2_1] (LARGE), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))

Subjects
geography, Tectonic subsidence, Plateau, geography.geographical_feature_category, Volcanic arc, Geology, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Fault (geology), Oceanography, Graben, Tectonics, Paleontology, Geochemistry and Petrology, Archipelago, 14. Life underwater, Reef, Geomorphology, ComputingMilieux_MISCELLANEOUS
Abstract

Resulting from the interplay between tectonics and eustatism, reef terraces are powerful markers of vertical movements at a scale of 1000 to 100,000 years. In the Lesser Antilles, they grow around every island of the archipelago and record both local and subduction-related tectonics. The recent acquisition and interpretation of very high-resolution bathymetry of Les Saintes submarine plateau, French West Indies, together with seismic reflection profiles, are a unique opportunity to study one of these submarine structures, at metric to kilometric scales, addressing the questions of its nature, age and growth environment, but also of the control of active tectonics on its formation. The 20 km wide Les Saintes reef plateau lies at about 45 mbsl. It is crosscut by NW–SE striking, north-dipping normal faults that belong to Les Saintes fault system and graben, which produced a Mw 6.3 earthquake in 2004. The plateau is composed of four 20 m thick reef units, piled up in “layer cake” morphology down to 110 mbsl. The upper unit has a fresh morphology and presents typical reef features, like barrier and lagoon, spurs and grooves, pinnacles, etc. From its morphology we propose that it grew during the Holocene last transgression. Below, the three other units likely formed during Pleistocene sea level highstands and were eroded during the low stands, as evidenced in seismic reflection profiles. This scenario would imply that Les Saintes plateau formed in a context of subsidence with a rate we evaluate to be of the order of tenths of mm/yr. Probably linked to local tectonics, we believe that this deformation is also related to plate-scale subduction processes, similarly to deformations occurring on the other islands of the Guadeloupe archipelago.

Published
2014
Full Text
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