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Auteur Sylvain Bonvalot |
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Detecting preseismic signals in GRACE gravity solutions: Application to the 2011 Tohoku Mw 9.0 earthquake / Isabelle Panet in Journal of geophysical research : Solid Earth, vol 127 n° 8 (August 2022)
[article]
Titre : Detecting preseismic signals in GRACE gravity solutions: Application to the 2011 Tohoku Mw 9.0 earthquake Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Clément Narteau, Auteur ; Jean-Michel Lemoine, Auteur ; Sylvain Bonvalot, Auteur ; Dominique Remy, Auteur Année de publication : 2022 Projets : 2-Pas d'info accessible - article non ouvert / Article en page(s) : n° e2022JB024542 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GRACE
[Termes IGN] gradient de gravitation
[Termes IGN] Pacifique (océan)
[Termes IGN] séisme
[Termes IGN] sismicité
[Termes IGN] subduction
[Termes IGN] tectonique des plaques
[Termes IGN] Tohoku (Japon)Résumé : (auteur) We conduct a global analysis of GRACE-reconstructed gravity gradients from July 2004 to February 2011, to test whether the deep signals preceding the March 2011 Tohoku earthquake can be detected before the event as a specific feature originating from solid Earth. First, we improve the angular resolution of the gravity gradients using two overlapping ranges of azimuthal sensitivity to investigate short-term signals of large amplitude aligned with the orientation of the Northwestern Pacific subduction. Then, we set-up a method to identify consistent solid Earth signals shared by different GRACE gravity models. Robust signals in a model are selected based on their spatial overlap and relative intensity with the signals of another model, so that their sensitivity to the GRACE data processing and ocean dealiasing product can be tested. We show that the dipolar gravity gradient anomaly before the Tohoku earthquake is nearly unique in space and time in the GRACE GRGS03 solutions. A well-resolved dipolar spatial pattern, typical of dislocations within the solid Earth and poorly sensitive to the ocean dealiasing model, is detected. In addition, the preseismic gravity gradient increase is highly consistent between the GRGS03 and CSR06 solutions, independently from their respective oceanic corrections, and can be clearly distinguished from rare anomalies of similar amplitudes all associated with the water cycle over continental areas. Our approach offers solutions for the continuous monitoring of the Pacific subduction belt to document transient slabs motions in real time from global satellite gravity fields, and their relation with shallower deformations and seismic events. Numéro de notice : A2022-605 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2022JB024542 Date de publication en ligne : 06/08/2022 En ligne : https://doi.org/10.1029/2022JB024542 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101384
in Journal of geophysical research : Solid Earth > vol 127 n° 8 (August 2022) . - n° e2022JB024542[article]Deep mass redistribution prior to the 2010 Mw 8.8 Maule (Chile) Earthquake revealed by GRACE satellite gravity / Marie Bouih in Earth and planetary science letters, vol 584 (15 April 2022)
[article]
Titre : Deep mass redistribution prior to the 2010 Mw 8.8 Maule (Chile) Earthquake revealed by GRACE satellite gravity Type de document : Article/Communication Auteurs : Marie Bouih , Auteur ; Isabelle Panet , Auteur ; Dominique Remy, Auteur ; Laurent Longuevergne, Auteur ; Sylvain Bonvalot, Auteur Année de publication : 2022 Projets : Université de Paris / Clerici, Christine Conférence : EGU 2022, General Assembly 23/05/2022 27/05/2022 Vienne Autriche OA Abstracts only Article en page(s) : n° 117465 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] Chili
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GRACE
[Termes IGN] gradient de gravitation
[Termes IGN] jeu de données
[Termes IGN] levé gravimétrique
[Termes IGN] prévention des risques
[Termes IGN] risque naturel
[Termes IGN] séisme
[Termes IGN] signal
[Termes IGN] subduction
[Termes IGN] tectonique des plaquesRésumé : (auteur) Subduction zones megathrust faults constitute a considerable hazard as they produce most of the world's largest earthquakes. However, the role in megathrust earthquake generation exerted by deeper subduction processes remains poorly understood. Here, we analyze the 2003 – 2014 space-time variations of the Earth's gravity gradients derived from three datasets of GRACE geoid models over a large region surrounding the rupture zone of the Mw 8.8 Maule earthquake. In all these datasets, our analysis reveals a large-amplitude gravity gradient signal, progressively increasing in the three months before the earthquake, North of the epicentral area. We show that such signals are equivalent to a water storage decrease over 2 months and cannot be explained by hydrological sources nor artefacts, but rather find origin from mass redistributions within the solid Earth on the continental side of the subduction zone. These gravity gradient variations could be explained by an extensional deformation of the slab around 150-km depth along the Nazca Plate subduction direction, associated with large-scale fluid release. Furthermore, the lateral migration of the gravity signal towards the surface from a low coupling segment around North to the high coupling one in the South suggests that the Mw 8.8 earthquake may have originated from the propagation up to the trench of this deeper slab deformation. Our results highlight the importance of observations of the Earth's time-varying gravity field from satellites in order to probe slow mass redistributions in-depth major plate boundaries and provide new information on dynamic processes in the subduction system, essential to better understand the seismic cycle as a whole. Numéro de notice : A2022-280 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.epsl.2022.117465 En ligne : https://doi.org/10.1016/j.epsl.2022.117465 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100288
in Earth and planetary science letters > vol 584 (15 April 2022) . - n° 117465[article]Height system unification and estimation of the lithospheric structure beneath Vietnam through high-resolution gravity field and quasigeoid modeling / Dinh Toan Vu (2021)
Titre : Height system unification and estimation of the lithospheric structure beneath Vietnam through high-resolution gravity field and quasigeoid modeling Titre original : Unification du système de hauteur et estimation de la structure lithosphérique sous le Vietnam utilisant la modélisation du champ de gravité et du quasigéoïde à haute résolution Type de document : Thèse/HDR Auteurs : Dinh Toan Vu, Auteur ; Sylvain Bonvalot, Directeur de thèse ; Sean L. Bruinsma, Directeur de thèse Editeur : Toulouse : Université de Toulouse Année de publication : 2021 Importance : 234 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse en vue de l'obtention du Doctorat de l'Université de Toulouse délivrée par l'Université Toulouse 3 - Paul SabatierLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données GNSS
[Termes IGN] données GOCE
[Termes IGN] géoïde gravimétrique
[Termes IGN] géoïde local
[Termes IGN] lithosphère
[Termes IGN] modèle de géopotentiel local
[Termes IGN] nivellement
[Termes IGN] quasi-géoïde
[Termes IGN] Viet NamIndex. décimale : THESE Thèses et HDR Résumé : (auteur) The goal of this work was twofold. The first part was devoted to the research of the size and physical shape of the Earth in Vietnam through the determination of a local gravimetric quasigeoid model. The second part was to better constrain the Earth's interior structure beneath Vietnam by determining the Moho and Lithosphere-Asthenosphere Boundary (LAB) depth models. For the first objective, a high-resolution gravimetric quasigeoid model for Vietnam and its surrounding areas was determined based on new land gravity data in combination with fill-in data where no gravity data existed. The resulting quasigeoid model was evaluated using 812 GNSS/levelling points in the study region. This comparison indicates that the quasigeoid model has a standard deviation of 9.7 cm and 50 cm in mean bias. This new local quasigeoid model for Vietnam represents a significant improvement over the global models EIGEN-6C4 and EGM2008, which have standard deviations of 19.2 and 29.1 cm, respectively, when compared to the GNSS/levelling data. An essential societal and engineering application of the gravimetric quasigeoid is in GNSS levelling, and a vertical offset model for Vietnam and its surrounding areas was determined based on the GNSS/levelling points and gravimetric-only quasigeoid model for this purpose. The offset model was evaluated using cross-validation technique by comparing with GNSS/levelling data. Results indicate that the offset model has a standard deviation of 5.9 cm in the absolute sense. Thanks to this offset model, GNSS levelling can be carried out over most of Vietnam's territory complying to third-order levelling requirements, while the accuracy requirements for fourth-order levelling networks is met for the entire country. To unify the height system towards the International Height Reference Frame (IHRF), the zero-height geopotential value for the Vietnam Local Vertical Datum W_0^LVD was determined based on two approaches: 1) Using high-quality GNSS/levelling data and the estimated gravimetric quasigeoid model, 2) Using the Geodetic Boundary Value Problem (GBVP) approach based on the GOCE global gravity field model enhanced with terrestrial gravity data. This geopotential value can be used to connect the height system of Vietnam with the neighboring countries. Moreover, the GBVP approach was also used for direct determination of the gravity potential on the surface at three GNSS Continuously Operating Reference Station (CORS) stations at epoch 2018.0 in Vietnam. Based on time series of the vertical component derived from these GNSS observations as well as InSAR data, temporal variations in the geopotential were also estimated on these permanent GNSS stations. This enables monitoring of the vertical datum and detect possible deformation. These stations may thus contribute to increase the density of reference points in the IHRF for this region. For the second objective, the local quasigeoid model was first converted to the geoid. Then, high-resolution Moho and LAB depth models were determined beneath Vietnam based on the local isostatic hypothesis using the geoid height derived from the estimated geoid, elevation data and thermal analysis. From new land gravity data, a complete grid and map of gravity anomalies i.e., Free-air, Bouguer and Isostatic was determined for the whole of Vietnam. The Moho depth was also computed based on the gravity inversion using the Bouguer gravity anomaly grid. All new models are computed at 1' resolution. The resulting Moho and LAB depth models were evaluated using available seismic data as well as global and local lithospheric models available in the study region. [...] Note de contenu : 1- Introduction
2- Theoretical basis
3- Data and map of gravity anomalies
4- The gravimetric quasigeoid solution
5- Quasigeoïd application for GNSS levelling and height system unification
6- Quasigeoid application for determination of the lithospheric structure
7- Conclusion and perspectivesNuméro de notice : 28495 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de Doctorat : Sciences de la Terre et des Planètes Solides : Toulouse : 2021 Organisme de stage : Geosciences Environnement Toulouse GET DOI : sans En ligne : http://www.theses.fr/2021TOU30050 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99240 Migrating pattern of deformation prior to the Tohoku-Oki earthquake revealed by GRACE data / Isabelle Panet in Nature geoscience, vol 11 n° 5 (May 2018)
[article]
Titre : Migrating pattern of deformation prior to the Tohoku-Oki earthquake revealed by GRACE data Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Sylvain Bonvalot, Auteur ; Clément Narteau, Auteur ; Dominique Remy, Auteur ; Jean-Michel Lemoine, Auteur Année de publication : 2018 Projets : 1-Pas de projet / Clerici, Christine Article en page(s) : pp 367 - 373 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GRACE
[Termes IGN] Japon
[Termes IGN] risque naturel
[Termes IGN] séisme
[Termes IGN] subduction
[Termes IGN] tectonique des plaquesRésumé : (auteur) Understanding how and when far-field continuous motions lead to giant subduction earthquakes remains a challenge. An important limitation comes from an incomplete description of aseismic mass fluxes at depth along plate boundaries. Here we analyse Earth’s gravity field variations derived from GRACE satellite data in a wide space-time domain surrounding the Mw 9.0 2011 Tohoku-Oki earthquake. We show that this earthquake is the extreme expression of initially silent deformation migrating from depth to the surface across the entire subduction system. Our analysis indeed reveals large-scale gravity and mass changes throughout three tectonic plates and connected slabs, starting a few months before March 2011. Before the Tohoku-Oki earthquake rupture, the gravity variations can be explained by aseismic extension of the Pacific plate slab at mid-upper mantle depth, concomitant with increasing seismicity in the shallower slab. For more than two years after the rupture, the deformation propagated far into the Pacific and Philippine Sea plate interiors, suggesting that subduction accelerated along 2,000 km of the plate boundaries in March 2011. This gravitational image of the earthquake’s long-term dynamics provides unique information on deep and crustal processes over intermediate timescales, which could be used in seismic hazard assessment. Numéro de notice : A2018-118 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1038/s41561-018-0099-3 Date de publication en ligne : 09/04/2018 En ligne : https://doi.org/10.1038/s41561-018-0099-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89558
in Nature geoscience > vol 11 n° 5 (May 2018) . - pp 367 - 373[article]GRACE gravitational signature of the 2011 Mw 9.0 Tohoku-oki earthquake / Isabelle Panet (2018)
Titre : GRACE gravitational signature of the 2011 Mw 9.0 Tohoku-oki earthquake Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Sylvain Bonvalot, Auteur ; Clément Narteau, Auteur ; Dominique Remy, Auteur ; Jean-Michel Lemoine, Auteur Editeur : Munich [Allemagne] : European Geosciences Union EGU Année de publication : 2018 Collection : Geophysical Research Abstracts, ISSN 1607-7962 num. 20 Conférence : EGU 2018, General Assembly 08/04/2018 13/04/2018 Vienne Autriche OA Abstracts only Note générale : EGU2018-9714 Langues : Anglais (eng) Résumé : (auteur) We present a analysis of the 2011 Mw 9.0 Tohoku-oki earthquake gravity variations in a wide space-time window surrounding the event. We identify earthquake-related gravity signals by searching for transient variations near the time of the earthquake in GRACE-reconstructed time series of gravity gradients at different spatial scales. The gravity gradients are expressed in spherical frames rotated along the radial axis in order to enhance gravity variations according to different orientations. Applied to different sets of gravity field models, our analysis allows us to evidence anomalous gravity signals starting a few months before the rupture across the regional subduction system, which cannot be explained by mass redistributions from water cycle sources around Japan nor by GRACE striping. After the rupture, the gravity variations propagate far within the Pacific and the Philippine Sea plates interiors.We further test the presence of the pre-seismic signals by also applying a statistical analysis of the gravity gradient time series, without knowledge on the consecutive rupture. Our findings show that satellite gravity brings unique information to monitor major plate boundaries, which could be used in seismic hazard assessment. Numéro de notice : C2018-070 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Poster nature-HAL : Poster-avec-CL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91462 Mass redistributions of the 2011 Mw 9.0 Tohoku-oki earthquake from GRACE / Isabelle Panet (2018)PermalinkComparative study of temporal variations in the earth’s gravity field using GRACE gravity models in the regions of three recent giant earthquakes / Valentin O. Mikhailov in Izvestiya, Physics of the Solid Earth, vol 50 n° 2 (March 2014)PermalinkRapport Quadriennal 2003-2006 [du] CNFGG, ch. French activities in ground gravimetry during the period 2003-2006 / Martine Amalvict (2007)PermalinkInsight into ground deformations at Lascar volcano (Chile) from SAR interferometry, photogrammetry and GPS data: Implications on volcano dynamics and future space monitoring / A. Pavez in Remote sensing of environment, vol 100 n° 3 (15 february 2006)Permalink