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Metamorphic transformation rate over large spatial and temporal scales constrained by geophysical data and coupled modelling / Gyorgy Hetényl in Journal of metamorphic geology, vol 39 n° 9 (December 2021)  

Public [article]  inJournal of metamorphic geology > vol 39 n° 9 (December 2021) . - pp 1131 - 1143 Titre : Metamorphic transformation rate over large spatial and temporal scales constrained by geophysical data and coupled modelling Type de document : Article/Communication Auteurs : Gyorgy Hetényl, Auteur ; Kristel Chanard , Auteur ; Lukas P. Baumgartner, Auteur ; Frédéric Herman, Auteur Année de publication : 2021 Projets : 3-projet - voir note / Article en page(s) : pp 1131 - 1143 Note générale : bibliographie We are grateful to the Swiss National Science Foundation for funding project OROG3NY through grant PP00P2_157627. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] anomalie de pesanteur [Termes IGN] croute terrestre [Termes IGN] géodynamique [Termes IGN] Inde [Termes IGN] modèle numérique [Termes IGN] roche métamorphique Résumé : (auteur) Metamorphic transformation rates are classically determined on decimetre-scale field samples and from laboratory experiments at smaller scales. Here we present a geophysical approach based on field data and joint geophysical–petrological modelling to quantify the average rate of metamorphic transformations at the 10–100-kilometre and million-year scales. The model simulates the eclogitization of Indian lower crust as it penetrates beneath southern Tibet. Metamorphic transformation of the lower crust is tracked by its densification, the effect of which is then compared to observed gravity anomalies. From the modelling we find that the Indian lower crust's overall densification requires a partially hydrated initial composition. Moreover, the modelled evolution of this densification compared to what is predicted by pressure–temperature–density grids is consistent with delayed, far-from-equilibrium metamorphism. The Indian lower crust descends underneath the Himalaya until beneath southern Tibet in a thermodynamically metastable state until the first dehydration reactions are reached. This observation is used to determine the average rate of metastable rock transformation to an eclogite facies assemblage, constrained at between ~6 × 10−9 and 5 × 10−7 g/cm2/year, and reaction affinity at 0.8–1.6 kJ/mol oxygen. Compared to field and laboratory data, this range of results matches the effective rates typically associated with regional metamorphism. This fit and correlation across the scales legitimates the use of transformation rates determined at small scales in large-scale geodynamic studies. Numéro de notice : A2021-789 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/jmg.12604 En ligne : https://doi.org/10.1111/jmg.12604 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98988 [article]

Orogenic collapse and stress adjustments revealed by an intense seismic swarm following the 2015 Gorkha earthquake in Nepal / Lok Bijaya Adhikari in Frontiers in Earth Science, vol 9 (2021)  

Public [article]  inFrontiers in Earth Science > vol 9 (2021) . - n° 659937 Titre : Orogenic collapse and stress adjustments revealed by an intense seismic swarm following the 2015 Gorkha earthquake in Nepal Type de document : Article/Communication Auteurs : Lok Bijaya Adhikari, Auteur ; Laurent Bollinger, Auteur ; Jérôme Vergne, Auteur ; Sophie Lambotte, Auteur ; Kristel Chanard , Auteur ; Marine Laporte, Auteur ; Lily Li, Auteur ; Bharat Koirala, Auteur ; Mukunda Bhattarai, Auteur ; Chintan Timsina, Auteur ; Nabina Bishwokarma, Auteur ; Nicolas Wendling-Vazquez, Auteur ; Frédéric Girault, Auteur ; Frédéric Perrier, Auteur Année de publication : 2021 Projets : 1-Pas de projet / Article en page(s) : n° 659937 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géophysique interne [Termes IGN] effondrement de terrain [Termes IGN] Himalaya [Termes IGN] Népal [Termes IGN] séisme [Termes IGN] variation saisonnière Résumé : (auteur) The April 25, 2015 Mw 7.9 Gorkha earthquake in Nepal was characterized by a peak slip of several meters and persisting aftershocks. We report here that, in addition, a dense seismic swarm initiated abruptly in August 2017 at the western edge of the afterslip region, below the high Himalchuli-Manaslu range culminating at 8156 m, a region seismically inactive during the past 35 years. Over 6500 events were recorded by the Nepal National Seismological Network with local magnitude ranging between 1.8 and 3.7 until November 2017. This swarm was reactivated between April and July 2018, with about 10 times less events than in 2017, and in 2019 with only sporadic events. The relocation of swarm earthquakes using proximal temporary stations ascertains a shallow depth of hypocenters between the surface and 20 km depth in the High Himalayan Crystalline slab. This swarm reveals an intriguing localized interplay between orogenic collapse and stress adjustments, involving possibly CO2-rich fluid migration, more likely post-seismic slip and seasonal enhancements. Numéro de notice : A2021-788 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3389/feart.2021.659937 Date de publication en ligne : 22/07/2021 En ligne : https://doi.org/10.3389/feart.2021.659937 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98985 [article]

Earthquake sensitivity to tides and seasons: theoretical studies / François Pétrélis in Journal of Statistical Mechanics: Theory and Experiment, vol 2021 n° 2 (February 2021)  

Public [article]  inJournal of Statistical Mechanics: Theory and Experiment > vol 2021 n° 2 (February 2021) . - n° 023404 Titre : Earthquake sensitivity to tides and seasons: theoretical studies Type de document : Article/Communication Auteurs : François Pétrélis, Auteur ; Kristel Chanard , Auteur ; Alexandre Schubnel, Auteur ; Takahiro Hatano, Auteur Année de publication : 2021 Article en page(s) : n° 023404 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géophysique interne [Termes IGN] analyse de sensibilité [Termes IGN] marée terrestre [Termes IGN] séisme [Termes IGN] sismicité [Termes IGN] variation saisonnière Résumé : (auteur) We investigate theoretically the effects of periodic-in-time modulations on the properties of earthquakes. To wit, we consider successively the one dimensional Burridge–Knopoff (BK) model and the two dimensional Olami–Feder–Christensen (OFC) model. Each model is modified to take into account either a modulation of normal stress or of shear stress acting on a fault. Despite the differences between the BK and the OFC model, several results are observed in both models. In particular, we observe that earthquake occurrences correlate with stress modulation. The correlation is strongly dependent on parameters such as the type of modulation, its frequency and amplitude, and in some cases on the magnitude of the considered earthquakes. Numéro de notice : A2021-790 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1088/1742-5468/abda29 En ligne : https://doi.org/10.1088/1742-5468/abda29 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98991 [article]

Analysis of IGS repro3 station position time series [diaporama] / Paul Rebischung (2021)  

Public contenu dans Earth and Space Science Open Archive ESSOAr / American Geophysical Union (2019)   Titre : Analysis of IGS repro3 station position time series [diaporama] Type de document : Article/Communication Auteurs : Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Zuheir Altamimi , Auteur ; Kristel Chanard , Auteur Editeur : Washington DC [Etats-Unis] : Earth and Space Science Open Archive ESSOAr Année de publication : 2021 Conférence : AGU 2021 Fall Meeting 13/12/2021 17/12/2021 New Orleans and virtual Louisiane - Etats-Unis Importance : 30 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse spectrale [Termes IGN] déformation de la croute terrestre [Termes IGN] effet de charge [Termes IGN] International Terrestrial Reference Frame [Termes IGN] série temporelle Résumé : (auteur) The IGS contribution to ITRF2020, based on the third IGS reprocessing campaign (repro3), comprises daily position estimates for 1905 globally distributed GNSS stations. As an essential step of the ITRF2020 preparation, a detailed analysis of the IGS repro3 station position time series has been carried out, including identification of offsets, modeling of post-seismic displacements, confrontation with deformation predicted by geophysical loading models, and characterization of systematic and random errors. This presentation covers the different aspects of this analysis, the methods used and the lessons learned. Numéro de notice : C2021-070 Affiliation des auteurs : UMR IPGP-Géod (2020- ) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : 10.1002/essoar.10509008.1 Date de publication en ligne : 06/12/2021 En ligne : https://doi.org/10.1002/essoar.10509008.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99607

IX Hotine-Marussi Symposium on Mathematical Geodesy. Review of reference frame representations for a deformable Earth / Zuheir Altamimi (2021)  

Public Titre de série : IX Hotine-Marussi Symposium on Mathematical Geodesy Titre : Review of reference frame representations for a deformable Earth Type de document : Chapitre/Contribution Auteurs : Zuheir Altamimi , Auteur ; Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2021 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 151 Projets : 2-Pas d'info accessible - article non ouvert / Conférence : IAG 2018, 9th Hotine-Marussi Symposium on Mathematical Geodesy 18/06/2018 22/06/2018 Rome Italie Proceedings Springer Importance : pp 51 - 56 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] coordonnées GPS [Termes IGN] erreur systématique [Termes IGN] International Terrestrial Reference Frame [Termes IGN] série temporelle Résumé : (auteur) Our planet Earth is constantly deforming under the effects of geophysical processes that cause linear and nonlinear displacements of the geodetic stations upon which the International Terrestrial Reference Frame (ITRF) is established. The ITRF has traditionally been defined as a secular (linear) frame in which station coordinates are described by piecewise linear functions of time. Nowadays, some particularly demanding applications however require more elaborate reference frame representations that can accommodate non-linear displacements of the reference stations. Two such types of reference frame representations are reviewed: the usual linear frame enhanced with additional parametric functions such as seasonal sine waves, and non-parametric time series of quasi-instantaneous reference frames. After introducing those two reference frame representations, we briefly review the systematic errors present in geodetic station position time series. We finally discuss the practical issues raised by the existence of these systematic errors for the implementation of both types of non-linear reference frames. Numéro de notice : H2021-002 Affiliation des auteurs : Géodésie (mi2018-2019) Thématique : POSITIONNEMENT Nature : Chapître / contribution nature-HAL : ChOuvrScient DOI : 10.1007/1345_2019_66 Date de publication en ligne : 17/05/2019 En ligne : https://doi.org/10.1007/1345_2019_66 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95512

Understanding the geodetic signature of large aquifer systems: Example of the Ozark Plateaus in Central United States / Stacy Larochelle (2021)  

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Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation / Alexandre Couhert in Journal of geodesy, vol 94 n° 12 (December 2020)  

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Accounting for spatiotemporal correlations of GNSS coordinate time series to estimate station velocities / Clément Benoist in Journal of geodynamics, vol 135 (April 2020)  

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A warning against over-interpretation of seasonal signals measured by the Global Navigation Satellite System / Kristel Chanard in Nature communications, vol 11 (2020)  

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Data-adaptive spatio-temporal filtering of GRACE data / Paoline Prevost in Geophysical journal international, vol 219 n° 3 (December 2019)  

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Sensitivity of acoustic emission triggering to small pore pressure cycling perturbations during brittle creep / Kristel Chanard in Geophysical research letters, vol 46 n° 13 (16 July 2019)  

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Review of Reference Frame Representations for a Deformable Earth / Zuheir Altamimi (2019)  

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Identification and extraction of seasonal geodetic signals due to surface load variations / Stacy Larochelle in Journal of geophysical research : Solid Earth, vol 123 n° 12 (December 2018)  

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Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series / Kristel Chanard in Journal of geophysical research : Solid Earth, vol 123 n° 4 (April 2018)  

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Constraints on transient viscoelastic rheology of the asthenosphere from seasonal deformation / Kristel Chanard in Geophysical research letters, vol 45 n° 5 (15 March 2018)  

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