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Data-driven gap filling and spatio-temporal filtering of the GRACE and GRACE-FO records / Louis-Marie Gauer in Journal of geophysical research : Solid Earth, vol 128 n° 5 (May 2023)  

Public [article]  inJournal of geophysical research : Solid Earth > vol 128 n° 5 (May 2023) . - n° e2022JB025561 Titre : Data-driven gap filling and spatio-temporal filtering of the GRACE and GRACE-FO records Type de document : Article/Communication Auteurs : Louis-Marie Gauer, Auteur ; Kristel Chanard , Auteur ; Luce Fleitout, Auteur Année de publication : 2023 Projets : TOSCA HYDROGEODESY / Article en page(s) : n° e2022JB025561 Note générale : bibliographie This study was supported by the CNES-TOSCA HYDROGEODESY project. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] données GRACE [Termes IGN] filtrage spatiotemporel [Termes IGN] traitement de données localisées [Termes IGN] valeur aberrante Résumé : (auteur) Gravity Recovery And Climate Experiment and Follow On (GRACE/-FO) global monthly measurements of Earth's gravity field have led to significant advances in quantifying mass transfer. However, a significant temporal gap between missions hinders evaluating long-term mass variations. Moreover, instrumental and processing errors translate into large non-physical North-South stripes polluting geophysical signals. We use Multichannel Singular Spectrum Analysis (M-SSA) to overcome both issues by exploiting spatio-temporal information of Level-2 GRACE/-FO solutions, filtered using the DDK7 decorrelation and a new complementary filter, built based on the residual noise between fully processed data and a parametric fit to observations. Using an iterative M-SSA on Equivalent Water Height (EWH) time series processed by Center of Space Research, GeoForschungsZentrum, Institute of Geodesy at Graz University of Technology, and Jet Propulsion Laboratory, we replace missing data and outliers to obtain a combined evenly sampled solution. Then, we apply M-SSA to retrieve common signals between each EWH time series and its same-latitude neighbors to further reduce residual spatially uncorrelated noise. Comparing GRACE/-FO M-SSA solution with Satellite Laser Ranging and Swarm low-degree Earth's gravity field and hydrological model demonstrates its ability to satisfyingly fill missing observations. Our solution achieves a noise level comparable to mass concentration (mascon) solutions over oceans (3.0 mm EWH), without requiring a priori information nor regularization. While short-wavelength signals are challenging to capture using highly filtered spherical harmonics or mascons solutions, we show that our technique efficiently recovers localized mass variations using well-documented mass transfers associated with reservoir impoundments. Numéro de notice : A2023-096 Affiliation des auteurs : UMR IPGP-Géod (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2022JB025561 En ligne : https://doi.org/10.1029/2022JB025561 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103213 [article]

ITRF2020: an augmented reference frame refining the modeling of nonlinear station motions / Zuheir Altamimi in Journal of geodesy, vol 97 n° 5 (May 2023)  

Public [article]  inJournal of geodesy > vol 97 n° 5 (May 2023) . - n° 47 Titre : ITRF2020: an augmented reference frame refining the modeling of nonlinear station motions Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur Année de publication : 2023 Article en page(s) : n° 47 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] International Terrestrial Reference Frame Résumé : (auteur) To better describe the shape of the constantly deforming Earth’s surface, the ITRF2020 is provided as an augmented terrestrial reference frame that precisely models nonlinear station motions for both seasonal (annual and semi-annual) signals present in the station position time series and Post-Seismic Deformation (PSD) for sites impacted by major earthquakes. Reprocessed solutions in the form of station position time series and Earth Orientation Parameters using the full observation history provided by the four space geodetic techniques (DORIS, GNSS, SLR and VLBI) were used as input data, spanning 28, 27, 38 and 41 years of observations, respectively. The ITRF2020 long-term origin follows linearly with time the Earth’s Center of Mass (CM) as sensed by SLR, based on observations collected over the time span 1993.0–2021.0. We evaluate the accuracy of the ITRF2020 long-term origin position and time evolution by comparison to previous solutions, namely ITRF2014, ITRF2008 and ITRF2005, to be at the level of or better than 5 mm and 0.5 mm/yr, respectively. The ITRF2020 long-term scale is defined by a rigorous weighted average of selected VLBI sessions up to 2013.75 and SLR weekly solutions covering the 1997.75–2021.0 time span. For the first time of the ITRF history, the scale agreement between SLR and VLBI long-term solutions is at the level of 0.15 ppb (1 mm at the equator) at epoch 2015.0, with no drift. To accommodate most of ITRF2020 users, the seasonal station coordinate variations are provided in the CM as well as in the Center of Figure frames, together with a seasonal geocenter motion model. While the PSD parametric models were determined by fitting GNSS data only, they also fit the station position time series of the three other techniques that are colocated with GNSS, demonstrating their high performance in describing site post-seismic trajectories. Numéro de notice : A2023-098 Affiliation des auteurs : UMR IPGP-Géod (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-023-01738-w Date de publication en ligne : 19/05/2023 En ligne : https://doi.org/10.1007/s00190-023-01738-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103231 [article]

Susceptibility of microseismic triggering to small sinusoidal stress perturbations at the laboratory scale / Martin Colledge in Journal of geophysical research : Solid Earth, vol 128 n° 4 (April 2023)  

Public [article]  inJournal of geophysical research : Solid Earth > vol 128 n° 4 (April 2023) . - n° e2022JB025583 Titre : Susceptibility of microseismic triggering to small sinusoidal stress perturbations at the laboratory scale Type de document : Article/Communication Auteurs : Martin Colledge, Auteur ; Jérôme Aubry, Auteur ; Kristel Chanard , Auteur ; François Pétrélis, Auteur ; Clara Duverger, Auteur ; Laurent Bollinger, Auteur ; Alexandre Schubnel, Auteur Année de publication : 2023 Article en page(s) : n° e2022JB025583 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] onde sismique [Termes IGN] oscillation [Termes IGN] risque naturel [Termes IGN] séisme [Termes IGN] sismicité Résumé : (auteur) Small transient stress perturbations are prone to trigger (micro)seismicity. In the Earth's crust, these stress perturbations can be caused by various sources such as the passage of seismic waves, forcing by tides, or hydrological seasonal loads. A better understanding of the dynamic of earthquake triggering by stress perturbations is essential to improve our understanding of earthquake physics and our consideration of seismic hazard. Here, we study an experimental sandstone-gouge-filled fault system undergoing combined far field loading and periodic stress perturbations (of variable amplitude and frequency) at crustal pressure conditions. Microseismicity—in the form of acoustic emissions (AEs)—strains, and stresses, are continuously recorded in order to study the response of microseismicity as a function of loading rate, amplitude, and frequency of a periodic stress perturbation. The observed AE distributions do not follow the predictions of either a Coulomb failure model, taking into account both constant loading and oscillation-induced strain rates, or a rate and state model. A susceptibility of the system's AE response to the amplitude of the confinement pressure perturbation is estimated, which highlights a linear relation between confinement pressure amplitude and the AE response amplitude, observations which agree with recent higher frequency experimental results on dynamic triggering. The magnitude-frequency distribution of AEs is also computed. The Gutenberg-Richter b-value oscillates with stress oscillations. Our experiments may help complement our understanding of the influence of low inertia stress phenomena on the distribution of seismicity, such as observations of dynamic triggering and seismicity modulation by tides or hydrological loading. Numéro de notice : A2023-095 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2022JB025583 Date de publication en ligne : 13/04/2023 En ligne : https://doi.org/10.1029/2022JB025583 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103211 [article]

Field optical clocks and sensitivity to mass anomalies for geoscience applications / Guillaume Lion (2023)  

Public Titre : Field optical clocks and sensitivity to mass anomalies for geoscience applications Type de document : Article/Communication Auteurs : Guillaume Lion , Auteur ; Gwendoline Pajot-Métivier , Auteur ; Kristel Chanard , Auteur ; Michel Diament , Auteur Editeur : Munich [Allemagne] : European Geosciences Union EGU Année de publication : 2023 Projets : ROYMAGE / Letargat, Rodolphe Conférence : EGU 2023, General Assembly 23/04/2023 28/04/2023 Vienne Autriche OA Abstracts only Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse de sensibilité [Termes IGN] anomalie de pesanteur [Termes IGN] chronométrie [Termes IGN] horloge optique Index. décimale : 30.60 Géodésie spatiale Résumé : (auteur) 350 years ago, the pendulum clock for astronomical observations was diverted to become an instrument for measuring gravity. The measurement of the parallax of Mars by Richer and Cassini from Cayenne and Paris showed that the period of a periodic oscillator depends on the gravity field. A link was thus established between the improvement of time measurement and the knowledge of the phenomena that govern it. Since then, the performance and nature of clocks have evolved considerably. Today, atomic clocks are used in various fields that are essential to modern society, such as the realisation of international atomic time (TAI), satellite navigation (GNSS), geodesy, the traceability of trading events, etc. In the framework of the french ANR ROYMAGE, we are interested in the contribution of a transportable optical field clock for geoscience applications by using the principle of chronometric geodesy. The idea is based on the gravitational redshift, a relativistic effect that predicts that the beat of a clock depends on the speed at which it is moving and the strength of the surrounding gravitational potential. In practice, this means that if we compare the beat of two clocks, then it is possible to directly measure a difference in gravitational potential (or a change in height) between these two clocks. This type of measurement is original because classical geodetic techniques only allow to determine the potential indirectly from gravimetric and classical levelling data. In this work, we model the gravitational signature (potential, acceleration and tensor) of a mass anomaly as a function of its geometry, depth, size and density contrast. These synthetic simulations allow us to identify which types of structures can be detected by clock comparison measurements with a relative frequency uncertainty fixed at 10-17-18-19 (i.e. a vertical sensitivity of less than 10 cm - 1 cm - 1 mm respectively). We are also interested in the spatial resolution required for a clock measurement to detect two mass anomalies depending on its orientation. Finally, we show that this new chronometric observable combined with gravimetry and gradiometry data could allow a better separation of the sources by adding an additional constraint thanks to the medium and long wavelength gravitational information it provides. Numéro de notice : C2023-003 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Poster nature-HAL : Poster-avec-CL DOI : 10.5194/egusphere-egu23-3646 En ligne : https://doi.org/10.5194/egusphere-egu23-3646 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103216

Ground deformation monitoring of the eruption offshore Mayotte / Aline Peltier in Comptes rendus : Géoscience Sciences de la planète, vol 354 n° S2 (2022)  

Public [article]  inComptes rendus : Géoscience Sciences de la planète > vol 354 n° S2 (2022) . - pp 1 - 23 Titre : Ground deformation monitoring of the eruption offshore Mayotte Titre original : Suivi des déformations liées à l’éruption au large de Mayotte Type de document : Article/Communication Auteurs : Aline Peltier, Auteur ; Sébastien Saur , Auteur ; Valérie Ballu, Auteur ; François Beauducel, Auteur ; Pierre Briole, Auteur ; Kristel Chanard , Auteur ; et al., Auteur ; Perrine Rouffiac , Auteur ; Pierre Valty , Auteur Année de publication : 2022 Article en page(s) : pp 1 - 23 Note générale : bibliographie REVOSIMA (Réseau de surveillance volcanologique et sismologique de Mayotte) Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées GNSS [Termes IGN] déformation de la croute terrestre [Termes IGN] données GRACE [Termes IGN] Mayotte [Termes IGN] séisme Résumé : (auteur) En mai 2018, l’île de Mayotte a été touchée par une crise sismique sans précédent, suivie en juillet 2018 par des déplacements de surface à terre anormaux. En cumulé, du 1er juillet 2018 au 31 décembre 2021, les déplacements horizontaux étaient d’environ 21 à 25 cm vers l’est, et la subsidence d’environ 10 à 19 cm. L’étude des données GNSS à terre, et leur modélisation couplée aux données des capteurs de pression en mer, ont permis de conclure à une origine magmatique de la crise sismique avec la déflation d’une source profonde à l’est de Mayotte, confirmée en mai 2019 par la découverte d’une éruption sous-marine, à 50 km au large de Mayotte ([Feuillet et al., 2021]). Malgré une géométrie de réseau non optimale et des récepteurs éloignés de la source, les données GNSS ont permis de suivre la dynamique profonde du transfert magmatique, via la surveillance des flux volumiques. Numéro de notice : A2022-917 Affiliation des auteurs : IGN+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article DOI : 10.5802/crgeos.176 Date de publication en ligne : 19/12/2022 En ligne : https://doi.org/10.5802/crgeos.176 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102409 [article]

ITRF2020 : un référentiel augmenté affinant la modélisation des mouvements non linéaires des stations / Zuheir Altamimi in XYZ, n° 173 (décembre 2022)

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Understanding the geodetic signature of large aquifer systems: Example of the Ozark plateaus in central United States / Stacy Larochelle in Journal of geophysical research : Solid Earth, vol 127 n° 3 (March 2022)  

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ITRF2020 and the ILRS contribution / Zuheir Altamimi (2022)

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ITRF2020 station position kinematic model / Zuheir Altamimi (2022)  

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Monitoring and modeling of the Sacramento Valley aquifer (California) using geodetic and piezometric measurements / Stacy Larochelle (2022)  

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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)  

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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)  

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

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

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Review of Reference Frame Representations for a Deformable Earth / Zuheir Altamimi (2021)  

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