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Coseismic and post-seismic signatures of the Sumatra 2004 December and 2005 March earthquakes in GRACE satellite gravity / Isabelle Panet in Geophysical journal international, vol 171 n° 1 (Octobre 2007)
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Titre : Coseismic and post-seismic signatures of the Sumatra 2004 December and 2005 March earthquakes in GRACE satellite gravity Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Valentin O. Mikhailov, Auteur ; Michel Diament
, Auteur ; Fred Pollitz, Auteur ; Geoffrey King, Auteur ; Olivier de Viron, Auteur ; Matthias Holschneider, Auteur ; Richard Biancale, Auteur ; Jean-Michel Lemoine, Auteur
Année de publication : 2007 Article en page(s) : pp 177 - 190 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données GRACE
[Termes IGN] géoïde local
[Termes IGN] ondelette
[Termes IGN] séisme
[Termes IGN] subductionRésumé : (auteur) The GRACE satellite mission has been measuring the Earth's gravity field and its temporal variations since 2002 April. Although these variations are mainly due to mass transfer within the geofluid envelops, they also result from mass displacements associated with phenomena including glacial isostatic adjustment and earthquakes. However, these last contributions are difficult to isolate because of the presence of noise and of geofluid signals, and because of GRACE's coarse spatial resolution (>400 km half-wavelength). In this paper, we show that a wavelet analysis on the sphere helps to retrieve earthquake signatures from GRACE geoid products. Using a wavelet analysis of GRACE geoids products, we show that the geoid variations caused by the 2004 December (Mw = 9.2) and 2005 March (Mw = 8.7) Sumatra earthquakes can be detected. At GRACE resolution, the 2004 December earthquake produced a strong coseismic decrease of the gravity field in the Andaman Sea, followed by relaxation in the area affected by both the Andaman 2004 and the Nias 2005 earthquakes. We find two characteristic timescales for the relaxation, with a fast variation occurring in the vicinity of the Central Andaman ridge. We discuss our coseismic observations in terms of density changes of crustal and upper-mantle rocks, and of the vertical displacements in the Andaman Sea. We interpret the post-seismic signal in terms of the viscoelastic response of the Earth's mantle. The transient component of the relaxation may indicate the presence of hot, viscous material beneath the active Central Andaman Basin. Numéro de notice : A2007-673 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1365-246X.2007.03525.x Date de publication en ligne : 01/10/2007 En ligne : https://doi.org/10.1111/j.1365-246X.2007.03525.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102773
in Geophysical journal international > vol 171 n° 1 (Octobre 2007) . - pp 177 - 190[article]ITRF2005: A new release of the International Terrestrial Reference Frame based on time series of station positions and Earth Orientation Parameters / Zuheir Altamimi in Journal of geophysical research : Solid Earth, vol 112 n° 9 (September 2007)
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Titre : ITRF2005: A new release of the International Terrestrial Reference Frame based on time series of station positions and Earth Orientation Parameters Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Xavier Collilieux
, Auteur ; J. Legrand, Auteur ; Bruno Garayt
, Auteur ; Claude Boucher
, Auteur
Année de publication : 2007 Article en page(s) : pp B09401 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] interférométrie à très grande base
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] orientation de la TerreRésumé : (auteur) Unlike the past International Terrestrial Reference Frame (ITRF) versions where global long-term solutions were combined, the ITRF2005 uses as input data time series (weekly from satellite techniques and 24-h session-wise from Very Long Baseline Interferometry) of station positions and daily Earth Orientation Parameters (EOPs). The advantage of using time series of station positions is that it allows to monitor station non-linear motion and discontinuities and to examine the temporal behavior of the frame physical parameters, namely the origin and the scale. The ITRF2005 origin is defined in such a way that it has zero translations and translation rates with respect to the Earth center of mass, averaged by the Satellite Laser Ranging (SLR) time series spanning 13 years of observations. Its scale is defined by nullifying the scale and its rate with respect to the Very Long Baseline Interferometry (VLBI) time series spanning 26 years of observations. The ITRF2005 orientation (at epoch 2000.0) and its rate are aligned to the ITRF2000 using 70 stations of high geodetic quality. The estimated level of consistency of the ITRF2005 origin (at epoch 2000.0) and its rate with respect to the ITRF2000 is respectively 0.1, 0.8, 5.8 mm and 0.2, 0.1, 1.8 mm/yr along the X, Y and Z-axis. We estimate the formal errors on these components to be 0.3 mm and 0.3 mm/yr. We believe that this low level of agreement between the two frame origins is most probably due to the poor SLR network geometry and its degradation over time. The ITRF2005 combination involving 84 co-location sites revealed a scale inconsistency of 1 ppb (6.3 mm at the equator), at epoch 2000.0, and 0.08 ppb/yr between the SLR and VLBI long-term solutions as obtained by the stacking of their respective time series. Possible causes of this inconsistency may include the poor SLR and VLBI networks and their co-locations, local tie uncertainties, systematic effects and possible inconsistent model corrections used in the data analysis of both techniques. For the first time of the ITRF history, the ITRF2005 rigorous combination provides self-consistent series of EOPs, including Polar Motion from VLBI and satellite techniques and Universal Time and Length of Day from VLBI only. A velocity field of 152 sites with an error less than 1.5 mm/yr is used to estimate absolute rotation poles of 15 tectonic plates that are consistent with the ITRF2005 frame. This new absolute plate motion model supersedes and significantly improves that of the ITRF2000 which involved six major tectonic plates. Numéro de notice : A2007-684 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1029/2007JB004949 Date de publication en ligne : 07/09/2007 En ligne : https://doi.org/10.1029/2007JB004949 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102733
in Journal of geophysical research : Solid Earth > vol 112 n° 9 (September 2007) . - pp B09401[article]Practical geodesy: part 5 chart projections / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 6 (01/09/2007)
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Titre : Practical geodesy: part 5 chart projections Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2007 Article en page(s) : pp 48 - 51 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Projections
[Termes IGN] altération
[Termes IGN] ellipsoïde (géodésie)
[Termes IGN] projection
[Termes IGN] projection Universal Transverse Mercator
[Termes IGN] système de coordonnéesRésumé : (Auteur) In the previous article, the importance of chart projections was discribed. An important aspect of projecting information from an ellipsoid on a flat surface is that the information will be distorded. In this article, some of these distorsions and their effect will be described. Copyright GEOinformatics Numéro de notice : A2007-419 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28782
in Geoinformatics > vol 10 n° 6 (01/09/2007) . - pp 48 - 51[article] Voir aussiRéservation
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Code-barres Cote Support Localisation Section Disponibilité 262-07061 SL Revue Centre de documentation Revues en salle Disponible Quasigeoid evaluation with improved levelled height data for Norway / D.I. Lysaker in Journal of geodesy, vol 81 n° 9 (September 2007)
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Titre : Quasigeoid evaluation with improved levelled height data for Norway Type de document : Article/Communication Auteurs : D.I. Lysaker, Auteur ; O.C. Omang, Auteur ; Bjørn Ragnvald Pettersen, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 617 - 627 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] géoïde gravimétrique
[Termes IGN] géoïde local
[Termes IGN] nivellement par GPS
[Termes IGN] Norvège
[Termes IGN] rebond post-glaciaireRésumé : (Auteur) GPS-levelling points are widely used to control gravimetric geoid or quasigeoid models. Direct comparison is often interpreted to reveal the accuracy of the gravimetric model, using GPS-levelling as a reference. However, both GPS and levelled heights contain errors, and in order to achieve a centimeter-accuracy geoid, these should be investigated. The Norwegian Height System NN1954 is known to contain large systematic errors due to postglacial land uplift in the area. In this study, the current height system and two revised versions, corrected for uplift, are applied to compute three sets of control quasigeoid heights in the southern part of Norway. These heights are then compared to various Nordic gravimetric quasigeoid models generated during the last two decades. In contradiction to some earlier studies, the accuracy of gravimetric quasigeoid models for this area are found to improve near-linearly with time. This is in accordance with expectations, since both data coverage and computation methods have progressed during this time. However, this study shows the importance of establishing accurate and error-free control data for geoid comparisons. Copyright Springer Numéro de notice : A2007-391 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-006-0129-6 En ligne : https://doi.org/10.1007/s00190-006-0129-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28754
in Journal of geodesy > vol 81 n° 9 (September 2007) . - pp 617 - 627[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-07071 RAB Revue Centre de documentation En réserve L003 Disponible 266-07072 RAB Revue Centre de documentation En réserve L003 Disponible Generation of study of high-resolution satellite gravity over the Sumatra earthquake region / Samprit Chatterjee in International Journal of Remote Sensing IJRS, vol 28 n° 13-14 (July 2007)
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Titre : Generation of study of high-resolution satellite gravity over the Sumatra earthquake region Type de document : Article/Communication Auteurs : Samprit Chatterjee, Auteur ; R. Bhattacharyya, Auteur ; T.J. Majumdar, Auteur Année de publication : 2007 Article en page(s) : pp 2915 - 2925 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] anomalie de pesanteur
[Termes IGN] carte gravimétrique
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données altimétriques
[Termes IGN] épicentre
[Termes IGN] gravimétrie spatiale
[Termes IGN] prévention des risques
[Termes IGN] risque naturel
[Termes IGN] séisme
[Termes IGN] Sumatra
[Termes IGN] tectonique des plaquesRésumé : (Auteur) We have utilized satellite altimetry data to generate the very high-resolution gravity anomaly maps to infer subsurface geological structures in the area of the devastating earthquake (and the corresponding tsunami) that struck the Indian Ocean near Sumatra (Indonesia) on 26 December 2004. In the present study, a high-resolution three-dimensional (3D) gravity image has been generated over a part of the eastern Indian offshore encompassing the Sumatran earthquake region apart from Ninety East Ridge, Andaman subduction zone, etc. Four latitudinal (2°, 3°, 4° and 8.6° N) gravity profiles have been generated across the epicentre (3° N/M w 9.0)/aftershock regions (4° N/M w 5.8 and 8.6° N/M w 6.0 and 6.6). A drastic change of gravity anomaly patterns (sim130 mGal) near the epicentre and the aftershock regions could be observed, which are however slowly diminishing further away from the epicentre. This gravitational difference might have been caused by the differences in plate tectonic processes. Minor/major gravitational differences in other areas may be due to the changes in densities of different lithospheric zones/sedimentary layers. Hence, our study further supports the idea that negative gravity and topography anomalies can be used as a predictor for occurrences of large earthquakes in subduction zones. Copyright Taylor & Francis Numéro de notice : A2007-336 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160601091829 En ligne : https://doi.org/10.1080/01431160601091829 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28699
in International Journal of Remote Sensing IJRS > vol 28 n° 13-14 (July 2007) . - pp 2915 - 2925[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 080-07081 RAB Revue Centre de documentation En réserve L003 Disponible Combined Earth orientation parameters based on homogeneous and continuous VLBI and GPS data / Daniela Thaller in Journal of geodesy, vol 81 n° 6-8 (June - August 2007)
PermalinkPractical geodesy: part 3 The geoid / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 4 (01/06/2007)
PermalinkAnalysis of a possible future degradation in the DORIS geodetic results related to changes in the satellite constellation / Pascal Willis in Advances in space research, vol 39 n° 10 (May 2007)
PermalinkA comparison of GPS, VLBI and model estimates of ocean tide loading displacements / I.D. Thomas in Journal of geodesy, vol 81 n° 5 (May 2007)
PermalinkDORIS satellite phase center determination and consequences on the derived scale of the Terrestrial Reference Frame / Pascal Willis in Advances in space research, vol 39 n° 10 (May 2007)
PermalinkThe topographic bias by analytical continuation in physical geodesy / Lard Erik Sjöberg in Journal of geodesy, vol 81 n° 5 (May 2007)
PermalinkAirborne LaCoste & Romberg gravimetry: a space domain approach / M. Abbasi in Journal of geodesy, vol 81 n° 4 (April 2007)
PermalinkPractical geodesy : Part 2 The ellipsoid / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 3 (01/04/2007)
PermalinkDetermination of the free core nutation period from tidal gravity observations of the GGP superconducting gravimeter network / B. Ducarme in Journal of geodesy, vol 81 n° 3 (March 2007)
PermalinkPractical geodesy: Part 1 The basics / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 2 (01/03/2007)
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