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Modelling and Inversion of High Precision Gravity Data / E. Lewi (1997)
Titre : Modelling and Inversion of High Precision Gravity Data Type de document : Thèse/HDR Auteurs : E. Lewi, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - C Sous-collection : Dissertationen num. 471 Importance : 145 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9511-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur local
[Termes IGN] Darmstadt
[Termes IGN] gradient de gravitation
[Termes IGN] levé gravimétrique
[Termes IGN] lissage de données
[Termes IGN] matrice
[Termes IGN] problème inverse
[Termes IGN] tour (bâtiment)Index. décimale : 30.42 Gravimétrie Résumé : (Auteur) In this work, the scope of the present day gravity data acquisition, processing and interpretational technique in using weak signal gravity anomalies, to study mass distributions, has been tested. To carry out this test, measurements were taken in Darmstadt and Bremen. The study in these areas, that encompasses the different stages of gravity data measurement, analysis and modelling procedures, has led to the development of some new methods and algorithms. The survey in Darmstadt was aimed at recovering the shape, location and density of two Rain Water Reservoirs, from measured gravity data. On the other hand the survey in Bremen was aimed at computing the vertical component of the gravity gradient within the "Drop Tower Bremen".
At first, the implementation of a spectral analysis technique in choosing a sampling interval that avoided aliasing effects was discussed and demonstrated, using the data in the Darmstadt survey area. The simulation of data, for this analysis, was partially carried out using an algorithm that can compute the gravitational attraction of cylindrically shaped bodies. This algorithm, which has reduced the well-known problem in computing the gravitational attraction of vertical cylinders on points that lie outside the axis of symmetry, is developed based on an existing theoretical relationship. The effectiveness of this algorithm was also tested in modelling the effect of the different steal and concrete structures in the "Drop Tower Bremen". Besides this, the need to apply a modified terrain correction procedure for data measured at a certain height above the surface of the ground has been shown.
One of the major findings of this study, is the development of a trend analysis method that makes use of the polynomial fitting technique. This technique is advantageous in its capability to suppress the role of the residual in determining the trend surface. Especially its capability to incorporate a priori information about the trend surface enables the modelling procedure to focus on the trend surface only. In addition, the method estimates the densities for the Bouguer and terrain reductions in an environment where all other effects, other than the elevation dependant term, are modelled using different polynomial terms. In conjunction with this, the role of anomalous gradient effect in gravity data interpretation has been discussed and its effect in the Darmstadt survey area has been analysed.
The other major finding of the present study is the development of a three-dimensional gravity inversion technique. This method makes use of diagonal weighting matrices to reduce the need for large computer memory and to save large computational time. Besides this, the use of a priori information together with a regularization method that depends on the misfit between the measured and model data iteratively, leads to the desired stable solution. Based on this three-dimensional gravity inversion method, a software which can be used for different applications has been developed. The test made on simulated data and the field gravity data, in the Darmstadt survey area, showed the effectiveness of the method both in error-free and error contaminated data. The test made on error-free data, simulated by simple shape three-dimensional models, particularly showed the capability of the method in recovering the causative body using a minimal amount of a priori information. The inversion of measured gravity data taken from the Darmstadt survey area showed not only the effectiveness of the inversion method but also the ability of the present day gravity data interpretation technique in analysing weak signal gravity anomalies.
The comparison of the upward continued gravity data and that measured at different heights of the "Drop Tower Bremen" confirmed the validity of Newton's inverse square law, within the accuracy of the survey. Moreover, through the use of this comparison between the measured and analytically continued gravity data, the vertical component of the gravity gradient has been computed with high accuracy. In general, the study in both the Darmstadt and Bremen survey areas showed that the gravity method, if effectively used, can serve as a tool in locating mass distributions, even if these masses generate only weak signal gravity anomalies.Numéro de notice : 28023 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63370 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28023-01 30.42 Livre Centre de documentation Géodésie Disponible 28023-02 30.42 Livre Centre de documentation Géodésie Disponible vol 70 n° 12 - October 1996 - The Geodesist's handbook = le manuel du géodésien 1996 (Bulletin de Journal of geodesy) / International association of geodesy
[n° ou bulletin]
Titre : vol 70 n° 12 - October 1996 - The Geodesist's handbook = le manuel du géodésien 1996 Type de document : Périodique Auteurs : International association of geodesy, Auteur Année de publication : 1996 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] Association internationale de géodésie
[Termes IGN] gravimétrie
[Termes IGN] système de référence altimétriqueNuméro de notice : 266-9609 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Numéro de périodique Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=6411 [n° ou bulletin]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-96091 RAB Revue Centre de documentation En réserve L003 Disponible 266-96092 RAB Revue Centre de documentation En réserve L003 Disponible Borehole data and stochastic gravimetric inversion / G. Strykowski (1996)
Titre : Borehole data and stochastic gravimetric inversion Type de document : Monographie Auteurs : G. Strykowski, Auteur ; National survey and cadastre of danemark, Auteur Editeur : Copenhague : Kort & Matrikelstyrelsen Année de publication : 1996 Collection : Publications 4 Series, ISSN 0905-1279 num. 3 Importance : 220 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-87-7866-013-8 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] géophysique
[Termes IGN] gravimétrieIndex. décimale : 30.40 Géodésie physique Numéro de notice : 66655 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=61631 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 66655-01 30.40 Livre Centre de documentation Géodésie Disponible Crustal deformation of the Yellowstone volcanic field from precise measurements of temporal gravity changes and supplementary leveling and GPS data / Felix Karl Arnet (1996)
Titre : Crustal deformation of the Yellowstone volcanic field from precise measurements of temporal gravity changes and supplementary leveling and GPS data Type de document : Thèse/HDR Auteurs : Felix Karl Arnet, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 1996 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 056 Importance : 125 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906513-79-9 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] champ de pesanteur local
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GPS
[Termes IGN] géophysique interne
[Termes IGN] levé gravimétrique
[Termes IGN] nivellement direct
[Termes IGN] volcan
[Termes IGN] Wyoming (Etats-Unis)Index. décimale : 30.82 Applications géophysiques de géodésie spatiale Résumé : (Auteur) The Yellowstone caldera in northwest of Wyoming, U.S.A, shows high rates of height and gravity changes. The height changes were monitored by precise leveling, which was first conducted in 1923 and remeasured every few years since 1975. Gravity measurements were first carried out in 1977 and repeated almost annually since 1983. Both measuring types were concentrated on a line crossing the northern part of the caldera. A GPS network was installed additionally in 1987. It covers the whole national park region and was remeasured every second year. The measurements showed, that the Caldera experienced an uplift of up to 0.8 m from 1923 to 1984. Since 1984, the trend reversed and the heights decreased up to 14 em. The gravity values along the same line changed up to 60 ± 12 µgal ( 1 µgal = 10 8 m S2 ) from 1977 to 1986. Until 1993, the gravity increased again up to +60 ± 12 µgal. The GPS results showed within the bounds of accuracy the same height changes as the precision leveling. In addition, horizontal displacements of up to 3 em towards the middle of the caldera were observed. Furthermore, it showed that the area of downshift expands partly considerably over the borders of the Yellowstone caldera. The factor between the height and gravity changes is a value that can be used to detect mass changes at depth. This value varies strongly from year to year. Over longer time spans, it converges towards the freeair gravity gradient of 0.3 mgal/m, where no mass changes occur. Finite element modeling shows, that the earth's crust in the Yellowstone National Park does not behave like an ideal elastic material. The horizontal displacements are significantly smaller than expected from the height changes. This is explained by the geology heavily disturbed by a lot of fault zones. Numéro de notice : 45614 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-001549641 En ligne : http://dx.doi.org/10.3929/ethz-a-001549641 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=58404 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 45614-01 30.82 Livre Centre de documentation Géodésie Disponible 45614-02 30.82 Livre Centre de documentation Géodésie Disponible Die Weiterführung der geodätischen Arbeiten der Internationalen glaziologischen Grönland-Expedition (EGIG) durch das Institut für Vermessungskunde der TU Braunschweig 1987-1993 / C. Homann (1996)
Titre : Die Weiterführung der geodätischen Arbeiten der Internationalen glaziologischen Grönland-Expedition (EGIG) durch das Institut für Vermessungskunde der TU Braunschweig 1987-1993 Titre original : [La poursuite des travaux géodésiques de l'expédition glaciologique internationale au Groenland (EGIG) par l'institut de la science de l'arpentage de l'université technologique de Braunschweig] Type de document : Monographie Auteurs : C. Homann, Auteur ; D. Moller, Auteur ; H. Salbach, Auteur ; et al., Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1996 Collection : DGK - B Sous-collection : Angewandte Geodäsie num. 303 Importance : 79 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-8585-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] altitude
[Termes IGN] déformation de la croute terrestre
[Termes IGN] Groenland
[Termes IGN] levé gravimétrique
[Termes IGN] positionnement par GPSIndex. décimale : 30.02 Géodésie - travaux divers Numéro de notice : 39859 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Recueil / ouvrage collectif Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=42513 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 39859-01 30.02 Livre Centre de documentation En réserve M-103 Disponible 39859-02 30.02 Livre Centre de documentation En réserve M-103 Disponible Eléments de géodésie / Gilles Canaud (1996)PermalinkFigure de la Terre / F. Chambat (1996)PermalinkGravity field mapping from a combination of satellite altimetry and sea gravimetry in the Mediterranean Sea / D. Arabelos (1996)PermalinkJournées Luxembourgeoises de Géodynamique / Manfred Bonatz (1996)PermalinkJournées recherche du LAREG [Laboratoire de Recherche en Géodésie] du 19 mars 1996 / Laboratoire de recherche en géodesie (1996)PermalinkLevés gravimétriques de reconnaissance / Y.H. Poudjom-Djomani (1996)PermalinkLevés gravimétriques de reconnaissance / D.B. Boukeke (1996)PermalinkLevés gravimétriques de reconnaissance / D.B. Boukeke (1996)PermalinkMéthodologie moderne de la détermination du géoïde, application à la réalisation d'une référence verticale opérationnelle / Zhiheng Jiang (1996)PermalinkOn the improvement of gravimetric geoid undulations and oceanographic dynamic topography though a conbination with satellite altimetry and the application of a modified Kalman filter algorithm / D.A. Smith (1996)Permalink