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Der Mittelmeerraum. Numerische Modellierung der Lithosphärendynamik im Vergleich mit Ergebnissen aus der Satellitengeodäsie / O. Heidbach (2000)

Public Titre : Der Mittelmeerraum. Numerische Modellierung der Lithosphärendynamik im Vergleich mit Ergebnissen aus der Satellitengeodäsie Titre original : [L'espace méditerranéen : modélisation numérique de la dynamique de la lithosphère comparée aux données de la géodésie spatiale] Type de document : Thèse/HDR Auteurs : O. Heidbach, Auteur Mention d'édition : 1 Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2000 Collection : DGK - C Sous-collection : Dissertationen num. 525 Importance : 98 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9564-9 Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] bassin méditerranéen [Termes IGN] champ de vitesse [Termes IGN] données GPS [Termes IGN] lithosphère [Termes IGN] Méditerranée, mer [Termes IGN] méthode des éléments finis [Termes IGN] modélisation 3D [Termes IGN] positionnement par GPS [Termes IGN] positionnement par télémétrie laser sur satellite [Termes IGN] tectonique Index. décimale : 30.82 Applications géophysiques de géodésie spatiale Résumé : (Auteur) The collision of the African and Arabian plates with Eurasia results in complex tectonic structures in the Mediterranean region. Broad deformation belts have developed along the border of the plates. Values deviating significantly to those of rigid body motion models are measured with the geodetic satellite methods SLR (Satellite Laser Ranging) and GPS (Global Positioning System). Aim of the investigation is to create a three-dimensional dynamic model of the Mediterranean. The numerical problem is solved with the finite element method. The resulting velocity field on the surface of the model is compared with the GPS- and SLR-data. This leads to new information about geodynamic processes of the lithosphere. In addition, the question is investigated if this numerical model can be used for a prediction of the surface velocity field and the deformation rate. The model is built up of various modules. It takes into consideration the radius of the Earth, the variation of topography and Mohorovicic discontinuity and the thickness of the lithosphere. The structure of the subduction- and collision zones will be represented as contact surfaces with Coulomb-friction. Kinematic boundary conditions from the NUVEL-1A rigid body model and the slab pull stress at the Hellenic and Calabrian arc are implemented as further boundary conditions. The rheology of the upper crust consist of an ideal elastic-plastic body. Its yield strength is computed with the linear Mohr-Coulomb criteria. The lower crust and the lithosphere is assumed to be an ideal visco-elastic body. In the first model series L of the complete Mediterranean region the viscous body is linear, in the second series NL of the Eastern Mediterranean the viscous body is described with non-linear power-law dislocation creeping. By varying the different model parameters their influence on surface deformations is examined. Finaly it becomes evident that the slab pull stress and the friction coefficient have the strongest effect on surface deformation. With a slab pull stress of 150 MPa and a friction coefficient between 0,2 and 0,35 the model shows the best results. Taking into further consideration the different yield strengths under compression and extension the model leads to a mean deviation of ±24,2% (magnitude) and ±10,8° (azimuth) in comparison with 40 GPS and SLR-stations within the Aegean-Anatolian block. The main pattern of the model velocity field corresponds with the geodetic observations. The extension in the Aegean and the west drift of the Anatolian block can be clearly seen. But locally, deviations still occur. By using a big scale model it is possible to identify the main dynamic processes and necessary constraints and boundary conditions for smaller scale models can be determined. Numéro de notice : 68821 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62020

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
68821-01	30.82	Livre	Centre de documentation	Géodésie	Disponible