Centre de documentation
scientifique

Gravito-Viskoelastodynamik für verallgemeinerte Rheologienmit Anwendungen auf den Jupitermond lo und die Erde / K. Wieczerkowski (1999)

Public Titre : Gravito-Viskoelastodynamik für verallgemeinerte Rheologienmit Anwendungen auf den Jupitermond lo und die Erde Titre original : [Dynamique gravito-élastique pour les rhéologies généralisées avec applications sur Io, la lune de Jupiter et sur la Terre] Type de document : Thèse/HDR Auteurs : K. Wieczerkowski, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1999 Collection : DGK - C Sous-collection : Dissertationen num. 515 Importance : 130 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9553-3 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géophysique interne [Termes IGN] déformation de la croute terrestre [Termes IGN] dynamique [Termes IGN] Jupiter (planète) [Termes IGN] rhéologie [Termes IGN] Terre (planète) [Termes IGN] viscosité Résumé : (Auteur) The work presented in this thesis is based on the viscoelastic field theory for spherical and self-gravitating planets, as described by Wolf (1997). Considering tidal and surface loading problems for chemically layered planets, we first formulate the field equations governing incompressible deformations in the isopotential-local form and derive their general solutions. We then give the field equations for compressible deformations (in the material-local form) and, following the procedure of Gilbert & Backus (1968), we derive their general solutions. All solutions incorporate the rheology in the form of a general relaxation function in order to study the influence of any given linear rheology on the tidal or loading problem. We parametrise the linear viscoelastic rheology using the Maxwell, Zelmer, Burgers and Caputo body. As an application of the theory to a tidal problem, we consider simple planetary models and derive closedform solutions for the Love-Shida numbers, which describe the deformation and gravity perturbation of a planet under tidal forcing. We find that the global rate of tidal dissipation depends much more on the type of viscoelasticity than on the given density structure or the presence of a liquid core. Of the four rheologies studied here, the commonly used Maxwell body gives the lowest global dissipation rate. For a realistic choice of parameters the compressibility has only a small influence on the Love-Shida numbers. When using very small bulk and shear moduli, however, the system shows instabilities. As a numerical application we compute the tidal dissipation rate in the Jovian satellite lo for the rheologies listed above. In particular, we map for each rheology a parameter space of shear modulus and viscosity for which the global dissipation rate corresponds to lo's global heat flow. Furthermore, we calculate the volumetric tidal dissipation rate inside lo for the different types of viscoelasticity. As an application of the theory to a surface loading problem we estimate the viscosity of the upper mantle beneath Fennoscandia, using post-glacially uplifted strand lines. The estimation method is based on McConnell (1968), who used strand lines of different age and height above present sea level to compute a regional relaxation time spectrum (IRTS). We adapt the estimation method for spherical Earth models and include formal propagation of data uncertainties. Following a recommendation by Wolf (1996) we compute a new IRTS for Fennoscandia based on an improved strand-line reconstruction by Donner (1995). Compared with the commonly used IRTS from McConnell (1968) we find that the improved IRTS has longer relaxation times for Legendre degrees 10-20 and 61-73. Considering the uncertainties of the improved IRTS, which are computed from the strand-line uncertainties, we find that the improved IRTS does not exclude the IRTS derived by McConnell. The inversion of the improved IRTS following the method of Mitrovica & Peltier (1993) yields a mean viscosity of (5 ± 1) X 1020 Pa s in the upper mantle (depth region 100-510 km). At greater depth (300-800 km) we find a value of (2 ± 1) X 1021 Pa s. When averaged over both depth ranges, the new viscosity estimate is in good agreement with the classical value of 1021 Pa s (Haskell, 1935). Numéro de notice : 53816 Affiliation des auteurs : non IGN Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=59537

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
53816-02	47.10	Livre	Centre de documentation	En réserve M-103	Disponible
53816-01	47.10	Livre	Centre de documentation	En réserve M-103	Disponible