Syllabus
* Geoid in for a static and dynamic mantle
Relationship between seismic velocity anomalies and densities. Gravitational signal of density anomalies in the mantle. Spectral representation of the gravity. Concept of dynamic topography and its relationship to the real topography. Isostatic compensation. Can we determine the dynamic topographies of the surface and internal density interfaces?
* Flow in the mantle and deformation of density interfaces
Stokes' problem. Rheology of mantle and lithosphere. Spectral solution of the Stokes' problem in a spherical shell. Selfgravitation. 'Realistic' rheologies. Inclusion of lateral viscosity variations.
* Boundary conditions
What are the appropriate boundary conditions? Plate velocities, free slip and no slip. Approximation of mechanical behaviour of the lithosphere: Membrane dynamics. Role of lateral viscosity variations close to the boundaries.
* Inferences of viscosity from the geoid
Formulation of the inverse problem. Parameterization of density and viscosity. Local and global inverse techniques. Recent papers and models. Comparison with results of mineral physics experiments and postglacial rebound analyses.
* Literature
- B.H. Hager, R.W. Clayton: Constraints on the structure of mantle convection using seismic observation, flow models and the geoid, in: Mantle Convection, Plate Tectonics and Global Dynamics, W.R. Peltier ed., Gordon and Breach Science Publishers, New York etc., 1989.
- Selected research papers from J. Geophys. Res., Geophys. J. Int., PEPI and EPSL.
- A. Tarantola: Inverse Problem Theory. Elsevier, 1987.
Annotation
Geoid in a static and dynamic Earth. Spectral methods to solve the Stokes problem in the Earth mantle.
Seismic tomography and the density models of the mantle. Boundary conditions.
Lithosphere. Inferences of viscosity from the geoid.