by K. Lambeck, R. Sabadini and E. B08Chi Viscosity is one of the important material properties of the Earth, controlling tectonic and dynamic processes such as mantle convection, isostasy, and glacial rebound. Yet it remains a poorly resolved parameter and basic questions such as whether the planet's response to loading is linear or non-linear, or what are its depth and lateral variations remain uncertain. Part of the answer to such questions lies in laboratory observations of the rheology of terrestrial materials. But the extrapolation of such measurements from the laboratory environment to the geological environment is a hazardous and vexing undertaking, for neither the time scales nor the strain rates characterizing the geological processes can be reproduced in the laboratory. General rules for this extrapolation are that if deformation is observed in the laboratory at a particular temperature, deformation in geological environments will occur at a much reduced temperature, and that if at laboratory strain rates a particular deformation mechanism dominates over all others, the relative importance of possible mechanisms may be quite different at the geologically encountered strain rates. Hence experimental results are little more than guidelines as to how the Earth may respond to forces on long time scales.

This volume opens up new perspectives on the physics of the Earth's interior for graduate students and researchers working in the fields of geophysics and geodesy. It looks at our planet in an integrated fashion, linking the physics of its interior to the geophysical and geodetic techniques that record, over a broad spectrum of spatial wavelengths, the ongoing modifications in the shape and gravity field of the planet. Basic issues related to the rheological properties of the Earth's mantle and to its slow deformation will be understood, in both mathematical and physical terms, within the framework of an analytical normal mode relaxation theory. Fundamentals of this theory are developed in the first, tutorial part. The second part deals with a wide range of applications, ranging from changes in the Earth's rotation to post-seismic deformation and sea-level variations induced by post-glacial rebound. In the study of the physics of the Earth's interior, the book bridges the gap between seismology and geodynamics.

This volume opens up new perspectives on the physics of the Earth's interior for graduate students and researchers working in the fields of geophysics and geodesy. It looks at our planet in an integrated fashion, linking the physics of its interior to the geophysical and geodetic techniques that record, over a broad spectrum of spatial wavelengths, the ongoing modifications in the shape and gravity field of the planet. Basic issues related to the rheological properties of the Earth's mantle and to its slow deformation will be understood, in both mathematical and physical terms, within the framework of an analytical normal mode relaxation theory. Fundamentals of this theory are developed in the first, tutorial part. The second part deals with a wide range of applications, ranging from changes in the Earth's rotation to post-seismic deformation and sea-level variations induced by post-glacial rebound. In the study of the physics of the Earth's interior, the book bridges the gap between seismology and geodynamics.

by K. Lambeck, R. Sabadini and E. B08Chi Viscosity is one of the important material properties of the Earth, controlling tectonic and dynamic processes such as mantle convection, isostasy, and glacial rebound. Yet it remains a poorly resolved parameter and basic questions such as whether the planet's response to loading is linear or non-linear, or what are its depth and lateral variations remain uncertain. Part of the answer to such questions lies in laboratory observations of the rheology of terrestrial materials. But the extrapolation of such measurements from the laboratory environment to the geological environment is a hazardous and vexing undertaking, for neither the time scales nor the strain rates characterizing the geological processes can be reproduced in the laboratory. General rules for this extrapolation are that if deformation is observed in the laboratory at a particular temperature, deformation in geological environments will occur at a much reduced temperature, and that if at laboratory strain rates a particular deformation mechanism dominates over all others, the relative importance of possible mechanisms may be quite different at the geologically encountered strain rates. Hence experimental results are little more than guidelines as to how the Earth may respond to forces on long time scales.