Applications of Normal Mode Relaxation Theory to Solid Earth Geophysics
The normal mode relaxation theory is developed from basic principles for a spherical, self-gravitating and stratified Earth, and is targeted towards new perspectives on the physics of the Earth’s interior for graduate students and researchers working in the fields of geophysics and geodesy. This theory allows us to study 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 are introduced, in both mathematical and physical terms, within the framework of an analytical normal mode approach. After the fundamentals of this theory developed in the first, tutorial part, some applications will be presented, in 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 normal mode relaxation theory bridges the gap between seismology and geodynamics.