Learning Outcomes and Assessment

Our aim in this course is to show how concepts from physics, especially from classical physics and continuum mechanics, can be used to understand the structure and evolution of the Earth, and to a lesser extent, the other terrestrial planets. Our approach is entirely different from that taken in Part IA Geology, and assumes no knowledge of that material. The course is intended for students who are theoretically inclined, and focuses on quantitative and mathematical parts of geophysics. Some of the lectures will be given by the other members of the Department of Earth Sciences whose research is related to topics discussed within the course.

Synopsis

Introduction to geophysics: Theories of planetary formation, composition of terrestrial planets and the bulk composition of the Earth, origin of the crust, mantle, and core, large scale static structure of the Earth.

Plate tectonics: Rotation vectors and poles of rotation, triple junctions, present-day plate motion, reconstructing past plate motions.

Continuum mechanics: Fundamentals of solid mechanics, variational principles, measures of deformation and stress, constitutive theory, material symmetries.

Seismology and elastic wave propagation:  Linearised elasticity, plane wave propagation, elastodynamic Green function, seismic waves in stratified media, asymptotic ray theory, effects of self-gravitation and rotation, the free oscillations of the Earth and eigenfunction expansions.

Earth structure:  Travel time observations, dispersion measurements from surface waves, spherically symmetric Earth structure, seismic tomography, constraints on density from free oscillations and the Adams-Williamson equation.

The earthquake source: Kinematic models for earthquakes, point source approximations and moment tensors, earthquake location, determination of source mechanisms.

Thermal and mechanical structure of plates: Structure of oceanic and continental plates, isostasy and gravity, thermal models, depth of the oceans, subduction, the elastic layer.

Dynamic processes: Heat sources, thermodynamics of convection, convective regime of the mantle, the cooling of the mantle, thermal history of the mantle.

BOOKS

The solid Earth, Fowler C M R (2nd edn CUP 2004)

This is an excellent general book on geophysics. It covers about half of the course, but uses less mathematics than we do. Fowler’s discussion of seismology is briefer than that of the present course, and she does not discuss mantle convection and dynamics at all.

Theoretical Global Seismology, Dahlen F A & Tromp J (Princeton 1998)

A comprehensive monograph on theoretical seismology. It covers the course material at a similar level, but includes additional topics and goes into more detail. Particularly good on the fundamentals of continuum mechanics.

The excitation and propagation of elastic waves, Hudson J A (Cambridge 1980)

A concise and elegant book dealing with the fundamentals of elastic wave propagation. Largely at the right level, though it does contain some more advanced material making use of complex variable techniques.

Geodynamics, Turcotte D L & Schubert G (Wiley 2002)

This covers much of the material of the course except seismology, at about the same mathematical level that we will use. It contains many problems with their solutions.