This book is written primarily for Earth scientists faced with problems
in thermo- mechanics such as the flow and evolution of ice-sheets,
convection currents in the mantle, isostatic rebound, folding of strata
or collapse of cavities in salt domes. Failure, faults, seismic waves
and all processes involving inertial terms will not be dealt with. In
general such scientists (graduate students beginning a Ph. D. for
instance) have too small a background'in continuum mechanics and in
numerical computation to model conveniently these problems, which are
not elementary at all. Most of them are not linear, and therefore seldom
dealt with in treatises. If the study of reality were clearly cut into
two successive steps: first to make a physical model, setting up a
well-posed problem in thermo-mechanics, and second to solve it, the
obvious solution would be to find a specialist in computational
mechanics who could spend enough time on a problem which, although maybe
crucial for on-going fundamental research, has little practical interest
in general, and cannot be considered properly as a noteworthy progress
in Mechanics. But this is not the way Science develops. There is a
continuous dialectic between the building up of a model and its
mathematical treatment. The model should be simple enough to be
tractable, but not oversimplified. Its sensitivity to the different
components it is made of should be investigated, and more thought is
needed when the results contradict hard facts.
