Wave and Rays in Seismology ─ Answers to Unasked Questions

The author dedicates this book to readers who are concerned with finding out the status of concepts, statements and hypotheses, and with clarifying and rearranging them in a logical order, in words of Mario Bunge. It is thus not intended to teach tools and techniques of the trade, but to discuss the foundations on which seismology — and in a larger sense, the theory of wave propagation in solids — is built. A key questions is: why and to what extent can a theory developed for an elastic continuum be used to investigate the propagation of waves in the Earth, which is neither a continuum nor fully elastic? But the scrutiny of the foundations goes much deeper: material symmetry, effective tensors, equivalent media; the influence (lack thereof) of gravitational and thermal effects and the rotation of the Earth, are discussed ab initio.