This textbook has been developed from 25 years of experience teaching seismology at the universities of Madrid and Barcelona. The text is at an introductory level for students in the last years of European licentiate or American upper-division undergraduate courses and at similar levels in other countries. As a first book, no previous knowledge of seismology, as such, is assumed of the student. The book's emphasis is on fundamental concepts and basic developments and for this reason a selection of topics has been made. It has been noticed that sometimes even graduate students lack a true grasp of the very fundamental ideas underlying some aspects of seismology. The most fundamental concepts are developed in detail. Simple cases such as one-dimensional problems and those in liquid media are used as introductory topics. Mathematical developments are worked out in complete detail for the most fundamental problems. Sometimes more difficult subjects are introduced, but not fully developed. In these cases references to more advanced books are given.

The book presupposes a certain amount of knowledge of mathematics and physics. Knowledge of mathematics at the level of calculus and ordinary and partial differential equations as well as a certain facility for vector and tensor analysis are assumed. Cartesian, spherical, and cylindrical coordinates and some functions such as Legendre and Bessel functions are used. Tensor index notation is used preferentially throughout the book. Fundamental ideas about certain mathematical subjects are given briefly in Appendixes 1–4.