Acoustic and Elastic Wave Fields in Geophysics, Part I, Volume 37 (Methods in Geochemistry and Geophysics)

This book is dedicated to basic physical principles of the propagation of
acoustic and elastic waves. It consists of two volumes. The first volume
includes 8 chapters and extended Appendices explaining mathematical aspects
of discussed problems. The first chapter is devoted to Newton's laws, which,
along with Hooke's law, govern the behavior of acoustic and elastic waves.
Basic concepts of mechanics are used in deriving equations which describe
wave phenomena. The second and third chapters deal with free and forced
vibrations as well as wave propagation in one dimension along the system of
elementary masses and springs which emulates the simplest elastic medium.
In addition, shear waves propagation along a finite and infinite
string are discussed.
In chapter 4 the system of equations describing compressional waves is derived.
The concepts of the density of the energy carried by waves, the energy flux, and
the Poynting vector are introduced. Chapter 5 is dedicated to propagation of
spherical, cylindrical, and plane waves in homogeneous media, both in time and
frequency domains. Chapter 6 deals with interference and diffraction. The
treatment is based on Helmholtz and Kirchhoff formulae. The detailed discussion
of Fresnel's and Huygens's principles is presented. In Chapter 7 the effects of interference of waves with close wave numbers and frequencies are considered. Concepts such as the wave group, the group velocity, and
the stationary phase important for understanding propagation of dispersive waves are introduced.
The final chapter of the first volume is devoted to the principles of
geometrical acoustics in inhomogeneous media.