ABSTRACT
This chapter introduces some basic concepts of waves that are necessary to the understanding of the use of waves in geophysics, in many respects, waves are a more difficult topic than the presented static methods. In geophysics, the most important characteristic of waves is that they propagate. Propagation means traveling with a certain speed and, because waves propagate, it is possible to directly measure distances. Taking a 'snapshot' of water waves and measuring surface elevation as a function of distance from the shore and then taking another snapshot a very short time later, there would be a similar pattern of crests and troughs. Waves have been characterized by their wavelength, period or frequency, phase, and direction of oscillation relative to propagation. To illustrate the mechanisms of scattering, first consider only a single crest from among the many parallel crests and troughs associated with a water wave propagating towards a beach.
