# Translations:Geometric seismology/4/en

Fortunately, simplifying approaches can explain many of the phenomena associated with seismic wave propagation. In many respects, seismic waves are similar to light waves. During the past several centuries, physicists and mathematicians have built up a very extensive body of principles, based almost entirely on geometric reasoning, to explain what is known about light. This doctrine deals exhaustively with the ideas of raypaths and wavefronts and is known as *geometric optics*. It is readily possible to adapt many of these principles to explain seismic waves as well as acoustic waves. These fields of study are known as *geometric seismology* and *geometric acoustics*. Although this approach does not suffice to explain everything in which we are interested as geophysicists, it quite adequately accounts for many important phenomena. Insofar as it is capable of dealing with problems in seismic wave propagation, it agrees with the dynamic theory of elasticity.