This introduction to seismic wave behavior describes Snell's Law and how it applies to layers in the earth. It addresses reflected, refracted, critically refracted, and head waves. Seismic waves travel at different speeds through...

A brief video will illustrate how a ping announces refracted seismic waves. [0:34]

Explains how any type of wave can be refracted, and how this applies to seismic waves and to our understanding of the Earth's structure. [9:21]