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]

How fast does sound travel through the rocks? And how does seismic velocity vary through different depths? See how scientists measure individual pieces of seafloor samples to get a better understanding of how the cores are related to...