P Waves and S Waves in the Crust
![cartoon of two cross-sections of crust](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/eq-ed-seismic-waves.gif?itok=4Ms-BMhk)
Detailed Description
P Waves alternately compress and stretch the crustal material parallel to the direction they are propagating. S Waves cause the crustal material to move back and forth perpendicular to the direction they are travelling.
Sources/Usage
Public Domain.