P Waves
A P wave, or compressional wave, is a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving. The P stands for primary, as P waves are the fastest of the 3 wave types.
S Waves
An S wave, or shear wave, is a seismic body wave that shakes the ground back and forth perpendicular to the direction the wave is moving.
Surface Waves
A surface wave is a seismic seismic wave that is trapped near the surface of the earth.