Seismic waves

Graphic - pwave
Animation of a P-Wave Source
In an earthquake a sudden rupture of the earths’ structure releases a vast quantity of energy which travels outwards across the earth’s surface in the form of seismic waves. These waves exist in a variety of forms. The figures above and below show two of them. Geologists refer to them as P-waves (above) and S-waves (below). (P for primary, S for secondary: the P-waves travel faster and get to you first!). We might also label them as ‘longitudinal’ and ‘transverse’. For more information, visit the UPSeis site.
Graphic - swave
Animation of an S-Wave Source