P waves and S waves
Mackenzie
There are two main ways of describing the waves of motion recorded by a seismograph.
P Waves
P waves are primary waves, which are the fastest seismic wave, and therefore the first to arrive. These waves can move through solid rock as well as fluid, such as water. They are also known as compression waves because they pull and push on the rock they moves through. P waves force particles to move the same direction as the wave, and appear as wavy lines.
S Waves
S waves are secondary waves, which are the ones felt in an earthquake. They are slower and can only move through rock; not water. These waves move particles up and down or side to side, perpendicular to the direction of the wave. They appear to be snake-like on a chart and have a ragged pattern.
P Waves
P waves are primary waves, which are the fastest seismic wave, and therefore the first to arrive. These waves can move through solid rock as well as fluid, such as water. They are also known as compression waves because they pull and push on the rock they moves through. P waves force particles to move the same direction as the wave, and appear as wavy lines.
S Waves
S waves are secondary waves, which are the ones felt in an earthquake. They are slower and can only move through rock; not water. These waves move particles up and down or side to side, perpendicular to the direction of the wave. They appear to be snake-like on a chart and have a ragged pattern.