EQ Monitoring Basics
The fastest wave, and therefore the first to arrive at a given location.
Also known as compressional waves, the P wave alternately compresses and expands material in the same direction it is traveling.
Can travel through all layers of the Earth.
Generally felt by humans as a bang or thump.
The S wave is slower than the P wave and arrives next, shaking the ground up and down and back and forth perpendicular to the direction it is traveling.
Also know as shear waves.
Surface waves follow the P and S waves.
Also known as Rayleigh and Love waves.
These waves travel along the surface of the earth.