Tips for Picking P, S, and Surface Waves

1) Seismic Wave Overview

The fastest waves, and therefore the first to arrive at a given location are P waves or compressional waves. Like sound waves, they move by alternately compressing and expanding material in the direction they are traveling.

The next large arrival is the S wave. It travels through the earth moving material up and down and side to side perpendicular to the direction of motion.

The last to arrive are Surface waves, which travel slower than P and S waves and move the ground like a rolling ocean wave (Rayleigh) or side to side like a S wave (Love).

For animations of seismic wave motions go to: http://earthquake.usgs.gov/4kids/4grownups/4grownups_seis.html

Rayleigh wave

2) Tips for Picking Seismic Waves

P wave is the first arrival

S wave is the next large arrival

If the event is large and distant you will also record Surface waves

Love wave

P

SSP

Surface