Seismic Wave Motions—4 waves animated

An earthquake generates seismic waves that penetrate the Earth as body waves (P & S) or travel as surface waves (Love and Rayleigh). Each wave has a characteristic speed and style of motion. The animations below illustrate both the propogation of the wave as well as the motion of particles as the wave passes. 

TO VIEW THE ANIMATIONS, you must click on each of the 4 green arrows below. 

Or simply click "Download all" to get all four animations.

Key Points:

Wave propogation and particle motion for...

  • Body Waves - Primary (P) & Secondary (S) Waves
  • Surface Waves - Rayleigh & Love Waves

P-wave Motion

Seismic P waves are also called compressional or longitudinal waves, they compress and expand (oscillate) the ground back and forth in the direction of travel, like sound waves that move back and forth as the waves travel from source to receiver. P wave is the fastest wave.

Particle motion consists of alternating compression and dilation.  Particle motion is parallel to the direction of propagation (longitudinal).  Material returns to its original shape after wave passes.

Animation by Larry Braile,Purdue University. 

Animation Novice
S-wave Motion

S Wave—secondary body waves that oscillate the ground perpendicular to the direction of wave travel. They travel about 1.7 times slower than P waves. Because liquids will not sustain shear stresses, S waves will not travel through liquids like water, molten rock, or the Earth’s outer core. S waves produce vertical and horizontal motion in the ground surface.

Particle motion consists of alternating transverse motion.  Particle motion is perpendicular to the direction of propagation (transverse).  Transverse particle motion shown here is vertical but can be in any direction.  However, Earth’s layers tend to cause mostly vertical (SV; in the vertical plane) or horizontal (SH) shear motions.  Material returns to its original shape after wave passes.

Animation by Larry Braile,Purdue University. 

Animation Novice
Rayleigh-wave Motion

Rayleigh Waves—surface waves that move in an elliptical motion, producing both a vertical and horizontal component of motion in the direction of wave propagation.

Particle motion consists of elliptical motions (generally retrograde elliptical) in the vertical plane and parallel to the direction of propagation.  Amplitude decreases with depth.  Material returns to its original shape after wave passes.

Animation by Larry Braile,Purdue University. 

Animation Novice
Love-wave Motion

Love Waves—surface waves that move parallel to the Earth’s surface and perpendicular to the direction of wave propagation.

Particle motion consists of alternating transverse motions.  Particle motion is horizontal and perpendicular to the direction of propagation (transverse).  To aid in seeing that the particle motion is purely horizontal, focus on the Y axis (red line) as the wave propagates through it.  Amplitude decreases with depth.  Material returns to its original shape after wave passes.

Animation by Larry Braile,Purdue University. 

Animation Novice