Rayleigh Waves
http://demonstrations.wolfram.com/Ray...
The Wolfram Demonstrations Project contains thousands of free interactive visualizations, with new entries added daily.
Rayleigh waves are seismic surface waves of low frequency that make the ground shake in an elliptical motion, with amplitude decreasing with depth.
Contributed by: Enrique Zeleny Based on a program by: Yu-Sung Chang
Audio created with WolframTones:
http://tones.wolfram.com