Low-frequency sound in the ocean can be "viewed" in the form of time versus frequency "spectrograms" (warm colors represent strong energy) or "listened to" if the natural sound is raised to human hearing by "speeding up" the original signals. These sample sounds represent seismic and biological sources, as well as sounds of unknown origin.

Seismic	Whale	Man-made	Mystery
Listen Tremor South of Japan speed 16x wav: 1.18MB	Listen Blue Whale NE Pacific speed 10x wav:384KB	Listen Airguns speed 10x wav:809KB	Listen Equatorial Pacific unknown source speed 16x wav: 29K

Links to each sound category:

• Seismic
• Marine Mammals
• Man-made
• Unidentified Sounds

Use QuickTime player to listen to the sounds.