Not for surfing: Tsunamis

Graphic - tsunami

The waves we are used to seeing (perhaps jousting with) at our favourite beach have wavelengths of order 100 m and travel at speeds of order 1 ms-1. Tsunami’s are rather different. They have wavelengths of order 100 km and speeds of 200 ms-1 (or over 400 mph!). They arise from some large scale impulsive disturbance to the ocean, such as an earthquake, a landlside, or a meteor. A Quicktime Movie of this can be accessed below.

Tsunami
(QuickTime Movie. Requires free QuickTime player, available for PC or Mac. Linux users can also play QuickTime; consult your distribution's software manager and/or documentation.)

Reference: http://www.geophys.washington.edu/tsunami/