What makes a tsunami wave a wave of such a long wavelength?

[Highlander-SP]

Does anyone know what makes a Tsunami wave a wave of such long wavelength. Also could there be apart from a physical barrier, a way of decipating wave energy.

 

[IanP]

Re: tsunami

Once a tsunami has been generated, its energy is distributed throughout the water column, regardless of the ocean's depth. A tsunami is made up of a series of very long waves. The waves will travel outward on the surface of the ocean in all directions away from the source area, much like the ripples caused by throwing a rock into a pond. The wavelength of the tsunami waves and their period will depend on the generating mechanism and the dimensions of the source event. If the tsunami is generated from a large earthquake over a large area, its initial wavelength and period will be greater. If the tsunami is caused by a local landslide, both its initial wavelength and period will be shorter. The period of the tsunami waves may range from 5 to 90 minutes.

More info here:
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Regards,
IanP