Tsunami 2004

A tsunami is a very large sea wave that is generated by a disturbance along the ocean floor. This disturbance can be an earthquake, a landslide, or a volcanic eruption. A tsunami is undetectable far out in the ocean, but once it reaches shallow water, this fast-traveling wave grows very large.

Tsunami

Japanese term (literally meaning "big wave") now generally used for an unusual, very large wave or series of waves. Tsunamis are generated either by submarine earthquakes, by landslides or by effects of volcanic eruptions (such as the collapse of a caldera in the sea). Tsunamis have long wavelengths and small wave heights on the open sea. As water depth decreases near land the wavelength diminishes and the wave height increases dramatically which may lead to catastrophic flooding of coastal areas. Tsunamis may deceive coastal residents in that a wave trough may a arrive before the first wave crest.