seismic sea wave

A large seismically generated sea wave which is capable of considerable destruction in certain coastal areas, especially where submarine earthquakes occur. Although in the open ocean the wave height may be less than one meter it steepens to hights of 15 metres or more on entering shallow coastal water. The wavelength in the open ocean is of the order of 100 to 150 km and the rate of travel of a seismic sea wave is between 640 and 960 km/h. (Source: WHIT)