The massive security operation surrounding Barack Obama's inauguration showed that he will be the most protected president in the history of the United States. Photo: REUTERS.
The physics of a tsunami. Tsunamis can have wavelengths ranging from 10 to 500 km and wave periods of up to an hour. As a result of their long wavelengths, tsunamis act as shallow-water waves. A wave becomes a shallow-water wave when the wavelength is very large compared to the water depth. where g is the acceleration due to gravity (= 9.8 m/s2) and H is the depth of water.
Tsunami ('soo-nar-me') is a Japanese word; 'tsu' meaning harbour and 'nami' meaning wave. Tsunamis are sometimes incorrectly called tidal waves but have nothing to do with tides. Tsunamis can travel up to 950 kilometres per hour - as fast as a passenger jet! Tsunami waves move outwards, away from their source. One or more waves can be created per event.