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.
So, unlike normal waves that are caused by wind forces, the driving energy of a tsunami moves through the water, not on top of it. Therefore, as the tsunami travels through deep water -- at up to 500 or 600 miles per hour -- it's barely evident above water. A tsunami is typically no more than 3 feet (1 meter) high.