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.
The life cycle of a deployed tsunami buoy is approximately 2 to 4 years. The Bureau's maintenance regime involves the replacement of the surface buoy and the sea-floor pressure sensor every one to two years. The devices retrieved during regular maintenance are refurbished and made ready for the next redeployment.