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.
Most tsunamis are not devastating. Scientists can and do measure tsunamis which are as small as a few centimeters. These events rarely make the news. The tsunamis which are 'devastating' are the very largest (and rarest) ones. What I think you really want to know is how far inland tsunami waves can go for the largest events with 10-1000 year recurrence intervals. (Civilization-ending events such as the Santorini eruption that destroyed the Minoan civilization are less frequent, while the biggest subduction zone earthquakes are generally one in 100-1000 years.