8 m/s/s) and the water depth. In the Pacific Ocean, where the typical water depth is about 4000 m, a tsunami travels at about 200 m/s, or over 700 km/hr. Because of the fact that a wave loses its energy at a rate that is inversely proportional to its wavelength, tsunami not only transfer through the water at high speeds, but they can also travel great distances with limited energy losses.

             As a tsunami leaves the deep open ocean waters and travels into the shallower waters near the coastline, it changes form. The tsunami will start to "feel" the bottom of the ocean, which means the bottom of the wave will be slowed by the rising landmass, but the top of the wave travels unhindered. This caused the wave to pile up and gain height. The height of the wave can grow to be several meters or more as it approaches the coast of a landmass.

             Just like other water waves, tsunami begin to lose energy as they rush onshore. Part of the wave energy is reflected offshore, while the shoreward-propagating wave energy is dissipated through bottom friction and turbulence. Despite these losses, tsunami still reach the coast with tremendous amounts of energy. Tsunami have massive erosional potential. Tsunami can strip beaches of sand that may have taken tens of decades to accumulate and they undermine trees and other coastal vegetation. Tsunami are capable of inundating (flooding) hundreds of meters inland past the typical high-water level, the fast-moving water associated with the inundating tsunami can crush homes, fling watercraft and land vehicles and totally destroy other coastal structures which lie in its path. Tsunami may reach a maximum vertical height onshore above sea level, which results in a runup height of up to 30 meters or more.

             Over the span of time, several catastrophic tsunami have made landfall. At least one notable tsunami occurs approximately each year worldwide.