Tsunamis

A tsunami is a series of waves travelling across the ocean with extremely long wavelengths (distance between the waves). Oceanographers often refer to them as seismic sea waves, as they are usually the result of a sudden rise or fall of a section of the earth's crust under or near the ocean. This rise or fall in sea level is the initial formation of a tsunami wave.

Tsunami waves can also be created by volcanic activity and landslides occurring above or below the sea surface. These types of activity produce tsunamis with much less energy than those produced by submarine faulting. When these waves approach the shore, the speed of the wave decreases as they begin to "feel" the bottom. It is at this time that the height of the wave increases drastically. As the waves strike shore they may inundate low-lying coastal areas resulting in mass destruction and in many instances loss of life.

Often a tsunami is incorrectly referred to as a tidal wave. Tidal waves are simply the periodic movement of water associated with the rise and fall of the tides produced by the gravitational attraction of the sun and moon. Tsunamis have no connection with the weather nor with tides.