A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, usually an ocean.
Earthquake, volcanic interruption, and other underwater explosions cause tsunamis.
The term of tsunami comes from two Japanese words tsu meaning harbor and nami meaning wave.
Tsunamis are referred as tidal waves but in the recent years the term as fallen out of favor because tsunamis have nothing to do with tides.
Tsunamis have a small wave height offshore, and a very long wavelength often hundreds of kilometers long, which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimeters above the normal sea surface.
When the wave enters shallow water, it slows down and its height increases.
Regions with a high tsunami risk use tsunami warning systems to warn the population before the wave reaches land.
Computer models can predict tsunami arrival, usually within minutes of the arrival time.
A 2004 earthquake in the Indian Ocean measuring 9.0 on the scale set off a tsunami that struck at 10 Asian and three African countries, leaving at least 130,000 people dead.
The 2011 earthquake in japan caused a 9.0 tsunami, 9,523 deaths, 2,775 injured, 16,094 people missing, and 125,000 buildings damaged.
Not counting the 2011 tsunami in Japan, there were 26 tsunamis that killed at least 200 people or more in the last century.
Most tsunami occur in the Pacific and Indian Oceans. The boundary of the Pacific Ocean experiences frequent earthquakes.
In the open ocean, a tsunami can travel as fast as 950 kilometers per hour, which can be represented by the speed of a passenger jet.
It loses speed as it approaches land, but it does not lose much of its energy. As it slows down, the height of the waves build.