Tsunami

Tsunami that occurred in 2004 in Thailand. The water of the wave can be seen in the palm trees in the background.

A tsunami is a chain of fast moving waves in the ocean caused by powerful earthquakes or volcanic eruptions. Tsunami has a very long wave. It can be hundreds of kilometers long. Usually, tsunami starts suddenly. The waves travel at a great speed across an ocean with little energy loss. They can remove sand from beaches, destroy trees, toss and drag vehicles, damage houses and even destroy whole towns.Tsunamis can also be caused by meteorite impacts.

The water will draw back from the coast half of the wave period prior to the wave getting to the coast. If the slope of the coast is not deep, the water may pull back for hundreds of metres. People who do not know of the danger will often remain at the shore.

Estimated tsunami travel time forecast map for the 2011 Sendai tsunami, Japan.

Tsunamis can not be prevented. However, there are ways to help stop people from dying from a tsunami. Some regions with lots of tsunamis may use warning systems which may warn the population before the big waves reach the land. Because an earthquake that caused the tsunami can be felt before the wave gets to the shore, people can be warned to go somewhere safe.

The deadliest tsunami recorded was on December 26, 2004. It was caused by an earthquake. The earthquake was said to have a magnitude of 9.3 on the Moment magnitude scale. It was centered in the ocean near the coast of Sumatra, Indonesia. Over 215,000 people died from this disaster. The giant wave moved very quickly. Hundreds of thousands of people in Indonesia, Sri Lanka, Thailand, India, Somalia, and other nations, were killed or injured by it.

Tsunamis are often called tidal waves. This is misleading, because tsunamis are not related to tides.

Other pages

• Great Chilean Earthquake
• 2004 Indian Ocean earthquake
• 2011 Sendai earthquake and tsunami
• Earthquake engineering