10 Facts About Tsunami

10 Facts About Tsunami - Tsunami recently hit the Pacific and killed more than 100 people in Samoa. What causes tsunamis and what to look out for?

The word 'tsunami' comes from Japanese, and translated as "harbor wave '. Tsunami used to be called 'tidal wave', but the term is its use by scientists has shifted.

Consists of a series of tsunami waves, known as the wave train, not a single wave. For a large tsunami, the waves suddenly and the first is not always the greatest.


Most tsunamis are caused by undersea earthquakes. 8.0 magnitude earthquake as the cause of the disaster Samoa, according to the U.S. Geological Survey. An earthquake can cause tsunamis if they have enough strength in depth and adequate water.

Approximately 80 percent of all tsunamis occur in the Pacific Ocean.

Theory of underwater earthquakes are located behind the first tsunami raised by the ancient Greek historian Thucydides, in the year 426 BC, in his book "History of the Peloponnesian War."

Volcanic eruptions, major landslides, meteorite impacts and underwater nuclear explosions can also cause tsunamis, as well as tropical cyclones or other weather conditions. A tsunami caused by the storm known as the 'destruction of Burma meteotsunami'seperti event in 2008.

Regardless of the size of a big wave when they hit the ground, the amplitude (wave height) from the tsunami at least three meters in the open ocean, whereas the wavelength (the distance between two peaks) along the 120 miles. At this point the tsunami will reach speeds over 500 mph.

When the tsunami reaches shallow water, waves to shrink and make the short wavelengths, but the amplitude is higher. The wave then slowed down, however he still has a speed around 50 mph.

Predicting the tsunami was very close to impossible. In some cases, warnings of nature can be seen at the time of the water along the coast suddenly receded, in a phenomenon called drawback. This happens when a trough tsunami waves reach the ground before mounting.

A British girl aged 10 years, Tilly Smith had saved nearly a hundred people with knowledge of the Indian Ocean tsunami late in 2004.

He had learned about the drawback of a geography lesson and warned his family and then chain to others. He had the chance a speech to the UN and has an asteroid named after 20,002 Tillysmith.