Tsunami

1. Tsunami Kim Britsch, Olivia Storey, and Alex Martin

2. What is a tsunami? • A tsunami is a series of water waves that is caused by the displacement of a large volume of a body of water. • A tsunami may travel hundreds of kilometers across the deep ocean, reaching speeds of about 450 to 500 mph. • Upon entering shallow coastal waters, the wave, which may have been only about a foot or two high out at sea, suddenly begins growing rapidly. By the time it reaches the shore, it may become a towering wall of water 15m (50 ft) high or more, capable of destroying entire coastal settlements.

3. Causes • A tsunami can be generated by ANY disturbance that displaces a large water mass from its equilibrium position. • Most often, it is an earthquake that triggers a tsunami, but other possible contributors are: undersea landslides, volcanic eruptions, explosions, and rarely, impacts of cosmic bodies (such as a meteorites in the ocean),

4. Where tsunamis occur • About 80 percent of all tsunamis occur within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common.

5. Warning Sign • A tsunami’s trough, the low point beneath the wave’s crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.

6. References • Tsunamis and earthquakes. (2010, January 05). Retrieved from http://walrus.wr.usgs.gov/tsunami/ • Natural disasters. (1996, November). Retrieved from http://www.fiu.edu/~longoria/natural/ • Tsunamis: killer waves. (2005). Retrieved from http://environment.nationalgeographic.com/environment/natural-disasters/tsunami-profile.html

7. Tsunami Video • http://www.youtube.com/watch?v=j9JDzBTwiig