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The TSUNAMI. Developed and Presented by Victor Holmes
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The TSUNAMI Developed and Presented by Victor Holmes 7/1/2005
What is a Tsunami? • A Tsunami is a wave or series of waves that is generated by a disturbance that vertically displaces the water column. • Common causes are earthquakes, landslides, volcanic eruptions, explosions, and even the impact of a cosmic body (i.e. meteorite).
So, What exactly is happening? How do they form? • One scenario is that an earthquake is the cause. In particular a subduction zone earthquake. In contrast, an earthquake along a strike-slip fault may not raise or drop the ocean floor.
The below animation shows how a volcano causes the Tsunami Earthquakes and Landslides raise the water column just as effectively EARTHQUAKE LANDSLIDE VOLCANO
Are Tsunamis and Tidal Waves the same? • Not officially. Since the waves really have nothing to do with the tides, the term “Tidal wave” is misleading. • However, many people refer to them as the same thing because they give the appearance of the tide rushing in as opposed to cresting waves people are used to seeing that are caused by winds. Tsunami or “Tidal wave” Wave from wind
The 2004 Indian Ocean Tsunami • This animation shows the path of the Indian Ocean earthquake that caused the Tsunami. • It was a large portion of the boundary between the Burma plate and the Indo-Australian plate that slipped. The earthquake was said to be greater than 9.0 magnitude, and nearly 600 miles of the boundary shifted an average of 35 feet.
Some Statistics • Tsunamis vary indegrees of severity; the 2004 Indian ocean one was one of the largest in documented history, and THE DEADLIEST Tsunami ever. • It claimed 226,000 lives; one of the deadliest natural disasters ever recorded, and second to only the Shansi China earthquake which claimed 830,000 lives.
Countries Hit by the 2004 Tsunami
More Stats… • In the deep waters where it originated, the Indian ocean Tsunami showed a swell of only 2 feet high, but the wall of water that made it to land was as high as 100 feet in some areas!
Big and FAST • The speed of a Tsunami has been measured to over 500 mph • That is as fast as a jet aircraft! • By the time they get to land, however, the speed is reduced significantly to ten’s of miles per hour. The 2004 Tsunami hit land between 40 and 50 mph. About the speed of a car, but still very powerful.
How far can a Tsunami Travel? • Tsunamis, based on the cause and severity, can travel thousands of miles. • Factors such as obstacles can limit where they go, but an unobstructed Tsunami has been Known to travel 10,000 miles.
Even though a Tsunami may travel for thousands of miles, it does not lose much energy. This is what makes it so deadly. • Unlike a cresting wave, the Tsunami is moving from the lowest point of the sea floor to the top of the wall of water; the entire column is traveling. • As mentioned earlier, it does lose speed as the depth shallows, but the force is still immense.
Are we safe? • Tsunamis have already hit Alaska, Hawaii, and California. • Studies show that potential for a Tsunami is great from the Pacific Ocean. It is very tectonically active, therefore the risk is increased. • Potential for an earthquake caused Tsunami on the East coast is less, but the possibility for a Tsunami does exist. Remember, Tsunamis can be caused by several types of disruptions. BUT WAIT……….
DON’T RUN YET! There areusually some warning signs
What can we do? • Althoughthere is nothing that can be done to stop a Tsunami, often there are warning signs and/or warning systems to allow time to escape. • Earthquakes, if felt, should be taken as primary warning system if you live by the coast • There are several established warning system that incorporate technology by using buoys in known fault zones
Established divisions known as the Pacific Tsunami Warning Center (PTWC) and the Alaskan Tsunami Warning Center (ATWC) are constantly monitoring highly sophisticated equipment to provide as much warning as possible. • Often, a short time before a Tsunami hits, the waters recede significantly from the shoreline. If this is noticed, one should head for higher ground. • If the Tsunami is very large, it will have a series of waves. Usually the first one is NOT the most severe. The wavelengths are very large on average, and it could take from 5 minutes to 45 minutes for the second wave to hit land. This is what catches many unfamiliar people off-guard.
The Aftermath • Tsunamis are one of the greatest natural disasters that can occur. Lives are lost when they strike, as well as millions of dollars in property damage. • If in an area that can be affected by a Tsunami, take heed to all of the warning signs. • And if all else fails…………
Some interesting pictures Before and after pictures of land after a Tsunami
Some interesting fish……. umbrella_mouth_gulper_eel viperfish black_dragonfish crab blob_fish fangtooth Claimed to have come from the 2004 Tsunami……..This is false, but they look cool!!
References • Lutgens, F. K. & Tarbuck E.J. (2005). Foundations of Earth Science, 4th ed. New Jersey: Pearson Education Inc. • http://www.solcomhouse.com/tsunamis.htm • http://www.infoplease.com/spot/tsunami.html#tsunami • http://whyfiles.org/068tsunami/ • http://community.webshots.com/album/250908938sKSGYt/0 • http://en.wikipedia.org/wiki/Tsunami • http://seattlepi.nwsource.com/local/211012_tsunamiscience07.html • http://news.nationalgeographic.com/news/2005/01/0103_050103_US_tsunami.html • http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake • http://wwp.mega-tsunami.com/ • http://www.prh.noaa.gov/itic/ • http://www.pbs.org/wnet/savageearth/tsunami/ • http://www.noaa.gov/tsunamis.html