Tsunami Report

Nadia 

Science 7B

Mrs. Medenica

Tsunami Report

Tsunamis are a series of giant waves that are caused by underwater disturbances such as earthquakes, volcanic eruptions, landslides or meteorites. The word “Tsunami” comes from Japanese “tsu” meaning harbor and “nami” meaning wave.  In the open ocean a tsunami can travel almost 1000 kilometers per hour which means that it can cross the whole ocean in just a few hours! As a tsunami approaches a coast it hits the beach floor which causes it to increase in amplitude but decrease in wavelength. Also, tsunamis usually become visible only as they approach the coast and can be only 1 meter tall in the deep sea making them hard to detect. Underwater earthquakes cause about 85% of all tsunamis. In order for an underwater earthquake to create a tsunami it has to have a magnitude of minimum 6.5. The strongest tsunamis occur in zones of subduction which are places where the oceanic crust sinks into the mantle.  About 7% of tsunamis are caused by landslides. Landslides can cause local waves but can hardly create big waves that travel through entire oceans. Volcanic eruptions cause only about 5% of all tsunamis and don’t usually create powerful tsunamis. Almost 80% of all tsunamis occur in the Pacific Ocean, mostly occurring in countries that border “The Ring of Fire”. This is because “The Ring of Fire” is a region of high seismic and volcanic activity and includes several subduction zones.

The results of a tsunami are usually devastating. When tsunamis hit a coast they can cause a lot of damage such as: destroying and washing away buildings, killing or seriously injuring people, washing away resources, trees and vegetation. Hundreds or even thousands of people die because they had very little time to evacuate. Also, deathly diseases can be spread by tsunamis if corpses of animals and people start to rot they will attract insects that will spread sicknesses to the population.

One type of warnings you might get, if you live near a coast, before a tsunami occurs is a strong earthquake. Since the epicenter of an earthquake is usually in the ocean the earthquake on land is much weaker, so if an earthquake starts in a tsunami danger region it is better to get as far away from the coast as possible in order to be safe. A tsunami starts its way to the coast straight away after the earthquake happens, and it will reach the coast in few hours. Another warning is a warning system which consists of a network of sensors that detect incoming tsunamis and a structure that issues alarms when a tsunami is detected. But, this warning system is not always efficient because the time before the tsunami strikes is too short for people to evacuate or move far inland. This is why some scientists say that it is far better for people to start evacuating as soon as they feel a shaking that lasts more than 30 seconds.

If you get a warning before a tsunami and you live near a coast, you should make an emergency kit and evacuate inland or to the highest point possible. Before a tsunami strikes the water usually recedes far away from the coast, baring the seabed for hundreds meters of even kilometers. The most important thing when this happens is not to stay at the beach to collect the shells or fish because the tsunami will occur in several minutes to half an hour. Another way to find out if a tsunami will occur soon is to watch your pets/animals behavior because animals can often feel disasters in advance. During the tsunami go not get close to the beach because you might get covered by the wave and remember to put living beings before you possessions. Do not return to your home before the local officials tell you it is safe and that the danger of an incoming wave is over. Also, you should stay away from buildings in disaster areas that the tsunami has hit because they might collapse.

Scientists around the world are trying to create a more effective way to warn people about incoming tsunamis. The International System of Tsunami Alerts in the Pacific Ocean was created by governments of tsunami dangered countries and scientists. 4 tsunami stations were put to work at the north part of the Pacific Ocean and 3 more stations around the state of Oregon. Each of these stations is supplied with a registrator of pressure which is an appropriate change, since there is a big change in pressure when the giant waves form. After the registrator of pressure records the movement of waves the station gives a signal to a buoy that it on the surface of the sea.  Then, the bouy sends a signal to a satellite which transfers the signal to the Earth’s stations located on land which send a warning if there is a chance of a tsunami.

In conclusion, tsunamis are one of the most dangerous natural disasters and have many disastrous consequences. The main reason for the emergence of these waves are underwater earthquakes. But, the destructiveness of these waves relies on many factors which is why thankfully, tsunamis don’t happen very often.

Sources:

"Tsunamis." Home. FEMA, n.d. Web. 05 Mar. 2013.

"Tsunami- EnchantedLearning.com." Tsunami- EnchantedLearning.com. N.p., n.d. Web. 05 Mar. 2013.
"Effects of Tsunamis." Universe Today RSS. The Universe Today Team, n.d. Web. 05 Mar. 2013.
"Tsunami Facts and Information." Bureau of Meterology. Australian Government, n.d. Web. 05 Mar. 2013.