Tsunamis





What is a tsunami?


The word tsunami is originated from Japan, meaning harbor wave("tsu" meaning harbor and "nami" meaning wave.) A tsunami is a series of waves, made in an ocean or other body of water by anTsunamis.jpg earthquake, landslide, volcanic eruption, or meteorite impact. Tsunamis are happen from these because they release loads of energy in quick movements. A tsunami can be created when convergent or a destructive plate shift and vertically displace overlying water. Tsunamis cause huge destruction when they hit land. After a tsunami hits land, danger can be expected hours after the first arrival wave. Tsunami waves are said to not break and curl like other common waves. Coastlines hit by a tsunami will be extremely eroded. Flooding can occur hundreds of meters inland after a tsunami. There isn't a specific tsunami season. Any coastal region can be hit by a tsunami. Tsunamis may go up a river or stream that lead to the ocean. Tsunamis travel faster than a human being can run. Tsunamis do not have a certain time that they can hit. A tsunami can hit shore any time in the day or night.
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Tsunamis



Causes of tsunamis


Many tsunamis are caused my submarine earthquakes. Earthquakes that cause tsunamis are usually of moderate or high magnitude. Earth is a system ofTsunami_Causes.jpegconstantly moving plates that separate about two inches a year. A tsunami can occur when two plates collide. When two plates collide the impact creates an earthquake. The earthquake can then generate a tsunami. If there is an earthquake near water, most likely a tsunami will occur.The size of a tsunami depends on the magnitude of the earthquake. Tsunamis can be caused by an erupting volcano in the ocean. Gas bubbles erupting underneath the ocean can also trigger a tsunami. The Pacific Ocean is most at risk due to the large amount of geologic activity that occurs below the water. During or after an earthquake, an underwater landslide can occur. The falling rocks and sediment impact on the water and create huge tsunami waves. Meteorites can also cause a tsunami. When a meteor strikes the water, the impact of the falling space rock causes the water to ripple and create massive waves. Meteorites are one of the least likely causes due to the fact that most space objects melt before hitting Earth.




Characteristics


A tsunami has a wavelength of about 200 kilometers. A wave like this travels about 500 mph. In the deepest parts of an ocean, the waves can travel up to 600mph. Tsunamis usually have an aptitude of about 1 meter, which makes it difficult for detection. Approaching shore, wave shoaling compresses the wave and the velocity of the tsunami slows way down(below 50 mph). The wavelength shrinks to 12 mi. and the amplitude grows drasNOAA_wave_height.giftically producing the visually wave that people near shores can see. It may take a few minutes for the giant wave to reach full height, because the wavelength is still long. Besides largest tsunamis, the approaching wave doesn't break. When a tsunami wave peak meets shore, the temporary rise in sea level is referred to as run-up. As wave speed slows down, the wave height increases. About 80% of tsunamis occur in the Pacific Ocean. Tsunamis that occur in the Pacific Region are usually caused by earthquakes. They can occur anywhere where there is a large body of water. The first part of a tsunami to reach shore is a trough called a drawback. The highest part of the wave is called the crest, the difference between the crests is the wavelength, the speed of the wave is velocity, run-up is the distance traveled by a tsunami, draw down is when the water quickly recedes, inundation is the area the tsunami struck. A normal ocean wave only causes movement in the uppermost layer of the water column, however a tsunami wave causes movement from the entire water column(surface to ocean floor.)

Danger of a tsunami


Before a tsunami hits land, near shore water will kinda move away, and it will expose the ocean floor. A few ways scientist can help to predict a tsunami is by using a series of sensors that detect the waves approaching shore and an infrastructure that provides alarms, so that people can quickly evacuate areas. Sometimes animals that live near the shore can sense the tsunami approaching shore, ta3m_tsunami_risk_high.jpghey will start running in the opposite direction. When a tsunami is approaching shore, it will have a noise similar to a train. If water pulls away from the shore, that could be a sign of a tsunami. After a tsunami strikes land, the whole area will be flooded. The floods can be very dangerous, because they bury cars, buildings, and typically anything in the area under a huge field of water.


Warning- A tsunami is highly at risk.
Watch- A tsunami may occur, but hasn't yet been verified.

The largest earthquake recorded took place in Chile in the month of May 1960. This earthquake generated an enormous tsunami that rsuhed across the Pacific and killed many people on the island of Hawaii and Japan




Reducing the Risks


In Japan a popular way to try and prevent a tsunami is to build a tsunami wall. These walls are usually 4.5 meters in height. Floodgates and channels are used to redirect the tsunamis wave. It's still hard to figure out how much destruction a tsunami will cause and how big they will be. Developtsunami_hazard_full.gifing better tools for prediction can be hard, however scientists are trying to improve older tools. Still, reducing the risks can be very hard when no one knows how strong a tsunami will be.
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Destruction


One tsunami can destroy a whole coastline. Tsunamis can destroy an entire village near a coast, and remove all the sand on beaches, that can take years to re-build up. Houses near shore can be completely demolished in a matter of seconds with nothing left but a few walls standing. Ships and boats can get carried onto shore and be crashed into building and trees. Tsunamis can take down giant trees and leave them uprooted. Many people along shores can lose their lives. People that live near the shore may not be able to pay for the damage costs, which forces them to have to move elsewhere and leave their homes. Gas lines can be busted due to the impact of the wave on a building. Tsunami waves are more destructive on a shore or in a bay. The states with the highest risks of a tsunami are Hawaii, California, Oregon, and Washington.

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Recent Activity


In the month of January, a devastating earthquake hit the grounds of Haiti. Soon after this happened, a tsunami swept in. The tsunami destroyed manytsunami-wave1.jpghouses and buildings. This set of tsunami waves caused three people to lose their lives. One wave hit about 62 miles from the epicenter of the earthquake. The bays along Port-au-Prince and the coast of Hispaniola were also hit by waves from the tsunami. Scientists are wanting to further investigate the cause of these great waves, because normal tsunamis are caused by earthquakes of at least 7.0. Tsunamis are very rarely ever heard about occurring in the Caribbean.

In 2004 a giant earthquake with a magnitude of 9.15 triggered an enormous tsunami wave train. This wave train swept across the ocean and struck land. The quake and tsunami together killed 230,000 people in Indonesia, Sri Lanka, Thailand, Malaysia, and Somalia.