By: Courtney Stryke ♥ 12/20/06 Blue Tsunamis By: Courtney Stryke ♥ 12/20/06 Blue

What is a tsunami: A Tsunami is a series of huge waves that happen after an undersea disturbance, such as an earthquake or volcano eruption. The waves travel in all directions from the area of disturbance, much like the ripples that happen after throwing a rock. The waves may travel in the open sea as fast as 450 miles per hour. As the big waves approach shallow waters along the coast they grow to a great height and smash into the shore. They can be as high as 100 feet. They can cause a lot of destruction on the shore. They are sometimes mistakenly called "tidal waves," but tsunamis have nothing to do with the tides.

What Causes Tsunamis: Most tsunamis are caused by earthquakes generated in a subduction zone, an area where an oceanic plate is being forced down into the mantle by plate tectonic forces. The friction between the subducting plate and the overriding plate is enormous. This friction prevents a slow and steady rate of subduction and instead the two plates become stuck.

Where do Tsunamis occur: Generally the danger of a tsunami occurring exists where earth- and lake-quakes are possible, in areas where tectonic plates collide with each other, drift past each other or collide, as well as in other areas with geological faults. They also occur in the Pacific ocean as it is located on a plate mostly made of water. The Pacific ocean is also surrounded by the Ring of Fire, a highly active volcano and earthquake zone.

A Diagram of a Tsunami: This is how a tsunami starts. When movement along a fault moves the seafloor upward, water is also pushed upward and becomes tsunami waves.

Historical Event About Tsunamis: On the morning of December 26, 2004 a magnitude 9.3 earthquake struck off the Northwest coast of the Indonesian island of Sumatra. The earthquake resulted from complex slip on the fault where the oceanic portion of the Indian Plate slides under Sumatra, part of the Eurasian Plate. The earthquake deformed the ocean floor, pushing the overlying water up into a tsunami wave. The tsunami wave devastated nearby areas where the wave may have been as high as 25 meters (80 feet) tall and killed nearly 300,000 people from nations in the region and tourists from around the world. The tsunami wave itself also traveled the globe, and was measured in the Pacific and many other places by tide gauges. Measurements in California exceeded 40 cm in height, while New Jersey saw water level fluctuations as great as 34 cm.

Ten Facts about Sumatra: The tsunami was in the Indonesian island of Sumatra. It was a undersea earthquake that started this tsunami. The earthquake that caused the tsunami was a magnitude 9.3 earthquake. The earthquake resulted from a complex slip. The earthquake triggered a series of devastating tsunamis. The earthquake deformed the ocean floor, pushing the overlying water up into a tsunami wave. The waves reached to 25 inches high (80 feet) This tsunami killed nearly 300,000 people from nations in the region and tourists form around the world. The tsunami itself traveled the globe. Eighteen countries around the Indian Ocean sustained damage from the tsunami.

Sumatra Video:

Safety Measures: Before During After If there is noticeable recession in water away from the shoreline this is nature's tsunami warning and it should be watched. You should move away immediately. During After Stay away from flooded and damaged areas until officials say it is safe to return. Stay away from debris in the water; it may pose a safety hazard to boats and people. Turn on your radio to learn if there is a tsunami warning if an earthquake occurs and you are in a coastal area. Move inland to higher ground immediately and stay there.

Pictures of Tsunamis:

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