Powerful Tsunami Essays

Submitted By LLARUE77
Words: 722
Pages: 3

By: Jacob Dodds

What is a tsunami?
 Pronounced soo-nahm-ee
 From the Japanese word for harbor wave
 A series of huge waves that happen after an undersea disturbance, like an earthquake or volcano eruption.
 The waves travel in all directions from the area of disturbance, sort of like the ripples that happen after throwing a rock in a pond or lake.

 Tsunami can also be caused by underwater landslides and can even be started by the impact of a large meteorite plunging into the ocean. This was common in Earth’s ancient past.

 The waves can travel in the open sea as fast as 600

miles per hour.
 As the big waves approach the shallow waters along the coast they grow very tall and smash into the shore. They can be as high as 100 feet.
 They are sometimes mistakenly called "tidal waves," but tsunami have nothing to do with the tides. Where do tsunamis happen?
 About 80 percent of tsunamis happen within the
Pacific Ocean’s “Ring of Fire,” an active area where plate shifts make volcanoes and earthquakes common.
 In the United States, Hawaii is the state at greatest risk for a tsunami. They get about one a year, with a damaging tsunami happening about every seven years.
Alaska is also at high risk. California, Oregon and
Washington experience a damaging tsunami about every 18 years.

How do we know when a tsunami might happen?
 Tsunami Warning Centers in Honolulu Hawaii and Palmer

Alaska monitor disturbances that might trigger tsunami.
When a tsunami is recorded, the center tracks it and issues a warning when needed.
 The National Oceanic and Atmospheric Administration
(NOAA) has a system of buoys that are called the DeepOcean Assessment and Reporting of Tsunami, or DART.
 The sensing devices on these buoys contain pressure sensors for determining a wave's size by gauging the weight of the water column passing over it. This information is relayed to the surface buoy and then to a satellite. The satellite then beams the information to the two Tsunami
Warning Centers in Alaska and Hawaii.

 The low point between the wave’s crest is called the trough. The trough of a tsunami often reaches the shore first. When this happens, it causes a vacuum effect that sucks the coastal water out toward the sea and exposes harbor and sea floors. This is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water usually hit the shore about five minutes later. Recognizing this can save lives.

 A tsunami is usually made up of a series of waves, called a wave train, so its damaging force may become more destructive as each wave reaches shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to at risk locations.
 Some tsunamis do not appear on shore as massive breaking waves but instead look like a quickly surging…