Disaster+plan+-+Tsunamis

Tsunamis A very large ocean wave caused by an underwater earthquake or volcanic eruption. Not only earthquakes cause tsunamis but volcanic eruptions, any kind of explosion, and landslides. Tsunamis are unlike the waves we see at beach or lake, tsunamis are much bigger and deadly. A tsunami, can have a wavelength in excess of 100 km! As a tsunami approaches shore, that the wave begins to slowly grow in height. Just like other water waves, tsunamis begin to lose energy as they touch a part of land while the wave energy is going through the bottom friction and turbulence.

//Tsuamies are large ocean waves that can move as fast as 500 mph. A sign for a tsunami is the water retreating off the shore. WHAT TO DO IF A TSUNAMI HITS;//
 * //**IMMEDIATLY** turn off water, gas, and electricity. Move to higher ground.//
 * //If a warning is issued **NEVER** go down to the beach and watch it come, you will never live to tell about it.//
 * //A tsunami is a series of waves. The first one is usually the least dangerous so stay away the waves will get bigger as they go on. Listen to a portable radio to know when it is safe to return.//
 * //After returning to the area hit by the tsunami, all food and water must be checked for contamination before it is eaten. All buildings must not be entered until they are checked for gas leaks. only give first aid if you know what you are doing.//
 * //Tsunami warnings are most likely to be issued after earthquakes with 6.5 magnitude or higher.//
 * //Tsunamis can not be predicted, so if you live in a dangeroeus area, stay aware.//

A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet, onto land. These walls of water can cause widespread destruction when they crash ashore. These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami. Most tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common. Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean. Tsunamis race across the sea at up to 500 miles an hour—about as fast as a jet airplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way. In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously. A tsunami’s trough, the low point beneath the wave’s crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives. A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach 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 vulnerable locations. Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas. The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.

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.

The 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. Click on the camera to see photos and learn more about the buoy system.

A small tsunami at one beach can be a giant wave a few miles away. Do not let the small size of one wave make you forget how dangerous tsunami are. The next wave could be bigger. Get away from the shoreline right away. When you see a tsunami it is too late to escape. And stay away until you hear the "all clear" from officials. A tsunami is a series of waves, not a single wave, and the danger may not be over when you think it is.

The waves travel in all directions from the area of disturbance, much like the ripples that happen after throwing a rock. 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 tsunami have nothing to do with the tides.

The magnitude of the earthquake was originally recorded as 9.0 (Richter scale), but has been upgraded to between 9.1 and 9.3. At this magnitude, it is the second largest earthquake ever recorded on a seismograph. This earthquake was also reported to be the longest duration of faulting ever observed, lasting between 500 and 600 seconds. It was large enough that it caused the entire planet to vibrate at least half an inch, or over a centimeter. It also triggered earthquakes in other locations as far away as Alaska. 1964, an Alaskan earthquake generated a tsunami with waves between 10 and 20 feet high along parts of the California, Oregon and Washington coasts. =In 1946, a tsunami with waves of 20 to 32 feet crashed into Hilo, Hawaii, flooding the downtown area. 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.= Most tsunamis occur in the Pacific region but they are known to happen in every ocean and sea. Although infrequent, tsunamis are a significant natural hazard with great destructive potential. They can only be dealt with effectively through programs of warning, mitigation, and education. =**__Pictures of tsunamis__**=