Tsumani’sBy Jessica Scheper

http://redcrossla.org/news/files/2010/02/tsunami-wave1.jpg

Tsunami

• Pronounced Soo-Nahm-ee

• It is a Japanese word that means “Harbor Wave”.

What causes Tsunamis?

Tsunamis are caused by large disturbances on the ocean floor. The most common cause of Tsunami’s are Earthquakes, but they can also be caused by Volcanic eruptions, landslides, or meteorites.

http://www.pinoygigs.com/blog/2010/02/philippines-on-tsunami-alert-level-2/

Underwater Earthquakes, caused by moving plate tectonics, send tons of rock shooting upward with tremendous force. The energy of that force is transferred to water. The energy pushes the water upward over normal sea level. Gravity acts on the water dispersing the energy horizontally and creating huge waves that travel to shore.

http://static.howstuffworks.com/gif/tsunami-formation

Most common cause; Earthquakes

Tsunami The Tsunami’s ability to maintain speed is related to the depth of the water. A tsunami moves faster in deeper water and slower in shallow water.

A tsunami can travel 300 miles an hour, as fast as a jet. Traveling hundred of miles in the deep sea the wave is typically only 3 feet high. But as the wave approaches shallow water it grows to a great height.

Hitting the Shore 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.

The wave’s crest and its enormous volume of water typically hit shore five minutes or so after the surging of the tide.

When a tsunami hits shore it does so usually in a series of waves, called a wave train. This train may last several hours.

Destruction

When Tsunami’s hit the shore line the waves can be 100 feet tall. The energy that the tsunami has carried over the ocean is now compressed and the power of a wave overwhelms whatever is in its path.

These powerful walls of water are capable of inflicting widespread destruction. They have destroyed large buildings and entire towns. They have lifted boats high out of water and thrown them back to shore. They have bent parking meters to the ground.

http://environment.nationalgeographic.com/environment/photos/tsunami-indian-ocean/#girl-rubble-pile_169_600x450.jpg

Where do Tsunami’s Occur?

Tsunamis are most common in the Pacific Ocean. People on open beaches, at low-lying areas of the beach, by bay mouths or bay tidal flats, in low parts of coastal towns and cities, and near mouths of rivers draining into the ocean are in greatest danger from tsunamis.

Famous Tsunamis

December 26, 2004: A massive earthquake off the coast of Sumatra generates tsunami waves that wreck coastlines in 10 countries, killing more than 280,000 people.

August 16, 1976: A tsunami hits the Moro Gulf region of the Philippines, killing 5,000 people.

March 28, 1964: The Good Friday earthquake in Alaska creates a tsunami that envelopes the Alaskan coastline. The same tsunami also hits Oregon and California. A total of 132 people die. http://www.ngdc.noaa.gov/nndc/struts/results?eq_1=25&t=101634&s=0&d=4&d=44

Hawaii 1957

http://www.ngdc.noaa.gov/nndc/struts/results?eq_1=25&t=101634&s=0&d=4&d=44

December 2004 Sri Lanka

December 2004 Sri Lanka

Be Safe!When you see this sign, pay attention to the evacuation route.

If you hear a tsunami warning alarm, listen.

Do not go to shore. Do not assume that only 1 wave will hit.

http://www.oregongeology.com/sub/earthquakes/Coastal/Tsubrochures.htm