1. Tsunamis

2. Definition and Cause Tsunami translates to mean “harbor wave”
Caused by…
Underwater earthquakes
Underwater landslides
Collapse of islands
Volcanic eruptions on islands
Asteroids and comets although this has never been witnessed, many experts speculate it is likely and would cause a great deal of damage to our Earth as we know it
NOT the same thing as a tidal wave has nothing to do with tides and can travel for miles

3. How do they Happen?
A disturbance under the ocean causes a sudden movement of the ocean floor.
This movement on the ocean floor is mirrored by the water at sea level.
Usually happen at subduction zones.
Not always smooth; plates will stick together sometimes and then suddenly slip which creates large disturbances along ocean floor
The water is pushed higher than normal, which causes a powerful wave that ripples out from the epicenter of the disturbance (usually an earthquake).

4. All at sea…
Tsunami waves travel very fast averaging at speeds of 500 mph.
Tsunamis are not usually seen until they hit shore because the large waves remain underwater until they hit land and have no place left to go.
Waves are very far apart far out at sea and the ripples are not very high above sea level (only the tip of the large wave below sea level)
Wind-driven waves are only moving in a shallow layer at the top of the ocean, but tsunamis result in water movement thousands of feet deep in the ocean

5. When it hits the coast…
When a tsunami leaves deep water and approaches shore, the waves slow down and grow higher. The waves also get closer together.
The tsunami may hit the coast in different ways depending on the shape of the seafloor near the coast as well as the shape of the coast itself. It will then either:
Flood the shore suddenly
Draw back (as if taking a big breath) and then crash onto the shore

6. Tsunami Impact
Tsunamis can damage entire villages and cities in an instant.
They can kill or injure many people and also leave many people homeless.
Since many countries that experience tsunamis rely on seaports for trade and travel, it is highly devastating when a tsunami destroys the entire shoreline including docks, ships and other equipment used in daily life.

7. How do these disasters happen?
Tsunami Animation