How is a tsunami formed?

Answer 1

A tsunami is a Japanese word for "big wave". A tsunami is kind-of like a hurricane but not that severe and it only last for some minutes, unlike a hurricane which could last for hours or so.

A tsunami will take place ONLY in warm waters. Tsunamis can hit along the coast of the ring of fire. California, Washington. Oregon, Hawaii, and the Japan coastline are all potential areas.

The Tsunami is only about 1 metre high when it is deep waters, but when it get more shallow the waves get slower and bigger.

A tsunami wave it would depend on the size of the earthquake to tell how big the tsunami's size.

Tsunamis are known to kill lives, destroy homes, and ravage countries. If you are ever in a tsunami, it is like a HUGE wall of water slamming into you over and over again. Tsunamis kill a lot of people whether they not know how to swim, or not, because of the fierce strength of the initial wave, subsequent waves, and the undertow created by gallons of rushing water.

Tsunamis occur when there is a sudden large displacement of water. There are three main causes of tsunamis:

1.Seismic activity

2.Submarine landslides

3.Cosmic Impacts

The first way is caused by a mega thrust earthquake. An example of this is the tsunami of Boxing Day 2004. Mega trust earthquakes occur when techtonic plate boundries suffer a large veritcal displacement. The upward movement of the land causes a large displacement of the water causing the wave. Seismic waves carry the water's waves out of the water to the surface. The displacement pulls water back from the shore, causing a large major wave to build in size and intensity. (Displacement would be similar to dropping a marble into a glass of water while tilting the glass to one side.)

The second way is called a Mega Tsunami (which can be much larger than a normal tsunami) is caused by a landslide or meteor impact into the sea. An example of this happened on the 9th July 1958 in Lituna Bay in Alaska. A earthquake measuring 7.7 on the Richter scale caused 90 million tonnes of rock to fall directly into the sea. It caused a wave 524 meters high.

Tsunamis are formed if there is a very big earthquake or earth tremers that shake the earth to at least 6.0 on the Richter scale.

The third way is more rare: a cosmic impact from a meteor. The result is mostly the same.

Interestingly, a tsunami will cause the water along the shore to pull away, adding more and more water to the "big wave". Many people get so mesmerized by the unusual sights at the shoreline that they don't recognize the impending danger.

Also of interest, animals often recognize the danger and run inland. The theory for this is that animals can sense the movement of the ear and hear changes in the waves much faster than humans recognize these.

Answer 2

A tsunami is one or more water waves caused by a large displacement of water. This is typically in an ocean but the large lakes of the world are big enough to allow a tsunami to form. Tsunamis are usually caused by undersea earthquakes. It is rare, but a tsunami can be cause by an avalanche or landslide that displaces a large volume of water or even an asteroid or comet hitting the ocean.

A tsunami commonly forms when there is a dramatic uplift or fall of the ocean bottom associated with a submarine earthquake. In that case a large volume of water suddenly drops and surrounding water rushes in or a large volume of water is uplifted and water flows away from the area. Tsunami waves are not like normal ocean waves which do not result in a net transport of water. When a tsunami wave forms it is because a large volume of water is entering or leaving an area of the ocean. For this reason the propagation of a tsunami is different and very fast, hundreds of kilometers per hour.

Tsunamis form wherever an undersea earthquake can form, so they are particularly common at the boundary of the Earth's tectonic plates. These plates have areas where they are particularly active, the Pacific "ring of fire" being the most well known.

Typically a tsunami exhibits several waves in succession separated by minutes or hours. This will depend on the character of the original disturbance being fast or slow or limited to a small area or large. When tsunamis propagate across the ocean, they have a small amplitude a few inches (centimeters) high but they extend for hundreds of kilometers. Since there is actual flow of of a large volume of water associated with a tsunami, this height increases as the volume of water approaches the shallower coastal region. At the coast, the height is a fraction of a meter (a few feet) to hundreds of meters.

Answer 3

Most Tsunamis originate at subduction zone, where one tectonic plate slides beneath another.