Tsunami

A tsunami is a natural phenomenon consisting of a series of waves generated when a large volume of water in the sea, or in a lake, is rapidly displaced. Tsunami are known for their capacity to violently flood coastlines, causing devastating property damage, injuries, and loss of life.

The principal sources of tsunami are:

Large submarine or coastal earthquakes, in which there is significant displacement of the seafloor or coast
Underwater landslides (which may be triggered by an earthquake or volcanic activity)
Large coastal cliff or lakeside landslides
Underwater volcanic eruptions

A tsunami can occur at any season of the year and at any time, day or night. On the open ocean tsunami waves are small and barely noticeable but when the waves enter shallow water they will rise in height. Some tsunami can be very large and can rapidly and violently inundate coastlines, causing loss of life and property damage.

Other waves can be small but still dangerous to those near or in the coastal water. It is important to remember that not all earthquakes will generate a tsunami, and that earthquakes are not the only sign of an impending tsunami so it is critical to know what to do as a precaution if you are in a vulnerable area.

Click on the animation below to see how a tsunami works:

(supplied by TVNZ)

Tsunami

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