All oceanic regions of the world can experience tsunamis, but in the Pacific Ocean and its marginal seas, there is a much more frequent occurrence of large, destructive tsunamis because of the many large earthquakes along the margins of the Pacific Ocean.

All low lying coastal areas can be struck by tsunamis, some of them can be very large; their height can be as great as 10 meters or more (30 meters in extreme cases), and they can move inland several hundreds meters, depending on the slope of the ground.

A tsunami consists of a series of waves with crests arriving every 10 to 60 minutes. Often the first wave may not be the largest. The danger from a tsunami can last for several hours after the arrival of the first wave. Sometimes a tsunami initially causes the water near shore to recede, exposing the ocean floor.

The force of some tsunamis is enormous. Large rocks weighing several tons, along with boats and other debris, can be moved inland hundreds of meters by tsunami wave activity, and homes and buildings destroyed. All this material and water move with great force, and can kill or injure people.

Tsunamis can occur at any time, day or night, and they can travel up rivers and streams from the ocean. They also can easily wrap around islands and be just as dangerous on coasts not facing the source of the tsunami.

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¹ Tammy Haitoku (http://www.tsunamiwave.info)