What causes a tsunami?

A tsunami is usually caused by a powerful earthquake under the ocean floor. This earthquake pushes a large volume of water to the surface, creating waves. These waves are the tsunami.

In the deep ocean these waves are small. As they approach the coast these waves get bigger and more dangerous. Tsunami waves can cause tremendous damage when they reach land.

A tsunami can also be triggered by a volcanic eruption, landslide, or other movements of the Earth’s surface.

Map of Earth's tectonic plate boundaries.

Check out this animation showing how a tsunami usually occurs.

Harbour wave

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