Tsunami

Introduction

Tsunami are large sea waves caused by earthquakes, undersea landslides, volcanic eruptions or even large objects, such as meteorites, falling into the sea.

They can travel at about 600 km an hour across deep oceans (as fast as some jet planes), and can be 10-30 metres high when they reach land.

In Hawaii the Pacific Tsunami Warning Center detects and warns countries about tsunami that may affect them.  However, a tsunami generated close to New Zealand’s coast could arrive so quickly that there is little or no time to warn people.

The risk to New Zealanders is higher than it used to be because more people live near the sea. Previously bare coastline now has houses built close to the water’s edge.

Tsunami Sign
Photo courtesy of Ilan Kelman

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