Tsunami hazards

Tsunami result from the displacement of water caused by earthquakes, underwater landslides, volcanic eruptions or even meteorites.

A series of waves spreads out across the ocean like ripples when a stone is thrown into a pond.

The waves can be tens of metres high when they break onshore. However, smaller tsunami (less than one metre in height) are more common. These come onshore as non-breaking waves, rather like a rapidly rising tide.

In the Wellington region, tsunami may be caused by distant earthquakes near South or North America. Local tsunami can be caused by undersea landslides in the Hikurangi Trough or Cook Strait or by earthquakes on an offshore fault.

A local tsunami, caused by the 1855 Wairarapa earthquake, washed over Lyall and Evans Bays and flooded shops along Lambton Quay.