A tsunami is a series of fast travelling ocean waves generated by disturbances like earthquakes, volcanic eruptions, landslides and even meteor impacts. On reaching shallower water a tsunami can create large onshore waves and unpredictable water flows, putting boats, coastal structures and people at risk.

Warning Signs

Warning signs of an approaching tsunami can include extreme changes in water depths - especially a sudden receding tide - or an earthquake that is felt in a coastal area.

Listen to broadcasts by maritime radio, Coastguard, AM/FM radio stations and local civil defence for further safety information.

Official warnings are only possible for distant and regional source tsunami. Official warnings are issued by the National Emergency Management Agency, and your local council or Civil Defence Emergency Management Group may also put out warnings through radio, tsunami sirens and other local procedures (e.g. emergency services vehicles with PA systems, or telephone trees).

Find out more about the smartphone Hazard app which is another way of receiving official alerts on our smartphone alerts page. Listen to broadcasts by maritime radio, Coastguard, AM/FM radio stations and local Civil Defence for further safety information.

Moving your boat to deeper water - yes or no?

A boat in deep water that’s well clear of the coast may be able to ride out a tsunami event safely. When a distant event has triggered a tsunami, there may be time to move a boat to  deeper water before the tsunami arrives.

If a tsunami is generated near New Zealand, there may be no time to move a boat because the tsunami waves could arrive within minutes. In this case the safest strategy is to leave the boat and follow local tsunami evacuation procedures to get to safe ground.

Tutukaka Marina warning system

Tutukaka Marina is particularly prone to the effects of tsunami events. A tsunami warning system for small craft – consisting of a siren and a yellow quick-flashing all- round light – is on the marina’s breakwater. When activated, it means that the marina entrance is unsafe to pass (both in and out) – skippers should contact the marina on VHF Channel 7 for further advice.

Tsunami siren at Tutukaka Marina.