Aotearoa NZ · Geophysical
Hikurangi Tsunami
ElevatedA local-source tsunami from the Hikurangi subduction zone off the East Coast, arriving in minutes.
- Likelihood
- ~26% chance of an M8+ Hikurangi event in 50 years
- Impact
- Catastrophic for coastal East Coast communities
- Horizon
- Any time
Background
What this actually is
The Hikurangi subduction zone runs offshore from Marlborough to East Cape, where the Pacific plate dives beneath the Australian plate. It is capable of an M8-9 earthquake and is the largest tsunami source affecting New Zealand.
For a local-source event, the first waves reach the nearest coast in as little as 7-15 minutes. That is far too fast for any official warning system. The earthquake itself is the warning.
Distant-source tsunami from South America or the Kermadec Trench give hours of warning and are handled by official alerts, but they are a much smaller threat to life than the local case.
Aotearoa
What it means for New Zealand
Gisborne, Hawke's Bay, Wairarapa and eastern Marlborough face the shortest warning times. Wellington and Christchurch also have modelled inundation zones. Every coastal council publishes evacuation zone maps — blue, orange and yellow — that most residents have never looked at.
Watch for
Early warning signs
- LONG or STRONG, GET GONE: shaking that lasts more than a minute, or is strong enough that it is hard to stand, means evacuate immediately without waiting for an official warning
- Sudden sea level change, unusual roaring noise, or the sea receding
- National Emergency Management Agency tsunami advisories for distant sources
Action
How to prepare
- 01
Look up your council's tsunami evacuation zone map today and know whether your home, work and school are in one
- 02
Walk your evacuation route on foot — roads will be blocked and driving kills people in tsunami evacuations
- 03
Go inland or uphill and stay there for several hours; later waves are often larger
- 04
Keep shoes and a grab bag accessible for a night-time evacuation
Go deeper
Where to find more information
In an emergency
New Zealand's official channels
- Get Ready — household preparedness
- Civil Defence / NEMA
- GeoNet — quakes, volcanoes, tsunami
- MetService severe weather warnings
In a life-threatening emergency call 111. RNZ National is New Zealand's designated lifeline broadcaster — keep a battery radio.
Connected
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