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Most tsunamis that arrive at our shores will not flood land but can still create strong, dangerous currents and surges in harbours, estuaries, river mouths and along beaches. Occasionally, larger tsunamis can flood coastal areas and threaten lives and property.
If you:
Feel an earthquake that shakes for longer than a minute, OR
Feel an earthquake that is so strong it is hard to stand up, OR
See the sea behaving strangely or hear the sea making loud, roaring noises
Then move inland or to higher ground, out of the blue tsunami evacuation zone, as soon as the shaking stops. Do not wait for an official warning, an emergency mobile alert on your phone, sirens, or for someone to tell you to leave. There may not be time for an official warning.
If you are not in the blue tsunami evacuation zone you do not need to evacuate after a long or strong earthquake. Evacuating if you don’t need to can cause more traffic jams, making it harder for those in the blue zone to get out.
You can find tsunami evacuation zones and what they mean for other parts of New Zealand on the National Tsunami Evacuation Zone Map.
Tsunamis are several long, powerful waves caused by a sudden movement of the sea (or lake) floor, or by something falling into the water. Most tsunamis are caused by large underwater earthquakes, but they can also be caused by volcanic eruptions or landslides under or into the water.
Canterbury’s coastline is exposed to tsunamis created both close to our shores as well as across the Pacific Ocean. Our biggest tsunami threats are large earthquakes on the Hikurangi and Kermadec subduction zones off the coast of the North Island, on the Puysegur subduction zone south of Fiordland, or off the coasts of Central or South America. Where a tsunami comes from determines how much warning time is available.
You can find out more about Canterbury’s tsunami hazard, including tsunami modelling and reports, on the Environment Canterbury website.
The blue tsunami evacuation zone replaced Canterbury’s previous red, orange and yellow tsunami evacuation zones in October 2026. This change was part of a national move to one tsunami evacuation zone to make it simpler and easier for people to know what to do after a long or strong earthquake, or in an official tsunami warning.
The blue tsunami evacuation zone is based on modelled flooding from ‘worst case’ tsunamis from several different locations, both close to our shores and across the Pacific Ocean. You can see the modelled tsunami flooding in our Canterbury Tsunami Model Results webapp. The evacuation zone covers small tsunamis that may not flood much, if any, land as well as rare, large tsunamis that could flood a lot of land.
In drawing the evacuation zone we also consider:
areas that might not be flooded but could be cut off or isolated by debris-laden tsunami water,
how easy the zone is to communicate – we will often move the zone boundary slightly inland to run along a road or other easily identifiable landmark,
the risks of evacuating too many people, such as traffic jams and accidents and delays for people closer to the coast,
the location of parks, schools and aged care facilities.
Tsunamis are not like regular waves. Just check out this video of one of the 2010 Chile tsunami waves coming into the Avon Heathcote Estuary (Ihutai) – it doesn’t look that high, but it packs a punch.
