What if there’s a tsunami in New Zealand?
If the tsunami is local, the best thing to do is to move inland as quickly as possible – if possible, either over 10m above sea level or over 1km inland.
If you are close to the sea and experience a significant earthquake (say shaking lasting longer than 1-2 minutes) then move inland – preferably to the highest ground you can reach or, if the ground is flat, as far inland as possible. Stay away from rivers too, which may transfer the effects of the tsunami further inland. Do not wait to be told to evacuate – the earthquake is your warning and there may not be enough time for an official response.
If you see the sea rapidly receding at an unusual time this is also an indicator of a tsunami and you should also move inland.
There are likely to be a train of waves and the first wave may not be the biggest so do not go back to the shore after the first wave has passed. Rapid changes in sea level and strong currents may persist for several days after the tsunami first arrives.
Because these are further away you will not feel the earthquake that caused the tsunami. In this case you will have to rely on official warnings. Remote South American tsunami take over 12 hours to propagate to New Zealand. DART buoys (Deep-ocean Assessment and Reporting of Tsunami) measure pressure differences under the ocean to detect tsunami waves and can indicate whether or not a tsunami has been generated.