All of New Zealand’s coastline is at risk of tsunami. Knowing the warning signs and the right action to take can help save lives. Find out what to do before, during and after a tsunami.

Get ready before a tsunami

  • Work out what supplies you may need and make a plan together.
  • Know your tsunami evacuation zones. Make sure you know where to go, whether you are at home, at work or on holiday.
  • Understand the different types of warnings: Natural, Official and Unofficial.
  • Regularly practise your tsunami evacuation by signing up for New Zealand ShakeOut, our national earthquake drill and tsunami hīkoi.
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In an emergency, you may be stuck at home for three days or more. Figure out what supplies you need and make a plan to work out what you need to get your family through.

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Make a plan online with your family/flatmates/friends to get through an emergency. Think about the things you need every day and work out what you would do if you didn’t have them.

What to do during a tsunami or when a tsunami warning is issued

Know the natural warning signs and take action

For a local source tsunami, which could arrive in minutes, there won’t be time for an official warning. It is important to recognise the natural warning signs and act quickly.

If you are near a shore and experience any of the following, take action. Do not wait for official warnings.

  • Feel a strong earthquake that makes it hard to stand or a long earthquake that lasts more than a minute
  • See a sudden rise or fall in sea level
  • Hear loud or unusual noises from the sea

Drop, Cover and Hold during the shaking. As soon as the shaking stops, move immediately to the nearest high ground, out of all tsunami evacuation zones, or as far inland as you can.

Remember, Long or Strong, Get Gone. 

Walk, run or cycle if at all possible to reduce the chances of getting stuck in traffic congestion.

Take your animals with you only if it will not delay you. Do not spend time looking for them and if you are not at home, do not return to get them.

While evacuating, avoid hazards caused by earthquake damage, especially fallen power lines.

Do not return until an official all-clear message is given by Civil Defence.

Long or Strong, Get Gone

Remember, Long or Strong, Get Gone.

Drop, Cover and Hold during the shaking. Protect yourself from the earthquake first.
As soon as the shaking stops, move immediately to the nearest high ground, out of all tsunami evacuation zones, or as far inland as you can.

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Official warnings

When tsunami travel across the ocean from far away, we have more time to warn people what to do.

The National Emergency Management Agency is responsible for issuing tsunami warnings in New Zealand.

Tsunami warnings are published on www.civildefence.govt.nz and Twitter @NZCivilDefence. Tsunami warnings will also be broadcast on radio and television. An Emergency Mobile Alert may also be issued if there is a threat of flooding of land areas.

Warnings may also be broadcast through siren, phone, mobile text, loud hailer or other local arrangements. Contact your local Civil Defence Emergency Management Group to find out about the warnings you can expect to receive in your community.

Immediately follow the advice of any emergency warning. You may receive warnings from one or several sources. Respond to the first source.  Do not wait for more messages before you act.

Unofficial or informal warnings

You may receive warnings from friends, other members of the public, international media and from the internet. Verify the warning only if you can do so quickly. If official warnings are available, trust their message over informal warnings.

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The National Emergency Management Agency has information on finding your local Civil Defence Emergency Management Group.

What to do after a Tsunami

Only return home once you are told it is safe to do so.

Keep listening to the radio or following your local Civil Defence Emergency Management Group online for information and instructions.

If there was an earthquake, expect aftershocks. Aftershocks may generate another tsunami. Be prepared to evacuate.

Stay away from coastal water, tidal estuaries, rivers and streams for at least 24 hours after any tsunami or tsunami warning, as even small waves create dangerous currents.

Avoid areas impacted by the tsunami. Your presence might hamper rescue and other emergency operations and put you at further risk from the residual effects of tsunami flooding, such as contaminated water, crumbled roads or other hazards.

  • A tsunami is a wave or series of waves caused by the sudden displacement of water by an earthquake, volcanic eruption, landslide or even a meteorite impact. They can travel many thousands of kilometres across the oceans at speeds of up to 800 kilometres per hour.

    Tsunami waves contain considerable energy, so travel much further compared to ordinary coastal waves and even small tsunami can be dangerous to those in or near the water.

    New Zealand’s entire coastline and some of our larger lakes are at risk of tsunami.

    Tsunami can violently flood our shores, causing devastating property damage, injuries and loss of life.

    The biggest tsunami in New Zealand are likely to be caused by events close to our shore and can arrive within minutes.

    There are three different types of tsunami, depending on where they start. 

    Distant

    Distant tsunami are generated from a long way away, such as from across the Pacific in Chile. In this case, we will have more than three hours warning time for New Zealand and we will have time to issue official warning messages.

    Regional

    Regional tsunami are generated between one and three hours travel time away from their destination. An eruption from an underwater volcano in the Kermadec Trench to the north of New Zealand could generate a regional tsunami. We will have time to issue official warning messages.

    Local

    Local tsunami are generated very close to New Zealand. In this case, we probably won’t have time to issue an official warning, so people in coastal areas need to take immediate action. Remember — Long or Strong, Get Gone — if you feel an earthquake that makes it hard to stand, or lasts more than a minute, move immediately to higher ground, out of all tsunami evacuation zones or as far inland as possible.

Find out more about what you need to do before, during and after these hazards.