Tsunami in Hawke's Bay

A tsunami is a series of fast traveling waves caused by large disturbances on the ocean floor, such as earthquakes, landslides or volcanic eruptions. In the deep ocean, tsunami pass almost unnoticed, but as they reach shallow coastal waters nearer to land, they change dramatically - a wave of one-to-two metres at sea can grow into waves measuring more than 30 metres in height. A tsunami is made up of very turbulent water – even a small tsunami wave can knock you off your feet.

Near source tsunami: An earthquake will be the only natural warning of a local tsunami – don't wait for official warnings or instructions – there will not be time. It is vital to use your own initiative, as every minute counts. Everyone in all tsunami evacuation zones must move quickly to areas where they are safe – uphill or inland. (To see how self-evacuation saves lives, read about Kamaishi School, in Japan).

Regional or far source tsunami: If a tsunami is coming from much further out to sea, you will not feel an earthquake and there will be an official Civil Defence warning. Evacuate from the zones (red, orange or yellow) as advised in the warning.

Hawke's Bay is at risk from:

Near-source tsunami: Our biggest is risk is from the Hikurangi subduction zone (sometimes called the Hikurangi Trench), just off our coast – this is New Zealand’s largest active fault. If the subduction zone ruptures in a large earthquake, it may  rapidly send a tsunami towards our coast.

Regional and far-source tsunami: Because of New Zealand’s position in the Pacific Ocean, the east coast is also at risk from tsunami travelling from much further away. In this case, you will not feel an earthquake and there will be enough time to get expert advice, issue warnings and organise an orderly evacuation.

For a near-source event natural warnings, like any of those below, will be the only warning of a tsunami, so don’t wait for official warnings, go immediately to high ground or, if the surrounding area is flat, go as far inland as possible. Evacuate all tsunami evacuation zones (red, orange and yellow), if any of the following occur:

• A STRONG earthquake which is hard to stand up in
• A weak, rolling earthquake which is unusually Long; a minute or more
• You see unusual sea behaviour, such a sudden sea level fall or rise, or the sea is making loud and unusual noises, especially roaring like a jet engine.

If you are in a coastal tsunami evacuation zone and there is a Long OR Strong earthquake don’t wait for an official warning. There will not be time. Go immediately to high ground or, if the surrounding area is flat, go as far inland as possible. 

If you are in the water, get out immediately and move to higher ground or inland – staying in the water is very dangerous.

A Long earthquake is one that lasts longer than a minute; a Strong earthquake is one that is hard to stand up in. It is better to err on the side of caution and evacuate if you are unsure.

Everyone in ALL of the tsunami evacuation zones – red, orange and yellow should evacuate, preferably on foot or by bicycle. Check if you are in an evacuation zone here.

First, check if your home, school or workplace is in a tsunami evacuation zone here.

Understand what that zone means

All zones (red, orange and yellow) must evacuate if there is a Long or Strong earthquake.

In the case of tsunami coming from far away, providing lots of warning time, specific zones may be asked to evacuate by Civil Defence Emergency Management.

Plan your evacuation route

Walking, running or biking are better than driving, because roads may be damaged in the earthquake or there may be too many cars on the road, causing traffic jams. The aim is for you and your family to be safe.  There is a route guide for those who live or work along the Napier and Hastings coastline: Plan your route - it can be difficult to know in which direction it is best to head in some of these areas.

Remember you may have to take this route at night. Know the route, practice it with your family, and have a torch. Aim to have more than one route too, in case you need to change route on the day.

You and your family or flatmates need to plan where you will go and how you will get there. Preferably evacuate on foot or by bicycle – traffic jams in a tsunami are dangerous. Get into the habit of knowing where you can find flat shoes, a torch and your Emergency Grab Bag in the dark, in case you need to evacuate in the night.

1)      Check whether you live, work or play in a tsunami evacuation zone here, and determine your fastest routes to safety.

2)      Make a plan with your household which includes where you will go and how you will get there. Keep your emergency grab bag in an easy-to-find place.

3)      Practice your routes regularly – tsunami hikoi week is a great excuse to encourage family, friends, and colleagues to walk your evacuation route together.

Have grab bags ready for everyone in your household. Include water, essential medicines, lightweight snacks, a torch, copies of important documents and photo ID. Pet food if applicable – remembering you have to carry the bag as you evacuate so don’t make it too heavy.  Visit getready.govt.nz for more advice on what to pack.

There will not be time to get expert advice and a large earthquake is likely to damage power, internet, and cell phone systems.  There will be very little warning of a tsunami if the earthquake is near our coast (the Hikurangi Subduction Zone).  

Every minute will count, and by the time Civil Defence Emergency Management has got a warning out it will be too late. There are more than 30,000 properties within Hawke’s Bay’s tsunami evacuation zones, so getting a ‘door knock’ is not possible.

Evacuating immediately after a Long OR Strong earthquake is your responsibility. Be a leader and encourage those around you to follow.

By the time Civil Defence Emergency Management gets a warning up and you search it on-line, it will be too late. Every minute counts so: Long OR Strong – Get Gone.

Encourage them to work out what emergency supplies they need – in an emergency, they may be stuck at home for three days or more – the getready.govt.nz website has a list of supplies to help you get through.

During an earthquake, remind them to ‘Drop, Cover and Hold’ until the shaking stops.

They may be able to provide you with shelter if you have to evacuate following an earthquake. Ask them and make them part of your plan.

 Once you are in a safe place, listen to a radio or search online for information on the situation. Remember, the first tsunami wave may not be the largest. Do not return to any of the tsunami evacuation zones until an official ‘all clear’ has been given.

The zones are used when tsunami come from far away, like from Chile, providing time for warnings. You will not feel an earthquake, and only some zones may be asked to evacuate by Civil Defence Emergency Management.

While vertical evacuation could be an option in some circumstances, you need to be aware the building might not withstand the impact of a tsunami, as it hasn’t been designed for that. You could also be isolated in a building for days before help can get to you, and there is the risk of fire. If you choose to evacuate vertically, you should go to at least the third floor. If your building doesn’t have a third floor, staying is not a good option.

Find out more in 'More Information' below - Tsunami Vertical Advice Information

You don’t have to. However, the sticker will remind you, your family, neighbours, community and any visitors that this is a risk and what you need to do to.

Once you are in a safe place, search on radio or online for information on the situation. Remember, the first tsunami wave may not be the biggest and there are likely to be many waves. Wait for an official 'all clear' before returning to a tsunami evacuation zone.