Tsunami News

World Tsunami Awareness Day

Published: Sun Nov 5 2023 10:00 AM

Tsunamis are uncommon events and can be extremely deadly, but they needn’t be. Today, on World Tsunami Awareness Day we join the National Emergency Management Agency (NEMA) in urging Aotearoa New Zealand to take a few minutes to check their tsunami zone and get familiar with small actions that could make a big difference in an emergency.

World Tsunami Awareness Day

World Tsunami Awareness Day

World Tsunami Awareness Day

Are you Tsunami ready? – five simple hacks that could save your life.

Just ‘Five Simple Hacks’ could help save you and your family in the event of a tsunami, NEMA says. “We’re concerned that the number of New Zealanders who know that Long or Strong means Get Gone has fallen from 87 per cent last year to 75 per cent this year,” NEMA chief science advisor Professor Tom Wilson says.

“This is a big worry, because in a local-source tsunami – like one caused by an earthquake on the Hikurangi fault along the North Island’s East Coast – immediate self-evacuation is key to survival.”

Preliminary research into the 5 March 2021 tsunami sequence show that in an event, people often wait for an official warning, when they should leave straight away.

“Our Five Simple Hacks are quick, easy and will save lives,” NEMA’s Director of Civil Defence Emergency Management John Price says. “No matter what the emergency is, being safe starts with taking action to keep safe.

“For example, nearly everyone who took steps to prepare before Cyclone Gabrielle found this made a positive difference.

“To mark World Tsunami Day, take a few moments with your whānau today – and find out what to do if a tsunami strikes.”

  1. Know Your Zone: find out if the places you live, work and play are in a tsunami evacuation zone Tsunami evacuation zones — Get Ready — Emergency preparedness in New Zealand

  2. Have a “prep talk” with your whanau – and if you’re in a tsunami zone, work out a way to evacuate without using your car In a disaster will you be ready? Have a prep talk (60 seconds) - YouTube

  3. Learn the natural warning signs: Long, Strong, Get Gone. If you’re near the coast and an earthquake is long (more than a minute) or strong (it’s hard to stand up), then get gone to higher ground immediately. Tsunami — Get Ready — Emergency preparedness in New Zealand

  4. Work out what you need in your evacuation grab bag. Work out what supplies you need — Get Ready — Emergency preparedness in New Zealand

  5. Practise your tsunami hīkoi (evacuation) so you know what to expect. https://getready.govt.nz/en/emergency/tsunami/tsunami-hikoi/

Do we need to worry about tsunamis in Aotearoa New Zealand?

In short, yes we do. In Aotearoa New Zealand, we have a long history of tsunamis. Mātauranga Māori of tsunami that occurred pre-European arrival (some of which were devastating) provides vital knowledge for helping us understand and prepare for future events.

Our coastlines also contain evidence of these past tsunamis, recorded in the geology as layers of shell, sand, and tiny marine creatures that were washed up by the event.

Since the 1840s, written records suggest that at least 68 tsunamis have reached our shores. Of these, six were over 5 m high. You can learn more about these events from our New Zealand Tsunami Database.

How do we know a tsunami is coming?

To help us detect and understand tsunami, we have 12 Deep-ocean Assessment and Reporting of Tsunami sensors (DART) monitoring changes in sea level deep in the Pacific Ocean and a network of 18 coastal sea level gauges near New Zealand’s shores, to pick up possible tsunami activity.

READ: All about the DART network and how it works

For tsunami coming to New Zealand from around the Pacific, we have more time to evaluate and assess the possible threat – sometimes up to 12 hours if the tsunami is coming from South America, Alaska, or Japan.

If the tsunami is generated by a large earthquake, our National Geohazards Monitoring Centre (NGMC) will pick up the earthquake signals and be able to activate our duty officers and the Tsunami Experts Panel (TEP) right away to help build understanding of the potential threat to New Zealand. Otherwise, if we receive a warning from the Pacific Tsunami Warning Center in Hawaii, or one of our DARTs activates, the NGMC immediately contacts our duty officer who will escalate to the TEP to assess the information.

Through these teams, GNS provides advice to the NEMA who issue national warnings and support regional Civil Defence and Emergency Management Groups with regards to regional warnings as well. DARTs from New Zealand and other countries, as well as national and international coastal sea level gauges, help the tsunami experts in the TEP refine our estimates of the tsunami arrival and the potential effects on New Zealand coastlines. Our sensor information also feeds into the Pacific Tsunami Warning Center’s estimates of the tsunami threat.

For a local source tsunami, which could arrive within minutes, there won’t be time for an official warning. Drop, Cover, and Hold, and Long or Strong, Get Gone are crucial messages to remember when you feel shaking. Our analysts at the NGMC follow the same processes, and then immediately get to work – analysing the event and escalating to duty officers and the TEP to ensure the best possible advice is available as fast as possible to NEMA.

However, it is important to recognise the natural warning signs and not wait for an official warning. As soon as the shaking stops, move immediately to the nearest high ground or as far inland as you can to get out of the tsunami evacuation zones. Even if you can’t get out of your evacuation zone, go as far or as high as you can – every metre makes a difference. Remember, Long or Strong, Get Gone.

READ: More about tsunami, learn the warning signs and the right action to take

Only messages issued by the National Emergency Management Agency (NEMA) represent an official warning status for New Zealand. Go here for the latest NEMA updates.

Media Contact: 021 574541 or media@gns.cri.nz