Sarah Stuart-Black: NZ needs to be prepared for a tsunami

Evacuation route signs in case of tsunami on Phi Phi Island, Thailand, are a reminder to be prepared. Photo / Brett Phibbs

COMMENT: "Long or Strong, Get Gone." Evacuate immediately – don't wait for anything.

That was a key theme as top international tsunami experts gathered in Wellington last week under the Unesco Intergovernmental Oceanographic Commission to develop a firmer grasp of tsunami risk in the Southwest Pacific.

Tsunami is at the forefront of our minds for good reason; the devastating Boxing Day tsunami of 2004 and more recent deadly events such as the Samoa tsunami in 2009, the Japan tsunami in 2011 and, on September 28 this year, the tragic tsunami in Indonesia.

These are more than just international headlines. They are reminders to be prepared. New Zealand's islands mean a lot of coastline with a lot of our people living there. Add to that our seismically active country – as last month's 6.2 Taumarunui quake demonstrated.

Ongoing research, systems that monitor, detect, and issue warnings of tsunami, and all of us knowing what to do, are key to being prepared.

Thankfully, a large destructive tsunami has not impacted on New Zealand since our coastlines have become densely populated. In 2016, we had two local source tsunami, one from the East Cape earthquake, and then the Kaikōura earthquake, which generated a tsunami despite the epicentre being inland.

Both showed how unpredictable tsunami can be and, importantly, how quickly they can arrive. Fortunately, nobody was hurt or killed by those waves.

The more we know, the better placed we are to keep ourselves, our families and our communities safe. And we are learning more about tsunami hazards.

For example, recent GNS Science research on the Kermadec Trench north of New Zealand has shown we may not strongly feel large quakes that could generate a tsunami just one hour's travel time away. This has led to arrangements to trigger evacuations if earthquakes originating in the Kermadecs meet certain thresholds.

The Government is acting on many fronts to manage our tsunami risk. As part of the emergency management system reforms, work is under way to speed up tsunami warnings.

The Ministry of Civil Defence and Emergency Management and GNS Science, together with Civil Defence Emergency Management Groups, are working to strengthen and streamline our tsunami risk management arrangements.

Later this year, GNS Science will open its 24-7 centre to monitor and detect all geohazard risks including tsunami. The recently launched emergency mobile alerts system allows agencies to issue smartphone notifications.

Our "Long or Strong, Get Gone" campaign started in late 2016. Encouragingly, research shows 90 per cent of Kiwis know what to do if they feel a long or strong earthquake near the coast. We've added a tsunami hikoi to the annual New Zealand ShakeOut drill and more than 870,000 Kiwis took part just two weeks ago.

Heed official warnings. But don't wait for them. If you have felt an earthquake longer than a minute or it is hard to stand up, get moving. An earthquake like that is simply the best and fastest warning.

Every minute and every metre you head inland after that earthquake counts. Find out from your local council if you're in an evacuation zone. Practise your evacuation route. Have a household plan and a grab bag. Know how to stay informed; we issue alerts through multiple channels, such as radio, TV, Emergency Mobile Alerts, social media and the www.civildefence.govt.nz website.

A large tsunami hitting our shores is not a matter of if, it is a matter of when. The good news is that knowing the right actions can keep us, our families and our communities safe.

• Sarah Stuart-Black, director, Civil Defence Emergency Management.