Hikurangi fault poses tsunami risk: Hawke’s Bay urged to prepare to evacuate

• The Hikurangi Subduction Zone poses a significant earthquake and tsunami risk, with a one in four chance of an event in the next 50 years.
• Shane Briggs from Hawke’s Bay Civil Defence advises immediate evacuation from Hawke’s Bay’s blue zone after a long or strong earthquake.
• Residents should prepare emergency bags and learn escape routes, avoiding cars to prevent road congestion.

Off the coast of Hawke’s Bay, a giant slumbers – but could wake at any time.

The Hikurangi Subduction Zone is where the Pacific plate drops westward under the Australian plate. It sits just off the east coast of the North Island.

Subduction zones generate the largest earthquakes and tsunamis in the world. The Hikurangi Subduction Zone is close to shore and a tsunami from this source would arrive within 10 to 20 minutes of a long or strong earthquake, allowing no time for official warnings.

Recent research, led by Charlotte Pizer from Victoria University, indicates a one in four chance of a Hikurangi Subduction Zone event in the next 50 years.

Acting group manager at Hawke’s Bay Civil Defence Shane Briggs said it’s impossible to predict where and when an earthquake or tsunami could hit.

“There’s a massive envelope for where it could be and what it might be,” Briggs said.

Last year, Civil Defence updated its tsunami evacuation map to a single blue zone, highlighting which settlements would be the most at risk should a large tidal surge hit.

When an earthquake hits, Briggs says the best thing to do is “get gone” out of the blue zone and not wait for an evacuation order to come through.

“The natural warning sign is a reliable sign and it will always work,” he said.

“Long or strong is a pretty clear signal.”

A long earthquake is considered to be around a minute and strong is when it would be hard to stand up.

Acting group manager at Hawke’s Bay Civil Defence Shane Briggs. Photo / Jack Riddell

But Briggs says people should not just run up the nearest hill, but focus on getting out of the blue zone.

“It’s not always about going for height, and in fact if we all try and go for the hill, it’s just going to congest that area,” he said.

“For many people, it’s easier, quicker, and safer for them just to move inland.”

Briggs recommends learning your quickest escape routes from work and home and practising them.

But he says to avoid using a car when evacuating.

“If we’ve got everyone jumping into vehicles, there’s going to be accidents and that’s just going to clog the roads.

“What that means is people who actually need to use the road, those that have disability issues, the elderly, will not be able to leave.

“If [disabled and elderly] people are living in the blue zone, they need to have a plan about what they are going to do.”

He recommends having an emergency bag ready to go.

“If we’re talking about a wave that is arriving in 20 minutes and it takes you 10 minutes to find all the things, you’ve halved the amount of time you’ve got to evacuate,” he said.

“If you’ve got a bag by your door ready to go, you can just leave.”

Hawke’s Bay Civil Defence is currently looking for volunteers to help out during an emergency and invite all those interested to their open night, Tuesday April 1 at 309 Lyndon Rd East, Hastings from 7pm.

More details are available on their website.

Jack Riddell is a multimedia journalist with Hawke’s Bay Today and spent the last 15 years working in radio and media in Auckland, London, Berlin, and Napier. He reports on all stories relevant to residents of the region.