Our research is galvanising community action

It’s where the Pacific tectonic plate dives beneath the east coast. A rupture could produce large earthquakes and tsunamis. A significant event could strongly impact our largest population centres including Auckland, Wellington and Christchurch.

High-impact research into the zone’s behaviour is yielding invaluable information for more reliable forecasts of the hazard and risk which the zone poses to Aotearoa New Zealand.

One of the research team’s leaders is geophysicist Dr Laura Wallace from GNS Science. She says the main aim is to drive better community preparedness in the event of a rupture.

Since 2016, we have been leading several onshore and offshore projects investigating the behaviour of the Hikurangi subduction zone. Much of this is being supported under a five-year MBIE-funded Endeavour programme.

Laura Wallace

Research Associate

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https://www.youtube.com/watch?v=Zm1fHWLFjWY – East Coast LAB - The Hikurangi subduction zone transcript

The Hikurangi subduction zone is one of the major plate boundaries in New Zealand its mostly focused in the North Island and it is where the Pacific plate is basically

diving down westward beneath the eastern part of the North Island.

The Hikurangi subduction zone is Aotearoa New Zealand's largest and most active fault running offshore from Gisborne down to the top of the South Island.

Recent science suggests the likelihood of a Hikurangi fault rupture may be higher than initially understood

We now know the Hikurangi subduction zone earthquake and tsunami has the potential to be similar to the tsunami in Japan in 2011

The reality is, it is not a matter of if, but when

East Coast Life at the Boundary is a project that brings together scientists, emergency managers, and other experts from across the east coast to make it easy and exciting to learn more about natural hazards and how they can affect us

We're working together with Civil Defence, emergency services and many other organisations to develop and test the Hikurangi Response Plan. Matauranga Māori speaks of large tsunami and since written records Aotearoa New Zealand has been impacted by 10 tsunamis higher than five metres.

In 1947, Gisborne experienced a tsunami that was up to 10 metres high in some locations. So the Hikurangi subduction zone has actually generated earthquakes in the past the largest one in the historical records was in 1947.

There were actually two earthquakes generated on the subduction zone and March and May of 1947 offshore of Gisborne and these weren't particularly large in the scheme of things.

It was only about a magnitude 7.2 they weren't magnitude 8 or magnitude 9 but they did actually cause quite large tsunami for the size of the earthquake given what we would expect that size of earthquake to cause.

We know a large earthquake and tsunami is something we will face in our lifetime, or that of our children and grandchildren.

Emergency managers are planning for it, but how prepared are you?

Everyone must prepare, as we are all part of Civil Defence

What people really must do to be prepared for this is to make sure.

A) if there is a tsunami they know their evacuation route and they can get to higher ground very quickly

and then,

B) have a plan with their family to met back up with their families and make sure everyone in their family knows what to do in the event of an earthquake or tsunami

and,

C) make sure that they're prepared to survive at home with enough food and water until things get back on track.

All this may sound overwhelming, but we must all know what to do. Practice your drop, cover and hold, and tsunami hīkoi to high ground or inland by foot or bike.

We know practicing these two things works as it helped save over 95% of people’s lives in Japan in 2011 who safely evacuated in time. Remember, if it’s long or strong, get gone!

You can find out more about preparation and planning at www.happens.nz

You can check your tsunami evacuation zones on your local Civil Defence group website.

https://www.youtube.com/watch?v=Zm1fHWLFjWY

A large Hikurangi subduction zone earthquake and tsunami- it's not a matter of if, but when. This video explores what the Hikurangi subduction zone is, how scientists, emergency managers and other experts are planning for it

This work is advancing our knowledge about the earthquake potential of the plate boundary and the physical processes behind it

Dr Laura Wallace geophysicist GNS Science

Since 2016, we have been leading several onshore and offshore projects investigating the behaviour of the Hikurangi subduction zone. Much of this is being supported under a five-year MBIE-funded Endeavour programme.

“This work is advancing our knowledge about the earthquake potential of the plate boundary and the physical processes behind it,” says Dr Wallace.

To share our findings and build public awareness and resilience, we have partnered with East Coast Life at the Boundary (LAB). This programme brings together scientists, emergency managers and other experts, with communities along the North Island’s East Coast.

This past year we invested considerable effort in public engagement and education. Our scientists joined with NIWA and East Coast LAB to present talks in 11 communities in the North Island, reaching more than 1100 people.

“They have also been involved with school fieldtrips and educational visits to East Coast schools when undertaking fieldwork in the region," Laura says.

We hope this will help inspire the next generation of scientists.”

Laura Wallace GNS Science

The Hikurangi subduction zone research programme involves deep partnerships with international research institutions. These have helped advance this country’s reputation as a focal point for the investigation of subduction plate boundary processes, leading to an unprecedented NZD$70 million of international investment in projects to understand the Hikurangi subduction zone. For example, Aotearoa New Zealand has been chosen as one of three global focus sites for subduction zone research under the US National Science Foundation GeoPRISMS programme.

Hik scientists present to over 400 people at one of the popular public — East Coast Life at the Boundary

This year, GNS Science also embarked on a new project with Japanese collaborators investigating the parallels between subduction zones in northeast Japan and Aotearoa New Zealand, led by Dr Dan Bassett. A key aim is to compare the causes of earthquakes on both subduction zones and shed light on the types of future earthquakes the Hikurangi fault may produce.

In another project, led by Dr Grant Caldwell, scientists from GNS Science and Tokyo Institute of Technology, in collaboration with Chorus Ltd, used the underground copper wire telephone network to measure small changes in the Earth’s natural magnetic and electrical fields at sites across the Gisborne region. The novel measurement technology can be used to better monitor physical changes inside the fault, and improve understanding of the earthquake and tsunami risk to the East Coast.

Our collaborators

The Hikurangi subduction zone programme is a multi-disciplinary collaboration between GNS Science, NIWA, Victoria University of Wellington, Canterbury University, the University of Auckland, East Coast Life at the Boundary (LAB), and iwi/taiwhenua partners. There is also an extensive network of international collaborators in the United States, Japan, the United Kingdom and Europe.

The importance of this research is immense. It has galvanised action across civil defence and emergency management groups along the East Coast

Lisa Pearse Team Leader, Hazard Reduction Hawke’s Bay Civil Defence Emergency Management Group

"It brings together emergency managers and scientists together to better understand the information needed and the key interdependencies to plan for something our communities have never experienced. Understanding this risk enables our communities to identify potential consequences ahead of time. This allows us to better anticipate what might happen in the future, to help minimise losses and, we hope, ultimately it will save lives," says Lisa Pearse.

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