Could climate change trigger earthquakes in Hawke's Bay? NZ's biggest fault line may have the answer

Could climate change be triggering some of Hawke's Bay's earthquakes?

Scientists hope a 900-metre-long sediment core taken from off the coast can help them uncover the answer.

East Coast Lab and the International Ocean Discovery Programme (IODP) in Texas have joined forces to scan the sediment core from New Zealand's "largest and most active fault line", the Hikurangi Subduction Zone.

Project lead researcher Dr Lorna Strachan said the idea that a warmer global climate and higher sea levels could increase the frequency of earthquakes and volcanic eruptions has been around for a while.

But it has never been tested, Dr Strachan said.

"This project is the first to actually test this very important question."

Earthquakes are a regular occurrence in Hawke's Bay, and as sea levels rise, understanding how sea levels could impact the frequency of these events would help scientists create more accurate earthquake forecasting.

The study of sediment cores is a key part of the research. They were taken by drilling down into the seafloor, capturing layers of marine mud, sand, volcanic ash, bits of shells and anything else that has accumulated on the seafloor.

The scanning process is a long one, taking up to 100 hours to scan each section, and before that each centimetre of core must be inspected and prepared to ensure a successful scan.

Dr Adam Woodhouse scanning a section of the Hikurangi Subduction Zone sediment core at the Texas A&M University campus. Photo / Supplied

Since March, IODP micropalaeontologist Dr Adam Woodhouse has been meticulously scanning sections of the core to find out the make-up of each layer of sediment.

"I'm shooting x-rays into the sediment to explore the relationship between volcanoes, earthquakes and global climate," Dr Woodhouse said.

"I feel incredibly lucky to get to do what I do.

"Understanding the make-up of each layer of sediment requires a lot of information."

Once scientists understand the colour, density, magnetism and geochemical composition, each layer will show what was happening on the Hikurangi Subduction Zone over the last million years.

"We are currently in a period of warmer climates, so if the core shows that higher sea levels and warmer climate do in fact increase our risk of earthquakes and volcanic eruption, that will impact forecasts."

Scanning the sediment is one important step in the three-year long Marsden funded project.

The Marsden Fund awards grants to support excellence in STEM, social sciences and humanities in New Zealand by providing grants for investigator-initiated research.

Marsden fund grants are "difficult to get and are a great achievement," Dr Strachan said.

In the final year of the project East Coast Lab is looking at including mātauranga Māori, the traditional knowledge of local Māori, to its hypothesis.