For the first time, researchers are digging into the seismic history surrounding the Taupō Fault Belt to unlock insights into how the “twin threats” of earthquakes and volcanoes could collide and impact communities and infrastructure in the region.

While Taupō is better known for its volcanic activity, it is also exceptionally seismically active compared to many other volcanic regions around the world, said lead researcher Dr James Muirhead (University of Auckland), whose work is funded through the Natural Hazards Commission Toka Tū Ake (NHC).

“The Taupō supervolcano sits in the heart of central North Island, a land actively stretching and pulling apart,” Muirhead said.

“This geological tension creates fault lines that spark earthquakes.

“These earthquakes can shake up molten rock [magma] deep underground, making it more mobile and explosive.

“As the magma rises, it can also unlock and trigger fault lines, leading to earthquakes.

“It could be a dramatic feedback loop of seismic and volcanic activity.”

The region’s dynamic activity has long been a perfect subject for study.

However, a massive eruption 1,800 years ago has left much of the area’s geological history buried under thick volcanic deposits.

“This massive eruption blanketed the land with metres of ash and pumice, making it nearly impossible to track earlier earthquakes in the soil,” Muirhead said.

“What we’re left with is a thick volcanic layer, marking a singular moment in time.”

To get around this, Muirhead and his team are using ground-penetrating radar (GPR) technology – essentially an X-ray for the earth—to locate areas where volcanic layers are thinner.

In these regions, they’ll dig deep trenches to uncover and study the soil layers, revealing evidence of past earthquakes and volcanic eruptions.

“This groundbreaking research will let us peer back into a 25,500-year history of earthquakes along the Taupō Fault Belt,” he said.

By analysing the sequence of volcanic deposits and the displaced sediment layers caused by earthquakes, the team can estimate the magnitude and timing of past events – providing an unprecedented glimpse into the region’s seismic and volcanic activity.

Dr Jo Horrocks, NHC chief research and resilience officer, highlights the broader significance of this work: “Natural hazards rarely occur in isolation.

“This research will shed light on how often earthquakes and volcanic eruptions occur together, and the potential scale of these events.

“If a large earthquake strikes, should we brace for an eruption? Or could a series of smaller tremors signal an impending eruption?

“Understanding these patterns will help communities and emergency planners prepare impact of future events.”

Additionally, the research will offer valuable insights into fault lines, helping guide land-use planning in the region.

“By knowing where the largest faults lie, we can better safeguard communities and critical infrastructure from earthquake damage,” Horrocks said.

This project is funded through an NHC biennial grant, which supports early to mid-career researchers working on projects to bolster New Zealand’s resilience to natural hazards.

NHC’s next round of biennial research funding opens in May 2025.

It is being conducted in collaboration with researchers from GNS Science and the Victoria University of Wellington.