Experts investigating Waikato fault line which could generate 6.7 magnitude quake

Experts have launched an investigation into the earthquake risk of a newly discovered fault line in the Waikato, which could potentially generate a 6.7 magnitude earthquake.

Scientists recently discovered the Te Puninga fault, which lies 27km from Hamilton and about 3km from Morrinsville, due to improved aerial mapping tools.

Dr Pilar Villamor, an earthquake geologist at GNS Science who is heading up the project, said researchers estimated the magnitude based on the fault's 25km length.

Experts investigating Waikato fault line which could generate 6.7 magnitude quake

"If it ruptured, Morrinsville would potentially experience the same level of shaking Christchurch had during the 2010 Darfield quake," she said.

"And it would be relatively strong in Hamilton as well."

GNS Science experts have now begun a research project funded by the Earthquake Commission into the fault which lies in a part of New Zealand that is traditionally seen as safe from earthquakes.

The team will dig trenches across the fault to expose soil layers displaced in earthquakes over the past 20,000 years. 

They plan to take samples from each layer, which will be dated by experts at the University of Waikato and in Spain.

Pilar Villamor from GNS Science, left, and Kelvin Berryman watch Kate Clarke scraping layers in the trench.
Pilar Villamor from GNS Science, left, and Kelvin Berryman watch Kate Clarke scraping layers in the trench. Photo credit: Peter Drury-EQC
The project team at work in a trench near the Tatua Dairy Factory in Waikato.
The project team at work in a trench near the Tatua Dairy Factory in Waikato. Photo credit: Peter Drury-EQC

"This will tell us how often the fault has ruptured, and the magnitude of the quakes it has produced," Villamor said.

"That information in turn will help us to understand the risk of future earthquakes in the area and how to prepare for that risk."

Earthquake Commission research manager Dr Natalie Balfour said it would help the community to be better prepared for any potential earthquakes.