Researchers from the University of Otago have set up a network of seismometers in Southland that they say will fill a “seismic blind-spot” to uncover hidden fault lines in the region.

The project, backed by Toka Tu Ake EQC’s University Research Program, has installed seismometers across 19 sites in New Zealand’s Southland region to track seismic activity.

Lead Researcher Jack Williams says that while the region historically experiences low numbers of earthquakes, the distance between existing sensors likely means many minor quakes go unrecorded.

“These new sensors will be roughly 30km apart, which will give us a much better idea of active fault lines in Southland,” Dr Williams said.

He says previous seismic activity is often indicated by surfaces where land has been uplifted and broken, but weather conditions in Southland make it harder to detect past tremors.

“We can see a lot of scarring in the Central Otago landscape from prehistoric earthquakes because it is dry, but the weather in Southland is very wet, and so the evidence from past earthquakes is removed from the landscape much more quickly,” Dr Williams said.

He says the project’s importance comes from identifying previous cracks to provide clues on where active faults are present.

“Clearly, the surface may not always tell you what goes on below,” he said.

Toke Tu Ake EQC Research Manager Natalie Balfour says the initiative forms a “crucial part” of comprehensive research conducted by the university to understand hazard levels in low-seismic regions.

“We fund approximately $20m in natural hazard research each year to better understand our natural hazards so we can support communities, local councils and decision makers to be better prepared by making more informed decisions,” Dr Balfour said.

“Finding out more about unknown fault lines in Southland helps us understand less frequently occurring earthquakes so the region can better prepare.”

Toka Tu Ake EQC says regions in Central Otago and Fiordland have implemented similar measures to track earthquake activity but admits there is still a “significant knowledge gap about the upper crust fault lines and seismicity in Southland itself”.

Dr Williams says the region’s location lies at the junction of multiple geological terrains that could influence where earthquakes occur.

He says the data recordings will provide the team with “invaluable” research to assess the “true seismic hazard in Southland”.