'Groundbreaking': Newly discovered faults could pose seismic risk to Hamilton

Hamilton is currently classified as having relatively low to moderate seismic risk.
Hamilton is currently classified as having relatively low to moderate seismic risk. Photo credit: Getty

A new study is looking at whether recently discovered fault lines in Hamilton could pose an earthquake risk to the city.

Hamilton was once thought to be devoid of active faults, but scientists say that is no longer the case.

In 2015, researchers were alerted to a possible fault in the city's northern suburbs. Upon investigation 25 faults were discovered in the region.

Findings released last year indicated that any earthquakes in the area were more likely to be localised and less life-threatening. 

The faulting splits off sending smaller faults in different directions. The result is that it is more difficult to predict where the fault lies could rupture and plan city layouts accordingly. 

The new study, by a team of scientists at the University of Waikato, will now explore the seismic activity of the faults more accurately. 

Because the faults don't reach the earth's surface, it is difficult to directly assess how frequent and intense their activity is, scientists said.

The study will examine the liquefied volcanic-ash layers found in many small lakes scattered throughout the faults to test the frequency and activity of the faults over the last 20,000 years. 

"This project will be groundbreaking, as no one has ever identified volcanic-ash layers in lakes as being liquified," says Professor David Lowe, the project co-leader.

Lake Ngaroto is around 20,000 years old and contains some liquefied volcanic-ash layers.
Lake Ngaroto is around 20,000 years old and contains some liquefied volcanic-ash layers. Photo credit: Frans Van Schief

Data from the project will be shared with the Waikato Regional Council and ultimately used to provide earthquake hazard maps for Hamilton.

"These maps will greatly improve hazard planning and mitigation strategies by policymakers, and provide data for the National Seismic Hazard Model which informs the New Zealand Building Code," said Professor Lowe.

Hamilton's building codes are currently based on the fact that the city has a relatively low to moderate seismic risk, but depending on the investigation's results that could change, said Professor Lowe.

Newshub.

 

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