Magnitude 6.8 earthquake possible on Auckland faultline - study
· RNZA faultline in Auckland now considered active has the potential of creating a magnitude 6.8 earthquake if it was to rupture, a new study shows.
In a media release, researchers from the University of Auckland say an earthquake caused by the Mangatangi faultline - which runs alongside the Hunua Ranges - would likely result in "serious consequences" for people living in South Auckland and possibly central Auckland, too.
The study has been published today in the New Zealand Journal of Geology and Geophysics.
According to co-author Dr James Muirhead, the study highlights how little is known about Auckland's seismic history.
The Mangatangi faultline is considered active as it has ruptured within the past 10,000 years. Any fault that has moved within 125,000 is considered active.
Dr Muirhead said: "Auckland's level of hazard is obviously nothing like Wellington's or much of the South Island, but it may be significantly higher than the public and policymakers believe - we need more factual information to know."
The researchers say continued expanision south of the city is putting more people and infrastructure at risk - given the close proximity to the faultline.
Lead author Hannah Martin said although the fault may not rupture for tens of thousands of year, it remains an active fault "with the potential to generate a large earthquake in a region that doesn't expect one".
Muirhead said although people don't usually feel them, earthquakes occur in Auckland every year.
He and two other authors from the study are continuing to research Auckland faultlines to determine how active they are.
They are using advances mapping, ground-penetrating radar and trenching, according to the media release.
One of the researchers Dr Jennifer Eccles said: "It's always better to plan based on evidence rather than on our best hopes or worst fears."
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