WELLINGTON, May 27 (Xinhua) -- New research has identified an active fault near New Zealand's largest city, suggesting earthquake risk for Auckland may be higher than previously understood.
The Mangatangi Fault, running along the Hunua Ranges about 50 km south of the city, is capable of generating an earthquake of up to magnitude 6.8, said a press release by the University of Auckland on Wednesday.
The study, published in the New Zealand Journal of Geology and Geophysics, found the fault has ruptured within the past 10,000 years. Any fault that has moved in the past 125,000 years is considered active.
"If the whole fault ruptured, there would likely be serious consequences for people living in South Auckland, and possibly further into central Auckland as well," said geologist James Muirhead from the University of Auckland, the study's co-author.
This is the first time a faultline in the Auckland region has been radiocarbon dated, highlighting limited knowledge of its seismic history, Muirhead said, adding that Auckland's hazard "may be significantly higher than the public and policymakers believe."
Auckland experiences earthquakes every year, but most are too small or distant to be noticed, he noted.
The findings come as Auckland expands southwest, bringing more people and infrastructure closer to the fault. Researchers say raising the city's hazard level would tighten building code requirements. Auckland was exempted last year from earthquake-prone building rules due to its low risk.
"This is an active fault with the potential to generate a large earthquake in a region that doesn't expect one," said Hannah Martin from the University of Auckland who was the lead author of the research. Enditem
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