Earthquake risk in New Zealand's largest city higher than assumed: study
Wellington, May 27
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, Xinhua news agency reported.
Earthquakes happen every day in New Zealand. Instruments record the ground shaking from over 20,000 earthquakes in and around the country each year. Most are too small to be noticed, but between 150 and 200 are big enough to be felt. Between 1840 and 2016, earthquakes in New Zealand caused 501 deaths directly or indirectly.
— IANS
Reader Comments
It's surprising that Auckland was exempted from earthquake-prone building rules. NZ is literally on the Pacific Ring of Fire! This study is a wake-up call. Indian cities like Delhi, Mumbai, and Kolkata face similar risks from Himalayan thrust faults. We should all learn from this and improve preparedness. Science doesn't lie. 🙏
This is why we need strict enforcement of seismic codes everywhere. In India, builders often cut corners to save costs. The new buildings in Auckland must also be inspected properly. I hope NZ authorities take this seriously. Lives are more important than real estate profits. Ye film khatam hone se pehle hi kuch karna chahiye (We should act before this movie ends).
As someone living in an earthquake-prone area of Himachal, I can relate. We have frequent small tremors but officials rarely prioritize retrofitting old buildings. I appreciate this research—it gives Auckland a chance to act proactively. I hope the Indian government also funds more studies on our active faults near urban centers. Preparation saves lives, as we saw in Japan's 2011 response. 💪
Interesting study but I think the article overstates the risk. A magnitude 6.8 is serious but not catastrophic—Auckland has modern construction. Also, radiocarbon dating just gives a rough timeframe. The 2011 Christchurch earthquake was much worse because it was shallower and closer. Let's not panic but definitely do better planning. Respect to the researchers though. 🇳🇿
This is a good lesson for Indian metro cities too. Delhi, for example,
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