Earthquakes: Can a warning system save New Zealand from the Big One?

Willow Woolrich and her classmates at Napier's Ahuriri School take part in a nationwide 'Shake Out' earthquake drill in 2021. Scientists have been exploring earthquake early warning tech that could give Kiwis crucial seconds to prepare before shaking starts. Photo / Warren Buckland

• Scientists are working on technology to provide a few seconds of warning before earthquakes.
• The research comes as a magnitude 5.7 earthquake struck Wellington after 5am this morning, with over 37,000 people reportedly awakened by the jolt.
• Massey University researchers have identified a trigger point, which could be used for a national early warning system.
• But as Jamie Morton explains, any attempt to create one would run into some big challenges.

“A bit of a rumble... then boom,” said one Lower Hutt resident.

“Lots of noise - and rock ‘n’ roll,” said another person 200km away in Whanganui.

It wasn’t this morning’s 5.7 quake they were describing - but one that hit in the same region on September 22, 2022, and which some 45,000 people from Invercargill to Kaitaia reported feeling.

Aside from forcing flights away from Wellington, it wasn’t unlike many of the two-dozen-or-so other quakes of that scale - just like today’s and last Tuesday’s 5.0 jolt - which rock our shaky isles in a given year without causing major damage.

But for scientists, the event yielded a trove of valuable data that’s taken us a small step closer to answering a long-standing question: can we warn people before the big one hits?

When the quake’s precursory “P-waves” rippled through the ground – seconds ahead of “S-waves” that cause damaging shaking – they were successfully picked up by low-cost seismic stations researchers had set up in peoples’ homes around the lower North Island.

Building on that work, Massey University’s Chanthujan Chandrakumar and his colleagues recently trawled through a decade of Canterbury quake data to pinpoint a certain P-wave threshold, at which an early warning system might be triggered.

Such systems, Chandrakumar said, had the potential to offer a few critical seconds to stop trains, shut off gas valves, power down machinery – and ultimately save lives.

Is NZ ready for its own system?

Scientists expect we’ll never be able to precisely forecast quakes like we can the weather – but warning people the moment they strike is already a reality.

There’s perhaps no more impressive example than Japan’s highly sophisticated, billion-dollar network, which instantly fired out tsunami warnings as soon as 2011′s devastating 9.1 earthquake hit, helping 90% of people near the epicentre to take action to save themselves.

New Zealand similarly faces the catastrophic danger of a quick-fire tsunami off our coast, along with the ever-present risk posed by the web of faults running through our country.

But unlike Japan, and a handful of other nations like China, Taiwan and South Korea, we have no state-funded system.

The closest capability available here is a Google app that pings messages to Android users before shaking starts – it’s based on phone data rather than local sensors - and a privately-run network used by some councils, ports and power companies.

Google's Android app, based on phone data rather than GeoNet sensors, is the closest thing Kiwis have to a personally-accessible earthquake early warning system - but it's caused confusion in previous events here.

Unsurprisingly, one of the biggest barriers to a national network is cost.

It’d likely take tens of millions of dollars to set up and run - and require a massive upgrade to the GeoNet network that many of us turn to for quick quake information - although some experts have pointed to the potential mass-deployment of cheaper sensors like those used in Chandrakumar’s study.

Another major hurdle is our complex tectonic setting, meaning we can’t simply adopt methods and technology used overseas, GNS seismologist Dr Anna Kaiser said.

But there was much groundwork that scientists could do now to ready the country for a system.

While researchers like Chandrakumar’s group have been exploring approaches under a government-funded programme, GNS has been running its own project to rapidly characterise quakes.

One tool, called FinDer, has already been trialled on quakes the size of last week’s and successfully simulated on major events like the Canterbury and Kaikōura events.

Kaiser said the next steps beyond these pilot studies would be drawing together scientists to design a national system - something that’d also require close government involvement and investment.

To date, there’s been no sign that the Government is ready to take that step.

Earlier this year, National Emergency Management Agency civil defence and emergency management director John Price pointed out to RNZ that early warning systems were often expensive to implement and could provide little-to-no warning in some cases.

“Any earthquake early warning system would need to work with Aotearoa’s geography, population distribution and emergency response systems, and would need to balance the cost of building and maintaining such a system against the benefits of receiving early warnings.”

Would Kiwis do the right thing?

Another question was whether Kiwis would use a system properly - and studies suggest there’s a long way to go.

When researchers recently surveyed Kiwis on Google’s app, they found 86% said they’d protect themselves if they received a prompt from it – yet just 5% that got an alert immediately took the right step of drop, cover and hold.

Another big issue was low public awareness about the systems – most who received the Google alerts thought they’d come from a government agency - and what they could and couldn’t do.

“In particular, these systems can miss earthquakes - and the closer you are to the epicentre of the earthquake, the less likely you are to get a warning,” said Dr Lauren Vinnell, of Massey’s Joint Centre for Disaster Research.

Massey University researcher Dr Lauren Vinnell.

“Without knowing these limitations, people may rely on getting a warning and not take action when they feel an earthquake start.”

Early warnings could indeed still prevent many of the injuries that come with earthquakes, she said, such as prompting people to drop to the ground before being thrown off their feet by the shaking.

“However, this requires people noticing the alert, processing what it means, choosing how to respond and then taking that action - this is quite a lot to ask in what is likely to be only seconds,” she said.

“In many places in the world, public earthquake early warning systems are still new and developing - so we don’t have a whole lot of evidence of their benefits yet.”

Jamie Morton is a specialist in science and environmental reporting. He joined the Herald in 2011 and writes about everything from conservation and climate change tonatural hazards and new technology.

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