Alarque shake-up: Why New Zealanders want an earthquake early warning system

After one of the most shocking decades in New Zealand’s history, the Kiwis overwhelmingly want the country to build a system to give us all a head start as future shocks hit.

Earthquake warning systems (EEW) work by detecting and responding to the fastest traveling P-waves of an earthquake before the slower but more damaging S-waves arrive, allowing people to prepare for a few seconds.

Unlike Japan, Mexico and now parts of the US, New Zealand does not have a nationally funded earthquake early warning system.

Researchers have now received a clear signal from the public that they want one – and they have even heard exactly what it should look like.

In a recently published study, a team from Massey University and GNS Science surveyed people and groups around the country, and held talks with representatives of aid services, utilities and the construction, health and education sectors.

Overall, they found organizations and the public was drawn to a New Zealand system, hesitant results of a survey showing that 97 per cent of people thought one would be useful, or at least somewhat useful.

“People wanted to be warned of moderate to strong tremors, for example at a level similar to the 2013 Cook Strait as Kaikoura earthquakes in 2016 as experienced in Wellington,” said study lead author Dr Julia Becker, of Massey’s Joint Center for Disaster Research.

“They thought it would have primary benefits for life safety because it would inform people in advance and allow them to, cover and hold before shaking began, moving away from dangerous areas or taking safety actions when expelling gas.”

They further found how people thought that a warning before shaking began they could prepare themselves mentally, and be ready to respond.

“In some cases, you could use the alert to turn it off automatically or on certain features, such as gas valves, road warning signs – but participants thought they could only use automation for features that were easy to turn on and off again, said Becker.

“They were concerned that shutting down some features before shaking, such as water, for example, could be too disruptive for the public in the long run, especially if the shaking was not very strong when it was a false alarm.”

People were particularly interested in New Zealand that had a system with an array of sensors that could communicate with each other.

“From a warning point of view, people also wanted to have nationwide consistency, with people consistently receiving warning messages about a preferred language,” she said.

“There was quite a bit of discussion between groups that the channel’s preference could be a warning via a mobile broadcast of mobile phones, via the existing Emergency Mobile Alert System.”

How New Zealand could just build a system was what she and her colleagues explored in further studies.

“Cost is another barrier, and one that can be solved by creating a network of different types of sensors, some of which are expensive, but others, low cost.”

While the ShakeAlertLA app in California hyped a lot when it launched recently, users were furiously left that it did not warn them of a 7.1 hideout that hit shortly thereafter.

Officials had to point out that shaking in LA County had not reached a point that would likely result in major damage, as seismologists warned that lowering the threshold could make people accustomed to the warnings.

New Zealand’s current GeoNet capacity includes hundreds of onshore seismic instruments, a range of tsunami meters that measure water levels, and geodetic data entered by more than 180 continuous GPS (CGPS) stations.

In 2013, a GNS Science report used a scenario similar to the March 1947 tsunami earthquake off the coast of Gisborne to assess GeoNet’s detection capability and potentially required network updates.

After testing a range of algorithms for detection and classification with the simulated data, the authors of the report concluded that such an earthquake could be detected in real time by the network.

However, it found that a large part of the geodetic sensor network would be upgraded to stream the data and provide accurate information.

“GeoNet’s continuous GPS network is currently far from easily accessible for a tsunami early warning system,” the report found.

At the time the report was written, only 37 of the CGPS ​​sites provided real-time data, and a real-time processing procedure was not available.

Creating an early warning system for earthquakes would require a “substantial effort” from GeoNet personnel, a “significant increase” in funding, along with the development of procedures and technology to process data in real time.

But New Zealand had one form of an EEW system in the Kiwi company Jenlogix’s network of P-wave detecting Palert units, now used by various councils, universities, district health boards, ports, and power companies.

The units all streamed data to a central server, but also had triggers that could activate local emergency systems – such as stopping an elevator on the next floor and opening the doors, or shutting down the gas supply.

The data was also made available to others such as GeoNet and KiwiRail’s Rapid Alert system.

“I think international EEW is here to stay, and given that New Zealanders would like to explore options for it, we need to continue our understanding of how we can make this work for our local context,” Becker said. .

“Because we started researching to expand the benefits for New Zealanders, we have the opportunity to build something different from other countries – something that fits our desired outcomes.”

Update for the NZ hazard model

The study comes as officials update a model that shakes the chance and strength of earthquakes in various parts of New Zealand, to reflect the latest science.

The National Seismic Hazard Model (NSHM) is widely used by government and industry to estimate the likely impact of earthquakes on the country, buildings and infrastructure of the country.

“It helps us understand the expected shaking that could occur over a period of time in a particular area, for example the next 10, 50 or 100 years,” explained GNS Science’s general manager of science, Peter Benfell.

“This information is essential for New Zealand to build resilience and manage risks to safety, security and the economy from seismic events.”

Originally made in the 1980s, the most widely used version of the model was developed in 2002.

“We are revising the model for the entire country and will update the details for all regions, based on our latest research,” said Dr. Matt Gerstenberger, the GNS scientist leading the update.

“Exactly how the danger could change is different for different parts of New Zealand, based on local geology as well as frequency and types of earthquakes affecting the region.”

The work is jointly overseen by GNS and the Ministry of Business, Innovation and Employment (MBIE), with input from the Earthquake Commission, engineers, universities and research institutes.

“While the NSHM is important for so many parts of New Zealand, a revision of the model does not mean that there will be immediate changes to the systems that use the model, such as the Building Code,” said John Sneyd, general manager of MBIE of building system performance.

“We will ensure that all changes are well planned, in line with government policy and will be introduced over time.”

The revised model is expected to be ready by mid-2022.

In parallel, research is underway to better understand and model how the Wellington region, including the Wellington Basin, is shaking in response to earthquakes.

“We hope to incorporate this into the revised NSHM,” Gerstenberger said.