When a 5.3 magnitude quake rattled Wellington and the top of the South Island this week some Kiwis got a warning message before the shaking could even be felt.
New Zealand's one of only two countries selected to trial Google's early warning system which means those with Android phones get sent an alert a few seconds before a shake of magnitude 4.5 or more.
Seismologist Dr Caroline Holden is one of a team of scientists working on possible ways to get an early earthquake warning system, or EEW, rolled out across the whole country.
“On Tuesday something really exciting happened; we had a magnitude 5.3 about 100 kilometres off Wellington, quite deep but strong enough to be felt. Some people received an early warning before incoming shaking… It showed that kind of technology works,” she said.
Holden says people get an advance warning of a few seconds - enough time to drop, cover and hold or protect those using public transport.
“It can provide warnings to the National Emergency Management Agency, EQC, NZTA, they can slow trains and stop elevators between levels and so on,” she explained..
“When an earthquake starts it sends two types of waves, the first set of waves are quite small but really fast and so lucky for us we can capture those waves... then we can develop an algorithm in order to predict incoming shaking at a particular location.”
While the Google trial is phone-based, scientists at Massey University’s CRiSiS Lab are looking at other options, like a device which could be placed in people’s homes.
“The devices we are looking at are dedicated to detect ground motion, they are better compared to what you get in mobile phone devices,” Dr Raj Prasanna said.
It could take some time to develop a system that works for New Zealand. It took more than a decade to develop the early warning models in place in the US and Japan.
“I'm really keen to think about our vulnerable population as well, people who don't have access, people who don’t have resources and may not be able to access high-end tech,” he said.