Google researchers have detailed the failings of the Android Earthquake Alerts (AEA) system during destructive earthquakes in Turkey in 2023, after the company previously said that the system “performed well”.

Two major earthquakes affected south-east Turkey on 6 February, 2023, killing more than 55,000 people and injuring more than 100,000.

The first earthquake hit at 4:17 a.m., at a time when many people were asleep in buildings that collapsed around them.

Deadly disaster

In spite of the severity of the quakes, however, Google’s system only sent a relatively small number of its highest-priority alerts to users’ phones, the company acknowledged.

The AEA system works by detecting tremors that affect people’s Android phones, determining whether the movement is caused by an earthquake, and estimating its severity.

The system’s highest-priority alert emits a lout alarm, shows a notification that takes up the entire screen and overrides the phone’s Do Not Disturb setting.

Ten million people could have been sent this alert in 2023, giving them up to 35 seconds to get to safety, Google researchers said in the journal Science.

Instead, only 469 people received this type of “Take Action” alert, they said.

About 500,000 people were sent a lower-level warning that designates “light shaking” and does not override Do Not Disturb.

The company had previously said the system “performed well” following a BBC investigation in 2023.

The company told the BBC that the system is not designed to replace national alert systems.

“Every earthquake early warning system grapples with the same challenge – tuning algorithms for large magnitude events,” Google said.

Algorithm ‘limitations’

In Science, the Android developer said the failure was due to “limitations to the detection algorithms”.

The system estimated the first quake at 4.5 to 4.9 on the moment magnitude scale, when it was actually a 7.8, they said.

The second quake was also underestimated.

Google’s researchers later adjusted the algorithm and simulated the first quake again, finding that the system sent out 10 million Take Action alerts to those most at risk, and a further 67 million lower-level Be Aware alerts to those further away from the epicentre.

Industry watchers expressed frustration that Google only released information about the system’s poor performance two years after the deadly events.

They said Harold Tobin, director of the Pacific Northwest Seismic Network, told the BBC that there is a danger that national governments might believe Google’s system is effective enough that they might hold off on their own efforts.

“Would some places make the calculation that Google’s doing it, so we don’t have to?” he said.