Android telephones have introduced early quake warnings to 98 nations

Android smartphones around the globe have been actively serving to present earthquake alerts utilizing their acceleration sensors. Between 2021 and 2024, these telephones despatched hundreds of profitable warnings to folks dwelling in quake-prone areas in 98 nations.

Since 2020, Google has included its Android Earthquake Alert (AEA) system in its telephones to detect seismic P- and S-waves that precede an earthquake and supply alerts. The firm and the University of California Berkeley’s Seismology Laboratory have launched information in a brand new paper in Science, detailing the efficiency and strategies of the algorithm over the past three years.

The AEA system was first rolled out within the U.S. in 2020, adopted by New Zealand, and Greece in 2021, after which the remainder of the world.

It issued alerts for 11,231 occasions, together with forward of the Turkey-Syria (magnitude 7.8), the Philippines (6.7), and Nepal (5.7) occasions, all in 2023, and the 6.2-magnitude occasion in Turkey in April 2025. In the Philippines, Turkey-Syria, and Nepal quakes, customers obtained 10 to 60 seconds of advance warning.

The system has so far detected greater than 18,000 quakes of various magnitudes, together with greater than 2,000 sturdy quakes (reasonable shaking or extra on the MMI scale) and issued a complete of 79 crore alerts. The AEA crew additionally surveyed customers between February 2023 and April 2024. Some 79% of 1.5 lakh customers stated they discovered the alerts very useful.

AEA crowdsources alerts from a telephone’s accelerometer, a sensor that measures acceleration. On stationary telephones, accelerometers can sense the faster-moving P-waves from an earthquake, which stretch and squeeze the geological materials they move via.

When an accelerometer senses these waves, it sends a sign to Google’s earthquake detection server, which then analyses information from different telephones close by to substantiate the wave is actual.

This information is collected and processed quickly along with the waves’ location and magnitude. The objective is to problem an alert earlier than the slower and extra damaging S-waves arrive. While P-waves can journey via each solids and liquids, S-waves transfer solely via solids. They additionally transfer up and down, displacing the fabric they transfer via.

AEA doesn’t monitor floor waves, the third sort of wave to reach in an earthquake. Surface waves are a lot slower and traverse solely the outermost layer of the crust, and are usually answerable for essentially the most aboveground harm.

Algorithm at work

To detect an earthquake, all smartphones financial institution on their accelerometers to sense vibrations on surfaces and in air. Earthquakes produce many such vibrations earlier than the power that causes harm truly reaches a location. The extent of harm attributable to a quake will increase with every sort of wave that reaches a location on the floor.

The algorithm estimates the gap to the epicentre in considered one of two methods. If it’s inside 200 km of the floor, it’s equal to the time distinction between the arrival of the S- and P-waves multiplied by 8 km/s. For deeper epicentres, the algorithm consists of extra strategies to account for the waves’ movement via the mantle.

The algorithm points two sorts of alerts: ‘BeAware’ alerts for impending mild shaking and ‘TakeAction’ alerts for stronger shaking; the latter are accompanied by an audio warning that overrides ‘do not disturb’ settings. Alerts will also be manually enabled and disabled.

According to the paper, the system has elevated the variety of folks with entry to earthquake early warning by almost an element of 10: from round 25 crore folks in 2019 to 250 crore folks in 98 nations.

The authors of the paper, who’re additionally affiliated with Harvard University and Google Germany, additionally highlighted the AEA’s shortcomings — together with its incapability to precisely estimate the magnitude and tendency to relay warnings after shaking has begun.

They additionally documented these points intimately and specified tweaks to repair many points, together with decreasing the median absolute error within the first estimates of a quake’s magnitude from 0.5 to 0.25. They additionally traced three false positives within the 11,321 occasions to 2 hurricanes and one mass telephone vibration from an unrelated alert, and included fixes for alerts to be issued sooner.

“The proliferation of low-cost sensors in consumer products provides opportunities for new observations of our physical environment that are both dense and global in scale. AEA makes it possible to make global observations of earthquakes,” the authors wrote.

Sandhya Ramesh is a contract science journalist.

Published – July 27, 2025 05:40 am IST