Many social media users in Venezuela reported receiving alerts on their Android smartphones moments before Wednesday’s earthquake, which killed more than 900 people.
Google’s Android and Apple’s iOS both include the ability to display government alerts during emergencies like earthquakes.
But the search giant also last year detailed its system that uses billions of Android smartphones around the world to detect earthquakes in the first place.
How it works
Almost all smartphones contain an accelerometer, a motion sensor used for tasks such as flipping the screen when users turn it sideways.
This same sensor “can also detect ground shaking caused by an earthquake,” Google wrote in a July 2025 blog post.
Accelerometers can detect the initial fast “P” wave of a potential earthquake, sending information about the tremor to a Google server.
By quickly cross-referencing many such reports, the system can “confirm that an earthquake is occurring and estimate its location and magnitude,” Google said.
“The goal is to warn as many people as possible before the slower, more damaging S-wave of an earthquake hits them.”
Google offers two stages of alerts.
“BeAware” warns of weaker shakes, while for more violent shakes, “TakeAction” takes control of the screen and emits a loud sound even when the phone is in silent mode.
How effective is the system?
Google said last year that its systems had already sent 790 million alerts to individual phones, warning of more than 2,000 potentially dangerous earthquakes detected as of April 2021.
While this gives many more people than before access to early warning information, there have been hiccups.
Android phones failed to issue warnings ahead of devastating February 2023 earthquakes that killed nearly 60,000 people in Türkiye and Syria.
Google said last year that it had since updated its algorithms to avoid a repeat.
The company also apologized in February 2025 for a false alert sent to some Android users in Brazil.
This week in Venezuela, hundreds of people praised Google on X, some including unverified videos of alerts urging people to leave buildings.
And Apple?
Beyond government warnings, Apple says on its website that users in the United States and Taiwan can also receive alerts from other “alert issuers” about earthquakes.
The company did not respond to AFPQuestions about how this system works at the time of publication.
The iPhone giant also hasn’t enlisted its users’ phones for a distributed detection system like Google’s.
The hundreds of millions of iPhones around the world, however, are able to transmit the alerts they receive to other nearby Apple devices that don’t have mobile reception or WiFi connections, which could potentially help vital warnings get through.
