The scene was repeated with small variations in homes, businesses and companies throughout Venezuela: a bell rings insistently on the cell phone, people hear it, look at the screen and, after a brief uncertainty, leave the place to protect themselves. Seconds later, everything starts to shake.

This is how Google's earthquake warning system warned millions of Venezuelans about the double earthquake that occurred in that country on June 24.

The earthquake warning was sent to 11.4 million people in Venezuela who, according to the technology giant, had a period that varied from a few seconds to two minutes to react before feeling the onslaught of the powerful 7.2 magnitude earthquake that, seconds later, was followed by another magnitude 7.5.

In that context, and given that Venezuela does not have a national early warning system for this type of event, it is likely that Google's system has helped prevent deaths and injuries.

How does it work?

Millions of small seismometers

An article published in 2025 by Marc Stogaitis, principal software engineer for Android, explains how Google has worked to develop an earthquake early warning (EEW) system using measurements they can obtain from the global network of Android phones.

“The accelerometer of an Android phone – the same sensor that rotates the screen when the device is placed on its side – can also detect ground movement caused by an earthquake,” he explains in the text.

This instrument, as he points out, is used to detect the initial P wave of an earthquake and sends a signal to Google's seismic detection server.

As there are millions of Android phones around the world, the system is fed with information from devices located in the affected area, allowing Google to estimate the location, scope and intensity of the earthquakes. And then they send the alerts to all Android devices in the affected area.

The advantage of accelerometers measuring P waves is that they travel at a higher speed and are less destructive than the secondary waves - also called S waves - generated by an earthquake. This saves valuable time.

The only requirement is that the phones that capture these waves have to be stationary.

According to Google, the objective of this system is to collect information quickly and alert as many people as possible before the most destructive S waves arrive.

Two types of alert

Android only sends notifications when earthquakes of magnitude 4.5 or greater are recorded and offers two types of alerts:

The phones must have connectivity through either the cellular network or Wi-Fi and must have both location and EEW activated to receive alerts.

According to Google, during the double earthquake in Venezuela, both types of alerts were issued and around 1.4 million users received the most severe warnings asking them to take measures to protect themselves.

In its article in 2025, the technology company said that its earthquake warning system was available in a hundred countries. In many of these, such as Venezuela, they lack their own earthquake warning system.

According to Google, this system has allowed the number of people in the world who have early warnings of earthquakes to multiply by 10, going from 250 million in 2019 to 2.5 billion in 2025.