How Phones Alerted Millions Before Quakes Shook Venezuela
How Phones Alerted Millions Before Quakes Shook Venezuela
Publish Date: 2026-06-27 01:23:00
Source Domain: www.nytimes.com
Jose Flores was driving with his family to see “Toy Story 5” on Wednesday in Caracas, Venezuela, when a loud earthquake alert went off on his wife’s Google Android phone. Six seconds later, he felt the earth starting to shake.
Venezuela does not have a national early warning system of its own, but people with Android phones received alerts from Google’s Earthquake Alerts system, which can pull data from more than two billion phones equipped with built-in accelerometers. The same sensor that detects rotation on the screen can also sense vibrations from seismic waves.
Three seconds after the quake started underground
Seismic waves reached the surface and were picked up by phones.
Phones detecting seismic activity
Google said the system, which is available in nearly 100 countries, sent warnings that reached 11.4 million people on Wednesday, giving users seconds or up to two minutes notice before back-to-back powerful earthquakes struck.
Several countries, including Japan, Mexico, Canada and the United States, have government-operated early warning systems. These largely rely on widespread regional networks of underground sensors that detect earthquakes and can send alerts to most phones — iPhone or Android — via government alert settings that are often enabled by default.
When earthquakes hit, they send out two types of waves that travel at different speeds. The fast-moving and milder primary waves, or P-waves, travel at four miles per second and are less likely to cause destruction. The slower and stronger secondary waves, or S-waves, travel at about half that speed and produce shaking.
When P-waves start radiating from the epicenter, Android phones sense the vibrations, start collecting data and send it back to Google servers for processing. The servers use information from many phones to figure out if an earthquake is happening. The phones have to be stationary — on a tabletop or in a bag on the floor, for example, and not in the pocket of…
