The feature, known as the Android Earthquake Alerts System, uses sensors inside Android smartphones to help identify vibrations that may indicate an earthquake. When enough devices detect similar movement in the same area, Google’s system can issue an alert to users nearby.

The tool is already active in Portugal and can provide warnings shortly before or just after seismic shaking is detected, depending on the distance from the epicentre and the strength of the quake.

To check whether the function is enabled, Android users can go to their phone settings, enter the “Safety and emergency” section and look for earthquake alerts. The wording may vary slightly depending on the device and Android version.

The system works by using the accelerometers already built into smartphones. These sensors can detect sudden movement, and when multiple phones register similar signals at the same time, the data can help identify possible seismic activity.

For iPhone users in Portugal, there is currently no equivalent Google alert system. Apple devices may display government emergency alerts in some countries, but Portugal does not yet have a nationwide earthquake early-warning system integrated into iOS.

Alternative for iPhone users

The main alternative for iPhone users is the official sismos@IPMA app from the Portuguese Institute for Sea and Atmosphere. The app allows users to consult recent earthquakes, view epicentres on a map and access official IPMA information.

However, the IPMA app does not operate as an early-warning system in the same way as Google’s Android tool. Instead, it provides official information after seismic activity has been registered.

The difference between Android and iPhone systems became a topic of discussion after recent earthquakes were detected across the Atlantic region, with some Android users receiving automatic notifications while iPhone users did not.

Portugal is located in a seismically active zone, making earthquake information particularly relevant for residents, especially in areas such as the Algarve, Lisbon region and the Azores.

While mobile alerts cannot prevent earthquakes, they can give users quicker access to information and may provide valuable seconds to react in certain situations.