Ever wondered why some phones receive an early warning before an earthquake occurs?

Monday, 27 July 2026

In the early hours of Saturday 25th July, a magnitude 5.9 earthquake caused severe shaking, 5km south of Taumarunui at a depth of just nine kilometres.

GeoNet saw more than 23,000 felt reports on the event page, and across the motu, some Android users reported getting an alert on their phones before/ during the earthquake.

Android cellphones have a function called the ‘Android Alert System.’ This is based off very small accelerometers* that can sense vibrations which indicate that an earthquake may be happening.

*What’s an accelerometer you might ask? They’re electronic sensors that measure changes in physical speed, motion, tilt, and vibration. If an Android phone senses movement that could be an earthquake, it sends a signal and an approximate location to the Android earthquake detection system. The system then looks at information from many phones in the same area to work out whether the movement that has been sensed is actually an earthquake, rather than just a few people dropping their phones at the same time.

There are three types of warnings that you may receive if you have an Android phone. These include:

• ‘Be Aware Alert’ - sent to users who may experience light shaking from an earthquake that is M4.5 or greater. This alert will not override Volume or Do Not Disturb settings.
• ‘Be Ready Alert’ - sent to users who may experience moderate to strong shaking following a large earthquake. This alert may break through Do Not Disturb settings.
• 'Take Action Alert' - sent to users who may experience moderate to severe shaking after a magnitude 4.5 or greater earthquake. This alert will override Do Not Disturb settings and will turn on your screen and play a loud sound.

These alerts are not to be confused with the Emergency Mobile Alerts (EMA’s), which are official messages sent by authorised emergency agencies to all compatible mobile phones - Android, Apple or anything else you may be using.

Sending EMA’s is a manual process, and while predicting the future would be useful for many reasons, these unfortunately cannot be sent before an earthquake. Earthquakes happen extremely quickly with little-to-no warning, and the best thing you can do to prepare is to learn and practice Drop, Cover, Hold.

Want to learn more?

Visit the Get Ready website to learn more information about Drop, Cover, Hold and other ways to keep yourself safe in an earthquake: Drop, Cover and Hold — Get Ready (NZ Civil Defence) — Emergency preparedness in New Zealand

You can also visit the Get Ready website to learn more about Emergency Mobile Alerts: Emergency Mobile Alert — Get Ready (NZ Civil Defence) — Emergency preparedness in New Zealand

If you would like to know more about the Android Earthquake Alert System, visit: Crisis Stories Page: Android early earthquake warnings