On Monday, August 3, 2026, a number of Egyptians woke up to a warning sound from their Android phones, telling them about an impending earthquake and urging them to take protective measures. Just a few seconds later, the buildings actually began to shake.
According to initial estimates, the earthquake struck around 3:00 AM Cairo time, measuring 5.2 on the Richter scale, according to the National Research Institute of Astronomy and Geophysics in Egypt. The tremor was felt in Greater Cairo and several other governorates.
But how did the phone know that an earthquake was coming before its owner felt it? And does this mean that Google has become capable of predicting earthquakes?
The short answer is "no," the earthquake had already started before the warning was issued, but its powerful waves had not yet reached the user's location.
To understand the concept, let's start with tectonic plates, which are huge rocky slabs that make up the Earth's crust and the upper part of the mantle, and move slowly over a softer layer. When they collide, earthquakes occur.
Tectonic plates move continuously and very slowly. An earthquake begins when rocks suddenly break or slide along a fault line formed between two tectonic plates. The breaking process starts at a point known as the "focus," and the rupture then gradually extends along the fault.
From the rupture zone, energy is released in the form of seismic waves that spread within the Earth and to its surface, in a manner similar to the circles that widen on the surface of water after a stone is thrown into it. Therefore, the vibrations reach the nearby areas first, and then reach the more distant areas after several seconds or perhaps minutes.
Smartphones contain a sensor called an "accelerometer," whose primary function is to detect the movement of the device. For example, it is responsible for knowing that the user has turned the phone to change the orientation of the screen.
Google has used this sensor to transform millions of phones into a kind of global network of tiny seismometers. When the phone is stationary, the accelerometer can pick up some ground vibrations, particularly in areas close to the earthquake's epicenter.
The system doesn't rely on a single phone, because a device falling off a table or a heavy truck passing by could cause a similar vibration. Instead, it searches for a large number of phones in the same area that recorded a similar pattern of movement at the same moment.
When this happens, phones send brief data to Google servers, which use algorithms to estimate the earthquake's location, strength, and the areas where the shaking is expected to reach.
Then alerts are sent to the phones of users located in the path of the seismic waves. Google researchers presented details of this system and its results in a study published in 2025 in the prestigious journal Science.
According to the study, user surveys showed that 85% of those who received the alert actually felt the tremor, and 36% of them received the alert before the shaking began, which is equivalent to the efficiency of expensive traditional monitoring networks in areas that lack such infrastructure.
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