During the 6.2 magnitude earthquake in Istanbul on April 23, some smartphone users received early warning alerts just seconds before the shaking began. Thanks to this feature provided by Google, many people were able to escape quickly during the earthquake that struck off the coast of Silivri in the Marmara Sea.
Experts shared their assessments with Anadolu Agency (AA) regarding the operation and reliability of the early warning system.
Geological engineer Okan Tüysüz emphasized that the earthquake was not the expected great Marmara earthquake, noting that the fault had not completely ruptured. If it had, an earthquake of more than magnitude 7 could have occurred.
Tüysüz said that aftershocks would continue for at least a week and potentially for a month or even longer, adding: “There is a major unruptured fault in the Marmara Sea that we expect to produce an earthquake. When it will rupture remains unknown.”
Tüysüz also mentioned that an early warning system is being developed by the Kandilli Observatory, saying: “There are two types of waves in earthquakes: ‘P’ and ‘S’ waves. The first wave travels at about 7 kilometers per second, and the second at about 4 kilometers per second. There is a time difference between them. When the first one arrives, some devices detect it. Once it is detected, it is certain that the second one will follow, and you are notified.”
Tüysüz explained that the system is built around this concept: “If you are 8-10 kilometers (5-6.2 miles) away from the earthquake’s epicenter, you might have only 1-2 seconds. If you’re further away, this time can stretch to 8-10 seconds. As the earthquake wave travels to you, there is a delay that can provide precious seconds to flee or take shelter – though in places close to the fault line like Istanbul, it may not give people much time. Still, it can cut electricity, stop trains and shut off gas lines.”
He added: “We already have such a system in the Marmara Sea. It shuts off gas and electricity, stops subways and high-speed trains. The system is functioning, but it hasn’t yet developed to a level where it can be used reliably by the public.”
Tüysüz also warned that these notifications can sometimes cause panic: “Because the time is so short, sometimes people might react poorly. You might have just one second and in that second, someone might jump out of a window.”
IT expert Osman Demircan stated that early warning alerts are currently only available on Android devices and explained how the system works.
Demircan said: “By design, phones can react when we pick them up. If the phone is stationary and the ground begins to shake slightly, it interprets those vibrations as a potential earthquake. It also analyzes signals from other phones in the area to determine whether it is indeed an earthquake and begins sending alerts.”
He emphasized that these alerts do not predict earthquakes but warn during the event itself: “What enables these alerts is the vibration data collected from stationary phones. The first point of vibration, the impact area and the estimated arrival time of the shaking are analyzed. If you get a message and then the earthquake happens a few seconds later, that means the quake already started before the alert. These systems cannot predict quakes in advance.”
Demircan affirmed the reliability of the collected data, explaining: “It’s quite reliable because it doesn’t rely on just one phone. The system collects data from all phones that have this feature enabled and that have given permission to share data. It also uses AI to evaluate the data statistically. So far, it hasn’t caused any problems. Whenever a quake was reported, it actually happened. Sometimes people receive the alert but don’t feel the quake – this is usually because they are at the outer edge of the affected area.”
Highlighting the importance of internet connectivity, Demircan added: “Android users who enable the earthquake warning system and location services can both send and receive this information. An internet connection is essential because the system needs to retrieve the data from somewhere. Without it, you won’t receive the alert.”
Demircan concluded: “In some of the videos I watched after the quake, there were families who managed to leave their homes within five seconds. Sometimes, five seconds can really save lives. In stronger, more destructive earthquakes, these systems could be life-saving for many families.”