Our phones can alert us to earthquakes — but there’s a catch

{"text":[[{"start":null,"text":"

"}],[{"start":8.1,"text":"The writer is a science commentator"}],[{"start":11.18,"text":"As the years fly by and I spend more time squinting at shrinking fonts, I have become used to switching my phone from portrait to landscape orientation. Smartphones contains an accelerometer, a component able to sense when the phone moves and in which direction; this prompts the display to adjust. The same sensor enables step-counting."}],[{"start":35.11,"text":"According to a paper published in Science last week, inbuilt accelerometers can also turn networks of Android smartphones into crowdsourced earthquake detection systems. Smartphones might be less sensitive than traditional seismometers but, when shaking en masse, they become a useful tool for quake-spotting, especially in populated areas lacking conventional warning systems."}],[{"start":64.45,"text":"The innovation is undoubtedly good news, especially as feedback surveys show that users overwhelmingly trust it. Advance notice of even a few seconds allows people to follow potentially life-saving advice to “drop, cover and hold on”. But this comes with policy implications: the data and algorithms count as proprietary information, which independent seismologists cannot easily access. While civil and elected authorities are responsible for keeping citizens safe, what happens when some of the information that makes a difference lies in private hands? We may face this question more often as tech companies find new ways to parse the data collected by our omnipresent devices."}],[{"start":113.69,"text":"The analysis was led by Richard Allen, director of the Berkeley Seismology Laboratory at the University of California and a visiting researcher at Google. It looks at the free Android Earthquake Alerts system, rolled out from 2020 as a default option on Android devices in 98 countries."}],[{"start":135.07999999999998,"text":"The system relies on detecting sudden increases in acceleration produced by the seismic waves associated with earthquakes. When many phones in a region are triggered, the information, together with approximate location data, is sent to Google servers. If the shaking matches the pattern for an earthquake, then the system estimates its magnitude, time of origin and “hypocentre” (its origin below ground). For magnitude 4.5 quakes or higher, an alert goes out to phone users in the region, in the hope of warning people before the worst shaking. AEA also shares messages from existing warning systems, such as ShakeAlert in the US."}],[{"start":181.07999999999998,"text":"By March last year, the system had detected more than 11,000 events globally and issued more than 1,200 alerts. Two levels of alert can be sent out, depending on quake size and distance from the origin: a “BeAware” message or a louder “TakeAction” notice capable of overriding do-not-disturb settings."}],[{"start":204.45999999999998,"text":"Cross-checking with seismic catalogues afterwards showed that more than 99 per cent of the 11,000 detected quakes turned out to be genuine. The system was duped very occasionally by thunderstorms and mass notifications causing multiple phones to vibrate at the same time. Researchers have since revised the algorithms to cut the risk of false alarms."}],[{"start":230.29999999999998,"text":"But, in common with other systems, it struggled with the most powerful earthquakes. The rarity of large-magnitude events means training data for algorithms is sparse. The Android system underestimated the magnitude of the devastating 7.8 and 7.5 earthquakes in Turkey in 2023 and issued lower-level alerts. One flaw, since corrected, was that the alerts themselves caused some phones to vibrate, masking some tremors."}],[{"start":266.69,"text":"Allen Husker, a seismologist at the California Institute of Technology in Pasadena, told Nature he found the AEA “very impressive” but added he would feel better if independent scientists could access the data and algorithms."}],[{"start":285.37,"text":"Richard Allen and co-author Marc Stogaitis, a principal software engineer at Google, told the FT that the system was not meant to replace official earthquake detection or alert systems, while acknowledging it was valuable in places that lacked them. They added: “We recognise the importance of transparency and are committed to building trust in the system.” They point out that Google welcomes academic collaboration, including through a visiting researcher programme, but the company’s commitment to user privacy meant “sharing data from users’ phones to help further research is a challenging path”."}],[{"start":325.47,"text":"These are fascinating times. Between 2020 and 2023, the Android system increased the number of people signed up to quake alerts from 250mn to 2.5bn. A technology company is inspiring levels of trust and offering a measure of crisis protection that many governments cannot. In some quarters, that should perhaps merit a tremor."}],[{"start":361.1,"text":""}]],"url":"https://audio.ftmailbox.cn/album/a_1755657248_2302.mp3"}