Yesterday afternoon a magnitude 5.1 earthquake hit the San Francisco area, the largest in the area in the better part of a decade. But for those carrying an Android phone, there was an early warning to the earthquake for residents of San Francisco and the nearby areas and The Governor’s Office of Emergency Services says about 90,000 people received an alert on their phones seconds before they felt the quake.
In 2020, Google released the “Android Earthquake Alerts System,” which crowdsources data from Android smartphones to offer an early warning when an earthquake is about to strike your area.
Brian Ferguson, Deputy Director of Crisis Communication and Public Affairs at the Governor’s Office of Emergency Services said “We actually have the most advanced technology in the country in terms of helping people get notifications even before shaking starts. And this is one of the biggest events we’ve actually had since the system launched,”.
The system works by using the sensors on your phone to detect an earthquake’s “P-Wave,” which is a smaller initial wave that arrives before the more destructive “S-Wave.” Using your phone and those of people around you, the system can detect an earthquake and offer a few precious seconds of early warning. The system expanded worldwide in 2021 but, in the California area, it interacts with “ShakeAlert,” a service designed by researchers at Berkley and which is integrated into Android’s system. “ShakeAlert” uses proper seismometers to detect and send these alerts from the USGS.
In the time since the system went online, Google has shared examples of when it worked, including in a 4.5 earthquake in Los Angeles as well as a later 6.7 quake in the Philippines in 2021, where many expressed how the system gave them several seconds of warning before the quake could actually be felt.
Google’s VP of Engineering for Android, Dave Burke, came to Twitter hours after the quake to show what the system detected. In the tweet below, he shows the system’s estimate of the P and S waves.
Earthquake in SF Bay Area today. Yellow/red represents shaking Android phones acting as seismometers. Circles are our inferred estimate of P & S waves. Earthquake alerts sent instantaneously to surrounding phones before the waves hit pic.twitter.com/8pumt19ReI
— Dave Burke (@davey_burke) October 26, 2022
The early warning notifications sent out hit Android phones almost instantaneously, with many noting the seconds of warning on Twitter, and many others asking why Apple’s iPhones don’t mirror the same functionality. A member of Google’s security team for Android expressed that this comes from the “power of open” while relying his experience of seeing his Android phone alert the quake seconds before it hit, while an office visitor’s iPhone didn’t get an alert until after the quake had already struck.
My Android phone alerted me to today's earthquake several seconds before it struck. Office visitor with an iPhone received the alert several seconds after. We were very close to the epicenter. #powerofopen
— David Kleidermacher (@DaveKSecure) October 26, 2022
If you have an Android phone, you should’ve automatically received the alert. But iPhone users need to download the MyShake app and set their location in order to get the alert.