FRESNO, Calif. – If you received a warning ahead of Tuesday night’s 5.2 magnitude earthquake that originated near the Kern County city of Lamont, you were likely one of millions, according to Governor Gavin Newsom’s office.
Those alerts originated from ShakeAlert, a public safety notification system devised by the U.S. Geological Survey (USGS) and rolled out across California in 2019. Earthquakes travel so fast across the Earth’s surface that alerts may arrive with only seconds before shaking actually begins. But Robert de Groot, USGS’s ShakeAlert team lead, says every second counts.
“The recommended protective action is drop, cover and hold on. And that should only take a person just a couple of seconds to do,” he said. The notifications can also be used by important infrastructure like public transit systems, hospitals and fire stations.
“Anything we can do to decrease the time between when we detect the earthquake at the surface to when something arrives on someone's phone—or that train slows down or the water valve is closed or the firehouse door opens—anything we can do to shave that time down is going to be helpful to us,” de Groot said.
Shakealert relies on data recorded by a network of hundreds of seismographs distributed throughout the Western states, as well as a handful of vastly powerful computing centers.
“It works on the idea that we detect an earthquake once it reaches the surface of the Earth,” said de Groot. “We move that information really fast to a processing center, and…that processing center, in basically one second or so, is able to determine an estimate of the size of the earthquake, where that earthquake is located and how much shaking can occur around that quake.”
That information is passed to Google and other companies that then send alerts to mobile phones within shaking distance of the quake, similar to how AMBER Alerts and severe weather warnings are delivered.
Whether or not someone receives a notification when they should depends on a handful of external factors, including the strength of their network connection, but also which operating system powers their phone.
If you’re an Android smartphone user, you should automatically be enrolled in public safety notifications like these. You can check whether they’re allowed in your phone’s “Wireless Emergency Alerts” settings.
If you use an iPhone, you may not necessarily be enrolled, and can check for permissions within your phone’s “Local Awareness” settings.
To be doubly prepared, you can download a free app called MyShake, which delivers push alerts depending on your home base and customizable notification settings.
