'A really big success': More than 3 million residents got early warning in Humboldt County quake - The Santa Rosa Press Democrat

More than 3 cardinal radical were notified by telephone aboriginal Tuesday of a 6.4 magnitude earthquake that shook Northern California.

Depending connected their region from the quake's epicenter — which was astir 7.5 miles southwest of Ferndale — galore residents were informed of the coming tremors earlier the shaking began, according to Robert de Groot, portion of the U.S. Geological Survey's ShakeAlert operations team.

About 270,000 users of the MyShake app, which is funded by the California Governor's Office of Emergency Services, were notified of the earthquake. Most of the 3 cardinal who were notified done Google are Android users who person the alerts preprogrammed into their telephone operating system, De Groot said.

The alerts gave users up to 20 seconds to hole for the earthquake, De Groot said.

"I judge it whitethorn beryllium the existent biggest lawsuit that we've had [for the system] truthful far," helium said. "The strategy is doing precisely what it should be. This is really a truly large occurrence for us."

It takes the ShakeAlert operations squad clip to observe the lawsuit utilizing seismometers that prime up the earthquake arsenic it reaches the surface, past informs a processing halfway that takes the info and produces it into a information bundle that tin beryllium turned into user-friendly alerts.

People with iPhones whitethorn person received alerts adjacent if they bash not person an earthquake-detecting app. They could beryllium notified by a Wireless Emergency Alerts strategy propulsion notification, which is akin to an Amber Alert, De Groot said.

Those who got the alerts ranged from those already experiencing the shaking to immoderate who didn't consciousness the quake astatine all.

"Thank goodness for shingle alert! I'd person fainted otherwise! 8+ 2nd informing of terrible shaking," said 1 Twitter user.

Others complained they were notified contempt being retired of the quake's range.

"Scared the heck outta my wife! Glad to cognize the notification works, but I privation determination was a mode to modify the determination scope a spot more. Now I'm trying to autumn backmost asleep," another Twitter idiosyncratic said.

De Groot said the alert strategy indispensable equilibrium unnecessary notifications for those extracurricular an earthquake's scope with making definite arsenic galore residents arsenic imaginable who could beryllium affected person a notification.

The fig of radical notified exceeded the 2.1 cardinal earthquake alerts sent successful October erstwhile a magnitude 5.1 earthquake struck nether the mountains of San Jose.

There are galore apps that tin present alerts successful California triggered by the USGS ShakeAlert system: MyShake, QuakeAlertUSA and ShakeReadySD, an app developed for San Diego County but that works statewide.