California earthquake puts early warning system to the test
When sensors detected the first signs of a powerful earthquake striking the northern California coast, an alert was sent to 3 million smartphone users telling them to “Duck, Cover, Hold.” It was hailed as the largest test yet of the alert system since its public launch.
But people most scared by magnitude 6.4 earthquake Early Tuesday morning they said the alert did not give them enough time to take cover as the tremor shook the foundations of homes, knocked out power and water to thousands and injured more than a dozen people.
Jimmy Eller, who was sitting in his parked Chevy Malibu while working as a security guard, said he was already in the middle of the violent earthquake when he noticed his phone had turned on with the warning. He was more focused on what was happening outside when the streetlights began to sway.
“Everyone was wobbling, turning on and off,” Eller said. “I could see switches and wires in the distance flashing like lightning. It was terrifying. You could see everything moving and shaking.”
Earthquake centered near the small town of Ferndale, about 210 miles (345 kilometers) northwest of San Francisco. It was the largest that the ShakeAlert early warning system has alerted to, since its public launch in California three years ago.
“It’s really a first and innovative tool in the nation that hopefully saves lives,” said Brian Ferguson, spokesman for the California Governor’s Office of Emergency Services.
ShakeAlert was developed by university researchers and is operated by the US Geological Survey. It is one of the few earthquake alert systems created in different parts of the world over the past decades, including Japan and Mexico. But the new technology, which is operating in California, Oregon and Washington, is not without its challenges.
Before alerts can be sent to people’s phones, several seismometers must detect movement below the Earth’s surface. That information can be processed to determine the location and magnitude of the earthquake. That process, from seismometer detection to sending an alert, is completely automated, said Robert de Groot, a scientist on ShakeAlert’s operations team.
Some people received the alert 10 seconds in advance. Because of how the system works, people closest to the center of the quake may not have been alerted until they felt the tremor, de Groot said.
Jen Olson, who lives in Arcata, about 25 miles (40 kilometers) from the epicenter, said she was woken by a tremor and her phone rang at the same time. She’s not sure what she woke her up first, but she said she woke her up. loud noise Y bright light of her phone probably helped her realize the severity of the earthquake.
Worried about her dog, who was sleeping in a crate, she got up quickly and headed for the back door, to take cover or get out if the house began to collapse.
“It might have taken me longer to wake up if the phone hadn’t been making a lot of noise,” he said.
Jay Parrish, the Ferndale city manager, said he was not aware anyone received the alert. Unlike a tsunami or flood where there is plenty of time to prepare for a possible disaster, he did not think that an earthquake alarm system could provide sufficient advance notice.
Told the alarm went off for about 10 seconds before the violent shaking, he said: “That could have saved one of my glass jars.”
It’s hard to pinpoint why someone who should have received the alert didn’t without more information, de Groot said. Some people may have disabled notifications from Wireless Emergency Alerts, the same system that runs the federal government that sends Amber Alerts to phones.
A glitch in an earthquake alert app for San Diego residents that relies on the system’s data falsely alerted people more than 650 miles (1,040 kilometers) from the epicenter.
This was the first time the system had alerted people in two states, California and Oregon, de Groot said. A study is underway to explore future alerts in parts of Alaska.
Several apps use ShakeAlert data to notify people that they could experience significant effects from earthquakes. People were alerted within a radius of about 250 miles (400 kilometers) from the epicenter of Tuesday’s northern California earthquake, said Richard Allen, director of the Seismology Laboratory at the University of California, Berkeley.
In a 2021 blog to postthe Seismology Laboratory explained why we don’t know when an earthquake will occur before it starts.
“The physical processes along a seismic fault before and during a rupture are so complex that seismologists have all but given up trying to achieve the elusive goal of predicting when a strong earthquake will strike,” it said.
The lab developed an app called MyShake that notified some 270,000 residents of the tremor.
“From a technical standpoint, I would say the system did a great job,” Allen said.
Allen said the next step is to help people understand the importance of dropping to the ground so they do it automatically, which could help prevent injuries.
About 140 miles (225 kilometers) from the center of the earthquake, Anna Hogan, a student at California State University Chico, was on the phone with her brother when an alert came through. She took cover. And even though she didn’t feel the quake, she’s glad she moved to a safer place.
As someone who has lived in earthquake prone areas like Alaska and San Francisco, you know the cost they can charge.
“It scared me, yeah,” he said of the alert. “But being able to shelter in place is better than not at all.”
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Citation: California Earthquake Tests Early Warning System (Dec 22, 2022) Retrieved Dec 22, 2022 from https://phys.org/news/2022-12-california-earthquake-early.html
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