California earthquake puts early warning system to the test

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California earthquake puts early warning system to the test

A cell phone customer looks at an earthquake warning application on an iPhone on January 3, 2019 in Los Angeles. Seconds before a magnitude 6.4 earthquake shook the Northern California coast, a telephone warning warned 3 million people to “Drop, cover, hold.” The event marked the largest test yet for an earthquake warning system launched three years ago. Credits: AP Photo/Richard Vogel, File

When sensors picked up the first signs of a strong earthquake shaking the Northern California coast, a warning was issued to 3 million smartphone users telling them to “drop, cover, hold.” It was hailed as the warning system’s largest test to date since its public launch.

But humans were rattled the most by magnitude 6.4 earthquake Early Tuesday, he said the alarm didn’t give them enough time to run for cover as the quake shook houses off their foundations, knocked out power and water for thousands and injured more than a dozen people.

Jimmy Eller, who sat in his parked Chevy Malibu while working as a security guard, said he was already in the throes of the violent earthquake when he noticed his phone lit up with the warning. He was more focused on what was happening outside when streetlights started swaying.

“They all wobbled, flashed on and off,” Eller said. “I could see breakers and wires flashing in the distance like lightning might look like. It was terrifying. You could see everything moving and vibrating.”

The earthquake was centered near the small town of Ferndale, about 345 kilometers northwest of San Francisco. It was the largest the ShakeAlert early warning system has warned about since it publicly launched in California three years ago.

“It’s truly a groundbreaking tool that’s the first in the nation to work and hopefully save lives,” said Brian Ferguson, a spokesman for the California Governor’s Office of Emergency Services.

ShakeAlert was developed by university researchers and is administered by the US Geological Survey. It is one of the few earthquake warning systems created in recent decades in various parts of the world, including Japan and Mexico. But the new technology, which is active in California, Oregon and Washington, is not without its challenges.

Before alerts are sent to people’s phones, multiple seismometers must detect movement below the Earth’s surface. That information can then be processed to determine the location and magnitude of the earthquake. That process, from seismometer detection to sending an alert, is all automated, says Robert de Groot, a scientist on the ShakeAlert operations team.

Some people received the alert with 10 seconds notice. Because of the way the system works, those closest to the quake’s center may not have received a warning until they were shaking, de Groot said.

Jen Olson, who lives in Arcata, about 25 miles from the epicenter, said she was awakened by shaking and her phone rang at the same time. She’s not sure what woke her up first, but she said it loud sound and clear light from her phone probably helped her realize the severity of the earthquake.

Concerned about her dog sleeping in a crate, she quickly got up and headed for the back door, either to take shelter or to get out if the house started to collapse.

“It might have taken longer for the vibration to wake me up if the phone hadn’t also been making a lot of noise,” she said.

Jay Parrish, Ferndale’s city manager, said he wasn’t aware anyone was getting the warning. Unlike a tsunami or flood where there is plenty of time to prepare for a potential disaster, he did not think an earthquake warning system could report sufficiently in advance.

When told the alarm went off about 10 seconds before the violent shaking, he said, “That might have saved one of my mason jars.”

It’s hard to pinpoint why someone who should have received the warning didn’t do so without having more information, De Groot said. Some people may have disabled notifications from Wireless Emergency Alerts, the same system operated by the federal government which sends Amber Alerts to phones.

California earthquake puts early warning system to the test

Dr. Lucy Jones, senior risk mitigation consultant for the US Geological Survey, describes how an early warning system could warn of an earthquake at a news conference at the California Institute of Technology’s Seismology Laboratory in Pasadena, Calif. on Jan. 28, 2014. Seconds before a magnitude-6.4 earthquake shook the Northern California coast, a telephone alert warned 3 million people to “Drop, cover, hold.” The event marked the largest test yet for an earthquake warning system launched three years ago. Credits: AP Photo/Reed Saxon, File

A glitch in an earthquake warning app for San Diego residents that relies on the system’s data falsely warned people more than 650 miles (1,040 kilometers) away from the epicenter.

This was the first time the system had alerted people in two states, both California and Oregon, de Groot said. A study is underway to investigate alerting in parts of Alaska in the future.

Several apps use ShakeAlert’s data to notify people who may be experiencing significant earthquake effects. People were warned within about 250 miles (400 kilometers) of the epicenter of the Northern California earthquake Tuesday, said Richard Allen, director of the Seismology Lab at the University of California, Berkeley.

In a blog from 2021 afterthe Seismology Lab explained why we don’t know when an earthquake will happen before it starts.

“The physical processes along an earthquake fault before and during a rupture are so complex that seismologists have almost given up trying to achieve the elusive goal of predicting when a strong earthquake will occur.

The lab developed an app called MyShake that alerted about 270,000 residents to the temblor.

“From a technical point of view, I would say the system has done a great job,” said Allen.

Allen said the next step is to help people understand the importance of falling to the ground so they do it automatically, which could help prevent injury.

About 140 miles from the earthquake’s center, Anna Hogan, a student at California State University, Chico, was on the phone with her brother when an alarm came through. She took cover. And while she didn’t feel the earthquake in the end, she’s glad she moved to a safer place.

As someone who has lived in earthquake-prone areas like Alaska and San Francisco, she knows the toll they can take.

“It scared me, yes,” she said of the warning. “But being able to shelter in place is better than nothing.”

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Quote: California earthquake challenges early warning system (2022, December 22) Retrieved December 22, 2022 from https://phys.org/news/2022-12-california-earthquake-early.html

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