PORTLAND, Oregon —
The earthquake early-warning system on the West Coast got a big upgrade recently.
ShakeAlert, the system that can send notifications of an impending earthquake, now uses data from satellites to better detect, and provide warnings for, the region’s largest temblors.
“While rare, earthquakes greater than magnitude 7 can have the greatest impact on human lives and infrastructure,” Robert de Groot, with the USGS ShakeAlert Operations Team, said in a statement. “Future major offshore earthquakes in the Pacific Northwest, which could be similar to the 2011 M 9.1 earthquake in Japan, underscore the importance of incorporating satellite data stream into the ShakeAlert System.”
The system uses a network of more than 1,500 ground-based seismic sensors that can detect the first signs of shaking and alert residents and government agencies before the ground starts moving where they are.
The lead time can range from a few seconds to more than a minute.
That can give residents time to take cover and government agencies to shut off water valves, stop trains or open firehouse doors to prevent them from jamming shut.
Those sensors do a stellar job of detecting small- to medium-strength quakes, said Diego Melgar, director of the Cascadia Region Earthquake Science Center and a professor at the University of Oregon, but the sensors might struggle with larger quakes above Magnitude 7.0.
“During really big earthquakes, the land, the coast — especially for the earthquakes we get in Oregon and Washington — will move out to sea by 9, 10, 12 feet,” Melgar said.
The seismic sensors can measure how quickly the ground is moving, but not necessarily how far it’s moving. Using GPS sensors and satellites solves that problem, Melgar said.
“That 12 feet, the seismometers struggle with that,” he said. “But because this is GPS technology, quite literally the same technology you have on your phone, if something moves 12 feet and it's moving 12 feet from Northern California to Washington, that’s not a Magnitude 7. That’s something really big.”
The Cascadia Subduction Zone, which runs off the West Coast, is due for another large earthquake, having last ruptured in 1700.
So, it’s not a matter of if, but when. That shouldn’t be a reason to cower in fear, though, Melgar said.
“It is an inevitability over the long run,” he said. “This is an example of how, rather than despair and have doom and gloom about the inevitability of these big events, there are things we can do.”
Most cell phones come preset to receive the alerts through the Wireless Emergency Alert system, but there are third party apps available for download as well.
Melgar said the system is a prime demonstration of how years of study and research, which often occurs out of public view, can have big benefits for communities.
“ShakeAlert is an example of getting off our hands and actually putting science and technology to societal use,” he said.