Earthquakes in the Puget Sound region usually start with no warning, leaving people to scramble for safety. But a new early-warning system, under development, could deliver emergency alerts to thousands of cellphones before the shaking begins.
The advance notice might come only a few seconds ahead of the earthquake if the epicenter is close. That might be enough time to stop the car, turn off the stove or get out of a dangerous location.
For a Cascadia subduction quake along the Washington coast, Kitsap residents might receive a warning of three to four minutes. That could be enough time to shut down industrial equipment, halt surgical procedures or get away from a dangerous building.
The ShakeAlert early-warning system, which is being constructed for the entire West Coast, relies on a network of seismometers to measure the first seismic waves that emanate from an earthquake. These initial waves, known as P waves, travel faster than the more damaging S waves and surface waves that follow.
Data are transmitted from the seismometers at the speed of light across wires or fiber-optic cables. Computers analyze the information to determine the size and location of the earthquake, said Bill Steele, communication director for the Pacific Northwest Seismic Network at the University of Washington.
When the system is fully operational, information about the coming earthquake will be routed to cellphone networks for transmission to mobile phones. An app on the phone will calculate when the user can expect the shaking to begin and possibly the intensity of shaking at that location.
"It takes about 4 seconds to analyze the data after four stations trigger the system," Steele said.
Currently operating on desktop computers, the system is being tested for accuracy and reliability, he said. Last year, when a small earthquake occurred near Olympia, the system was able to deliver a 12-second warning to Seattle. More than 20 agencies and businesses are now connected and testing the system.
Some of the existing seismometers need to be replaced to increase their speed of data transmission, Steele said, and additional ones are needed to better cover the areas where earthquakes are likely to occur.
"We're now going through and replacing instruments more than 20 years old," Steele said. "It will take a couple of years to do this."
The U.S. Geological Survey recently appropriated $5 million for the upgrades with funds going to the University of Washington, University of Oregon, University of California at Berkeley and California Institute of Technology. That's about 40 percent of the amount needed to complete the setup, Steele said. Initially, software development and research along with startup equipment were funded with an $8 million grant from the Gordon and Betty Moore Foundation.
The fully operational network will cost about $16 million per year to operate and maintain.
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