Earthquake alert system shows strong promise across Alaska
Their study, published in the Bulletin of the Seismological Society of America, found that denser and more evenly distributed seismic station networks could further increase warning times by 5 to 15 seconds. Alaska, home to tens of thousands of annual earthquakes and some of the most powerful in recorded history, stands to benefit significantly from such a system.
The findings could guide efforts to extend the U.S. ShakeAlert early warning network beyond California, Oregon, and Washington into Alaska.
"There were a lot of studies before EEW was widely available on the West Coast, where people were looking at different scenarios," said lead author Alexander Fozkos. "So we wanted a similar kind of science up here with numbers that are Alaska specific."
Fozkos and co-author Michael West modeled multiple earthquake types. For magnitude 8.3 quakes along well-known coastal faults, warning times could range from 10 to 120 seconds. Magnitude 7.3 crustal fault events in interior and southcentral Alaska might yield alerts between 0 and 44 seconds in advance. For magnitude 7.8 quakes along the dipping subducting slab beneath the state, potential warning times spanned 0 to 73 seconds.
Dense seismic station coverage along the coast explains the stronger performance there, said Fozkos. "I was not expecting decent warning times for the shallow crustal events, so that was the biggest surprise to me."
The research examined differences in warning times based on event magnitude, depth, fault style, and location. The team measured how long it would take to detect the quake, generate an alert, and how early that alert would arrive at a given location before peak ground shaking.
Instead of using the traditional S-wave arrival as the warning benchmark, Fozkos and West based their metric on peak ground motion - arguing that it better aligns with how people experience an earthquake. In large events, strong shaking may lag the initial S-wave by tens of seconds.
The study did not account for the time required to transmit and deliver alerts to users. "That could be a big challenge for Alaska, but I don't think it's going to be insurmountable," said Fozkos.
He also flagged operational issues such as limited access to remote seismic stations, especially in winter, and emphasized the need for system redundancy. The inclusion of ocean-bottom seismometers and distributed acoustic sensing could bolster detection capacity, especially for tsunamigenic offshore earthquakes.
Research Report:Earthquake Early Warning Scenarios for Alaska
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