Pacific Northwest Geodetic Array Quantifies Earthquakes

Scientists now can track the minuscule motions of shifting plates as they happen, thanks to an expanded network of GPS sensors that covers the region like a blanket and beams back data almost instantly.

"If the Pacific Coast or Mount Rainier moves a couple of centimeters, we'll see it within five seconds," said Tim Melbourne, director of the Pacific Northwest Geodetic Array, or PANGA. Once the network's "real-time" functions are fully operational, PANGA will be able to pinpoint some earthquakes more quickly and accurately than traditional seismometers — and eventually issue warnings before destructive shaking hits cities or tsunami waves slam the shore.

Scientists use the GPS data to calculate the gradual buildup of strain on faults and identify the places most likely to pop. Dozens of the sensors also sit atop structures such as the Alaskan Way Viaduct and Howard Hanson Dam, on watch for unexpected slumps or jiggles.

"The Northwest is really leading the nation in this right now," said Melbourne, a geology professor at Central Washington University in Ellensburg, where PANGA is based.

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