SAN FRANCISCO (AP) — The U.S. Geological Survey says a computer at its Berkeley station mistakenly concluded the Napa area of Northern California had been hit by a magnitude-5.0 earthquake.

Richard Buckmaster, a geophysicist at the agency's National Earthquake Reporting Center, says officials are trying to determine why the computer generated the "dubious or erroneous" alert Friday.

He says the center's equipment saw no evidence that Napa had experienced even a much smaller quake.

The false alarm created a flurry of activity for earthquake watchers and news media but otherwise disappeared from the USGS system with the strike of a delete button.

Buckmaster says such inaccurate reports are rare in California.

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