Dozens of residents across the county reported the shaking, which they said mostly caused windows and doors to rattle, at about 9:15 p.m. Tuesday, a time that Edwards Air Force Base said did not line up with any space shuttle activity, the Orange County Register reported Thursday.
Bob Dollar, a seismologist at the U.S. Geological Survey, ruled out an earthquake as the cause of the shaking.
"We did not record any earthquake tonight that could have caused this kind of shaking around Orange County," he said.
High explosive activities were scheduled for Tuesday at U.S. Marine Corps Camp Pendleton, but a base official said he did not notice any shaking and sounds and vibrations from live fire exercises at the base are rarely noticed beyond the southern-most portion of the county.
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