An alleged earthquake that rattled hundreds of thousands of homes in Southern California Friday morning wasn't actually an earthquake at all, seismologists say...
Dr. Lucy Jones, the state's top seismologist, says the jolt that rocked the area at 9:20 a.m. on Friday may have felt like an earthquake, but seismograms reveal there was no activity at that time.
Instead, the tremblor was the result of a sonic boom caused by a military aircraft, the Federal Aviation Administration reports.
NASA describes a sonic boom as "the thunder-like noise a person on the ground hears when an aircraft or other type of aerospace vehicle flies overhead faster than the speed of sound or supersonic."
(If you felt the sonic boom, you can report it to the U.S. Geological Survey HERE)