L.A. County residents may have felt a rumble Friday morning, but it was not a reported earthquake— instead a “sonic boom” that traveled through the air.

The Southern California Earthquake Data Center (SCED) reported that a micro “sonic” shake occurred at 9:20 a.m., a mile from San Dimas, but logging in at 0.0 magnitude suggests it was not an earthquake.

“People have been asking about the ‘earthquake’ in LA around 9:20 this morning,” seismologist Dr. Lucy Jones said on Twitter Friday.  “Many people report feeling it but the seismograms clearly show the earth was not moving, only the air. So it was a Sonic Boom.”

Jones suggested the shake may have been caused by an aircraft, but as of this writing, there has been no indication of what caused the sonic activity.


LA Weekly