A thunderous boom shook windows and rattled residents across San Diego County Friday and some took to social media looking for answers. As has become routine with such events, reasons proved elusive.
No earthquakes were detected in the area Friday, according to data from the U.S. Geological Survey, casting suspicion on the source of other similar "boom" events of the recent past — the military.
Recent boom events have been blamed on sonic booms, when aircraft travel faster than sound as sound and air pressure waves combine to create shock waves, according to the U.S. Air Force. If a supersonic aircraft turns or pulls up, those shock waves can be directed toward the ground and travel for miles.
San Diego is home to the Navy's 3rd Fleet, two nuclear-powered aircraft carriers and several Marine Corps fighter squadrons capable of supersonic flight.
Both San Diego-based aircraft carriers were in port at Naval Air Station North Island Friday morning, the Navy said. The aircraft carrier Nimitz, which frequently operates near San Diego, is currently deployed to the Philippine Sea, according to Pentagon photos published Friday.
A Naval Air Forces spokesperson told KPBS they had no information that Navy fighters were flying in the area at the time of the boom. Officials at Marine Corps Air Station Miramar did not immediately respond to questions about Friday's flights.
Ground-based ordnance is another potential source of noise.
Camp Pendleton, in north San Diego County, is home to the Corps' largest infantry division, the 1st Marine Division, and Marines frequently train with explosive ordnance at the base.
A spokesperson for the 1st Marine Division at Camp Pendleton was skeptical Friday's boom came from the base, saying most artillery wouldn't create shockwaves strong enough to be heard and felt across such a large swath of the county.
Another Marine at the base's firing range could not rule it out, however, because Marines were firing artillery on the base Friday.
