Here’s what might have caused the latest mystery boom over San Diego

An F/A-18 Hornet
An F/A-18 Hornet flies among the storm clouds while doing touch-and-go maneuvers at Marine Corps Air Station Miramar last year.
(K.C. Alfred / San Diego Union-Tribune)

The window-rattling boom that shuddered through parts of San Diego County this week may have been the result of aircraft from Marine Corps Air Station Miramar training over the ocean.

In a news release posted on Twitter, MCAS Miramar said two aircraft were training off the coast at the time the boom was heard just after 8 p.m. Tuesday.

“While MCAS Miramar cannot account for every sound event that occurs within the area, in this case the cause is possibly due to aircraft training occurring in the W-291 range, approximately 30 miles southwest of San Diego over the Pacific Ocean,” the statement said. “Two units departed from MCAS Miramar and were conducting simulated air-to-air combat training.”

Tuesday’s boom was the third in the county since February and rumbled through coastal and central San Diego. It was felt as far south as Tijuana and as far east as El Cajon.

Speculation about the cause of the boom ran the gamut from an earthquake (no, according to the U.S. Geological Survey) to highexplosive munitions training at Camp Pendleton (maybe, a Marine official said).


Although some thought it was a sonic boom, spokesmen for both the Navy and Marine bases with aircraft had said earlier in the week that it was not them.

The statement Saturday appeared to walk back that denial and added some information on the nature of sonic booms.

“There are many different factors that would cause a sonic boom to travel large distances from its source,” the statement read. “Variations in temperature and humidity can create atmospheric conditions that can cause sound waves to travel further than at other times.”

The statement noted that supersonic flights, while restricted over land, are allowed over the ocean under civilian and military regulations. “The practice has been occurring for well over the 24 years that the Marine Corps has operated from Miramar and continues to enhance the aerial combat skills of our pilots as they continue training and providing for the National Defense.”

The Twitter account for the base prefaced the release of the statement with a tweet reading, “So, about the other night...” and the hashtag #sandiegoboom.