Shake, Rattle & Roll: More Mysterious Booms Around San Diego County

Shaking reported around San Diego County at 2:40 p.m. on Tuesday

Downtown San Diego, California, shot during a helicopter photo flight as a winter storm cleared.
Getty Images

We will be updating this story as information warrants — Ed.

San Diegans were, once again, shaken by, well, SOMETHING, on Tuesday afternoon.

A shock wave or waves — or whatever it was — rocked houses up and down the county a little before 2:40 p.m. It didn’t take long for reports to trickle in from around the region from Poway to San Carlos, with some taking to social media.

It's believed to have been the fourth such event in a year in San Diego.

The now familiar round of checks began on Tuesday, with NBC 7 reaching out to the Navy (they are checking into it and will get back to us) and San Diego police (not aware of any calls reporting a sonic boom), as well as taking a look at Recent Quakes on the USGS website (the most recent quake was a M2.6, just under a hundred miles from San Diego, which doesn’t seem like enough to warrant what happened across the border).

USGS map of Tuesday afternoon’s quake in Baja California.

It may be worth pointing out that Camp Pendleton has warned neighbors to the north that it’s operating under a noise advisory: “Depending on atmospheric conditions, the sound of the explosions may be amplified and heard up to 50 miles away.“ NBC 7 emailed the base, asking if exercises were underway around 2:40 p.m.

“There was artillery and mortar training scheduled for the entirety of this week (Monday-Friday),“ 2nd Lt. Robert C. Nanna, a base spokesman, told NBC 7 early on Tuesday evening, “however, I do not have any information of any ‘mysterious booms and rattling’ from those exercises at this time.“

Maybe more worth noting: Canadian military aircraft have been training offshore in a dedicated area that the U.S. also shares with French flying forces. The Canadian detachment training in SoCal is expected to last the next two weeks.

Top Aces, a Canadian company that has been operating aircraft in the training area off the coast recently, told NBC 7 that whatever caused the boom on Tuesday could not have been caused by any of its planes because its “aircraft flying in that area don’t fly at supersonic speeds.”

December to Remember

Residents reported feeling a brief, violent shake at 11:36 a.m. last Dec. 28 in the Mission Hills and San Carlos neighborhoods of San Diego, as well as in Santee and El Cajon in East County.

Shortly after the jarring incident, many San Diegans took to Twitter and other social-media platforms. One person tweeted out that “san diego is cool bc im like oh wow just felt an earthquake but no actually it was a sonic boom.“ Another tweeted, “I’m just logging in to confirm if that really was an earthquake or if I was losing my mind lmao. San Diego acting real sus right now, quaking while it’s raining.“

Official confirmation of the incident was slow in coming, but an official with United States Geological Society said that there no quakes locally at that time.

Representatives for San Diego Sheriff’s and San Diego Police said Tuesday morning that they had not received any calls reporting the incident, and the National Weather Service said they were unaware of anything that might have caused the event.

NBC 7 put in a request for a statement with officials at Marine Corps Air Base Miramar and received the following reply:

“MCAS Miramar does not have the ability to track aircraft outside of its immediate airspace directly in and around the base. The FAA is the federal agency responsible for monitoring flight throughout San Diego and would best be able to answer your query."

NBC 7 asked the FAA if it could confirm whether any aircraft, military or otherwise, was operating at speeds in or around San Diego County at the time that could cause such an event?

“A sonic boom would only come from military aircraft operating in military airspace,“ FAA public-affairs specialist Steve Kulm replied. “I recommend contacting the military.“

Asked if any military aircraft were operating offshore from San Diego at approximately 11:36 a.m. on Tuesday, Marine Capt. Matthew “Red Bull” Gregory replied, “No, I cannot.”

Of course, the Marines are not the only branch of the military to operate locally; the Department of Defense, U.S. Air Force and U.S. Navy also fly in the offshore training ranges, a military spokesman told NBC 7.

NBC 7 also contacted the U.S. Navy regarding Tuesday’s incident.

“We have no indications that naval aircraft caused a sonic boom in or around the San Diego area today,” Cmdr. Zach Harrell, spokesperson for Commander, Naval Air Forces, said via email on Tuesday afternoon.

“Weird things happen all the time, and we find perfectly scientific explanations for them,“ the USGS's DeGroot said, adding later, “we find things that pique our interest and then we figure it out.“

June Boom

In June, an official with MCAS Miramar said a similar incident that occurred on June 8 was possibly due to aircraft training over the Pacific.

“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,“ MCAS said in a release. MCAS Miramar said two aircraft departed the base on June 8 and were conducting air-to-air combat training.

Since the mid-1970s, the Federal Aviation Administration (FAA) has largely restricted supersonic flight over land. However, over the Pacific and at that distance, supersonic speed is within all FAA statutes and military regulations, MCAS Miramar explained.

USGS Duty Seismologist Jonathan Tytell said the “event“ in June was picked up by three sensors: one in Rosarito, Mexico; another in Pala; and a third on Barrett Mountain. Tytell said the “event“ definitely wasn’t an earthquake.

‘Unknown Event’ in February

Another mysterious boom took place in February. The “unknown event,“ as the U.S. Geological Survey referred to it, had many San Diegans posting on social media that they heard a boom and felt sudden shaking.

Whatever it was, it was noticed at around 5:10 p.m. on Feb. 16, with many who reported the event concentrated in the southern half of San Diego County.

An on-duty seismologist for the USGS confirmed to NBC 7 at the time that there was no earthquake detected on sensors in the county during the same time frame.

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