People in many North County cities as well as some farther south reported hearing a large boom that rattled windows and shook buildings shortly before 1:30 p.m. Friday.

The source of the boom was not immediately clear, but it did not appear to be an earthquake or from a military exercise on Camp Pendleton.

The U.S. Geological Survey reported no earthquakes in the area around that time, and the Southern California Earthquake Data Center reported a “micro earthquake” with a preliminary magnitude of 1.6 at about 1:31 p.m. in Ocotillo Wells, about 100 miles east of Oceanside.

Several people on social media speculated the sound could have come from Camp Pendleton, but an official at the base said it was not behind the boom.


Robert Klenk, a civilian who works in the Range Operations Division office at Camp Pendleton, said he had received about 50 calls from people asking about the boom within an hour of hearing it. He said the exercises at the base were no different Friday than they had been all week, and he speculated that people may have heard a sonic boom.

Cmdr. Ronald Flanders, a Naval Air Forces spokesman at Naval Air Station North Island, said the boom did not come from the Coronado base because it has no jets.

1st Lt. Fredrick D. Walker for the 3rd Marine Aircraft Wing at Marine Corps Air Station Miramar said he was aware of media reports about a possible sonic boom, but none of its aircraft had reported one in San Diego air space.

A similar boom was heard from North County to Chula Vista on Jan. 15. As with Friday’s phenomenon, military officials at that time had no explanation for the sound, and the U.S.G.S. reported no earthquake in the area that day.


On the social media site Nextdoor, residents in Oceanside wrote that they heard a large boom that rattled their homes and frightened their pets.

“I felt the shock waves that made me fall right out of my chair,” one man wrote. “It felt like a bomb or an explosion to me.”

Another person wrote that a family member in Rancho Bernardo heard it, and another wrote that it set off car alarms.

One woman wrote that her son came running down the stairs and asked if she had fallen.


“I hope when I fall, the house doesn’t shake like that!” she wrote.

Another person reported hearing the boom from her home near Grossmont College in El Cajon.

On an Encinitas Next Door page, a woman wrote that she thought something might have crashed into her house, so she went outside to look. Another woman in Encinitas wrote that she was outside and heard two loud booms followed by one softer one.

