SAN DIEGO — Stop me if you’ve heard this before: San Diego residents felt shaking or heard a “boom” around the region Thursday afternoon but there was no immediate explanation.

People experienced the sensation around 3 p.m. Thursday. Twitter users described it as a series of “rumbles” or “booms” and chimed in from the South Bay to East County about the noise.

“It felt like (an) earthquake,” one user wrote. “I thought something fell on the roof at my work,” chimed in another.

The U.S. Geological Survey did not register any quakes of note in the area.

Camp Pendleton has a noise advisory active from 6 a.m. until midnight Thursday for both artillery and mine clearing line charge training at the base in North County, though it wasn’t clear if that could have caused the sensation.

Representatives at Camp Pendleton and Marine Corps Air Station Miramar have not yet returned requests for comment. FOX 5 also reached out to San Diego police and the sheriff’s department, who said they had nothing of note to report that may have caused the phenomenon.

A mystery “boom” is not a terribly unfamiliar experience for people who have lived in town for a while. San Diego has multiple military installations and small earthquakes aren’t uncommon, either.

A prominent example from this past summer eventually prompted an explanation from MCAS Miramar, which said a pilot had caused a sonic boom off the coast while simulating air-to-air combat for training purposes.

As one person on Twitter summed it up: “It’s so fun living in San Diego. Every now and then you get to play ‘was that an earthquake, sonic boom, or other military shenanigans?'”