Mysterious 'Boom' Rattles San Diego County

SAN DIEGO COUNTY, CA – San Diegans took to social media to report shaking and hearing a booming sound Thursday morning. From Miramar to Rancho San Diego, the mysterious "boom" was reported across the county, though most reports seem to have stemmed from East and South counties.

Patch reader David Marshall reported feeling rumbling in the South Bay.

"I thought someone was on the roof," said Marshall, who was at Saint John's Episcopal Church in Chula Vista. "It rumbled the doors and windows."

Bryan Gonzalez, also in Chula Vista, thought an earthquake shook the building.

"It felt like a big semi-truck passing the building where I work," Gonzalez said. "It shook the racks, and I thought it was an earthquake."

There have been no recent earthquakes reported in the area, according to the United States Geological Survey.

A reader named Gladys, who didn't provide her last name, said the boom "sounded loud and shook the windows" in Imperial Beach.

Other readers from the College Area, El Cajon, Jamul, Lemon Grove and National City shared similar experiences.

As of Thursday afternoon, the boom remained a mystery.

Camp Pendleton had a training session scheduled for Thursday, but military officials said live mortar fire would not produce the kind of impact or noise that has been reported in the region.

"There is routine mortar training being conducted on the base, but it is highly unlikely that an impact would be heard and felt all the way in San Diego," Cpl. Shellie Hall said.

Officials at the San Diego County Sheriff's Department and the San Diego Police Department told Patch they did not know of anything that could have caused the noise or the shaking.

"We checked with our watch commander who monitors calls for service within our jurisdiction," said sheriff's spokeswoman Melissa Aquino. "There's nothing to report on our end."

"As of right now, we have no idea what caused the noise," San Diego police spokeswoman Lisa McKean said.

Did you feel or hear it? Tell us in the comments or email Kristina.Houck@patch.com.

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