Carlsbad - Did your house shake on Sunday afternoon? You weren't alone. The cause of the loud boom and ground tremors felt and heard citywide on Sunday remains a mystery.

Theories about everything from oil rig explosions to shotgun blasts have been proposed, but city and county officials say they have no explanation as to what rattled windows and frightened animals just before 5 p.m. Sunday.

Many assumed the noise was the result of a sonic boom by military aircraft flying out of Holloman Air Force Base, but the base wasn't conducting any flights that day, said Holloman's Elah Murray.

"We stopped night flying on the 22nd of November," Murray said.

Tacy Farmer said that she was sitting in the living room of her home on North Lake Street Sunday when she and her daughter felt the boom resonate through the house.

"We all kind of paused and looked at each other, wondering 'did you feel that'," Farmer said.

"The whole house trembled and the windows shook," she said.

Residents across the city felt a similar phenomenon.

"We looked for smoke or flames, thinking perhaps it was an oil rig that blew up. We even thought, maybe it was a meth lab," said Amanda Harrington, who lives on Winchester Road off Old Cavern Highway.

But when she and family members stepped outside they saw no indication of an explosion.

Harrington said the windows in her kitchen were vibrating because of the boom, which she said felt like an explosion and not a sonic boom.

One Twitter user said it felt as if a tree had fallen on her home in La Huerta.

Other residents said it could be felt from as far south as the Cavern City Air Terminal and north to the Living Desert Zoo & Gardens State Park.

The U.S. Geological Service website has no reports of an earthquake in or near Carlsbad around the time of the event, and seismic equipment managed by the New Mexico Oil Conservation Division didn't reveal any recordable tremor data.

Capt. Jeff Zuniga of the Eddy County Sheriff's office said that despite the mysterious shaking, the sheriff's office did not receive any calls about the event or anything that might have been its source.

Zuniga, who said he was off duty at the time, said he heard what he described as a double boom, which seemed to originate north of the city.

Lt. Jennifer Moyers of the Carlsbad Police Department said their offices did not have any recorded dispatch calls regarding the incident or what might have caused it, and state police officials said they did not handle any calls regarding a possible source either.

Robin Cathey, who was out of town during the incident, said that she has been hearing about the boom from friends and neighbors and feels the lack of information about what might have caused the booming sound and tremors is frightening.

"We just want to know what caused it," Cathey said.