ALABAMA — It was about midnight on a night last week when Randy Smith took his dog outside and for the third time this year, heard the mysterious booms.

“Three times in a row I heard it,” Smith said. “It sounds as loud as a sonic boom. Maybe louder. As soon as it goes off, the dog starts growling and gets startled.”

Smith and his father, Laverne Smith, live at 748 Lewiston Rd. (Route 77) and have been hearing the booms for nearly two years now.

They cannot pinpoint the source of the noise.

“You can’t tell what direction it’s coming from,” Laverne Smith, 76, said. “The last good weather we had I was out near the shed and heard it.”

Last year they heard the booms about 10 times, sometimes during the day and sometimes at night.

“It seems to be just around here,” Randy Smith said. “I asked my sister who lives in Alabama Center and she hasn’t heard it.”

It is a phenomena that has sparked curiosity throughout the country for several years now.

The booms, however, have grown more frequent.

In December, people in Rhode Island, Alabama, Georgia, Texas and Oklahoma reported hearing unusual booms and explosions.

Newspaper reports revealed no unusual seismic activity in those regions and all the noises have yet to be explained.

In January, hundreds of people in northern Utah called emergency dispatchers reporting booms and shaking of the earth.

The cause remains a mystery, though the Air Force said it had done training exercises, dropping bombs in the desert.

Locally, 911 dispatchers in Chautauqua County were inundated with calls on Jan. 13, all reporting hearing a loud boom that shook houses.

Police eventually determined the noise came from a 20-year-old man using an explosive called Tannerite, a legal compound that when struck with a bullet explodes.

A few days later, on Jan. 16, residents in Gorham, Ontario County, reported a series of booms.

“It was just a loud, explosion-like sound,” Janet Koller told the Canandaigua Messenger Post. “We saw nothing. It was dark by then. It was hard to even tell what direction it came from. It shook the house.”

Ontario County sheriff’s officials said several people called to report the still unexplained booms.

Booms also were reported in Le Roy.

Former Daily News editor Ben Beagle said he was in his living room about 9 p.m. March 9 when he heard “some booms.”

“I thought it was just neighbors, maybe shutting doors or something. Then, about 9:09 p.m., a series of boom-boom-booms that I thought must be thunder.”

He checked the weather radar and all was clear, he said.

Genesee County Senior Dispatcher Gary Diegelman said the county’s 911 system did not receive any reports of booms.

He offered a few possible explanations for booms, at least those heard during the day.

Diegelman said the federal Bureau of Alcohol, Tobacco and Firearms often uses stone quarries in Le Roy and Alabama for training and detonating explosives.

“We’ve had them coming in the past few years and they probably make a good-sized blast,” he said. “At night, it’s possible it’s propane cannons they use on farms to scare away animals.”

Those, however, are usually heard during the spring and early summer when crops are planted are in various stages of growth.

Three farmers contacted this week reported they do not use propane cannons and weren’t aware of any local farmers that do, at least at this time of year.

So what’s going on?

Dr. Mark Castner, director of Braun-Ruddick Seismograph Station at Canisius College, told WIVB-TV in Buffalo that booms can be associated with an earthquake, quarry blasts, building implosions or sonic booms.

Seismographic records reported no unusual activity, however, and officials at Niagara Falls Air Reserve have had no aircraft flying in the area during the times of the reported booms.

The Smiths live near National Fuel’s Empire Pipeline for natural gas.

Could that be an explanation?

No, says spokeswoman Karen Merkel.

“I checked and we have no issues with the pipeline, we’re not doing any testing and we have no reported leaks,” she said. “We have nothing going on but we do want to be aware of it.”

The Smiths have no idea what causes the booms around their house.

“It doesn’t sound like gunfire or an explosion,” Randy Smith, 53, said. “It’s huge and it rattles everything in the house. I’ve looked around for lights or aircraft but I never see anything. I wish I could tell you I’ve seen lights for an aircraft but I can’t.”