“You could not miss it,” he said.
The fire department immediately began receiving calls from residents asking about the boom. Mr. MacDonald said he still isn’t sure.
“Fortunately, I’d gone to church this morning,” he said. “So I felt prepared.”
Dylan Mei, a dispatcher for the police department in Winchendon, Mass., said three residents of the town called to report that the “ground was shaking.” WCVB-TV reported that numerous residents emailed the station to share stories of hearing a loud boom and feeling the ground shake.
Don Blakeman, a geophysicist for the U.S. Geological Survey, said on Sunday that the National Earthquake Information Center had not detected any seismic activity in the area on Sunday. But that doesn’t entirely rule out that there might have been a minor earthquake, he said.
New Hampshire often gets small earthquakes, said Jessica Turner, a geophysicist for the U.S. Geological Survey. The last time was on Aug. 22, when an earthquake of 1.7 magnitude was recorded in an area south of Rochester, N.H., Ms. Turner said.
Paul D. Raymond Jr., a strategic communications administrator for the New Hampshire Department of Safety, said in an email on Sunday that the agency had seen people commenting about the noise online.
He said the statewide 911 center received only one call reporting a large boom around 11:30 a.m. in Lyndeborough, N.H., and no calls to the State Police dispatch center. Mr. Raymond pointed out that more than 400 people had shared their observations on volcanodiscovery.com, a website where people can report seismic-like activity.
Mr. Brian, who discussed his experience on Twitter, pointed out that his home is near the New Boston Space Force Station, a satellite tracking station that was recently transferred from the Air Force to the Space Force.