SKOWHEGAN -- The earth shook and buildings rumbled Thursday morning, according to at least a dozen residents who reported tremors in Anson, Madison, Skowhegan and Norridgewock.

Shortly before 10 a.m., the Somerset County Communications Center was inundated with calls from people who said they had experienced earthquake-type movement.

Despite numerous reports within the 15-mile radius, local and state authorities could find no documented account that any type of earthquake or tremor had occurred.

State geologist Bob Marvinney of the Maine Geological Service said that if an earthquake had occurred, it was not recorded by any of the instruments in Maine or New England.

Marvinney said he had contacted the New England Seismic Network, and authorities there said nothing was apparent: "I'm surprised we didn't pick up anything. There are other kinds of explanations like quarrywork and roadwork," he said.

An official at the National Weather Service said he also had heard no reports.

However, Emergency Management Director Robert Higgins Sr. said he is going to ask them to look again.

"I'd like them to relook at what they may have; this is the second occurrence in less than a week of such magnitude," he said.

Higgins said residents of Solon and South Solon last Friday reported what sounded like a loud explosion, during which houses and mobile homes in the area shook: "That would indicate a tremor, he said."

Residents who reported the shaking this Thursday said the tremors were strong.

Norridgewock's town manager, John Doucette, said the shaking and noise was so significant, it sounded like a Dumpster had fallen off a truck or a truck had hit the building: "We went outside to see if there was an accident."

More than a mile away, Jeffrey McGown, district manager of Waste Management on U.S. Route 2 in Norridgewock, said he was sitting in his office when the noise and shaking occurred.

"It felt like somebody with a delivery type of vehicle had backed into our building," McGown said. "I was on a conference call and I got up to see what had struck. We went out on the site and looked around, we thought maybe the town airport (nearby) had an experience. It was so localized, we thought a delivery truck had hit the front porch."

In Anson, about six miles away, the shaking was so strong, even off-duty dispatcher William Crawford called the Communications Center.

"I heard a loud boom that shook the house," Crawford said. "At first I thought it was the furnace. I asked my son 'Did you feel that?' It shook the couch. I thought maybe something fell upstairs, or maybe the chimney collapsed or something. I went outside to look around. You can see the town garage from the house; I thought maybe it was the back of the bucket banging. Nobody was at the town garage."

Late Thursday, Higgins said he checked with Guilford Industries to see if they were working the quarry in the Embden-Solon area: "They said they hadn't done any blasting since last fall. And it was no sonic boom-- not that loud and shaking that many buildings. It's just unexplainable, I guess."