KENNEBUNK, Maine — Residents in areas of Kennebunk, Kennebunkport and Arundel have reported hearing, and feeling, a mystery boom this morning, but no one can seem to pinpoint the cause.

Word of the rumbling, which happened around 10 a.m. Thursday morning, is abuzz on Facebook, with residents in areas of the three towns asking “what was that?” Some have said it sounded like a tree coming down in their yard, others wondered about blasting from area construction, or a clap of thunder.

Kennebunk Police Lt. Eric O’Brien said the department received a number of calls, but police have not determined the source. A dispatcher at the Kennebunkport Police Department also said they did not know where the boom came from, but she likened it to an earthquake.

A representative of the U.S. Geological Survey said that there is no record of any earthquake activity in Kennebunk or southern Maine Thursday morning.

Kate Mastrangelo, who was working in Arundel, said “I don’t know how else to explain it other than a boom.

“I could tell it was in the distance somewhere but I could hear it and at the same time the ground shook. It wasn’t like an earthquake shake, it just bumped,” she said.

Mastrangelo said she immediately thought of the furnace turning on for the first time this year or other equipment in the building, but then thought “no, that was too loud.”

Laura Snyder Smith, who works at the Kennebunk-Kennebunkport-Arundel Chamber of Commerce on Water Street in Kennebunk, said she and a colleague were sitting in the office when she felt a “boom” under her feet.

“I was like, ‘What the heck was that,’” she said. “It was like an internal ground rumble. I felt it under my feet. It’s hard to describe it, but it felt more like a boom than a rumble.”

She said a sound followed the rumble that sounded like something fell on the floor above her.

“It was very short,” Snyder Smith said. “I looked outside and it was business as usual. There were no trucks around. Nothing out of the ordinary.”