Residents thought it was a quarry blast or thunder or an attempt to blow up a beaver dam.

Instead, the U.S. Geological Survey said it was a 2.1 magnitude earthquake at 7:04 a.m. Monday. The quake centered about 3.1 miles underground in the Deep Run area of Lenoir County, North Carolina.

“I was just about to get out of the bed, and I heard what was like a thunder sound, and then I felt shaking — even the ceiling fan was making a noise,” resident Ashley Ledford told the Winston-Salem Journal.

The region is considered a “stable continent region” according to State Geologist Kenneth Taylor. The last recorded earthquake in North Carolina struck in 1994.

“There are lots of fractures in the earth in lots of places, and it takes a lot of time for the stress to build up to where you could have an earthquake,” Taylor said. “For example, when you look at earthquake history in Eastern North Carolina — let’s say everywhere east of Raleigh — the last time we had an earthquake in the coastal plain was in 1994. That was a magnitude 3.8 in Pamlico County.”