The US Geological Survey reported this afternoon that it had detected an earthquake in the town of Dracut, but later rescinded the report after realizing it was a quarry blast, state officials said.
The USGS alerted the Massachusetts Emergency Management Agency of a 2.2-magnitude earthquake in Dracut at about 2 p.m., but wrote back thirty minutes later to say it was blasting at a quarry, MEMA spokesman Peter Judge said.
The tremor was detected after a routine blast at Brox Industries on Methuen Street in Dracut, according to a spokesman at the neighboring quarry, New England Cement Block.
Paul Earle, a seismologist at USGS, said more quarry blasts are being detected by the agency because the agency’s capability is increasing to detect earthquakes with smaller magnitudes.
He said that in New England there are about “five times more detectable quarry blasts recorded than earthquakes.”
The agency rescinds its notices when it learns that the “earthquake” detected was actually a quarry blast, he said.
A message seeking comment from Brox Industries wasn’t immediately returned.