BUCKSPORT — A series of small earthquakes has been affecting the Bucksport-Searsport area since April 30, according to the Maine Geological Survey. As many as 30 very small quakes — called a swarm — have occurred. All measured less than 2 on the Richter magnitude scale, said Robert Marvinney, state geologist and director of the Maine Geological Survey.
He said there was no cause for alarm.
“This type of swarm has occurred before in Maine,” Marvinney said. “While local residents may feel these earthquakes, because they occur only a few miles below the surface, they are well below the magnitude 5 threshold at which damage might occur.”
The Maine Geological Survey, Maine Emergency Management Agency and the New England Seismic Network will continue to monitor the situation and provide updates as necessary, officials said.
Typically, Maine experiences several earthquake events of magnitude 2 or less each year, Marvinney said.
“These occur in response to the movement of large, rock plates that make up the earth’s crust, even though Maine is not near a plate boundary, where most of the large events occur, such as California and Japan,” Marvinney said. “The crust in Maine is still adjusting to the loss of thick ice at the end of the last ice age, and this may be a cause for some earthquakes.”
Similar swarms have occurred in the past, including about three dozen earthquakes in the Bar Harbor area in 2006.
Additional information can be found at http://aki.bc.edu/quakes_recent.htm.