Earthquakes: Information and preparedness in Maine & New Hampshire
Earthquakes in Maine
According to Henry N. Berry IV of the Maine Geological Survey, Department of Conservation "Seismic activity in Maine is typical of the Appalachian region of northeastern North America. There is a low but steady rate of earthquake occurrence. The earthquakes are presumably caused by modern stress being released occasionally along zones of weakness in the earth's crust, but a more specific cause for the earthquake activity is not known."
"The largest earthquake recorded in Maine between 1747 and 1992 was near Eastport in 1904 with a Modified Mercalli intensity estimated at VII. The largest accurate measurement was on June 15, 1973 from an earthquake just on the Quebec side of the border from northern Oxford County, Maine, with a Richter magnitude of 4.8 (Johnston, 1995). Most Maine earthquakes are of small magnitude. Many are too small to feel. No Maine earthquake has caused significant damage. The persistent activity, however, indicates that some crustal deformation is occurring and that a larger earthquake cannot be ruled out (Ebel, 1989)." Complete article and references may be found here. More information below:
An pdf article on New Hampshire earthquakes here.