An earthquake described as the strongest to hit the area in at least a decade shook southern Maine and coastal New Hampshire tonight, but there were no reports of major damage, authorities said.

"There definitely was an earthquake in Maine tonight," said Dr. Edward Chibaris of the Weston, Mass, Obsevatory. He said there appeared to be two mild quakes seven or eight minutes apart.

The U.S. Geological Survey's National Earthquake Information Centre in Golden, Colo., said the quake measured 3.8 on the Richter scale. It was centered due east of Brunwick on the Maine coast and about 35 miles northeast of Portland, said center spokesman Don Finley.

Donaldson Koons, chairman of the geology department at Colby College in Waterville, said the quake was "moderate" but still the strongest in this part of the country in 10 to 15 years.

The quake began at 9:34 p.m. and rumbled for several minutes. Tremors were felt as far away as northern suburbs of Boston, said Finley.

"We have no reports of any damage, except a couple of broken windows, and we're not sure about those," said a state police spokesman in Augusta.

Newspaper and radio stations reported calls fom people in Kittery, on the coast at the New Hampshire border, Rockland, about halfway up the Maine coast, and Bangor in south-central Maine.

In Wiscasset, where the Maine Yankee nuclear plant was shut down last month because of questions about its ability to withstand an earthquake, authorities reported no damage from the tremors.

In New Hampshire, the quakes were felt in Dover, Portsmouth and Seabrook, site of a controversial nuclear power plant now under construction, authories said.

The Ritchter scale is a measure of ground motion as recorded on seismographs. An earthquake of 3.5 on the Ritcher scale can cause slight damage in the local area, while a quake measuring 4 can cause moderate damage.