Bar Harbor, Maine Braces for More Quake Aftershocks

Additional aftershocks are possible in the days and weeks ahead after a series of four small earthquakes shook the BBar Harbor, Maine area last Sunday.

The tremors were normal aftershock activity from an Oct. 2 quake with a magnitude of 4.2, said John Ebel, director of the Weston Observatory at Boston College, which monitors seismic activity in New England.

Bar Harbor could be in for more earthquake activity in the near future, Ebel said, but there is no way of predicting when that might happen.

“It would not surprise me if over the next several days or few weeks that we would see a couple more events of this size or smaller,” he said. “On the other hand, it wouldn’t surprise me if nothing more happens. There is a slight chance that we could see something bigger, but the odds are against it.”

The first of the recent earthquakes shook the Bar Harbor area on Sept. 22, with smaller aftershocks felt six days later. The strongest of Sunday’s four quakes had a 2.9 magnitude, but no damage was reported.

“At 2.9, people probably heard a boom and felt a shake that lasted 5 seconds, or 10 seconds in some cases,” Ebel said.

A team from the Lamont-Doherty Earth Observatory at Columbia University plans to return to Mount Desert Island this week to collect data from four monitoring stations placed after the Sept. 22 quake.

The stations should help scientists pinpoint the epicenter of the quakes, said Won-Young Kim, a research scientist at the observatory.

Scientists have roughly determined the epicenter to within several kilometers, but the new data should pinpoint it to within 100 meters or less.

“We’re trying to understand where and how it occurred,” Kim said. “We should be able to tell how deep it was and if any faulting occurred.”

Historically, the New England region averages a magnitude 5 or stronger earthquake once every 50 years. An earthquake that strong can cause structural damage, Ebel said.

The Oct. 2 quake in Bar Harbor caused boulders to fall from ledges onto Acadia National Park’s loop road, but did not cause any structural damage. Park road crews had to use loaders and dump trucks to remove the rock debris.