A rare earthquake shook New England not long before the presidential debate began Tuesday night but there were no reports of damage or injuries. The 4.0 quake had its epicenter in southern Maine and was felt as far south as Connecticut, the AP reports.

In New Hampshire, where the quake was strongly felt, the Seabrook Station nuclear plant declared "an unusual event" but said it was not affected.

It is rare for an earthquake in the region to be strong enough to be felt across a wide area, but the region's geology can make a quake's effects felt across a larger area than a typical West Coast quake. Experts say New England is laced with undetected fault lines. "It is difficult to determine if a known fault is still active and could slip and cause an earthquake," the United States Geological Service says. "As in most other areas east of the Rockies, the best guide to earthquake hazards in New England and Long Island is the earthquakes themselves.