A mild earthquake centered in Salem County, N.J., rattled buildings on both sides of the Delaware River this morning, but did no significant damage, according to officials.

The Salem nuclear plants "are running operationally fine" and no critical infrastructure was harmed, said Robin Weinstein, spokesman for the county department of emergency services.

The loud rumbling made officers at the Delaware Memorial Bridge think at first that two tractor trailers might have collided, or a tanker might have exploded on the river, said Master Cpl. Joseph DiStefano, spokesman for bridge police.

But the bridge was not damaged, and no accidents resulted, he said.

The epicenter of the 2.8 magnitude quake, which began at 9:44 a.m., was 2 miles east-southeast of Pennsville, according to a report by the U.S. Geological Survey.

Pennsville lies about five miles south of the Delaware Memorial Bridge.

The rattling lasted only a few seconds, according to Weinstein, who is based in Woodstown, about eight miles from Pennsville.

To put the event into perspective, 10 stronger quakes occurred before noon Eastern Time today in North America, including Puerto Rico, Alaska, California, Washington state, the British Virgin Islands, Mexico and the Dominican Republic.

Hawaii also had a 3.0 magnitude quake.

The Jersey quake, though, was the only quake in the last seven days of 1.0 or stronger between New Hampshire and Tennessee.

Although Salem County 911 received about 150 calls this morning, no injuries were reported, Weinstein said.

"The engineering department will be out doing site inspections" today, checking roads, bridges and buildings, for example, he said.

Contact staff writer Peter Mucha at 215-854-4342 or pmucha@phillynews.com.