Progress Energy's Shearon Harris nuclear plant in Wake County was one of a dozen nationwide to declare an unusual event after Tuesday's earthquake, but plant operators barely felt the tremor and found nothing amiss after a thorough inspection.

State and local officials have evacuation plans in place for a major emergency, but the 5.8 magnitude earthquake was not felt by many of the engineers and technicians inside the Shearon Harris plant, said Progress spokeswoman Julia Milstead.

Plant officials declared an "unusual event" at 2:06 p.m. on Monday, following the Nuclear Regulatory Commission's criteria for ranking emergencies. An unusual event is the lowest of four emergency levels, and even so, it met only two of the the NRC's three criteria.

The seismic tremors were not strong enough to trigger the plant's earthquake monitors, even though the temblor was felt by some at the plant's administrative offices and shook up people throughout the Triangle.