Tennessee Area Called Vulnerable to Destructive Quake

A seismic zone concentrated in eastern Tennessee, the site of several nuclear power reactors and hydroelectric dams, poses the threat of a destructive earthquake, geologists said Thursday.

In the past decade the zone produced the second-highest amount of seismic activity of any region east of the Rocky Mountains, says a report in today’s issue of the journal Science.

The zone, about 30 miles wide and 180 miles long, includes at least two dozen hydroelectric plants and several nuclear power reactors operated by the federal Tennessee Valley Authority, one of the largest electric utilities in the United States.

“This zone has been known for some time but hasn’t been described in any of the U.S. Geological Survey maps that engineers building dams and buildings rely on to figure seismic hazards,” said Christine Powell, a professor of geology at the University of North Carolina in Chapel Hill.

“We felt it was time this zone should get the attention it deserved,” she added.

Jeffrey Munsey, a seismologist with the Tennessee Valley Authority, said the dams and nuclear reactors were built to withstand an earthquake of magnitude 5.8, the level of a temblor that occurred in neighboring southwest Virginia in 1897.

The strongest earthquake ever recorded in eastern Tennessee was magnitude 4.6.

“We don’t know whether (the zone) will ever generate a damaging earthquake,” she said. But it’s there, it’s very distinct, and people should take it into consideration.”

The zone is separate and distinct from the New Madrid zone in the central Mississippi River valley, which produced the most seismic activity in the eastern United States during the past decade.