Seismographs had been installed around the North Anna Power Station to detect earthquakes, but those were taken offline in the 1990s due to budget cuts, according to the state of Virginia website.
I thought as much. This things are supposed to have interior seismic instrumentation, but I assume that suffered the same fate. Seismometers would have had the digital needles blown off them in the vicinity, so we are looking for strong ground motion, but this is poorly calibrated. Ideally, we would want what we have in Canada, broad range seismic instrumentation on firm ground, but ha ha!