Two nuclear power reactors at the North Anna plant automatically shut down on 23 August after the grid failed following a 5.8 magnitude earthquake. People reported feeling tremors over a very wide area of the US eastern seaboard after the earthquake struck six kilometres below Mineral, Virginia, at 1.51pm. The units are owned by Dominion Virginia Power, whose spokesman Richard Zuercher told local reporters that four diesel generators started as expected to maintain cooling. However, one of the generators had to be replaced in order to repair a generator coolant leak. Dominion later announced that off-site power had been restored at North Anna, eliminating the need to rely on its back-up diesel generators. The plant was unaffected by several aftershocks that were felt in the region, the company said. Dominion's two-unit Surry nuclear power plant, also in the region, was not affected and continues to operate.