A strong aftershock with a preliminary magnitude of 7.0 jolted east and northeast Japan on Monday, killing one man, disrupting vital cooling operations at the crippled Fukushima nuclear plant, and knocking out power to about 220,000 households.
The epicenter of the quake was about 30 km west-southwest of Iwaki, Fukushima Prefecture, where it struck at a depth of only 6 km.
The temblor cut off external power to the pumps serving reactors 1, 2, 3 at around 5:16 p.m., but Tokyo Electric Power Co. revived power and resumed pumping operations at 6:05 p.m., according to the Nuclear and Industrial Safety Agency.