A 5.5-magnitude earthquake hit eastern Japan including the capital Tokyo early Sunday, the national meteorological agency said. The epicentre of the tremor, which struck at around 7:38 am (2238 GMT Saturday), was in Ibaraki prefecture, north of Tokyo, at a depth of 70 kilometres (44 miles). The crippled Fukushima nuclear power plant was shaken by the quake but there were no abnormalities reported, the plant's operator said.