A shallow 5.1-magnitude earthquake has hit eastern Japan, the US Geological Survey says, but there are no local reports of any damage.
The quake hit at 10.03am (1203 AEDT) in Ibaraki prefecture, 146 kilometres northeast of Tokyo, the agency said.
The tremor was 9.9 kilometres deep, USGS said.
Located roughly 80 kilometres southwest of the Fukushima nuclear plant, the quake was strong enough to gently rock high-rise buildings in the capital.
Japan Meteorological Agency earlier estimated the quake’s magnitude at 5.4.
It was followed eight minutes later by a very shallow 3.6-magnitude quake in the same area, according to the Japanese agency.
Tokyo Electric Power said the quakes did not affect the Fukushima plant, where crews are working through the holiday season to cool reactors crippled by the 2011 tsunami.