The quake hit at 10:03 am (0633 IST) in Ibaraki prefecture, 160 kilometres Northeast of Tokyo, and some 80 kilometres Southwest of the crippled Fukushima nuclear plant, according to Japan Meteorological Agency.

The tremor was 10 kilometres deep, the agency said. The initial quake was strong enough to gently rock high-rise buildings in the capital.

Tokyo Electric Power said the quakes did not affect the Fukushima Daiichi nuclear plant, where crews are working through the holiday season to cool reactors crippled by the 2011 tsunami.

 (Agencies)

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