An offshore quake with a magnitude of 6.2 shook northeast Japan on Thursday, swaying buildings in the capital Tokyo, but no tsunami warning was issued. The quake struck at 5:00 pm (0800 GMT) off Ibaraki prefecture in the Pacific, some 10 kilometres (6.2 miles) under the seabed, the Japan Meteorological Agency said. Tokyo Electric Power Company said the quake caused no damage to the stricken Fukushima nuclear power plant which was crippled following the March 11 earthquake and tsunami.