A magnitude 6.1 earthquake has struck off the northern coast of Japan's main Honshu island but there have been no tsunami warnings or immediate reports of damage.
The United States Geological Survey says the quake hit some 50 kms from the town of Namie, near the tsunami-ravaged Fukushima Daiichi plant.
Japan's meteorological agency measured the quake at 5.9, at a depth of 50 kms.
The operator of the Fukushima Daiichi plant, Tokyo Electric Power Co, said there were no immediate reports of impact on the plant.
Neighbouring Miyagi prefecture also had no reports of damage.