A magnitude-6.2 earthquake struck off Japan's battered northeastern coast, but there was no risk of a tsunami and there were no immediate reports of injuries or damage.
Japan's Meteorological Agency said the quake was centered off the coast of Ibaraki, about 224 kilometres east of Tokyo, at a depth of 10km. The agency said there was no danger of a tsunami from the quake.
Nearly 20,000 people died or were left missing across Japan's northeastern coast after a massive earthquake and tsunami on March 11. The disaster damaged a nuclear power plant, forcing another 100,000 people to leave their homes because of a radiation threat.
The operator of the tsunami-hit Fukushima Dai-ichi nuclear power plant, Tokyo Electric Power Co, said the plant's cooling functions were intact after Thursday's quake and there was no change to radiation levels around the plant. The plant is about 80 miles northwest of the epicenter.
Meanwhile, the US Geological Survey registered a magnitude 6.0 earthquake that hit off the coast of Cuba.
The quake happened early Thursday at 4.43am local time about 40km off Cuba's coast and 600km southeast of Cuba's capital Havana.
USGS geophysicist Randy Baldwin says earthquakes are common in that area of the sea and no tsunami warnings have been issued. He also said the quake wasn't expected to cause damage on land, citing its remoteness.