A powerful natural disaster struck off Japan's east coastal province of Fukushima on Saturday (local time), causing buildings to shake violently in Tokyo and causing widespread power outages.
At least two dozen people were injured, according to reports from the Kyodo news agency.
The epicentre of the quake was off the coast of Fukushima prefecture at a depth of 60km, the agency said, adding that a tsunami warning had not been issued.
The Japan Meteorological Agency said the quake was centered about 60 kilometres (37 miles) beneath the ocean bed. Fourteen aftershocks were recorded, it said, adding that a tsunami warning had not been issued.
The 2011 quake ranks as the most powerful ever recorded in Japan.
Some people were taking shelter at evacuation centres, and were being warned to practice social distancing because of the coronavirus pandemic.
An quake with a preliminary magnitude of 7.1 rocked northeastern Japan late Saturday, but there was no tsunami threat and no abnormalities were detected at nuclear plants in the region.
Chief Cabinet Secretary Katsunobu Kato addressed reporters after midnight and said evaluations were under way. It might have caused light to moderate damage.
Tokyo Electric Power Co. said there were no irregularities at the Fukushima Dai-ichi nuclear plant, which experienced meltdowns following a massive quake and tsunami 10 years ago.
Television footage also showed broken glass from shop fronts.
Fukushima nuclear plant operator Tepco also tweeted that it was checking on the status of the plant.
"I hear the ground rumbling". Among the hardest hit areas is the city of Soma in Fukushima, roughly 40 km north of Fukushima Daiichi nuclear plant, and the Zao ski resort in Miyagi Prefecture. It was not immediately clear if anyone was hurt.
The US Geological Survey registered the quake at a revised magnitude of 7.1 with a depth of 51 kilometers.
Earthquakes are common in Japan, one of the world's most seismically active areas.
The country is regularly hit by quakes, and has strict construction regulations meant to ensure buildings can withstand strong tremors.