The earthquake was centered about 60 kilometres (37 miles) beneath the ocean bed
The Japan Meteorological Agency said on Saturday that an earthquake of magnitude 7.0 on the Richter scale has hit off the coast of northeastern Japan. It also triggered widespread blackouts, but there appeared to be no major damage.
The United States Geological Survey (USGS) said that the earthquake hit Fukushima, Miyagi and other areas. It struck 90 km east-northeast of Namie.
Tremors were felt in Tokyo, to the southwest.
The earthquake was centered about 60 kilometres (37 miles) beneath the ocean bed, Japan Meteorological Agency said. Media reports have stated that there is no danger of a tsunami.
Some 950,000 households were initially without power, government spokesman Katsunobu Kato told a briefing carried on public broadcaster NHK. The blackouts appeared to be concentrated in northeast Japan, including Fukushima and neighbouring prefectures.
There were no irregularities at the Fukushima Daiichi and Daini nuclear power plants, or at the Kahiwazaki-Kariwa nuclear plant, owner Tokyo Electric Power Company Holdings said.
The utility also said there was no change in the radiation levels around its plants.
The quake hit off of Fukushima just weeks before the 10-year anniversary of the March 11, 2011, quake that devastated northeast Japan and triggered a massive tsunami that led to the world`s worst nuclear crisis in a quarter of a century - one centred at the Daiichi facility.
Earthquakes are common in Japan, one of the world`s most seismically active areas. Japan accounts for about 20% of the world`s earthquakes of magnitude 6 or greater.
(With inputs from Reuters)