Saturday's magnitude 7.3 quake that struck Japan's northeastern coast is believed to be an aftershock of the 2011 killer natural disaster that triggered massive tsunami in the same area, a seismologist said.
The USGS said the quake occurred at a depth of 54 kilometres (33 miles) in the Pacific, off Fukushima - near the epicentre of a 2011 killer quake which triggered a towering tsunami and killed more than 18,000.
The quake was 7.3 magnitude and was felt strongly in Tokyo, but a tsunami warning has not been issued. There were no immediate reports of irregularities from other nuclear plants in the area, such as Onagawa or Fukushima Dai-ni, government spokesperson Katsunobu Kato told reporters. It said the quake was considered an aftershock of the massive 2011 temblor.
It registered upper 6 on Japan's seismic intensity scale of 7 in the prefecture, one of the areas devastated by a massive quake and ensuing tsunami almost 10 years ago. 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.
The extent of damage from the landslide was not immediately clear, Kato said. But residents of Tokyo said this was the strongest quake they had experienced in years, possibly even since the 2011 quake.
While there was no tsunami warning generated by the quake, those near coastal areas were urged to move to higher ground as a precaution due to the likelihood of aftershocks.
The quake also caused the country's worst nuclear disaster - three reactors at the Fukushima Daiichi nuclear plant melted down, releasing radioactive materials into the air and more than 100,000 people were evacuated from the area.
Some people were taking shelter at evacuation centres, and were being warned to practice social distancing because of the coronavirus pandemic.