An earthquake with a preliminary magnitude of 6.0 struck Fukushima and other prefectures in Japan's east and northeast on Sunday, but there was no threat of a tsunami, the country's weather agency said.
There were no immediate reports of injuries or serious property damage following the quake, which occurred around 12:24 p.m.
The quake's magnitude was later revised upward from the initial estimate of 5.8, the Japan Meteorological Agency said.
The quake registered a lower 5 on the Japanese seismic intensity scale of 7 in Fukushima's Iwaki city, according to the agency. Its focus was at a depth of about 30 kilometers in the Pacific off Ibaraki Prefecture.
The quake registered 4 in some other parts of Fukushima and 3 in the neighboring prefectures of Miyagi, Yamagata, Ibaraki, Niigata and Tochigi.
No abnormalities were found at the Tokai No. 2 nuclear power plant on the coast of Ibaraki or at the Fukushima Daiichi and Daini nuclear power plants, their operators said.
There were also no major transport disruptions. JR East said it briefly suspended services on a section of the Tohoku Shinkansen bullet train line between Fukushima and Miyagi prefectures.