An earthquake with a preliminary magnitude of 4.9 struck Ibaraki Prefecture in eastern Japan on Wednesday, the weather agency said, though no tsunami warning was issued and there have been no reports of serious injuries or damage.
The quake occurred at around 5:40 p.m. at a depth of 51 kilometers. It measured an upper 5 on the Japanese seismic intensity scale of 7 in Shirosato, Ibaraki.
The Japan Meteorological Agency revised down the magnitude from the initial reading of 5.0 and also changed the depth from 50 km.
No abnormalities were reported at the Tokai No. 2 nuclear power plant located in Ibaraki, northeast of Tokyo, the prefectural government said.
The quake was also felt in the northeastern Japan prefecture of Fukushima, where there are also nuclear plants, as well as in Tokyo.
East Japan Railway Co. said its shinkansen bullet train operations were briefly suspended on a section between Omiya, Saitama Prefecture, and Koriyama, Fukushima due to a power outage following the quake.
The government set up a crisis management center at the prime minister's office.
The agency cautioned at a press conference that for areas that had felt a huge shake, there may be another earthquake within a week or so that could register up to an upper 5 on the intensity scale.