An earthquake registering a preliminary magnitude of 5.7 struck Kyushu early Monday, the Meteorological Agency said. No tsunami were reported.

The 2:52 a.m. temblor's epicenter was in southern Oita, according to the agency. The focus was around 60 km underground.

The Ikata nuclear power plant in Ehime Prefecture in Shikoku, across a strait from Oita, reported no anomalies from the quake, according to Shikoku Electric Power Co. and Ehime prefectural officials.

Firefighters in Beppu, Oita Prefecture, said a woman in her 70s fell from her bed in her home and sustained minor injuries to her right arm.

The quake's intensity on the Japanese seismic scale of 7 was upper-5 in southern Oita Prefecture, the Meteorological Agency said. It was lower-5 in western Shikoku and Kumamoto Prefecture and 4 in Ikata.