The earthquake registered off the western coast of Yamagata, roughly 30 miles southwest of the city of Sakata, according to Japan's Meteorological Agency. The shallow quake hit around 6 miles below the sea's surface.
The agency predicted that a tsunami of up to three feet could happen along the coast of the northwestern prefectures of Yamagata, Niigata and Ishikawa. Officials don't expect major damage as a result, The Japan Times reported.
All seven reactors at the Kashiwazaki-Kariwa nuclear plant in Niigata were offline and no abnormalities were reported.
Japan is one of the most earthquake- and tsunami-prone areas in the world. On March 11, 2011, a magnitude 9.0 offshore quake hit the northeast coast, causing a tsunami that took more than 18,000 lives and triggered a nuclear disaster at the Fukushima power plant.
On Monday, at least 12 people were killed and 135 others were injured when a 6.0-magnitude earthquake and 5.1-magnitude aftershock hit China's southwestern Sichuan province, officials said.
The Associated Press contributed to this report.