Authorities have issued a tsunami warning, with waves of up to one meter (3.28 feet) expected. Residents in coastal areas have been urged to move to higher ground and follow official evacuation instructions, the Japan Meteorological Agency (JMA) said.
Broadcaster NHK said that waves of up to that level may already have been recorded.
The Japanese government issued emergency earthquake warnings for Kumamoto, Nagasaki, Kagoshima, Fukuoka, Saga, Oita, and Miyazaki prefectures, all on Japan's southern Kyushu island.
MNA