An earthquake with a preliminary magnitude of 7.1 has struck Japan's Kumamoto south-western prefecture, according to the Japan Meteorological Agency (JMA).
The quake hit on Tuesday just south of the town of Uki, near the prefecture's capital city, local authorities reported.
Seismology authorities from Geoscience Australia and the United States Geological Survey reported the quake struck at a depth of 10 kilometres below the sea's surface.
A tsunami warning for a wave measuring 1 metre was issued after the earthquake, the JMA said.
The Japanese government also issued emergency earthquake warnings for Kumamoto, Nagasaki, Kagoshima, Fukuoka, Saga, Oita, and Miyazaki prefectures, all on Japan's southern Kyushu island.
Japan is one of the world's most earthquake-prone countries, with a tremor occurring at least every five minutes.
Located along the "Ring of Fire" of volcanoes and oceanic trenches partly encircling the Pacific Basin, Japan accounts for about 20 per cent of the world's earthquakes of magnitude-6 or more.
Kyushu Electric Power said there were no reports of irregularities at its Sendai and Genkai nuclear power stations after the earthquake.
Train operator JR Kyushu said it had suspended services, including its high-speed Shinkansen trains following the quake.
AP/Reuters
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