TOKYO - An earthquake with a preliminary magnitude of 7.1 struck Kumamoto prefecture in southern Japan on Tuesday, knocking out power to thousands of homes, stopping rail services and triggering warnings for tsunamis and aftershocks.

Companies including Sony and TSMC, the world’s largest contract chipmaker, have plants in the area of the quake. A Sony spokesperson said the company was checking the situation. TSMC did not immediately respond to a request for comment.

The government issued emergency earthquake warnings for Kumamoto, Nagasaki, Kagoshima, Fukuoka, Saga, Oita and Miyazaki prefectures, all on Kyushu, the southernmost major island in Japan.

A tsunami warning for a wave measuring 1 metre was issued after the earthquake, the Japan Meteorological Agency said. Local officials were quoted as saying they had not seen any signs of a tsunami yet.

Kyushu Electric Power said that about 40,000 homes had lost power as a result of the quake, while the railway company JR Kyushu said it had suspended services, including its high-speed bullet trains.

There were no irregularities reported at the nuclear power stations in the area, Japan’s nuclear regulation authority said.

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% of the world’s earthquakes of magnitude 6.0 or more.

A massive earthquake in Kumamoto 10 years ago killed 275 people and injured a further 2,739, according to an official count.

Toppled shelving is seen after an earthquake with a preliminary magnitude of 7.1, struck Kumamoto prefecture in southern Japan, on July 28, 2026. (Photo: Kyodo via Reuters)