Magnitude 7.3 quake triggers tsunami alert in parts of Japan

A powerful earthquake hit off Fukushima in north-east Japan last night, shaking buildings more than 200km away in Tokyo and knocking out power in millions of homes.

The magnitude 7.3 quake, which measured six-upper on Japan's seven-point seismic intensity scale, struck at 11.36pm (10.36pm in Singapore) off a region that was devastated in the deadly earthquake, tsunami and nuclear disaster on March 11, 2011.

The epicentre was off the coast of the Fukushima region, at a depth of 60km. Tsunami alerts were sounded in parts of the north-east coast, for waves of up to one metre.

Sirens also sounded in Tokyo and neighbouring Chiba, Kanagawa and Saitama due to the quake, with 2.1 million households plunged into total darkness, utilities company Tokyo Electric Power Co said, including 700,000 homes in Tokyo.

Another 1.48 million homes were without power in north-east Japan, reports said.

Train services were halted and highways shut, while Haneda and Narita airports closed their runways.

A bullet train service on the Tohoku Shinkansen was reportedly derailed between Fukushima and Shiroishi-Zao stations. There were some 100 passengers on board.

Prime Minister Fumio Kishida, whose government has set up a disaster emergency centre, said just after midnight that he was still gathering information, including the extent of damage. He urged residents to take full precautions to ensure their safety.

The authorities were also trying to ascertain if there were any abnormalities at nuclear plants, including the Fukushima Daiichi nuclear power facility.