TOKYO – A powerful 6.6-magnitude aftershock hit northeastern Japan on Monday, triggering a brief tsunami alert and forcing the evacuation of workers battling to avert a crisis at a stricken nuclear plant.
The tremor hit exactly one month after a 9.0-magnitude quake and tsunami ravaged northeastern Japan and knocked out cooling systems at the Fukushima Daiichi plant, triggering the worst nuclear crisis since Chernobyl.
“The company ordered workers to withdraw and stay in a quake-proof building,” said a spokesman for operator Tokyo Electric Power Company (TEPCO). “We don’t know how many workers were involved.”
TEPCO said the power supply to three stricken reactors at the plant was briefly cut, but later restored, and the injection of water into reactors one, two and three had resumed.
However some monitoring systems had been knocked out by the quake.
Emergency crews at the nuclear plant, which was crippled by the March 11 quake and tsunami, have been pumping in water to cool overheating reactors that have already caused several explosions.
Radiation has leaked into the air, soil and sea, forcing local residents to evacuate their homes and leading several countries to restrict the import of food products from Japan.
The latest quake was given an initial magnitude of 7.1 by the US Geological Survey, which later revised it downward to 6.6.
It hit 81 kilometres (50 miles) south of Fukushima city and 163 kilometres northeast of Tokyo and at a depth of 10 kilometres, causing buildings in the capital to shake.
Authorities in Japan issued a tsunami alert, but later lifted it. The Pacific tsunami warning centre said no widespread alert had been generated.
Tohoku-Electric Power Co. said power supply has been cut to some 220,000 households in Iwaki city, Fukushima prefecture, and other municipalities following the earthquake.
Media reports said a car had been buried in a landslide set off by the quake and several people injured in separate incidents, but this could not immediately be confirmed.
The quake hit at 5:16pm (0816 GMT), as Prime Minister Naoto Kan prepared to deliver a live address to the nation on Monday to mark one month since Japan’s worst quake in recorded history.
He postponed the speech and urged emergency workers to do all they could to save lives in the aftermath of the latest quake.
