A powerful aftershock rocked Japan’s tsunami disaster zone, killing at least four and triggering new concerns over nuclear power plants in a region still grappling with an atomic emergency. Electricity was cut across a huge area of northern Japan, forcing cooling systems at three nuclear plants to switch to emergency power and plunging more than 3.3 million households into darkness late Thursday night.
At least one backup supply remained online at all three plants, but the aftershock highlighted the potential risks of nuclear generation in an earthquake zone amid a battle to stabilise reactors at tsunami-hit Fukushima.
Officials and reports said four people had been killed by the 7.1 magnitude tremor, which struck off the coast near Sendai — one of the most powerful to hit Japan since the country’s worst post-war disaster four weeks ago. Thursday’s quake swayed buildings in the capital Tokyo, more than 300 kilometres away from the epicentre, and generated unease even well away from the coast.