A strong earthquake of 7.1 magnitude jolted Japan's northeast today on the one-month anniversary of the devastating quake and tsunami on the 11th of last month that had left thousands of people dead. Workers at the damaged Fukushima nuclear plant were evacuated following the latest quake.The epicentre of the latest quake, which occurred at 5.16 pm local time, was in an area in Fukushima prefecture, about 164 km northeast of Tokyo. It struck at a depth of just 10 kms. The tsunami warning issued immediately after the quake had been lifted. Last Thursday also, a 7.1-magnitude aftershock, which was the most powerful tremor since March 11 rattled the region, claiming four lives and leaving millions of homes without power.