Tokyo/Fukushima, Apr 11: A strong aftershock of magnitude 7.1 jolted Japan's northeast today on the one-month anniversary of the devastating quake and tsunami that had left thousands of people dead, prompting authorities to evacuate workers from the crippled Fukushima nuclear plant.
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, and it struck at a depth of just 10 km.
Residents in Tokyo also felt the jolts as buildings in the Japanese capital shook for nearly a minute. After the quake, Japan's Meteorological agency issued a tsunami warning, predicting a potential tsunami wave of two-metres in Miyagi, Fukushima, Chiba and Ibaraki prefectures.
Last Thursday also, a 7.1-magnitude aftershock, which was the most powerful tremor since March 11 magnitude-9 quake and tsunami, had rattled the region, claiming four lives and leaving millions of homes without power.
Tokyo Electric Power Company (TEPCO), the operator of the Fukushima nuclear plant crippled by last month's twin disaster, temporarily evacuated its workers, who have been battling hard to stabilise the facility, after the latest quake.
Authorities also announced widening of the evacuation zone around the radiation-leaking plant due to fears of contamination, as people across the country fell silent for a minute to remember thousands of people killed last month.
"The government has designated for evacuation areas where the radiation exposure level is expected to reach 20 millisieverts per year," Chief Cabinet Secretary Yukio Edano said.
A 20-km evacuation zone was earlier put in place around the Fukushima nuclear plant after it was badly damaged in Japan's earthquake and tsunami disaster on March 11.
With the crisis at the Fukushima plant dragging on, Edano said some municipalities within the 20-to 30-km radius of the power station would now be designated as additional evacuation areas.
The municipalities which will be part of the new evacuation zone include Katsurao, Namie and Iitate, all located in Fukushima prefecture.
Residents in these municipalities will be expected to move to different areas within one month, Edano was quoted as saying by Kyodo.
TEPCO has received a total of two trillion yen in loans from financial institutions in the wake of the massive damage caused to its facilities, including the Fukushima nuclear power plant, following last month's quake and tsunami.
"We will use the money to pay for facilities, repay existing debts and finance our operations, including corporate bond redemptions, fuel costs and expenditures necessary for reconstruction," it said in a statement.
Today's aftershock temporarily disrupted the vital process of coolant water injection into Nos. 1, 2 and 3 reactors of the crippled Fukushima plant for about 50 minutes.
It also cut off external power supply to the pumping machines for the three reactors. TEPCO revived the power supply and resumed water injection operation at 6.05 pm local time, according to the Nuclear and Industrial Safety Agency.
Meanwhile, Fukushima Governor Yuhei Sato declined to meet TEPCO President Masataka Shimizu, who visited the prefectural government office to apologise for the nuclear crisis, Kyodo said.
"What (the TEPCO President) should prioritise now is to settle the nuclear plant's trouble, and he should do his utmost to do so," a local government official quoted the Governor as saying and conveyed the message to the utility firm.
Shimizu was hospitalised in late March for hypertension and dizziness as the company continued to scramble hard to contain the nuclear crisis.
Earlier in the day, sirens wailed across Japanese cities and sombre ceremonies held in the memory of nearly 30,000 people killed or unaccounted for in the twin disaster that ravaged Japan's northeast last month.
A minute's silence was also observed in the memory of the quake victims, exactly a month after the mega quake and tsunami. PTI