Japan's quake-devastated northeast faced a fresh tsunami alert on Thursday after a massive 7.4 magnitude temblor shook the region, as engineers pumped in nitrogen into a reactor at the Fukushima nuclear facility in their desperate bid to prevent another hydrogen blast. However, the warning was lifted by about 90 minutes later, the Japan Meteorological Agency said.
The powerful earthquake jolted the Miyagi prefecture, 118 km north of Fukushima. The quake that hit 40 km under the water, prompted an immediate tsunami alert with authorities warning that it could trigger waves up to three feet high. The quake was felt as far away as Tokyo and Japan's national broadcaster NHK asked those in the quake-hit areas to evacuate to higher ground. Kyodo reported no immediate casualties or damage.
NHK said people in that area should evacuate away from the shore to a safe place. Workers were evacuated from Fukushima Daiichi nuclear plant after Thursday's tremors, reported CNN. Buildings as far away as Tokyo shook for about a minute.
NHK also reported a tsunami advisory for Iwate prefecture, saying a tsunami is expected to arrive in coastal regions there as well. The Pacific Tsunami Warning Center said based on all available data, "a destructive Pacific-wide tsunami is not expected and there is not a tsunami threat to Hawaii."
The US Geological Survey said the quake was centered 66 km from Sendai --- one of the areas worst hit by last month's quake -- 118 km from Fukushima, where a crisis has been under way at the nuclear plant since last month's tsunami. It took place shortly after 23:30 hours local time, the CNN reported.
A magnitude 9.0 earthquake on March 11 devastated northeast Japan and damaged the atomic facility at Fukushima that is presently the centre of the country's worst nuclear crisis since World War II. Officials said Thursday's earthquake caused no further damage to the crippled plant.
The fresh quake struck Japan as authorities mulled extending the evacuation zone around the radiation-leaking plant.
For the first time since the March 11 quake and tsunami, police in protective gear launched a search for around 2,500 people missing within the 10-20 km radius of the crippled plant, where such an operation had not been carried out before due to high levels of radiation.
A day after registering rare progress by plugging a 12-inch crack leaking highly radioactive water into the sea, the plant's operator Tokyo Electric Power Company said its workers injected chemically-stable nitrogen into the No 1 reactor, where a build-up of hydrogen gas had raised concerns about a possible radiation-leaking explosion.
Last month's hydrogen blasts at the No 1 and No 3 reactors following the quake and tsunami destroyed reactor buildings, causing release of radioactive steam. TEPCO said the operation to reduce the risk of a blast has gone smoothly, Kyodo reported.
The utility said it plans to pump nearly 6,000 cubic metres of nitrogen, an inert gas, over a six-day period, nearly four weeks after the twin disaster left over 27,000 people dead or missing. TEPCO also continued to dump low-level radioactive wastewater from the plant into Pacific Ocean to create storage for more highly contaminated water. Around 6,000 tonnes of water have been discharged so far.
As Japan battled to cool its overheating reactors, the number of foreign nationals, who left Japan in the week after the earthquake, was reported to be 240,000, up 100,000 from the previous seven days.
With inputs from PTI