Japan nuclear Crisis: At par with Chernobyl.

Japan raised the severity of its nuclear crisis at the Fukushima Daiichi nuclear plant to a level 7 from 5, putting it on par with the Chernobyl nuclear disaster in 1986.

The rating reflects the initial severity of the crisis not the current situation which has seen radiation levels drop dramatically.

The operator of the crippled nuclear plant said that they are concerned that the radiation leakage could eventually exceed that of the 1986 Chernobyl nuclear disaster.

Japan is struggling to regain control of the Fukushima Daiichi nuclear plant after a massive earthquake and tsunami devastated its northeast on March 11, and is facing a major humanitarian and economic crisis.

The International Nuclear and Radiological Event Scale (INES) ranks nuclear incidents by their severity from 1 to a maximum of 7.

Here are some comments on the higher rating:

HIDEHIKO NISHIYAMA, A DEPUTY DIRECTOR-GENERAL AT JAPAN'S NUCLEAR and INDUSTRIAL SAFETY AUTHORITY (NISA)

We think it's very different from the accident in Chernobyl. First of all, the emission of radioactive substances is about 10 percent of the amount of Chernobyl. In the case of Chernobyl, 29 people died due to rapid absorption of massive radiation. That's not the case in Fukushima.

In the case of Fukushima, we had an explosion due to leaked hydrogen, blowing the roof off a building but the reactor containment vessel and reactor pressure vessel remains in the original shape, despite some leaks. In the case of Chernobyl, they could not keep working after the accident due to massive leaks of radioactive substances. In Fukushima, we still have engineers working to resolve the situation.

MURRAY JENNEX, ASSOCIATE PROFESSOR SAN DIEGO STATE UNIVERSITY

I think raising it to the level of Chernobyl is excessive. It's nowhere near that level. Chernobyl was terrible -- it blew and they had no containment, and they were stuck.

Their containment has been holding, the only thing that hasn't is the fuel pool that caught fire. I don't see those as the same event. If they want to do that, that's fine. I think they're being overly pessimistic.

KENJI SUMITA, OSAKA UNIVERSITY PROFESSOR

Raising the level to a 7 has serious diplomatic implications. It is telling people that the accident has the potential of causing trouble to our neighbours.

I think a level 7 is very extreme.

JAPAN'S NUCLEAR INDUSTRY AND SAFETY AGENCY (NISA)

According to the INES rating procedure, a provisional rating is given at the onset of an accident. The rating remains on a provisional status until the accident is deemed over, when a final rating is given upon analysis by a committee of experts. As for Daiichi the problems are still ongoing. This is a preliminary assessment, and is subject to finalisation by the International Atomic Energy Agency.

Japan: Tsunami warning Issued

Japan temporarily issued tsunami warnings for parts of the north-east coast on Monday following a powerful aftershock exactly a month after a magnitude-9 earthquake created huge waves that killed an estimated 28,000 people.

NHK, the public broadcaster, warned of tsunami up to 2 metres high on the coast of Ibaraki prefecture after the magnitude-7.1 quake.

Although the waves were estimated to be much smaller than those that devastated Japan's north-east coast on 11 March, the meteorological agency warned people in Ibaraki to evacuate to higher ground. The warnings were later lifted.

The aftershock came as the government announced it was widening the evacuation zone around the Fukushima Daiichi nuclear plant due to high levels of accumulated radiation and rising fears about the long-term effects on residents' health.

The government's chief spokesman, Yukio Edano, said the current 20km evacuation zone would be extended to five other communities, including the village of Iitate, which lies 40km from the plant.

The village's 5,000 residents were told to prepare to leave their homes, although the evacuation would not take place immediately as radiation levels presented no immediate threat to health.

The Asahi newspaper said the zone would be widened to 30km in some areas, depending on wind direction, adding that residents would be given about a week to prepare.

"We have made a new decision about evacuations based on data analysis of accumulated radiation exposure information," Edano told a news conference. "There is no need to evacuate immediately."

About 70,000 people living within 20km of Fukushima Daiichi have already been evacuated, and another 130,000 living inside a band 20-30km away have been told to leave voluntarily or remain indoors due to disruption to supply lines and services.

Engineers at the plant say that although progress has been made in containing radioactive water that has built up beneath reactors, they are still no closer to restoring damaged cooling systems.

Until repairs are made they cannot cool overheated fuel rods that could cause a major leak of radiation if they go into full meltdown.

The government had ignored pressure from the International Atomic Energy Agency and environmental groups to widen the evacuation zone. The US has advised its citizens not to go within 80km of the plant.

Hidehiko Nishiyama, a spokesman for Japan's nuclear safety agency, apologised for the anxiety caused by radiation leaks, and warned that the cooling systems could take months to repair.

"It's still difficult to give a timeline regarding when we can resolve the problem," Nishiyama said. "We are very sorry for the evacuees who are anxious to see the problem resolved."

The governor of Fukushima prefecture, Yuhei Sato, criticised the decision first to ask people in the area to stay indoors, then to consider leaving and now to prepare for evacuation. "Residents are very confused about what to do," he said.

Earlier, Sato refused to meet the president of the plant's operator, Tokyo Electrical Power, Masataka Shimizu, who had travelled to Fukushima to apologise to the prefecture's people.

The tsunami warning was a chilling reminder of the events of a month ago, which were marked across the country by a moment's silence at 2.46pm.

More than 14,000 people are still missing, and 152,000 survivors are living in evacuation centres.

Reflecting on the damage to his prefecture, which is also at the centre of the nuclear power crisis, Sato said: "My chest has been ripped open by the suffering and pain that this disaster has caused the people of our prefecture. I can't find the words to express my sorrow."

The prime minister, Naoto Kan, placed a message in newspapers in several countries, including Britain, China and the United States, thanking the international community for its support.

Kan said the generosity shown towards Japan in its time of need demonstrated the human capacity for kizuna, or bonds of friendship, and vowed that Japan would emerge a stronger nation.

"We deeply appreciate the kizuna our friends from around the world have shown and I want to thank every nation, entity, and you personally, from the bottom of my heart," he said.

Japan rattled by aftershock 1 month after tsunami

A strong new earthquake rattled Japan's northeast Monday just hours after people bowed their heads and wept in ceremonies to mark a month since the tsunami that killed up to 25,000 people and set off a still-unfolding nuclear crisis. The quake, the second major aftershock in less than a week, was another jarring reminder of the magnitude-9.0 earthquake that spawned the massive wave March 11. People in a large electronics store in Sendai screamed and ran outside and mothers grabbed their children, but there were no immediate reports of more damage or injuries.

Officials said operations were not endangered at the tsunami-flooded Fukushima Dai-ichi nuclear complex, where power was cut by the aftershock but quickly restored. Japan's meteorological agency measured the aftershock at a magnitude of 7.0, but a U.S. monitor said it was 6.6. The epicenter of was just inland and about 100 miles (160 kilometers) north of Tokyo.

The Fukushima Dai-ichi plant is still leaking radiation after its cooling systems were knocked out by tsunami, and the government on Monday urged people in five additional communities near the plant to leave within a month, citing concerns about long-term health risks from radiation. People who lived within a 12-mile (20-kilometer) radius around the plant already have been evacuated.

With workers still far from bringing the plant under control, the bodies of thousands of tsunami victims yet to be found and more than 150,000 people living in shelters, there was little time for reflection on Japan's worst disaster since World War II.

People in hard-hit towns gathered for ceremonies at 2:46 p.m., the exact moment of the massive quake a month earlier.

"My chest has been ripped open by the suffering and pain that this disaster has caused the people of our prefecture," said Yuhei Sato, the governor of Fukushima, which saw its coastal areas devastated by the tsunami and is home to the damaged plant at the center of the nuclear crisis. "I have no words to express my sorrow."

In a devastated coastal neighborhood in the city of Natori, three dozen firemen and soldiers removed their hats and helmets and joined hands atop a small hill that has become a memorial for the dead. Earlier, four monks in pointed hats rang a prayer bell there as they chanted for those killed.

The noisy clatter of construction equipment ceased briefly as crane operators stood outside their vehicles and bowed their heads

Japan: Another Earthquake

A 7.1 magnitude earthquake rattled Tokyo over a minute on Thursday night. Weaker than the M 9.0 that struck on March11, the 7.1 scared many people.

A warning of a tsunami of up to 6 feet was issued by the Japanese meteorological agency after a M7.1 shake off the coast, 60 miles from Sendai and 90 miles from the crippled and leaking nuclear power plant at Fukushima. Tokyo, which felt the earthquake, is about 215 miles from the epicenter. The tsunami warning was lifted after 90 minutes. The earthquake occurred at 23.32 local time. At first the quake was reported at M7.4, later downgraded to 7.1.

This latest strong aftershock has knocked out power in several areas in the Northeast and may have further damaged the Fukushima plant. Workers have evacuated the plant until the danger of a tsunami generated by this latest shock is past.

Plates warped and strained

This earthquake was 25 miles deep and is thought to be an aftershock or a continuation of the pressure release from the warping of the tectonic plates as the Pacific plate slides under Japan. Thomas Heaton, California Institute of Technology geophysicist, said after the March 11 earthquake that even one of magnitude 9 may not release the strain.

Japan mostly lies on the Okhotsk Plate, which is long and moving in a southerly direction. On the west side of Japan is the Eurasian Plate, pushing eastwards, and on the opposite side is the Pacific Plate, moving to the west. The Okhotsk Plate is therefore sandwiched between the two massive plates and being assaulted from both sides.