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Massive earthquake in Japan

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Recent earthquakes: USGS

Sendai earthquake and aftershocks, USGS

BBC reported:

Japan’s most powerful earthquake since records began has struck the north-east coast, triggering a massive tsunami.

Cars, ships and buildings were swept away by a wall of water after the 8.9-magnitude quake, which struck about 400km (250 miles) north-east of Tokyo.

A state of emergency has been declared at a nuclear power plant but officials said there were no radiation leaks.

The death toll is unclear, but police say 200 to 300 bodies have been found in the port city of Sendai.

With train services suspended, there are millions of people on the streets of Tokyo tonight. The official advice is, if you’re safe, to stay where you are. But after the shock of the quake many people just want to get home.

Here in Tokyo, even though it wasn’t the epicentre, the quake was still felt very powerfully. The ground rolled and rumbled underfoot and you could hear the great skyscrapers creaking and cracking as they swayed.

Walking was like crossing the deck of a ship at sea. People poured down from their offices and stood in the street staring up.

The tremor, measured at 8.9 by the US Geological Survey, hit at 1446 local time (0546 GMT) at a depth of about 24km.

A tsunami warning was extended across the Pacific to North and South America.

Sydney Morning Herald reports:

The monster 8.9-magnitude earthquake which hit Japan was the country’s biggest ever and the seventh largest on record, according to US Geological Survey data.

ABS reported:

A passenger train with an unknown number of people aboard was unaccounted for in a tsunami-hit part of coastal Japan, Kyodo News reported Friday, citing police.

The East Japan Railway Co. train was running near Nobiru Station on the Senseki Line connecting Sendai to Ishinomaki when a massive quake hit, triggering a 10-metre (33-foot) tsunami, the report said.

The Hindu reported:

A Japanese coast guard official says a search is under way for a ship carrying 80 dock workers that was swept away when a tsunami struck the northeastern coast.

The vessel was washed away from a shipbuilding site in Miyagi Prefecture. That’s the area most affected by a massive offshore earthquake on Friday. The quake triggered the tsunami.

The Pacific ring of fire

BBC reported elsewhere:

“The earthquake happened on the Japan Trench which runs roughly north-south and the fault dips shallowly westwards towards Japan at about 15-20 degrees,” explained Dr John Elliott from the Centre for the Observation and Modelling of Earthquakes and Tectonics (Comet) at Oxford University, UK.

“Given the size of the earthquake, the fault is likely to have ruptured for about 500km.

“The previous earthquake to rupture probably the same section of fault was the 1933 M 8.4 earthquake (3,000 deaths) and had a large associated tsunami as well.”

As slipping occurs along these great lengths, the shifting sea floor lifts a great mass of water along the fault line, launching tsunami – principally along a line perpendicular to the fault, with lesser intensity in the directions along the fault’s length.

For Friday’s event, that means effects to the east – for instance at Hawaii – will be much more pronounced than those to the north and south.

The US-run Pacific Tsunami Warning Center said amplitudes (top to bottom of waves) of up 7.3m were recorded on the coast of Japan.

Japan’s Kyodo news agency reported that a 10m wave (33ft) struck the port of Sendai, carrying ships, vehicles and other debris inland.

Washington Post reported on a sad irony of preparations:

This event could roil the geological community in Japan. Scientists in Japan had developed a scenario in which a catastrophic earthquake would strike southwest of Tokyo on a different fault. That hypothetical earthquake had a name – the Tokai Earthquake – even though it hadn’t happened yet. Geologists placed strain meters throughout that region of Japan and closely monitored any signs of what they called “pre-slip,” a hypothesized precursor to an earthquake.

Maps showed very precisely where landslides would occur, and officials enumerated in advance the expected number of casualties and the amount of property damage. The seismic hazard maps for Japan, including one on the U.S. Geological Survey Web site, shows a relatively more modest earthquake hazard for the region where Friday’s quake struck.

Mar 12, 2011


Footage of explosion in the Fukushima nuclear reactor, a day after the earthquake.

Asia One brings news of a possible emergency at two of the nuclear power plants which were affected:

Japan warned of a possible radiation leak on Saturday as authorities battled to contain rising pressure at two nuclear plants damaged by a massive earthquake, and were moving tens of thousands of residents in the area out of harm’s way.

Tokyo Electric Power Co said it has begun steps to release pressure at its two nuclear power plants in Fukushima, located some 240 km (150 miles) north of Tokyo.

While some radiation leakage could be expected, Naoto Sekimura, a professor at the University of Tokyo, said a major radioactive disaster was not likely.

“No Chernobyl is possible at a light water reactor. Loss of coolant means a temperature rise, but it also will stop the reaction,” he said.

“Even in the worst-case scenario, that would mean some radioactive leakage and equipment damage, but not an explosion. If venting is done carefully, there will be little leakage. Certainly not beyond the 3 km radius.”

Kyodo news agency reported that authorities had begun evacuating about 20,000 people from the vicinity of one of the plants, the Daini plant. Prime Minister Naoto Kan, who was flying by helicopter to view the plant by air, had earlier ordered that residents within a 10 km radius to be evacuated from the other plant, the Daiichi plant.

March 16, 2011

The problem with the nuclear reactors continues, overshadowing the massive relief work needed to rehabilitate the more than half a million people displaced by the earthquake and tsunami. The news is indeed grim. Reuters reports:

Conditions at a stricken nuclear power plant in Japan have deteriorated so much that there is a growing consensus the crisis is greater than the Three Mile Island accident in 1979, and there are fears that it could get significantly worse.

Academics and nuclear experts agree the problems at the Fukushima Daiichi reactors are grave, and the solutions being proposed are last-ditch efforts to stem what could well be remembered as one of the world’s worst industrial disasters.

All six reactors at the complex have problems — be it blown-out roofs, potentially cracked containment structures, exposed fuel rods or just the risk of explosion that has been great enough to force emergency measures.

Of particular concern are a fire in a massive pool holding spent atomic fuel rods and a blast at the building housing the pool and reactor No.4. The pool is exposed to the elements, unlike the reactor core protected in steel and concrete.

“I would say that it has now eclipsed the Three Mile Island accident but it is not a Chernobyl,” said Keith Holbert, director of the Nuclear Power Generation Program at Arizona State University and an associate professor there.

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Written by Arhopala Bazaloides

March 11, 2011 at 3:50 pm

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