Our partners at Nature have a correspondent in Japan. On their blog The Great Beyond they post regular dispatches, which we reproduce below and will update as new articles come in.
Posted by Brian Owens on March 11, 2011 on behalf of David Cyranoski, in Tokyo.
In a land of people used to earthquakes, everyone is saying this one, which hit at 14:46 local time, is the strongest they've ever felt-and that's in Tokyo, some 400 kilometers southwest from the epicenter.
Scientists are calling it the biggest earthquake in Japan's tremor-filled history. Preliminary estimates from the USGS put the magnitude at 7.9, which have since grown to 8.9. Estimates of the depth range from 10-20 kilometres. This earthquake was 178 times as powerful as the 1995 Hanshin/Kobe earthquake.
Miyagi prefecture was pummeled the hardest. There Japan's earthquake intensity scale, which measures the amount of shaking at ground level, recorded a 7, the highest level. More than 20 deaths have been reported.
Tsunamis reaching 10 metres have hit the area and 3 metres tsunami are reported down all the way down the coast far past Tokyo.
Panic gripped Tokyo as bookshelves and installations in offices fell, people poured into the streets and more than a dozen buildings reported fire sending smoke billowing into the sky.
Trains are stopped as far down as Shizuoka, far south of Tokyo. Some phone lines are dead, but my internet is working. I'm writing minutes after the earthquake, stuck on a train that screeched to a halt and then bounced on the tracks.
Posted by Quirin Schiermeier on March 11, 2011
An earthquake at 9:46 PM Pacific Standard Time near the east coast of Honshu, Japan, with preliminary magnitude 8.9 has triggered a potentially large tsunami now propagating across the Pacific Ocean.
“This is the largest earthquake known in Japan," said Kevin McCue, a seismologist at CQUniversity's campus in Canberra, in a statement to the Australian Science Media Centre (AusSMC).
The quake originated some 400 kilometres north of Tokyo, at 24 kilometres depth. The sudden dislocation of the seafloor generated a tsunami which hit north Japan around 30 minutes later. The quake and tsunami have killed at least 18 people in Japan, and caused severe and widespread destruction.
"Japan has a rigourous earthquake building code and excellent tsunami warning system and evacuation plans," said James Goff, Co-Director of the Australian Tsunami Research Centre and Natural Hazards Research Lab at the University of New South Wales, in a statement to the AusSMC. "This event will likely provide a severe test for all of them.”
The first of possibly several large waves are expected to reach the Hawaiian Islands at around 03.00 am on Friday morning. Emergency services in Hawaii have begun to evacuate residents and tourists along threatened coastlines. In the Philippines, officials have ordered the evacuation of coastal communities along the country's eastern coast.
UPDATE: Associated Press reports that tsunami waves have reached Hawaii.
The Pacific Tsunami Warning Center says Kauai was the first island hit early Friday by the tsunami, and the waves surged in Waikiki. Officials predicted Hawaii would experience waves up to 6 feet, and officials spent hours evacuating ahead of the storms.
Image courtesy of Burak Uslu, NOAA
Posted by Mark Peplow on March 11, 2011
Japan has declared a nuclear emergency following the 8.9 magnitude earthquake that hit the country today.
Nuclear Engineering International reports that Onagawa, Fukushima Daiichi, Fukushima Daini and Tokai nuclear power stations have all automatically shut down.
According to Nature's Tokyo correspondent, David Cyranoski, Japanese media are reporting that the emergency core cooling system (ECCS) at the Fukushima #1 plant is not working due to a loss of electrical power, and problems with the backup diesel geenrator.
The reactor is currently relying on an alternate cooling system that circulates water using a pump system. This system can operate for about 7 to 8 hours. According to the Nuclear and Industrial Safety Agency of the government's industry ministry, this is the first time in Japan that the ECCS of a nuclear power station has not functioned.
Kyodo news reports that 2,000 residents near Fukushima nuclear plant have been advised to evacuate.
UPDATE: The Japan Atomic Industrial Forum has announced that the Fukushima reactor's core "still has a sufficient amount of water for cooling, with no danger of the nuclear fuel being exposed".
"Several emergency generator vehicles have rushed to the scene to provide the necessary power for the water supply," the statement says. It adds that the government will direct residents living with a 3-km radius of the reactor to evacuate.
Meanwhile, the US Air Force has delivered additional coolant to the Fukushima plant, Reuters reports.
UPDATE 22:45 GMT: IAEA reports that "pressure is increasing inside the Unit 1 reactor’s containment, and the officials have decided to vent the containment to lower the pressure. The controlled release will be filtered to retain radiation within the containment."
According to Kyodo News, "the amount of radiation reached around 1,000 times the normal level Saturday in the control room of the No. 1 reactor of the Fukushima No. 1 nuclear power plant, the Nuclear and Industrial Safety Agency said."
Posted by Geoff Brumfiel
Two Japanese nuclear power stations are struggling to contain damage from a major earthquake and tsunami, in what could become be the worst nuclear incident since the catastrophic Chernobyl accident of 1986.
This morning, the BBC has footage of what appears to be a massive explosion at the Fukushima Daiichi nuclear power station''s reactor number 1, which since last night has had trouble with cooling problems at its core. According to Kyodo news service, the blast occurred at 3:36 PM local time after a large aftershock shook the plant. Radiation levels on the premises have reached 1050 μSv per hour—about what an average person would receive in a year. The evacuation zone is currently extended to a 20 kilometer radius of the plant.
The explosion follows a difficult night at the power station, as engineers struggled to contain damage from a magnitude 8.9 earthquake that rocked the region on 11 March. The earthquake automatically put the three operating reactor cores at Fukushima Daiichi into shutdown mode, effectively halting the nuclear processes inside the core. Even after the reactor is shut down, however, it continues to require cooling, particularly in the first hours after an incident. Diesel generators initially supplied the necessary cooling water at Fukushima units 1 and 2, but they appear to have failed about an hour after the quake. The International Atomic Energy Agency says it now believes the tsunami that followed the earthquake was responsible.
Without enough fresh cooling water, the pressure in Fukushima 1 and 2 has begun to rise, as the cooling water covering the core boils into steam. The latest estimates from World Nuclear News, an industry publication, is that the pressure inside Fukushima Daiichi unit 1 is now 840 kPa, about double the reference value. Since this morning, reactor operators have been releasing radioactive steam from the containment vessel, while additional back up generators are brought in to restart the cooling pumps. As long as the reactor remains covered in water, a meltdown is unlikely, but if the core becomes exposed, then the temperature will rise until the uranium fuel begins to melt.
The impact of the explosion on the situation remains unclear, but press photographs indicate major damage to the building surrounding Fukushima 1. Kyodo reports that serious damage to the containment vessel is "unlikely" according to safety officials.
Meanwhile, at the nearby Fukushima Daini station, operators noticed an increase in the temperature of the plant's unit 1 and unit 2 reactors at around 5:30 am local time. Evacuations have begun around Daini in preparation for an emergency release of steam to relieve pressure in those units.
UPDATE: The IAEA confirms explosion at Fukushima 1, says authorities are preparing to distribute iodine tablets (release).
Posted by Geoff Brumfiel on March 12, 2011
At the end of a long day in Japan, there is a striking disconnect between the official statements (at least in the English media) concerning the Fukushima Daiichi nuclear plant and the actions being taken by authorities and the plant's owners.
Chief Cabinet secretary Yukio Edano has been reported as saying that an explosion earlier today at the Fukushima Daiichi nuclear plant did not occur at the site of Unit 1, despite pretty compelling footage of something that looks like a reactor building exploding. Japan's nuclear safety authority is reported as saying that the reactor itself remains in tact. "There is no possibility that radioactive substances will have leaked," Edano added in a televised statement.
The Tokyo Electric Power Company (TEPCO), in a statement, reported "a big sound around the Unit 1 and white smoke" shortly after another quake shook the area. But the company would not confirm whether the reactor itself was involved, saying only that four workers have been taken to hospital.
Those sorts of low-key statements do not match with the actions of the government or the power company. Late this afternoon local time, authorities announced that they were enlarging the evacuation zone surrounding the plant to 20 kilometers in radius. The International Atomic Energy Agency also reports that the Japanese are readying iodine tablets for distribution to the public.
Radioactive iodine is one of the largest health threats from any nuclear accident. The iodine can easily escape in gases vented from the reactor and is readily absorbed by the human body, where it becomes concentrated in the thyroid. Iodine tablets flood the thyroid, effectively lessening the uptake of any radioactive isotopes floating around. In a separate statement, TEPCO reports increased levels of radioactive iodine at the Fukushima site.
Meanwhile, the explosion has apparently prompted TEPCO to try flooding Fukushima Unit 1 with seawater. Such a decision reinforces the urgency of the situation. Nuclear plants are normally cooled with ultra-pure water, as any contamination can become radioactive (as well as interfere with the reactor's processes). Flooding the reactor with ocean water will almost certainly ruin the unit permanently. As Walt Patterson, an independent nuclear consultant, put it to BBC News: "This reactor will now be a write-off."
There has also been speculation on BBC this afternoon that the explosion was triggered by hydrogen gas from the reactor core. The gas would be created as water decomposes in the intense heat of the core, and, if that is what triggered the blast, it implies that temperatures are far higher than authorities have let on. There is a possibility that a partial meltdown has already taken place.
I still have not seen any update on Fukushima Daiichi unit number 2 or the two units experiencing difficulties at Fukushima Daini.
Of course, downplaying nuclear emergencies is nothing new, and the authorities do have an incentive to try and minimize panic as they increase the exclusion zone around the reactor. Yet from the evidence we have at the moment, the situation, to me at least, looks far more serious than official statements might lead one to believe.