0135: If you're just joining us, here's a quick recap on the main events in Japan: An 8.9 magnitude earthquake struck north-east Japan on Friday, killing at least 300 people - although that figure is widely expected to rise. As a huge relief mission gets under way, states of emergency have been declared at two nuclear plants. Up to 300 bodies were recovered from the port city of Sendai, in Miyagi prefecture, and a third of Kesennuma, a city in the same region, is said to be under water.
At least 200 people are dead in Japan, 700 are missing, and the death toll is increasing every hour since a devastating earthquake hit the country Friday, Japan's ambassador to the United States said. At least six million homes are without electricity, accounting for about 10 percent of Japan's households, he said. The government is responding to recovery efforts with 8,000 self-defense forces, and the Coast Guard is contributing 300 ships and 40 airplanes, he said.
Several high quality images of the devastation can be found here and here.
[6:15 p.m. ET, 8:15 a.m. Tokyo] As day breaks Saturday in Japan, tsunamis continue to wash ashore on the Pacific northeast coast, toss about cars and boats like toys and forcing residents to seek refuge on the roofs of buildings. A fire has broken out in the city of Kesennuma, NHK reports. At least 427 are dead, with 200 to 300 bodies unidentified, NHK reports.
0033: Naval and coastguard helicopters airlift all 81 people to safety from a ship that was swept out to sea by a tsunami, the AFP news agency reports, quoting Japanese media.
0239: Another powerful aftershock - with a magnitude of 6.8 - strikes the east coast, according to US seismologists quoted by the AFP news agency.
0311: A resident of a town near to the worst-hit city of Sendai tells the BBC: "We were shaken very badly by the quake. Unable to stand, everything inside the house just fell down. A large number of people in this town have actually had to be evacuated to schools and gymnasiums because they had no water, no power. It's pretty overwhelming, people here are just like looking gobsmacked by the whole situation.")
0314: Kana Akabane, from Chiba, writes: "Due to no transportation, my colleagues went back home on foot. They walked more than 20km to their home and it took five hours. I stayed at my office with four other colleagues overnight. During the night, we felt many earthquakes, some were small but the others were big. Our place is 400km away from Miyagi, but there are many cracks on the road. Water and clay comes out from the ground, so many cars stack. We want to go home, but recovery of trains is very slow and stations are packed with people who want to get on trains, which is very dangerous."
0319: The BBC's Mariko Oi in Tokyo says Tokyo Electric is warning that demand for electricity will outstrip supply by the early evening, so the firm is urging residents in the capital to save electricity.
0324: Michael Tonge, a teacher from Sendai, tells the BBC: "Going to take a few days for things to get a bit better. Still experiencing strong aftershocks. No trains running so many people stuck and sleeping rough in freezing conditions as had heavy snow storm just after quake when people running to go to evacuation points in parks.
ANN has compiled a list of all the anime, manga, and game industry members who've updated since the quake and confirmed they are alive.
0336: Naoto Kobaashi, from Tokyo, writes: "Situation in Tokyo is becoming normal now. But most of the information is in Japanese, so unfortunately the foreigners cannot understand them. So please report to the English speaking community in Japan the following : if you are in the hazard area, calm down and try to make a community to help each other. Also please do not use candles. If you have to leave the car out in the road leave the key inside. Emergency vehicles may have to use the road. If you are not in the hazard area please save electricity. All the power plants in Japan are sending their energy to north Japan. To do that all of Japan has to save the energy. Try not to call unless it's an emergency. There is a limit in phone line and save them for the people who really need it. Try use the 171 service or twitter for the information. Thank you for reading and your help can save lives."
Calculations suggest that an area of fault between 300 and 400 kilometres long by 100 kilometres wide slipped some 40 metres. The US Geological Survey puts their estimate closer to 20 metres. Consider those upper and lower boundaries on where the final figure will likely fall.
Latest Japan quake toll: 398 dead, 805 missing.
0401: More than 215,000 people are taking refuge in emergency shelters in the east and north of the country following Friday's massive quake, Japan's national police agency tells the AFP news agency.
0411: More from the BBC's Mariko Oi in Tokyo, who says more than four million households remain without electricity in northern Japan. She says phone companies are offering free public calls because mobile phone lines have been disrupted.
People have tried to draw out heliports in the middle of a school field with "SOS" and "1000 people" to try to get helicopters to drop off more food/water.
0419: Yukinori Mesuda, from Tokyo, writes: "We are in an historical, deep grief. Thousands are searching for their families with no luck, and can only pray or cry now. We will never lose hope. We shall get back into peaceful life with unity, wisdom and love. Please be with us."
0430: Thousands of people remain trapped in buildings surrounded by swirling floodwaters in Miyagi prefecture, authorities there tell the AFP news agency.
0432: Christopher Craig, in Sendai, writes: "Electrical power was restored this morning and the government has announced that some grocery stores will be opened to provide food and water. Aftershocks hit regularly, with almost continuous tremors since the first quake, but nothing has approached the strength of the initial shock."
0446: British mother-of-three Naomi Van Holbutt-Kirk describes emotional scenes at a school in Tokyo as she and other parents were about to collect their children. She says: "I could actually see my seven-year-old daughter crouched under a desk with her classmates... the building was swinging like a giant pendulum and I was just waiting for the sound of a crash from the adjacent building where my five-year-old son was still in his classroom. It did not collapse and the quake eventually stopped."
0449: Naomi Van Holbutt-Kirk adds: "While I was waiting on the street the next quake came, which was very frightening and can only be likened to the feeling of riding a wave on the pavement. Frightened mothers were screaming and crying, nobody knew where the safest place to be was and everyone was looking up at the shaking buildings... minutes later we were allowed into the building to collect our children."
0511: Japan scales back its tsunami warning for much of the country, and revokes "large tsunami" warnings for all but a stretch of the Pacific coastline closest to the epicentre of Friday's earthquake, Reuters reports.
0515: John Little, in Komagane-Shi, writes: "We're currently seeing pictures of an army helicopter making very daring landings on the narrow, congested roof of a hospital in Miyagi-ken to ferry the injured in and out. At the same time, people can be seen elsewhere hanging out of top-floor windows waving blankets and emergency flares to attract attention. Already this morning we've seen news helicopters (which aren't equipped for winching operations) directing rescue helicopters to trapped survivors."
0606: Masayuki Okumiya, in Tokyo, writes: "It is uncannily quiet. There are fewer people in department stores and it is much less crowded on trains. It is probably because we are tired of the pandemonium of yesterday, but also because we are just worried about the victims of the northen part of Japan. Can't describe this powerlessness, just watching the footage of tsunami and being unable to do anything for them."
0625: The quake death toll rises to more than 700, the AFP news agency reports.
0859: Tomoaki Furuno in Tokyo writes: "We Japanese appreciate offering of aid and heart-warming messages from the world. After the earthquake, I walked to the government offices to pick up my pregnant wife who works as a civil servant. I passed through thousands of people walking, because all trains stopped. We could not go get back home. Finally, I found something to eat and a building to stay in. We borrowed the blanket and stayed one night inside the building."
0948: Hirofumi Yokoyama, an official at Japan's Meteorological Agency, says people living along the Pacific Coast should remain on alert: "The possibility of tsunami with a height of 10m or higher is getting slimmer but we're still calling on people living along the coast of Tohoku region to be cautious because tsunami as high as three metres or more could still hit the area."
0951: Lan Murata in Kaneyama writes: "The heater has gone off hours before and now it's freezing. It was the biggest I ever felt. I always thought the earthquake drills were the waste of time at school. But I was wrong, I felt thankfulI that I didn't panic, our family is lucky that we have a drawer full of emergency goods. My mum is one who survived the earthquake in 1995 in Kobe. Some of the boards are loose on the stairs. But I can't move any further because a bookshelf is blocking the stairs."
From Richard Black, BBC environment correspondent: "Although Japan has a long and largely successful nuclear power programme, officials have been less than honest about some incidents in the past, meaning that official re-assurances are unlikely to convince everyone this time round."
The death toll has risen to 564 people and there are 600 people missing.
1040: Japanese authorities say troops found between 300 and 400 bodies in the coastal city of Rikuzentakata, which was devastated by the tsunami - NHK
1128: Car manufacturer Toyota says it will suspend operations at all 12 of its factories in Japan on Monday while it confirms the safety of its employees. One of its subsidiaries, Central Motor Company, has a factory in Miyagi prefecture, near Sendai, which produces the Yaris model.
1135: Alan Margerison, a British businessman living in Tokyo, describes the scene there as relatively calm. "I went out into Shibuya, one of the downtown areas, it's normally very busy on the weekend. Today there were not as many people around... there were people getting their hair done in the salons, I saw some people having their nails done. I think in Tokyo, people are trying to get back to life as it normally is, but they're also very worried about the news they're hearing."
1141: Prime Minister Naoto Kan urges people to take "responsible actions", to listen to the media.
1142: Naoto Kan: "This is an unprecedented disaster that we are suffering."
1151: Damian Grammaticus has just arrived in Sendai. He says there are truly astonishing scenes of devastation at the harbour there, there are shipping containers that have been swept inland and smashed against buildings and trees and rubble strewn across the streets.
1157: More from Damian Grammaticas in Sendai. "The streets are covered in mud that was swept inland. There are dozens and dozens of cars that were carried along, twisted and turned, and crushed by the wave. The gas and water have been cut off, fires burning are close to the seaside, and locals say hundreds of people died in this area."
1235: Meanwhile, a huge rescue and recovery operation is under way as Japan tries to deal with the aftermath of Friday's 8.9 magnitude earthquake, which has caused devastation in parts of the country. Stay with us for more minute-by-minute updates, reports from our correspondents on the ground, and your reaction from around the world. You can contact us via email, text or twitter.
1252: Japan's Fuji TV has run a screen caption saying that as many as 10,000 people are missing in the town of Minamisanriku in Miyagi prefecture.
1254: And Kyodo news has published photos of Rikuzentakata, where hundreds of people are feared dead. They show houses smashed to fragments - a scene of total devastation.
1257: Peter Old, of search and rescue charity RapidUK, told the BBC's World Service that while most people think of tsunamis as made of water, by the time the wave reaches inland, it is more like a mudslide. "Those people that would have been on the ground are likely not to have survived," he said.
1323: From Kyodo news: 9,500 people unaccounted for in Miyagi's Minamisanriku: local gov't.
1330: A magnitude 6 earthquake hit Fukushima at 2215 (1315GMT) on Saturday, Japan's NHK reports.
1355: At least 1.4m homes are without water following the quake, according to government officials. 59 water trucks have been sent to the worst-hit areas. Some 3m are without power and utility companies say it will take some time to restore supplies.
1401: The BBC's Rachel Harvey reports: "Stopped at fire station on edge of Sendai. Group of fire fighters said they have been looking for people all day. One small team among many, they said."
1416: In Fukushima residents are lining up in town centres to collect drinking water as helicopters airlift the injured to hospital, Reuters reports.
1432: NHK shows images from the centre of Sendai city, which appears to have suffered far less damage than its coastal suburbs.
1450: Two bullet train lines have resumed operating, NHK reports, and local train lines in Tokyo are slowly returning to normal.
1501: Rachel in Narita airport, Tokyo writes: "Right now I'm sitting in Narita airport, where I'll be spending the night before catching my delayed plane back to Sydney. When the earthquake hit I was right in the middle of Shibuya. At first I thought I was going to faint until I sensed the hush that spread across the square, as all the usual music and traffic noise ceased. Despite my continued shock at the devastation, my overwhelming impression is of the admirable way in which the Japanese people have handled the aftermath."
1511: All available personnel, vehicles, aircraft and vessels of Japan's Self Defence Force have been mobilised for relief efforts, up to a total deployment of 50,000, local media reports.
1526: Japanese Foreign Minister Takeaki Matsumoto to attend a G-8 ministers' summit in Paris next week but cancel trip to Britain: Kyodo
1531: Paul Ashton in Okayama City, Japan writes: "I have just returned from Kumamoto Island, in the south west of Japan by car. The journey was about 500 km. We passed 50 to 60 Japanese Self-Defence Force vehicles travelling in convoy in the direction of east Japan. The vehicles were carrying huge supplies of water, many large electricity generators, gasoline and large earth moving machinery. The whole country is in shock."
1555: Andrew Coad in Tokyo writes: "A strange hush still hangs over Tokyo with noticeably fewer cars on the roads. Taxis are operating and trains are getting back to normal schedules. Not such a good story in the stores - shopping today for bread, milk and water in several stores and there was none. The shelves are barren of all the key essentials as well as snack foods. Plenty of beer still, though."
NHK say 4,000 council houses have been made available for evacuees. Resources are available to build 4,300 houses, says government (NHK)
1609: The BBC's Rachel Harvey in Sendai: It is a very patchy picture - in the centre of the city there is power, traffic on the streets, but the shops are mostly closed and the place feels eerily quiet. If you drive out of the centre, there are areas in complete darkness. There are huge queues at every petrol station that is operating. I spoke to one man who said he had been in that queue for five hours. Now the station is rationing fuel to 20 litres per vehicle.
1615: Chris Hall in Tokyo writes: "I'm having trouble getting to sleep as there is an aftershock - small but big enough - every 10 minutes or so at the moment. The quake yesterday was the most frightening thing I have experienced. My partner and I ran out into the street and stood with other people from several buildings. Concrete walls bent and flexed as if they were made of rubber and I still can't believe they didn't snap or crumble. Near our flat there was a gas leak. My biggest worry is the nuclear plant. And it has been hard to get information."
1652: Residents and companies across Japan are being urged to save energy because of supply problems caused by damage to power generation facilities, The Japan Times reports. By noon on Saturday 5.1 million households in northern Japan remained without power, the paper said.
1712: Meanwhile the latest report from Kyodo news agency puts the official death toll at 687, with another 650 people missing. But it is not clear whether this figure includes between 200-300 bodies being transferred to Sendai city.
1829: Chinita in Kyoto writes: "It's been a really long and hard day for all Japan. Although I live in Kyoto where nothing happened, it's really depressing. What will be next? How will Japan survive this disaster? Everything feels like a really bad dream."
1847: Brittany Smith in Sendai, Japan writes: "I was teaching at school at the time of the quake, but I have since returned to my apartment. My electricity, gas, and water were shut off all day, but the power has recently turned back on. We're still getting small quakes off and on here, but nothing nearly as strong as the first few."
1917: The lights have been turned off at some of Japan's landmark buildings including the Tokyo Tower, Tsutenkaku Tower in Osaka, Rainbow Bridge in Tokyo and Bay Bridge in Yokohama, to help save electricity after the loss of the Fukushima nuclear plant, the Kyodo agency reports.
1958: More on power supply problems: Tokyo Electric Power Company, one of Japan's major suppliers, has suggested it could carry out intentional power outages on a rotating basis to tackle the problem, Kyodo reports.
2012: The Bank of Japan is to hold a policy meeting on Monday and has vowed to do its utmost to ensure financial market stability.
2019: Tokyo Disneyland is to close for about 10 days for safety checks, its operator says.
New tsunami waves reported ranging from 30 CM to 60CM high.
The National Weather Service warnings were later downgraded to advisories for the U.S. state of Hawaii, and the coastal areas of California and Oregon. Warnings remained in effect across wide swaths of the Pacific.
Advisories also were in effect along the California-Mexico border and in the coastal areas of Washington, British Columbia and Alaska, the weather service reported.
The initial warning list included Russia and Central American countries including Guatemala, El Salvador and Costa Rica. The quake, which struck near the coast of Honshu, Japan, on Friday afternoon local time, unleashed powerful pulses in the Pacific. Japan was the first nation to be hit, as a wall of water rushed inland, leveling houses and bashing cars in its path and killing hundreds. The waves also spread out across the ocean. "The tsunami is more than one wave, and the waves can be separated by 20 minutes or half an hour. So just because you see a wave come up and then go back in the ocean again, that doesn't mean it's over," said Gerard Fryer of the Pacific Tsunami Warning Center.
[8:30 p.m. ET, 10:30 a.m. Tokyo] Ecuadorian President Rafael Correa ordered the evacuation of the Galapagos Islands and of cities along the country's coast Friday.
[6:50 p.m. ET, 8:50 a.m. Tokyo] California Gov. Jerry Brown declared a state of emergency in Del Norte, Humboldt, San Mateo and Santa Cruz counties Friday after tsunami waves moved ashore in those areas.
The tsunami rolled across the Pacific at the speed of a jetliner but had weakened before it hit Hawaii and the US West Coast.
People signed up to this list receive info on the current developments in the area 24/7, also the German embassy will coordinate aid etc for people in need of any assistance.
1905: Across the Pacific, Chile has reopened its copper-exporting ports and recalled large ships that were sent out to sea to avoid the tsunami, but it warns fishermen to beware of continuing swells and currents, Reuters reports.
1938: More on the effects of the quake around the world: In Peru, the mayor of the town of Pisco says tsunami waves destroyed about 300 houses as they swept into the town square - about 400 people spent the night in tents.
People in Chile are reporting that the tsunami waves are hitting the Chilean coast right at this moment, according to this tweet.
NUCLEAR REACTOR PROBLEMS:
Here's some links trying to explain the situation: Arclight, a diagram, will add more as they appear...
[7:45 p.m. ET, 9:45 a.m. Tokyo] Potentially dangerous problems cooling radioactive material appear to have cropped up at another of the Tokyo Electric Power Company's nuclear plants. Kyodo reported Saturday the power company alerted authorities that the cooling system at three of the four units of its Fukushima Daini plant – which is different from the Fukushima Daiichi reactors, nearby in northeastern Japan in the Fukushima prefecture – has failed. The news agency also reported Saturday that Japan's nuclear safety agency ordered the power company to release a valve in the Fukushima Daiichi plant's "No. 1" reactor, in order to release growing pressure. This comes amid Kyodo's reports, citing the same Japanese agency, that radiation levels were 1,000 times above normal in the the control room of that facility's "No. 1" reactor.
0014: Japan declares a state of emergency at the Fukushima-Daini power plant, where three of its reactors failed, the Associated Press reports. It says a state of emergency is already in place at the nearby Fukushima-Daiichi plant, where two reactors failed.
0023: People living within a 3km (two-mile) radius of the Fukushima-Daini nuclear plant are told to evacuate, the AFP news agency reports.
0050: Reaction to events at two nuclear power plants 250km (160 miles) north east of Tokyo, where states of emergencies have been declared. Environmental group Greenpeace tells the AFP news agency "Japan is in the middle of a nuclear crisis with potentially devastating consequences". Campaigner Jan Beranek adds: "While the immediate focus is on minimising radiation release and keeping local people safe, this is yet another reminder of the inherent risks of nuclear power."
0059: Tokyo Electric Power, which runs the two stricken nuclear power plants, confirms it has released a small amount of vapour into the atmosphere to reduce pressure on one of its reactors. It tells AFP there are no health risks.
0107: Reaction just in from flight attendant Mark Richardson, who was on the sixth floor of Narita Airport when the quake struck: "It was absolutely terrifying, computers were flying off the office tables and it seemed to go on for ever," he says. "Now watching the footage of this quake on TV, I count myself very lucky. Aftershocks are still rattling our nerves every half an hour or so and my house looks like it has been raided by burglars."
0143: Tokyo Electric Power releases more radioactive vapour from a second sticken reactor, AFP reports.
0232: Back to concerns surrounding two stricken nuclear power plants: Steve Kerekes, from the Nuclear Energy Institute in Washington DC, says: "Even if there were to be a release of radiation, that in itself is not necessarily something that means the public is being harmed... the question would be 'what are the levels'?"
0256: More on the nuclear fears: James Acton from the Carnegie Endowment tells the BBC that releasing vapour from the reactors shouldn't damage the environment.
0258: Mr Acton adds: "If there is nothing worse than radioactive steam being released into the environment, then there's unlikely to be significant lasting damage to people outside of the plant. If the integrity of the core is lost and the core starts to melt, and much more radioactive steam is leaked out into the environment, then we could be in an extremely serious situation."
0302: A similar warning, but with a more doom-laden tone, comes from Edwin Lyman, a senior staff scientist at the Union of Concerned Scientists. He tells Reuters: "We don't have all the information but every indication is that the type of event that occurred there is one of the most serious things that can happen to a nuclear reactor."
0304: Mr Lyman goes on to raise the spectre of Chernobyl: "In the worst case the entire core could melt through the steel reactor vessel and escape into the containment building, and then the containment is the only thing that is standing between the radiation in the reactor and the atmosphere. There is a chance if that does occur that there will be over pressure, the containment can fail and you might have a release on the order of the Chernobyl accident."
0548: The plant's operator, the Tokyo Electric Power Company, tells AFP: "We believe the reactor is not melting down or cracking. We are trying to raise the water level."
Because we are barely getting anything detailed, a lot of times the media will take the information and run with it and claim was was said was 'NUCLEAR MELTDOWN I ACTION'
Things do appear grim, due to the fact that all efforts have failed to the point that they resorted to literally pumping water from hydrants into the reactor. However, all hope is not lost. The reactors are still within containment buildings, so even if the the rod is exposed and a meltdown occurs, the toxins may still be contained within the buildings without spreading to the outside environment.
I know how you feel but try to stay positive. All you can do is stay informed, spread the word, and keep positive thoughts in mind for the people in danger and the people trying to make things right.
HirokoTabuchi Let's hope: RT @dicklp Expert on NHK counsels caution, says Fukushima partial nuke meltdown controllable, current evacuation zone adequate.
Pressure successfully released from Fukushima No. 1 reactor: agency (15:31)
0803: Japan's NHK TV also has that report of an explosion, which it says was "near" the Fukushima-Daiichi plant. The Tokyo Electric Power Company - which runs the plant - says some workers were injured, NHK reports.
Several people appear to be injured at Fukushima nuclear plant - NHK
0810: Japanese media reports say that radioactivity has risen 20-fold outside the Fukushima-Daiichi plant.
"An explosion was seen at the Fukushima Daiichi Power Plant #1 stack, and the outer wall seems to be going. We're checking with the Nuclear and Industrial Safety Agency. We also have information from Tokyo Electric that several people were hurt."
"Those who live near the power plant: We are confirming this, but there is a possibility of radioactive material leaking out. Just to be sure, do not go outside. Shut off your fans and close your windows. If you are outside looking for shelter, make sure your skin is not exposed and get inside quickly."
[3:08 a.m. ET, 5:08 p.m. Tokyo] An explosion has been reported near a nuclear plant in northeastern Japan's Fukushima prefecture, Japanese public broadcaster NHK reported, citing the country's nuclear and industrial safety agency.
1052: Neil McKeown in Nakameguro, Tokyo writes: "The evacuation zone has been extended to 20km by the government. However TepCo [the Tokyo Electric Power Company] appeared in a news conference and promised to release new radioactivity readings after 6pm. It is now 7.30pm and they have not done so. People are getting extremely frustrated at the lack of news coming from TepCo and the government - they have yet to confirm if the building that suffered an explosion housed a reactor, and we have no indication how much radiation has been released or in what direction winds are blowing."
0822: The Associated Press cites Fukushima Prefecture official Masato Abe as saying the cause of the white smoke seen above the plant is still under investigation, and that it's unclear whether there was an explosion.
0828: Japan's NHK TV showing before and after pictures of the Fukushima-Daiichi plant. It appears to show that the outer structure of one of four buildings at the plant is no longer there.
About the Fukushima Daiichi Power Plant: Tokyo Electric reports that the ceiling of a structure at the plant exploded and the interior structure collapsed. Reports coming into the Tokyo Electric head office say that it may have been a turbine in the reactor, but something underneath shook, let out a sound like an explosion, and began emitting white smoke. Four people were injured.
0841: Malcolm Grimston, a nuclear energy expert from Imperial College London, has told the BBC that as long as any nuclear meltdown is small-scale, it can be contained: "For example, there was one in the Chapel Cross plant in south-west Scotland in the 1960s, and at the end of that it only affected two of what they call the fuel channels, the long tubes where the fuel is put. They simply sealed those off, there was no release of radioactivity offsite and the plant continued to operate for 30 years."
0847: NHK TV carrying advice to people to protect themselves against radiation. Experts say people should cover their mouths and noses with wet towels. Exposed skin should also be covered and people should wash after coming indoors. People should also avoid vegetables and other fresh food, as well as tap water, until authorities give the all-clear.
0850: Japan's Kyodo news agency reporting that four people have been injured in an explosion at the Fukushima-Daiichi plant.
0855: Some pictures have come through now on Japanese TV of that explosion. It looks very strong. You can see debris being blasted from the building, then a cloud of smoke mushrooming up from the plant.
0857: The BBC's Nick Ravenscroft was on his way towards Fukushima, but about 60km from the plant was stopped by the police and told it was too dangerous to proceed. He says there is lots of traffic coming in the other direction. Authorities in vehicles with sirens are making public announcements to the crowds.
0905: Japan's NHK TV says officials measured the level of radiation at the entrance of the Fukushima-Daiichi plant at 1529 Japanese time. If people are exposed to this level of radiation for an hour they'd receive the same amount of radiation they normally would in a year, the report says.
Power Plant security says that there was shaking and an explosion in the vicinity of the NPP1 turbine machinery. They're looking into countermeasures but don't know the full details yet.
Edano Press Conference (2): Furthermore, Edano said this about the explosion at the plant: "We are trying to precisely measure the levels of radiation. From what we have now, we think that the amount that came out is under control and was within predicted levels. We hope for the safety of those in the area."
0923: Before the explosion, the government had declared a state of emergency at five nuclear reactors after the generators pumping cooling water at the reactors failed.
0927: Japan's Nuclear and Industrial Safety Agency is investigating the explosion at the Fukushima-Daiichi plant. Meanwhile, Chief Cabinet Secretary Yuko Edano, has told journalists: "As to the evacuation of the residents, of course we will have to ascertain the level of the radiation and, of course, we will have to cope and take appropriate measures. But once we do the analysing and once we know the facts we will let you know."
The evacuation radius has been increased to 20km.
1009: "This is starting to look a lot like Chernobyl" Walt Patterson, an associate fellow with Chatham House, has told the BBC after seeing pictures of the explosion at the Fukushima-Daiichi nuclear plant. "The nuclear agency says that they have detected caesium and iodine outside the unit, which certainly indicates fuel melting at the very least," he says. "Once you have melting fuel coming into contact with water, that would almost certainly be the cause of the explosion."
1011: More from Walt Patterson of Chatham House. He says the presence of the radioactive caesium in the surrounding area does not pose a huge threat to public health in the immediate aftermath of the explosion. "What would be serious is if there was an explosion or fire that lifted this stuff high in the air, meaning it could get carried over a wide area."
1016: The BBC's environment correspondent Roger Harrabin says he understands the blast at the nuclear plant may have been caused by a hydrogen explosion - also one of the possibilities laid out by Walt Patterson of Chatham House. "If nuclear fuel rods overheat and then come into contact with water, this produces a large amount of highly-flammable hydrogen gas which can then ignite," our correspondent says.
1045: BBC environment correspondent Roger Harrabin says local officials believe the release of radiation following the nuclear plant explosion is likely to be small. He adds that nuclear incidents aren't always as serious as they may sound or appear, and actually, in terms of loss of life and destruction, accidents at hydroelectric plants are far more dangerous.
1052: Neil McKeown in Nakameguro, Tokyo writes: "The evacuation zone has been extended to 20km by the government. However TepCo [the Tokyo Electric Power Company] appeared in a news conference and promised to release new radioactivity readings after 6pm. It is now 7.30pm and they have not done so. People are getting extremely frustrated at the lack of news coming from TepCo and the government - they have yet to confirm if the building that suffered an explosion housed a reactor, and we have no indication how much radiation has been released or in what direction winds are blowing.
Japan's Nuclear and Industrial Safety Agency says serious damage to the nuclear reactor container is unlikely despite the explosion at the Fukushima-Daiichi plant - Kyodo news
1110: An attempt to explain the risk to the Fukushima nuclear plants following the earthquake: The plants are designed to shut down automatically, which halts the main nuclear fission reaction, but there is a residual amount of intense heat within the system. Back-up generators should kick in to power the cooling mechanisms needed to dissipate that heat - but if they fail, as appears to have happened here, temperatures rise. If this isn't stopped, the reactor vessel itself could eventually melt and leak.
1122: A full quote from Chief Cabinet Secretary Yukio Edano's press conference: "As reported, we have been informed that there was some kind of an explosive phenomenon at Fukushima No 1 nuclear power plant, although it has yet to be confirmed whether [the explosion] was that of a nuclear reactor itself. At present, after the talks among political party heads held a while ago, government officials including the prime minister and the minister of economy, trade, and industry, along with experts, are making all-out efforts to get hold of and analyse the situation, and to take measures."
1125: Chief Cabinet Secretary Edano also said that the current level of radioactivity at the power plant was "within the range that was anticipated" when it was decided that steam would be vented from the reactor to release pressure.
1147: Naoto Kan: Safety of people around the Fukushima nuclear plant is our number one priority - first we need to save lives, then we need to make it easier for people in shelters, based on experience from Kobe, he says. After that, reconstruction efforts.
1202: Government spokesman says the nuclear reactor container at the Fukushima-Daiichi plant has not been damaged, and the level of radiation has dropped following the explosion earlier on Saturday, AFP reports.
Government spokesman says the nuclear reactor container at the Fukushima-Daiichi plant has not been damaged, and the level of radiation has dropped following the explosion earlier on Saturday, AFP reports.
Chief Cabinet Secretary's Press Conference: The Source of the Explosion: "The water vapor that escaped as the water in the reactor evaporated went out into the space outside the containment vessel, and there became hydrogen, which interacted with oxygen and caused an explosion. There is no oxygen inside the containment vessel, so even if there is hydrogen [vapor], there will be no further explosion."
1211: More from Japanese PM Naoto Kan. He says the government will do its best to make sure "not a single person will suffer health problems."
1216: Government spokesman Yukio Edano says the pressure as well as the radiation at the Fukushima-Daiichi nuclear plant has fallen following this afternoon's explosion.
1218: It seems clear now from Mr Edano's comments that the nuclear plant building that was blown apart earlier did house a reactor, but the reactor was protected by its metal casing.
1227: So, attention has focused over the last few hours on the risk to two nuclear plants in north-eastern Japan, one of which was the site of a spectacular explosion that sent a cloud of dust and debris into the air. But officials say damage from the blast appears to be limited.
Containment Vessel: Injecting Ocean Water as a Safety Measure
According to Chief Cabinet Secretary Edano, from here on, to prevent the nuclear container and storage container from breaking, Tepco has decided to fill the containers with ocean water. In that case, to keep the atomic fuel from reaching critical pressure again, they will also put in boric acid, which will [attract/absorb neutrons? this is the part I totally don't understand].
For this process, preparations were made and confirmed with NISA, and having assessed things properly, according to Tepco, they began the operation to inject the ocean water at 8:20 PM.
1305: The International Atomic Energy Agency (IAEA) says Japanese authorities are making preparations to distribute iodine to residents in the area of both the Fukushima nuclear plants. The IAEA has reiterated its offer of technical assistance to Japan, should the government request this.
1320: Noriyuki Shikata, from Japanese PM's office tweets: "TEPCO's [Tokyo Electric Power Company] efforts to depressurize the container was successful. Additional measures are now taken tonight using sea water and boric acid."
1427: More than 300,000 people have now been evacuated from homes in northern Japan and that number will rise as the government increases the exclusion zone around the Fukushima nuclear power plant, Kyodo reports.
1443: Kyodo News: The four workers injured in the blast at the Fukushima No. 1 nuclear plant are conscious and their injuries are not life-threatening.
1459: At least three residents evacuated from a town near quake-hit Fukushima No. 1 plant have been exposed to radiation, both Kyodo and NHK report.
1602: US nuclear expert Joseph Cirincione tells CNN the full picture of what it happening at the Fukushima No. 1 reactor has yet to emerge: "The big unanswered question here is whether there's structural damage to this facility now. We saw the explosion early this morning. Are there other structural damages that may make a meltdown all but inevitable? We don't have any information from the power company on that."
1617: AFP: Japan nuclear agency rates nuclear plant accident in Fukushima at 4 on 0-7 international scale.
1622: More information on that figure: The 1986 Chernobyl disaster was rated 7 on the International Nuclear Event Scale; the 1979 Three Mile Island accident was rated 5
1631: Some more: The International Nuclear Event Scale was developed in 1990 by the International Atomic Energy Agency (IAEA). The rating of 4 for the Fukushima plant incident comes from an as yet unidentified official at Japan's nuclear safety agency, news wires report.
1705: A quick recap: There is continuing concern over the quake-hit Fukushima No. 1 reactor after a powerful explosion there early this morning. Japanese officials say the container housing the reactor was not damaged and that radiation levels have now fallen. But experts say it is not clear whether the situation is under control.
1739: More from that unidentified official at Japan's Nuclear and Industrial Safety Agency on rating the incident at the Fukushima nuclear plant on the IAEA scale of 0-7: "Right now we are considering the accident should be rated four. The rating may be changed in accordance with the development of the condition."
1807: If radiation has leaked from the Fukushima No. 1 nuclear plant, winds will likely blow it out over the Pacific Ocean, says the French Nuclear Safety Authority: "The wind direction for the time being seems to point the pollution towards the Pacific," said Andre-Claude Lacoste, speaking in Paris.
1820: The World Health Organisation says the public health risk from Japan's radiation leak appears to be "probably quite low": "We understand radiation that has escaped from the plant is very small in amount," World Health Organisation spokesman Gregory Hartl told Reuters news agency.
1910: Japanese workers in masks and protective clothing are scanning evacuees from the Fukushima area for radiation exposure, Reuters reports. Seventeen-year-old Masanori Ono says: "There is radiation leaking out, and since the possibility (of exposure) is high, it's quite scary."
2022: Reuters: The IAEA says it has been told by Japan that levels of radioactivity near the Fukushima No. 1 plant have fallen in recent hours.
2023: Reuters: The IAEA says the operator of the plant has confirmed that the primary containment vessel is intact following this morning's blast.
2039: Ian Hore-Lacy of the World Nuclear Association told the BBC he believes the situation at the nuclear power plant - where sea water is being used to cool the reactor core - is under control: "The point is that the heat, decay heat from the fuel drops off very rapidly. So after an hour, an hour following the shut down, it's down to about 2 or 3% I think. And after 24 hours it's down to half a per cent. So the amount of heat you've got to cope with right now is a small fraction of what there was initially."
2042: Reuters: The IAEA says it has been told by Japan that 140,000 people have been evacuated from areas around two nuclear plants.
2055: More on evacuations: According to an IAEA statement, 110,000 people have been moved away from Fukushima No. 1 plant. Another 30,000 have been evacuated from a 10km radius around Fukushima No. 2 plant. But full evacuation measures had not been completed.
2123: Reuters: The emergency cooling system is no longer functioning at the Fukushima No. 3 reactor, an official from Japan's Nuclear and Industrial Safety Agency has told journalists.
2130: AFP: The US Nuclear Regulatory Commission says it has sent two experts to Japan to help assist local authorities.
2141: IAEA Director General Yukia Amano: "The IAEA's emergency centre is working round the clock to monitor the situation and share information."
2145: Reuters: The number of people exposed to radiation near Fukushima No. 1 nuclear plant could reach 160, an official from the Japan Nuclear and Industrial Safety Agency has said. Nine people have shown signs of possible exposure.
Japan's nuclear safety agency says Caesium radiation suggests fuel has melted in Fukushima Daiichi reactor No. 1 - Reuters
Despite recent troubling developments, Japan has told the U.N. atomic watchdog there was an initial increase in radioactivity but levels "have been observed to lessen in recent hours." www.reuters.com
2212: Some clarification: It is the number three reactor at the Fukushima No. 1 plant where officials have just announced that the cooling system has failed. This morning's blast took place at the number one reactor at the same plant. "All the functions to keep cooling water levels in No. 3 reactor have failed at the Fukushima No. 1 plant," a spokesman for the operator said.
The U.N. agency statement said NISA had confirmed the presence of caesium-137 and iodine-131 in the vicinity of Fukushima Daiichi Unit 1. - Reuters
"Some developments following the major earthquake that struck northeast Japan: - More than 1,800 people likely dead or missing from the quake and tsunami, Kyodo news agency says. - Kyodo reports 10,000 people in one town unreachable. * Radiation leaks from a damaged nuclear plant and explosion blows off the roof, but authorities say radiation levels now lessening. * Around 110,000 evacuated from 20 km (12 mile) radius around the Fukushima Daiichi nuclear power plant, another 30,000 from 10 km (6 mile) radius around nearby Fukushima Daini plant. * Up to 160 people may have been exposed to radiation, nuclear safety agency says." - reuters.com
2224: A recap: Fukushima has two nuclear plants; Fukushima No. 1, which has six reactors (three of which were offline at the time of the quake) and Fukushima No. 2, which was four reactors.
2236: The US Nuclear Regulatory Commission says that the two experts it has sent to Japan are specialists in boiling water nuclear reactors, and part of a broader US aid team sent to the disaster zone.
TEPCO says it has started preparations for releasing pressure from Fukushima Daiichi No. 3 reactor after cooling failed TEPCO: Released steam from Fukushima Daiichi No. 3 reactor would contain small amount of radiation - Reuters
2252: Reuters: Operators are preparing to release radioactive steam from the number three reactor at Fukushima No. 1 plant, after the cooling system failed there.
[6:45 p.m. ET, 8:45 a.m. Tokyo] In addition to the United States, 24 countries have offered to provide assistance to Japan, including the dispatch of rescue teams, and the provision of relief supplies and transportation, the foreign minister said, according to Kyodo, among them: Australia, China, South Korea, Mexico, Thailand, New Zealand, Singapore, Indonesia, India, Russia, Turkey, Germany, France, Belgium, the United Arab Emirates, Switzerland and Jordan.
0203: New Zealand's Prime Minister John Key, whose country is dealing with the aftermath of its own earthquake crisis in Christchurch, confirms a rescue team will be sent to Japan. He says: "It's likely that the complete team of 48 will be leaving within the next 24 to 48 hours. We want to offer whatever support we can."
0220: As reports emerge of people calling for help, trapped under rubble, Gillian Dacey from search-and-rescue charity Rapid-UK, assesses their chances of survival. She tells the BBC: "In the right conditions they can survive at least four, and up to seven days. In some earthquakes, if the person who's trapped has some water or food, they can maybe survive 10 days, and we have heard of some extreme cases of up to 14 days, but the conditions have to be right."
0350: Sayaka Matsumoto, from the International Red Cross in Tokyo, says: "This is one of the largest disasters we've ever experienced, so the situation is very much unpredictable. But so far, we have mobilised more than 60 medical teams and more than 450 medical personnel."
0552: Clare Gollop, from search-and-rescue charity Rapid UK, tells the BBC: "We've had people here today packing kit and just checking that everything is ready to go. We've been organising flights... and we're literally just waiting for a request to go to help."
1037: Sayaka Matsumoto, from the Red Cross in Tokyo, says the organisation has sent more than 60 medical teams - some 450 doctors and nurses - to the worst-hit area. Those who have arrived in Sendai have opened a tent clinic in front of the city's main government building, she tells the BBC.
1112: UK Foreign Secretary William Hague says he has spoken to his Japanese counterpart and offered help with search and rescue, and victim identification. He says further details of the UK's assistance package will be announced later.
1143: Naoto Kan: More than 50-60 countries have expressed sympathies, US President Barack Obama has called.
1422: A US navy vessel is loading aid supplies in Singapore and will sail for Japan shortly, NHK reports.
1454: US Ambassador to Japan John Roos says America is "absolutely committed to helping Japan in any way possible". Air Force personnel and Marines based on the island of Okinawa will be sent to help with the rescue effort.
1515: Prime Minister Vladimir Putin says Russia will increase LNG supply from reserves on Sakhalin island to Japan if necessary: Reuters.
1539: Russia's Deputy Prime Minister Igor Sechin says Japan has requested more deliveries of coal and liquefied natural gas (LNG) to boost energy supplies: Reuters
1549: A five-member South Korean rescue team has touched down in Japan, Kyodo says; the first international team to arrive.
1717: Rescue teams from several nations are on their way to Japan; the first, from South Korea, touched down about two hours ago. A team from the UK is due to depart later this evening.
From NEI, the policy organization for the US nuclear industry: RT @AmbassadorRoos: On #Fukushima, our nuclear experts are directly in touch with Japanese experts and we are offering our full assistance.
2109: PacificFleet tweets: "USS Ronald Reagan arrived off coast of Japan, expected to provide refuelling support to Japan SDF helos conducting relief ops."
2114: The Japanese Red Cross says it has sent 62 teams including 400 doctors and nurses into the quake-hit area.
HOW YOU CAN HELP: Links to where you can donate money to help Japan:
For those of you who are short on money but still want to help out, Free Rice is a game where for every right answer you get, they'll donate rice to people in need in Japan.
FIRST JAPAN POST SECOND JAPAN POST Please be sure to check both of the previous posts as they both have incredibly helpful links and streams, but we wanted to try to keep this post with strictly the most recent information. I'll be doing my best to update this post throughout the day so please keep posting any links with new info in the comments!