A huge earthquake triggers a unforgiving tsunami in Japan.
Today's earthquake in Japan was the largest in Japan's history and measured a massive 8.9 magnitude. It happened 120km off the Japanese coastline and has caused a major tsunami causing extensive damage in Japan.
The Japanese media state that hundred's of people have died. The quake, recorded at 1415 local time (0546 GMT) caused an initial wave of around four metres in height and hit the north eastern coastline at the Miyagi prefecture within minutes.
"People were under their desks shouting and screaming" said one eyewitness.
The capital of the region, Sendai, was hit by the wall of water, with pictures showing the water completely engulfing the city airport and people seen racing to the roof.
Pictures showed the waters moving across the country taking buildings and moving traffic along with it. Aftershocks as high as 7.1 magnitude continued in the immediate aftermath raising fears of yet more tsunamis.
The Pacific Tsunami Warning Centre in Hawaii issued a tsunami warning for the entire Pacific basin, including Russia, Taiwan, the Philippines, Indonesia, Papua New Guinea, Australia, New Zealand, Fiji, Mexico, Guatemala, El Salvador, Costa Rica, Nicaragua, Panama, Honduras, Chile, Ecuador, Colombia and Peru.
Eyewitness: "buildings were visibly swaying"
Anthony Walker was at work in Tokyo when the quake struck. He told Channel 4 News: "I was on the sixth floor of a building in central Tokyo near the Imperial Palace having a normal day up until that point. We have an office of about 30-40 people and at first it felt like a standard earthquake like we have had over the last few days.
"However this time it continued to build to the point where everyone rushed to the exit. On the way down the stairs we were all clinging to the handrails to try and avoid falling down and outside it was possible to see the buildings visibly swaying.
"I have been in Japan for six years and this was far beyond anything I have experienced, particularly in terms of length and aggression."
Another eyewitness Chris Kimber, who is in Tokyo told Channel 4 News what he could see from his flat in Tokyo: "Out of my window I can see buildings and factories on fire, at first I thought my flat was on fire as I was returning from work.
"We get quakes all the time but the one today was really strong, people were under their desks shouting and screaming and the Japanese people in the office said it was the worst they have ever seen. It lasted probably a minute to 90 seconds and then there were some really strong after-shocks following that.
It is almost a thousand times more powerful that the recent earthquake in New Zealand Prof Bob Holdsworth
"I am now at home and I live quite high up, on the 40th floor and the building is still shaking. The advice I am getting though is to stay indoors as my building is safe."
Dan Pratt, a teacher in Inzaimakinohara east of Tokyo told Channel 4 News: "The room moved off centre by about a foot in each direction. Lots of books fell off the shelf and in my wife's shop all the booze came crashing down. It lasted for ages."
Outside it was possible to see the buildings visibly swaying eyewitness Anthony Walker
The shocks felt in Tokyo hit in the mid-afternoon and live pictures showed a high rise business building ablaze in the Odaiba. The magnitude of the quake was so great that it was felt as far away as Beijing in China, 1500 miles away.
The Red Cross and Red Crescent societies have said the wave is currently higher than some Pacific islands which it could wash over.
Japan quake: "1,000 times stronger than New Zealand quake"
Bob Holdsworth, professor of structural geology, in the department of earth sciences at Durham University said: "The magnitude of this event is staggering: it is almost a thousand times more powerful that the recent Christchurch earthquake in New Zealand and nearly one hundred times more powerful that the 2010 Haiti earthquake.
"It is slightly smaller than the Sumatra earthquake of 2004, a magnitude 9.1 event. These last two events combined killed over 500,000 people."
Japan's government has said a cooling function at Tokyo Electric Power's 9501.T Fukushima Daiichi nuclear plant was not working after a major earthquake but that it was trying to get backup power for cooling.
The government has declared an emergency situation as a precaution but there was no radioactive leakage and no damage from the cooling problem was expected at this stage, Chief Cabinet Secretary Yukio Edano told a news conference.
In a statement, the Japanese Prime Minister, Naoto Kan, said he was heading up an emergency disaster response headquarters, which had been set up to deal with the aftermath.
He asked the Japanese people to remain vigilant and calm, and to stay tuned to radio and TV reports.
Mr Kan said some nuclear power plants had stopped operating automatically and no radioactive leaks had been confirmed so far. The International Atomic Energy Agency (IAEA) confirmed this, and said it was seeking information on nuclear power plants in other countries which could be affected.
Stock market to open as usual on Monday
Tokyo stock exchange said it planned to open for trading in stocks and bonds as usual on Monday.
"As long as there are no major changes to the situation over the weekend, and if there's no physical damage to the (trading) system, we will resume trade as usual on Monday," said a spokesman for the bourse.
The quake triggered a late sell-off however, with the benchmark Nikkei average closing down 1.7 per cent.