A powerful earthquake has rocked north-east Japan, causing injuries and shaking buildings as far away as Tokyo. Read a selection of your comments below.
The following comments reflect the balance of opinion we have received so far:
I was on the Shinkansen at the time. We'd just left Fukushima slightly south of Sendai. The Shinkansen came to a halt, all the power went out and the electricity pylon nearby was shaking rapidly and the Shinkansen rocked side to side. Everyone on the train remained stoically calm, and just said, "Oh it's an earthquake." The Shinkansen couldn't move for around 5 hours, but then carried on as though nothing had happened. I think it was Japan wishing me farewell before I depart for Britain.
George Kane, Nagoya, Japan
My wife and I are on holiday in Tokyo staying on the 17th floor of a hotel near Tokyo Bay. Not knowing much about earthquakes or what to do when caught by one we decided to try to get out of the swaying building as quickly as possible. As we walked briskly along the corridor to the stairs, a cupboard door popped open which gave us both a jolt and spurred us on to get out! After making it down to the 15th floor, with the building still swaying, we decided just to go back to the hotel room and continue to get ready for the day ahead - what's to be will be, we thought! I must admit that I am glad we are leaving Tokyo tomorrow for somewhere less high rise.
Simon and Reiko Keen, London, UK
I live in Sendai, just east of the epicentre of the quake. I was sitting in a train about to depart Izumi-chuo subway station for Sendai station when the train started shaking. Having never experienced an earthquake before, I was not quite sure what had happened, I thought there may have been a train accident. Then the conductor announced that there had been a big earthquake. Confused, I asked my neighbours where the earthquake happened (explaining that I did not understand all of the conductor's Japanese message), and they said no-one knew. I could not get AU phone service, so I headed back to my apartment, where I found that some of my dishes had broken.
Brooke Lathram, Sendai, Japan
I live in Iwate Prefecture, the prefecture immediately north of Miyagi, where the earthquake happened. I was sitting at my desk at the school I work at when the ground started shaking. I had gotten used to smaller and shorter earthquakes since arriving here last year, so I thought this would be the same. How wrong I was! The shaking lasted for about 2 minutes and during that time became more intensified. Books were falling off book shelves and light fixtures were doing some moving of their own. Just about the time I thought to get up and stand in a doorway, the earthquake was finished.
Brendan, Hanamaki, Japan
I was on the 21st floor of a skyscraper in central Tokyo, and even there it felt like a pretty big earthquake. The building rocked - almost like a boat - from side to side for a good 5 minutes. I started to feel sea sick after a while! There's been a lot of earthquakes in Japan recently, it seems unusually active.
William Diviney, Tokyo, Japan
I'm currently on vacation and was having a nap when I felt my futon swaying from side to side. The shaking seemed to last about a minute and although I was aware that where I live wasn't the epicentre, I was worried as it was quite powerful and obviously serious somewhere else. As I live near the sea, I was worried about a tsunami following the quake but thanks to the TV information that quickly follows quakes here, I was well informed.
Phil Holden, Teacher, Near Yokohama
I have only been in Japan for a couple of months, and I have experienced a few tremors, but nothing of this magnitude. I work on the 5th floor of a building at Tennozu Isle in Tokyo, and at just before lunchtime the walls started creaking and the blinds started swaying heavily. Normally people don't even start, but today there were a few shrieks. The movement lasted for about 6 minutes and then things returned to normal. I guess you just have to trust that modern buildings are built to withstand earthquakes. I didn't realise it was anything until I saw the report on BBC news - if it makes British news as quickly as that, it must have been a big one.
Matt (English living in Japan), Tokyo, Japan
I'm a Canadian teaching English in Japan. My family and I were returning from Tokyo on the Shinkansen lines about 40 minutes after the quake happened. There were 6 trains affected by the quake, after 40 minutes we were able to leave Tokyo. The JR staff are very helpful and even when we arrived in our home of Toyama, all the train passengers were apologised to for the disruption to our travel. Luckily, we weren't hurt. I pray for those who have been hurt or killed.
Rod Redden, Toyama, Japan
I've been in Tokyo on business the last two weeks, and felt earthquakes in the middle of the night two weekends ago. (The first forced me to read the emergency escape card in my hotel room.) Nobody here thought much of those ones when I asked. Today's was different: people in the office were diving under desks, and I heard that in a meeting room another foreign visitor nearly freaked out. I seem to have a newly acquired 'reputation' because after stuffing my passport into my back pocket I opened my internet sms application and began texting my friends abroad what was going on! I may play it safer next time.
As a long time resident of Japan, and Sendai previously I have experienced my fair share of earthquakes. But today's was different and much more intense. My 11th floor Tokyo office shook from side to side for what seemed an eternity, and even after it stopped it still felt like it was swaying. Felt almost sea-sick afterwards! The longer one resides in Japan, the more one thinks, is this the long due big one!?
Jigme Pemba, Tokyo
I was just waking up when the earthquake shook our apartment in Tokyo, I thought I was dreaming. The only thing that fell was a plastic ladle spoon into the kitchen sink! But, I could hardly stand as the building we live in moved from side to side. My wife called me from her office checking if I was ok. Since living here there's been a quite a lot of quakes and tremors, bit different to Dorset! After a quake we turn on the TV to watch Japans NHK to see what the magnitude was. And we moan about the English weather!
Matt, Tokyo, Japan
I'm currently a Brit working 200 miles south west of the affected region and the tremors felt in Utsonomiya were considerable over a 1 minute period. The building I was in was well designed to cope with such tremors, although I could tell from the reactions of the local how serious this quake was.
Paul Connelly, Japan
I work in Ebisu in Tokyo and we felt the quake quite strongly here. The building was moving for a long time in comparison to other quakes we've felt here in the past. We watched a man who was holding a cup of coffee walking down a metal staircase opposite our building, he had trouble balancing.
All in all a scary experience being completely in the hands of mother nature.
Nic Brennan, Tokyo, Japan
I was in my office on the fifth floor of my company's building in the Chiyoda district of Tokyo. It was one of the longest and strongest quakes I have felt in a while. I had to move away from a bookshelf, as it looked like it might go over. One woman in my office got under her desk. I just stood in the middle of the room, holding on to a table, wondering if it was finally going to be the Big One. My hands were shaking quite a bit when it was finally over.
Nick McNeill, UK (Living in Japan)
I am in Tokyo on business and was in the lobby of an office building when the earthquake struck. I was also here for the one last month, and they were noticeably different. Whereas last month's quake had a strong side-to-side shake, this had a gentler wave-like shake to it that caused a moment of vertigo in me and the party I was meeting for lunch (who was still upstairs at the time).
Small things began to fall around the lobby. Remembering that vertical waves do the most damage, I bolted for the exit. Outside I saw puddles sloshing back and forth on the pavement, and when I looked up at the surrounding buildings, I noticed that the nearest one was visibly bobbing up and down in relation to the much taller one in the background.
The Japanese colleague I was meeting for lunch told me that she too thought that this one was unusual.
M Werneburg, Canada
The earthquake began while I was brushing my teeth. I instantly knew it was a big one, the movements were very strong, rather like my apartment was on jelly being shaken, not quickly but very strongly. I ran into my living room to stand under a strong door frame and I looked at my fish tank; the earthquake was so strong the water was almost splashing out of the tank. Another day in Japan, this came at no surprise, not for me and certainly not for the Japanese.
Chris Horsey, Saitama, Japan
Yes, I experienced this. I have spent a couple of years in Japan and this was the worst I have felt. I work on the 20th floor in the business district in Tokyo. Our building was built in the bubble period so it is made to withstand earthquakes by being constructed on tracks. While this is undoubtedly a good thing, it does have the result that the building sways a lot more than others, thus accentuating the feeling of movement. It was quite a frightening experience.
The earthquake was felt at Tokyo's Narita airport, about 180 nm from Sendai. The airport building was shaking from side to side for which seemed like a minute. Airport runway was temporarily closed for inspection with no irregularities found.
Tony M., Japan
Our building in Yokohama (at least 400km from the epicentre), was not shaking so much but rather swinging slowly in all directions for quite a long time. I live since 1997 in Japan, but never felt such a swinging earthquake. It was scary even at such a distance from the epicentre.
Vincent Van den Storme, Japan
The elevators in my building (in central Tokyo) all stopped running for about 15 minutes, which is rare. There was a marked difference in this quake to the one a few months ago. This one was characterised by a lot of sideways movement and not a sharp, upward thrust.
Dan Anley, Japan
I'm currently working in Japans tallest building, Landmark Tower. At about 11:45, the whole building started to sway from side to side in large motions. I went to look out the window and similarly all the other tall buildings were visibly shaking. I must say it looked quite bizarre. Due to the damping in this building, it took 5-10 minutes for the oscillations to stop completely and it felt a little like being on a boat in rough sea. Certainly made the morning more interesting!
Mihir B, UK, but currently in Yokohama
I'm living in Tokyo at the moment, and that was a weird earthquake, made me feel seasick... lasted for a rather long time. It's the first one where I've had time to see the buildings physically shake!
I'm beginning to wonder if it is time to return home (to Manchester) as that was the second level 6 earthquake to occur within a month. Maybe the faults are building up to the 'Big one' that so many people here are talking about!
Luckily it seems that there are very few injuries, and it's not disrupted the train system as widely as the last month!
Stuart Whitaker, Japan
Around 12.45 AM, we felt the earthquake shocks in Tokyo while we were in office on the 6th floor. The duration was around 10-12 seconds and intensity was felt as gradually increasing, office surroundings shaking with a magnitude never experienced before in the last one year. As it increased, we thought of running out of office, many actually did, but then vibrations were settled.
Tushar Ahire, Japan
The strong shaking from this quake probably lasted 30-60 seconds. It was primarily a sickening lateral movement. It was accompanied by a loud grinding ground noise not unlike the sound of an approaching train. Cars were bouncing up and down as if someone was jumping on the back bumper. Inside the house (second floor), it was very difficult to stand. Items fell from cupboards in the kitchen and from bookshelves. Incoming phone calls (cell and land line) could not be received, but outgoing cell phone calls were possible.
Dale Little, Japan, Shichigahama (Sendai)
I was working on the 5th floor of the City Hall in Sendai City, that is the largest city (1 million in population) and nearest city from the epicentre. I felt the vertical hard shakes for some 10 seconds and after that 20 to 30 seconds of horizontal shakes. The building of the City Hall is around 40 years-old, but I don't see anything fallen such as from cabinets. The people became so calm in Sendai right after the earthquake because there seems to be no damages and no electricity failure in downtown area. They are so confident about the infrastructure of the Sendai area. The subway system of the Sendai City has been in operation almost 4 hours after the quake. The life in Sendai is coming back towards normal daily life.
Gen Amano, Japan
My wife and I, in Tokyo, were in the house, and the horizontal shaking became stronger and stronger. My wife immediately turned off the gas, opened a window, and ran upstairs to retrieve our helmets and 'earthquake backpack', which contains bottled water, canned bread, chocolate, flashlight, a first aid kit, some slippers and a towel. The tremors continued for a long time but gradually subsided. The entire earthquake must have lasted about two minutes. I have lived in Japan for about twelve years and this was the longest earthquake I have experienced.
Jim Craig, Japan
My wife (who is expecting a baby) and I were attending outpatients clinic at Tokyo University Hospital when the earthquake struck. The tremor seemed to go on for 20-25 seconds and was relatively strong. By the time we had moved onto the Electro cardiac treatment suite (where there was a TV) reports were already circulating. As I lived in Sendai about 10 years ago (and where I experienced many an earthquake!) I was interested to see how the locals were coping. They seemed to take it in their stride like our doctor who, when the tremor hit, simply looked up from his notes and murmured "oh, another earthquake". By the way Mum and Dad, if you're reading this, no need to call: we're fine.
Matthew Salter, Tokyo, Japan
I live in Chigasaki, about 40km south of Yokohama. It was a 'biggie' alright...! We live about 100 miles away and the houses just rocked from side to side for about 30-40 seconds. They're not very pleasant when then occur.
Since I've been living in Japan for some years now I got somewhat 'used' to earthquakes but such a heavy one as this time I've never experienced before. On the 8th floor in central Tokyo the building started to move horizontally for at least 2 minutes. The window blinds hit the windows hard. Even my Japanese colleagues hardly ever experienced such an earthquake. There were no damages and nothing felt down.
Raymond Pourchez, Japan
When the earthquake occurred, I was working in the office near Sendai station. I have experienced earthquakes at many times, but today's one was so huge that I could not stand up and run away for the office. All elevators in the building were stopped. All trains and subways in Sendai are still stopped two hours after the quake.
Tomoya Kamino, Japan
I live in Shinjuku in Tokyo. I was in my fourth floor apartment in a recently built concrete apartment building when the quake struck. The motion built in intensity over maybe 10 -15 seconds, and then kept shaking in strong, slow stokes for what seemed like quite a long time - at least a minute. It felt quite different from the usual tremors. When it became clear that the intensity was fading, I stepped out onto the balcony to check on the buildings around me. Even then, my building felt like it was afloat. The best way to describe the feeling then was that it was exactly like when you step out of a boat after being at sea, and the ground still seems to be moving beneath your feet.
Julian Worrall, Japan
I was in my office on the fifth floor of my building here in Sendai. Once it hit I could see my hard-drive bouncing up and down. I held it down but other things in the office flew around. Luckily, the electrical power in the building shut down immediately once the earthquake reached a certain level. As the subways shut down, it took me hours to get home on the other side of the city.
Peter Connell, Japan
I was on my way to Fukushima Station to take the shinkansen back to Tokyo when the earthquake struck. Telephone and electricity cables along the road swung like crazy and the car I was in swayed from side to side for at least a minute. All trains have been suspended for at least 5 hours while the tracks are checked, and according to local government officials I spoke to in northern Fukushima, they are checking on residents in outlying areas.
James Hardy, Fukushima, Japan
My family and I were in our third floor apartment when we heard what sounded like a thunderclap. Then the whole place starting swaying back and forth. I rushed to secure an exit and turn off the gas, while my wife gathered up our two year old boy. I could hardly walk back to where they were the shaking was so strong. Miraculously nothing broke or fell off of the shelves. However, the water in my gold fish bowl did splash all over the place. Luckily the fish stayed in the bowl!
Robert Bowley, Fukusima, Japan
Wow, my adrenaline's still pumping from the shake. I'm situated in Iwaki City, just South of Miyagi prefecture. As I felt the shake, I instinctively stood up and grabbed onto loose items on my desk. Before I knew it, a dozen books were on the floor at my feet, having fallen from the bookcase behind me. It's quite something to feel an entire building shudder, not to mention the disturbing rattling noise which lasted for well over a minute.
Chris Mortimer, Japan
I was at my office and suddenly I felt my monitor, my desk shaking. Initially, the intensity was low but then it picked up gradually. At that time, everyone geared up with their helmets. What really surprised me was the length, the quake lasted for at least 40-50 seconds. I could actually see the building swaying from one side to another. I hope everyone is fine and there is no loss of life or property
Adnan Khan, Japan
I was cycling to work and initially thought I had a loose front wheel, so I stopped to check. Then I realised it was an earthquake since cars were shaking and electric pylons were swaying all around me. Just got home and not much damage, just a few broken glasses and fallen pots. Guess it was much scarier for those indoors.
Philip Wood, Sendai, Japan
We work on the 16th floor of a building in Osaka and again, like in many other quakes, our building swayed about 1 minute after. We teach English on a television/internet system and were in the middle of a lesson, our students come from all over Japan, one of my friend's students were in Sendai, my friend stated that he could see the student's room "falling apart" on the screen, then the student left the lesson. Our building is designed to survive an 8.0 quake in Osaka, but it still feels like a boat in the ocean. Even though the quake was nearly 600 kilometres away!
Anthony, Osaka, Japan
My office in Tokyo felt it, the tremor lasted for a couple of minutes, you could feel the building swaying from side to side.
I was on the 23rd floor of a central building in Tokyo. At around quarter to twelve, we felt the earthquake. I was pretty much amazed by how long the earthquake was. It lasted at least 40 seconds. The whole building was moving from sides to sides. we could see other neighbour building moving just as much. We had to wear some kind of hats in case anything fell. But nothing wrong happened.
The room started shaking horizontally in remarkably slow, well spaced shudders and went on for a good while, but as we have a basement flat I thought it was a pretty small quake. I felt a degree of dizziness, which is a new experience, but after last months quake, when I was on the 7th floor hiding under a table as the room bucked like a bronco, it seemed fairly minor.
Michael Pick, Tokyo, Japan
I was working in my office and suddenly could feel my monitor shaking. later as all of us on the floor looked at each other, it started shaking more. We would see other buildings move from our big glass windows. Since our building was a bit earthquake proof, it started oscillating even after the quake stopped. It all lasted close to 2 minutes.
I live about 80 kilometres from Miyagi, in Fukushima Prefecture and the quake was recorded here as a 5. I have been living in Japan for two weeks and it is my first experience of an earthquake. The walls shook at my place of work and various pictures fell down, crockery smashed, and a few people fell over. We rushed outside into an open space and watched the traffic lights swaying and various signs falling down.
Neal Brasier, Japan