7.3 Magnitude Earthquake hit Japan and Tsunami Warning Issued

Tokyo here - woke up just before 6AM with some pretty intense shaking, the strongest I've ever felt. Seemed to last forever. All ok now though. Usually just try to go back to sleep but my gf made me get up and put my jacket on. Too much excitement for this early. My friends family from Fukushima is visiting her, apparently they got up, turned on the TV for a few minutes then went back to sleep haha.

Maybe part of it is that I just woke up from a nap, and I'm still half asleep, but I laughed way too hard at this.In all seriousness, I hope everything is alright over there and you all don't get any crazy aftershocks. Stay safe, and stay warm!

06:27 (local Japanese time) The earthquake has by some been revised to a 6.9
06:28 There is also reports of an aftershock happening approx 1 minute ago at 5.3.
06:37 No 'irregularities' or radiation changes at the Fukushima plant according to spokesperson of the plant.
06:40 There is a concern that the tsunami will hit several times. The announcers on the NHK have not sounded this emotional since the large previous earthquake from 2011, and the news announcers keep commenting and reminding of the previous earthquake.
06:42 Observed tsunami spotted 20km out from the Fukushima coast at a buoy.
06:49 The Onagawa Nuclear Power Plant (seen here north of Fukushima) has no damages from the earthquake reported.
06:54 At 06:49 at the port of Onahama (a city in Fukushima region) a 60 cm tsunami was observed at the port.
07:05 The estimated tsunami height is expected to be 3m, but could be higher. A 60 cm tsunami has reached the shore but more is expected. The tide level keeps changing along the coasts so people should be wary for higher coming waves.
07:12 A second tsunami observed 20km off coast of Ibaraki region, just north of Tokyo
07:20 Reports that the cooling system at the Fukushima power plant has failed, not sure what this means for the power plant, more details will hopefully come soon.
07:32 There is no immediate danger at the Fukushima nuclear power plant, where the system that supplies the cooling water for the 3rd reactor has stopped. There is enough water to cool the reactor for a while.
07:35 The 2nd and 3rd wave of the tsunami are likely to be higher according to the news announcers at NHK
07:42 The Tsunami Advisory Zone has been extended north and south along the coast Image of current Tsunami Warning, via @Robertspeta
07:50 Update regarding the Fukushima cooling system: it's still uncertain what caused the stop in the cooling system and the temperature is slowly rising.
08:03 The Fukushima 3rd reactor cooling system has successfully been restarted, and TEPCO who own the plant will investigate further what happened and make sure everything is OK.
08:11 "A 3-meter tsunami warning has also just been added for Miyagi Pref., in addition to Fukushima." Via Steve Herman
08:15 The Japan Meteorological Agency has revised quake up to magnitude 7.4 from 7.3. The USGS previously rated the earthquake as a 7.3 but later changed it to a 6.9, so there are differing results on how strong it was as of right now.
08:15 1m 40cm wave observed at Sendai Harbor.
08:45 Reports of injuries but no casualties so far. TEPCO spokesperson says that at the Fukushima Power plant reactor the first tsunami wave measured at 1m, but the 2nd tsunami wave didn't reach enough height for it to be measured.
09:12 Not much updates as of now, evacuations are still in place and people are still told to not approach the coastline. People are also asked to be alert in the following couple of days (probably due to the risk of aftershocks). No updates of tsunami waves recently higher than 30cm, but the waves are now being reported further north and south along the coast too. There is still sea level differences so people should not relax, but stay alert.
I will continue editing this post with more info.

Currently, I'm about 320 km south of Fukushima and felt about 2 to 3 minutes of shaking in my apartment. The last large one in March 2011 was the only one that lasted longer that I experienced.There's a three meter tsunami warning which is serious, but nothing like the 10m that hit five years ago. There is an evacuation warning for Fukushima area though on TV.

Hey, dude, you don't owe us anything. Sorry if people become expectant of you. I have followed this account since its creation, and just wanted to let you know that you're awesome and I'm sure I can speak for many others when I say I really appreciate your tireless efforts to keep us updated.No matter what you end up deciding regarding this account, thank you so much for everything you've put into it. Much love, brother.

All big earthquakes he is here and he gives the best info, with the best answers on questions. TheEarthquakeGuy is the first thing I search after an earthquake to get the actual facts!It is tricky to know what the effects will be in those first few minutes, but offshore and shallow are not generally a good combination if you are worried about tsunamis. You need that water displacement, which is why I was waiting for the initial focal mechanisms to be calculated and published by USGS. It shows what the orientation of the fault could be, so when I saw it was not a thrust fault I relaxed a bit. I did not expect the focal mechanism to change so drastically from strike-slip to normal though; that was unusual.

Thank you for the information, Reddit is a big place and it's probably not fair to the earthquake guy that we rely on him so much despite the fact that there's several people who can help at any given time.Exactly the same thing happened five years ago - New Zealand experienced a major earthquake, then Japan experienced one a short while later. Can somebody knowledgeable fill me in on whether this is linked or just a coincidence?

Can someone explain to me what the reported size of the tsunami means? Does it mean the size of the wave is going to be 3 meters ( 10 feet )? Or does it mean everything within 3 meters of sea level will be effected? I mean, we get 10 foot waves in NJ during a tropical storm and it doesn't do that much damage..They are predicting the wave to be 3 meters high. That is 3 meters above the sea level, and is nothing like the waves you experience in storms. Those only hit the shore, while a tsunami is a huge amount of water moving inland and destroying everything in its path.