I heard about this today as soon as I woke up, and even though I know that Japan is infamous for earthquakes and other seismic/volcanic activity, I was surprised by the magnitude. The closest I've heard that it can be compared to was an account in the 800s AD, also accompanied by tsunamis of course. As if this wasn't enough, the main power and diesel generators at at least one Japanese nuclear reactor have gone offline, leaving only battery backups! If power can't be restored, the core will get hotter and hotter, causing coolant water to become steam! This creates a terrible choice, because if you don't vent it, it will explode, but if you do you have radioactive vapor as well as reducing the amount of coolant available. That option would only be feasible if a new power source was on its way, but it may be the only way to avoid such a catastrophe.
Many who were on airplanes from tokyo just heard about the full extent of the damage as they arrived at airports; some had only heard of a "little earthquake", and was apparently not taken as seriously at first, until it failed to stop as expected. Accounts I have heard place it at at least two minutes of increasing shaking, with buildings swaying ax people tried to save themselves and others.
I hope that all who are affected by this terrible disaster can receive help as soon as possible, and I am planning on donating something at least to help victims; being the lazy american I am, however, I will have to wait until such a group is formed. I haven't heard anything about the tsunami that reached the west coast of the US yet, and hope that the early warning was able to help people get to safety; early warning systems for earthquakes and tsunami are actually in place in japan, and are said to be the most extensive in the world. Unfortunately, due to how earthquakes send out waves, the most warning that can be given is about a minute before it hits. It sent automatic texts to phones and automated messages to disaster and EMS crews in tokyo and the surrounding area, apparently; it may have seemed like a superfluous expenditure to some people, but I am sure no one will call it useless now! A similar system is apparently being planned for installation in California, but it will be at least 5 years and who knows how much money to get it running.
Here's hoping everyone who was injured will recover
-Joel de Bunchastu