This is a great question. As you know Japan is prone to having earthquakes and they just had one recently. It was enormous in scale and it also triggered a tsunami. The damage was extreme and part of the reason for it was because it struck a nuclear power plant in Fukusima. There are several ramifications.
First, radioactive material is causing people to become ill. This radioactive material has also infected all the food in the area, which renders the food unsuitable for consumption. More recently, this radioactive material has been put into the ocean and we will not know the ramifications of this until later. So, there are lots of problems, even for the environment.
Second, from an economic point of view, the nations are linked together, especially a country like Japan. It is the third largest economy. Shipments of Japanese products for a time halted. This had an impact on the rest of the world that consumed Japanese products.
As for what the government is doing, they are trying their best. Natural disaster can happen to anyone and they do.