Please do not read the tabloids and take the word of those conspiracy theorists seriously. They are only out to create a illusion of mayhem so they can profit from it. I think you reassure your family that the authorities are doing the best they can to contain the situation. There have been quite a few major disasters like these around the world and the world still has not ended yet.
The whole entire world is collecting funds to help the victims of this catastrophe and the people of Japan. We are all doing the best that we can to offer a helping hand, sympathy and supplies.
Although many people are "evacuating" your prefecture, you shouldn't be swept up by this mass hysteria. On the other hand, I think you were right about taking a break from all this depressing thoughts. Enjoy your trip to Fukuoka!
I sincerely hope this letter will ease your fears of an imminent apocalypse. I know that your world has been turned upside down, but you have to bear with it and soldier on with your normal life. That said, I still think that you should prepare some essentials just for a worst case scenario. Remember to keep calm at all times!