“Why would another earthquake be bad?”
There is enough radiation in that plant to kill the Japanese economy and it’s citizens and make parts of it a wasteland.
Crack the containment vessels so that the radiation leaks - and what do you think will happen???
Now do you understand why an earthquake could possibly be a problem.
83 year old rice farmer escapes the tsunami on her bike
http://www.cnn.com/video/#/video/world/2011/03/16/dnt.tuchman.japan.woman.escape.bike.cnn
was a teenager when the US nuked Japan.
But the containment vessels have held through the other earthquake, and subsequent earthquakes are going to be not as bad.
The only problem I see is with the spent fuel rods that were not in containment vessels.