To be fair, the plants had no issues with the Earthquake itself. All reactors SCRAMmed exactly as they were supposed to at the first sign of instability. The tsunami damaged the backup generators for the cooling pumps. This despite their being 2 to 3 times higher than the worst recorded flood to date. Sadly, it was just one of those failures of imagination that will from time to time pop up and kick you in the nuts.
This whole thing is pretty intriguing to me. There really isn't any place on Earth better suited to dealing with Earthquakes and tsunamis. These guys were very well prepared and they're putting up a helluva fight in the aftermath. If this had happened in any other nation it would have been far more catastrophic. Strangely, it makes it harder to fully appreciate what these guys are doing. If 12 guys in Kazakhstan managed to keep a nuclear reactor from going supernova after two days with no cooling, we'd already be writing songs about them. Since it's Japan, who's kind of mastered this whole thing, I've just kind of figured that they'd take care of it.