formfeed writes "As the data from the Fukushima reactor is being reviewed it looks like the meltdown happened much earlier: '[T]he fuel rods in the No. 1 reactor were completely exposed to the air and rapidly heating five hours after the quake.' Apparently, the earthquake had caused a crack in the containment vessel. Which means, that even without the generators failing, the meltdown might still have happened. With this new data, it seems a similar incident could happen in an earthquake zone even without a tsunami."