The March 11th Japanese earthquake was 9.0 on the Richter scale and the strongest to hit Japan in the approximately 130 years of modern seismic records. It ranks the 4th strongest anywhere in the world in those records.
Tokyo Electric Power built the Fukushima nuclear plant to withstand at most an 8.0 and recent information indicates that major damage was done to nuclear facility, including the ability of the plants to cool reactors, by the earthquake itself, even before the tsunami hit.
So was the March 11th earthquake a black swan? Would it have been unreasonable to build for a 9.0?
Answering those questions now seems obvious.
It is also becoming clear that relying on the historical earthquake records is not sufficient to identify an earthquake Black Swan.