Hi Chris. You presented an interesting question in regards to the Diablo Canyon Nuclear Power Plant. The earthquake that rattled San Simeon on 12/22/2003 also rattled Diablo Canyon. The epicenter of this M>6.5 quake was about 35 miles north of the plant.

The Diablo Canyon was designed and built to handle shaking about TWENTY times as strong as this quake produced. That means it is designed to handle a quake of about M>7.0+. They say that there was very strong shaking at the plant site, but that the plant handled it well. It was not even necessary to reduce power or take the plant off-line both units continued to run at full power without a problem. Nothing was said about an automatic shutdown so I don’t know if they have one or not. I suspect they do, but the threshold might be higher then an M>6.5 at a distance.

The magnitude 7.3 earthquake in central Taiwan on 21 September 1999 caused three reactors at Chinshan and Kuosheng in the north of the island to shut down automatically. They were cleared to restart two days later. A fourth reactor there was being refueled. The two reactors at Maanshan in the south continued operating, but reduced power later due to damage to distribution facilities. A major concern following the earthquake was how quickly power could be restored to industry.

So my answer to your question, which is based on today’s ability to predict earthquakes is no. I would not evacuate any people nor would I shut down the Diablo Canyon power plant. 100 years from now my answer may not be the same. I don’t expect to be around then, but if I am I’m going to be the crankiest SOB that ever walked the face of the earth. Being that old makes one cranky. Take Care…Don the cranky one