[CliffordK (OP)]

Recently Japan had 4 of its Nuclear Plants shut down due to an earthquake.

http://finance.yahoo.com/news/Scientists-say-Japan-quake-rb-131622016.html;_ylt=AvEcpti3SLmPH..763uBAPe7YWsA;_ylu=X3oDMTE1c3BsaDV1BHBvcwMzBHNlYwN0b3BTdG9yaWVzBHNsawNzY2llbnRpc3RzamE-?x=0&sec=topStories&pos=main&asset=&ccode=

According to the article, at least US reactors are reasonably insulated against earthquakes.  However, there may still be a risk if the plants loose both an off site power source, and are no longer locally generating power.