Two of the United States' most important nuclear power plants - the San Onofre plant and the plant at Diablo Canyon - are both built in active earthquake zones.
One sits along the coast, while the other is along a geological faultline.
In the wake of Japan's earthquake and tsunami - and fears of a radioactive meltdown there - nuclear industry officials in the US have reassured the public that there is nothing to worry about on home soil.
But environmental groups have restated that nuclear power comes at an often steep price.
Al Jazeera's Rob Reynolds reports from Southern California.