Back in the 1970's oil prospectors discovered a large fault called the Hosgri, which is three miles from PG&E's Diablo Canyon nuclear plant on the Central Coast.
Now there is concern about a recently discovered fault called the shoreline. It runs a scant seven hundred yards from the reactors at Diablo Canyon.
JEANNE HARDABECK: "The shoreline fault kind of runs off the Hosgri fault like an exit ramp on a freeway.
Jeanne Hardabeck is the scientist with the U.S Geological Survey who discovered the fault. She says that the Shoreline itself could produce up to a 6.5 quake. But Hardabeck explained that when you have two fault lines near each other, it's possible they could rupture together.
JEANNE HARDABECK: "If an earthquake were to continue on to the Hosgri fault for some distance then that could increase the magnitude of that earthquake."
PG&E says it is studying the issue and that even with the uncertainty caused by the shoreline fault, the plant remains safe.
