LAGUNA NIGEL (CBS 8) - A 3.9 earthquake in Laguna Niguel could make history.
It may be the first along the San Joaquin Hills thrust fault discovered 13 years ago.
There were no reports of damage or injury from Monday's quake, but it is generating concerns, over the safety of the San Onofre nuclear plant.
Southern California Edison says there was no effect on its plant, which has been shutdown since January because of unrelated safety concerns.
The Alliance for Nuclear Responsibility says the plant needs more up to date seismic studies.
