Hi Don - I remember reading about this one myself -

There is an interesting video that I recently posted by a woman with the last name of Atwater from UCSB that shows the process of baja being formed - I'm not sure that exactly what is stated in the above article is exactly right or just another geologist's interpretation (in reference to a ship). There's an old saying - put 2 geologists together and you'll have 3 interpretations as to what happened! Here's a link to the movie:
http://rincon.gps.caltech.edu/hudnut/UCX_talk/Source_Files/Atwater_SoCal.mov

There's also the theory that the san andreas is moving eastward - or I should say the plate boundary may be moving to the east to go around the 'big bend' and thus render the san andreas inactive.

And one other thing I've heard is that if there is an earthquake - you WANT to be at San Onofre - its built to take it

Canie