Penny, John V has posted this here and I have discussed it over the years. Related to a comment at the SCEC meeting that the far southern San Andreas fault was 10 months pregnant, I thought John went too far on saying it was not so likely because it has not been active around there (or something like that).

But, it would be interesting for, say, Roger to look into small distributed quakes in an area before a M6+ quake in california. But, it would be difficult to do, because the map pattern may have something to do with it.
Chris