Hi Chris - thanks for the summary of Weldon's info. I have not read the article yet, but will.

Here are the probability figures for the northern segment of the san andreas fault
http://quake.wr.usgs.gov/research/seismology/wg02/losses.html

I can't seem to find much info on the southern section. At least, not in the way of official probability estimates. The maps linked below cover california and are for 50 years..

Canie

• Probabilistic Seismic Hazard Assessment Maps