In the bigger picture, we don't really know. We have data going back 150 years and that is really it. We still don't know if there are patterns or trends. So all that activitiy of a 6+ quake leading up to 06 in that cluster may have been a once in a millenia scenario, OR it could happen like that like clockwork every century. But my personal guess is that the Bay Area has another 100 years to go before entering another destructive quake pattern, and that goes for the Hayward fault. Every Fault in the bay area that has had trenches have shown intervals of decades to 250+ years. So its not inconceivable things will stay status quo there for another century at least 40 to 50 more years.