Glen...as Don's reservoir links may have said if I read them, it is known seismotectonics that higher fluid pressure in a fault will weaken the fault and can trigger earthquakes. the problem is to get the higher fluid pressure down to the depth at which earthquakes nucleate in California...but could happen. Also, the load of the water will redistribute stress so that some faults will be strengthened and some weakened. It is hard for me to look at your numbers and guess if the relation looks good...would have to plot up the quakes vs high stand lake levels...this is best done as areas (not a point in time) to show the errors in the dates. While high levels might advance the time of quakes a couple decades, the quake is still going to occur even without the high water if it has to wait too long. But...interesting idea...if you added 100 m of water to the region it would not amaze me if you trigged the "Big One"...
Chris