Don, as you know Parkfield would be a right-lateral earthquake, while San Simeon and Coalinga were both thrust quakes. Sure, they would have some delaying or advancing effect at Parkfield, but maybe not a lot....The San Andreas is trucking along at Parkfield at probably 30 to 35 mm/yr. Since 1966, about 900 mm (0.9) m of strain has accumulated. That might be good for a M6. One question is whether all elastic strain (I may or may not have this term right) was released in 1966 (whether you have to wait for the strain to build up-whether you could have more than 1 m of slip at Parkfield if it occurred soon. Or, could Parkfield hang in there and wait for 2, or 4 m of slip.....which would be a long wait.....Chris