Thanks Don. Don't suppose you could pull up some stats for those two mag. 5ish foreshocks to Loma Prieta to see if they also had no significant aftershocks...?

Canie, thanks for the clarification on subduction vs. strike-slip faults and aftershock sequences. My "theory" has to do with strike-slip faults only. (Very interesting, though, that deep subduction quakes have few aftershocks. I can picture why. Thanks.)

Dib: Thanks for the thumbs up on the idea. I wish I has the resources at hand to do a definitive study. My observation comes only from having watched earthquakes and their aftershock sequences for about four years now. I started noticing a pattern.

Anyone want to have some fun on a rainy Sunday and do a little computer digging? Don? Canie? Martin? Could prove my theory all wet.

Cathryn