After that first Loma Prieta foreshock in 88 there were NO aftershocks. I remember then seismologists going on the news to comment how weird they thought that was for a quake that size. Makes you wonder if the stress is so built up and the fault goes to let go only to get caught in a stronger snag thats preventing it from releasing anymore energy in both a bigger quake or in aftershocks.

After the 6.3 Joshua Tree quake in 92, what was the aftershock pattern to that one? As we know now that was the begining point for the whole rupture sequence that became Landers....