Don;

The problem with your last statement is the amount of energy required to raise a small quake to a large one.

If a fault has enough stored energy for a mag. 4.0, there's just no way for FFA or anything else to make it a 5.0.

Triggers can only work on a quake that's just about ready to go anyway. They can "trip the scales" and that's about all.

IMHO of course.

Roger