Hi Lowell. I wish there were a way to tell if a quake is a foreshock to something larger. There are a few instances in which a series of quakes were recognizable as foreshocks. That was the Hector Mine quake and the moderate quake near the Civic Center in LA. Other then those two I have never really been able to determine a foreshock from a common ordinary everyday run of the mill type earthquake. Take Care…Don in creepy town