A hereditary model illustrates a method devised to extrapolate a series of locations of probable progeny earthquake events based on previous "seed" earthquakes. Shadow Zone border P-rings are claimed as precursors to possible future earthquake event locations. The intersection of these P-rings with tectonic plate edges or major fault lines indicates future seismic event targets. The earth physics that underlie the behavior of this forecast method involves the interaction of the refracted P-waves with internal earth processes.