Foreshock for a big one?
Possibly. Folks have the tendency to forget that whever there are mountains, there are fault lines. And when fault lines slip and slide against one another, you get earthquakes. Happens out west more often than hereabouts, as the fault lines there are newer, and more active, but the reality is that no fault line is ever completely stable, and lines which have been inactive for long periods of time can, and do, become more active once again...
the infowarrior