The 4.7 was on the north end of the Elsinore fault. Further north the fault splits. The Elsinore continues a ways, curving westward where it turns into the Whittier fault. The more northerly split is the Chino fault.

My guess is, the 3.2 isn't an aftershock, but was certainly influenced by the 4.7. The area of the 3.2 is active, having had small quakes like this (and a couple larger) in recent years. So, we could indeed have more activity further north.

It could also be further south. The 4.7 was on the north end of the Elsinore fault zone, which hasn't had a major quake since 1910, which was further south.

More info here: http://www.data.scec.org/faults/lafault.html

Brian