[nmh]

How do you KNOW they are after shocks?

Couldn't it be just a plausible that they are new earthquakes?

Unless you can see them, you really can't distinguish between the two - at least that is what I have been told.

[Strategerist]

They're within a fault length distance of the 7.2, and are following a normal aftershock pattern. A 5.0 today in that location today is precisely what you'd expect as a routine aftershock of the 7.2 earthquake of a few days ago.

USGS calls them aftershocks; good enough for me.