I have heard it reported several places as a new quake.
Here is a link to a good USGS map. It does not say if it's an aftershock, or a new quake. To me, they're the definitive experts.
http://earthquake.usgs.gov/earthquakes/recenteqsww/Maps/10/145_35.php
Red lines - not red squares, but the long lines - are known "major" faults.
What is intriguing is that, like what happened in 1994 in Northridge, sometimes a fault is discovered when it ruptures, and not before. What is interesting about this area is, if you look around on the map (click the blue arrows to move 10* that direction), you'll note that this is in a cross of three major fault lines.
I would expect, then, that that this is either a new fault (and rupturing due to pressure from displacement earlier), or a quake that is an aftershock due to settling from land and water, and adjusting because of pressure. However, I don't know which it is.
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Herding Cats