The aftershocks are aligned with the north-south transform fault system (named the Colba Ridge) that separates the Cocos plate to the West and the Nazca plate to the East. Here is the local map with historic epicenters in gray and the mainshock and aftershock epicenters plotted as orange circles. Note that many of the historic epicenters also align along this fracture zone.
Here is a map with only the recent epicenters in orange.
Here is an updated moment tensor (Mwb). With these aftershocks, we can better interpret this as rupture on a N-S striking right-lateral fault.
Here is a more comprehensive view of the local and regional tectonics in this region. This is a compilation by Harley M. Benz and others.