Several earthquakes occurred in Chile today (March 11), and according to the U.S. Geological Survey, the quakes were “aftershocks” associated with the 8.8 Chile earthquake of February 27.  According to the USGS analysis, the earthquakes occurred in the region of aftershocks of the major earthquake.  Here is the USGS early analysis of today’s earthquakes:

The Chile earthquakes of March 11, 2010, 14:39 UTC and 14:55 UTC, occurred in the region of the plate boundary between the Nazca and South America plates, in the aftershock region of the great Chile earthquake of February 27, 2010. The March 11 earthquakes almost certainly occurred as the result of the change of regional stress caused by the February 27 earthquake. Preliminary analyses of their locations and seismic-wave radiation patterns, however, imply that the March 11 shocks occurred as the result of normal faulting within the subducting Nazca plate or the overriding South America plate, unlike the February 27 earthquake, which occurred as thrust faulting on the interface between the two plates. At present, the focal depths of the shocks are not known with sufficient precision to confidently determine within which of the Nazca or South America plate the earthquakes occurred.

Here is a map from the USGS showing the location of today’s main aftershock, which was located SW of Santiago, the capital of Chile.

Map showing aftershocks associated with Feb. 27 8.8 earthquake, as well as historical earthquakes, and the depth of earthquakes