10-08-2014, 02:53 PM
Royall - the East Pacific Rise is the eastern boundary of the Pacific tectonic plate. This link may help you picture it:
http://en.wikipedia.org/wiki/Ring_of_Fir...ct2_en.svg
The Southern East Pacific Plate is just the southern part of that boundary. I'm not sure exactly where it starts being the southern part, but would guess it's the boundary between the Pacific Plate and the Nazca plate. The earthquake looks to have occurred just south of intersection of the Pacific, Nazca and Antarctic Plates. Perhaps someone more expert than me can comment, but these boundaries are diverging (i.e., moving away from each other, similar to the boundary in the middle of the Atlantic) and aren't usually associated with large earthquakes, so think this is a little unusual. The big earthquakes usually occur where plates are colliding or sliding past each other.
http://en.wikipedia.org/wiki/Ring_of_Fir...ct2_en.svg
The Southern East Pacific Plate is just the southern part of that boundary. I'm not sure exactly where it starts being the southern part, but would guess it's the boundary between the Pacific Plate and the Nazca plate. The earthquake looks to have occurred just south of intersection of the Pacific, Nazca and Antarctic Plates. Perhaps someone more expert than me can comment, but these boundaries are diverging (i.e., moving away from each other, similar to the boundary in the middle of the Atlantic) and aren't usually associated with large earthquakes, so think this is a little unusual. The big earthquakes usually occur where plates are colliding or sliding past each other.