The Peru earthquake of September 25, 2013, occurred as thrust-faulting on
or near the thrust-interface at the boundary between the South America
plate and the subducting Nazca plate.
The Nazca plate subducts beneath the South America plate at the Peru-Chile
trench offshore of western South America, and the thrust interface between
the two plates dips east-northeast beneath the South American continent.
At the latitude of the earthquake, the Nazca plate moves to the east-northeast
with respect to the South America plate at a velocity of about 70 mm/y.