Nazca Plate
The USGS reported that the earthquake resulted from the release of stresses generated by the subduction of the oceanic Nazca plate beneath the South American Plate. In this region, known as the Peru-Chile subduction zone, the Nazca Plate thrusts beneath South America at a rate of approximately 79 mm/year in an east-north-east direction. This earthquake indicates subduction-related thrusting, likely on the interface between these two plates.