 Subduction of the eastern edge of the Nazca Plate under the western edge of the South American Plate occurs about 160 kilometers ( 99 mi ) west of Peru and Chile , at a rate of 9 to 11 centimetres ( 4 in ) per year at 30 degrees south latitude . This subduction process has resulted in the formation of the Peru – Chile Trench , an oceanic trench in the Pacific Ocean . It also produced the Andean Volcanic Belt and the rest of the Andes . 
