The Nazca plate is mostly an oceanic crust, however, converges with the South America plate to form mountains along the west coast.  This plate is moving around 10-15cm per year making it the fastest moving plate. This plate is responsible for 1960 Valdivia earthquake surrounding Chile and Argentina - the largest earthquake ever recorded scoring a 9.5 on the magnitude scale. This was so powerful, it affected Japan and New Zealand on the other side of the Pacific Ocean.