The earthquake was caused because of the great subduction zone bewteen the Nazca plate and the South American continental plate.Also this huge earthquake in chile made a giant zsunami go all the way to China and the Hawiian islands,It took the zsunami 15 hours to travel all the way to the hawiian islands.A series of earthquakes the day before the big earthquake had happened.Another thing is the earthquake resulted from a rupture along a fault where one tectonic plate slides under another at the west coast of South America.This earthquake exteneded a fault zone which was almost 1000km long and 300km wide.