
Residents look at a collapsed building in Concepcion, Chile, after an 8.8-magnitude struck central Chile.
Megathrust earthquakes occur in subduction zones where plates of the Earth's crust grind and dive. Saturday's jolt occurred when the Nazca plate dove beneath the South American plate, releasing tremendous energy.
The U.S. Geological Survey says 13 temblors of magnitude-7 or larger have hit coastal Chile since 1973.
The latest quake occurred about 140 miles north of the largest earthquake ever recorded.








