Here’s the really scary part: The largest earthquake ever recorded was a magnitude 9.5 in 1960 that also occurred in Chile’s subduction zone. The resulting tsunami killed 61 people in Hawaii and 138 in Japan. The quake and tsunami combined caused 1,655 deaths.

Both of these quakes occurred in what is called a subduction zone, where an oceanic plate is being pushed beneath a continental plate and back into the Earth’s mantle. A continuous subduction zone runs along South America’s Pacific border. Subduction zones are capable of bigger quakes than any other type of plate boundary, and are also responsible for the active volcanoes that ring the Pacific Ocean.