The Chile earthquake was caused by which plate interaction?

• A. North American
• B. Pacific
• C. South American (destructive)
• D. Caribbean

Answer: (C)

Destructive plate boundaries where an oceanic plate sinks beneath a continental plate produce the biggest earthquakes. In Chile, the oceanic Nazca/Pacific plate is being forced down under the South American Plate along the Peru-Chile trench. The friction at this subduction zone locks the plates and builds up immense stress, which is released in a powerful thrust earthquake and can generate a tsunami. That’s why the correct description is the South American plate at a destructive boundary—the interaction that drives Chilean earthquakes. The other options don’t fit the regional plate pair involved here, and simply naming the Pacific plate doesn’t specify the continental partner and boundary type.