According to the experts, the huge earthquake that hit off the coast of Chile belongs to an "elite class" of mega earthquakes. The magnitude- 8.8 quake was a "megathrust," which is considered the most powerful earthquake on the planet.

Megathrusts happen when one plate dives under another. Saturday's tremor unleashed about 50 gigatons of energy and broke about 340 miles of the fault zone.

The quake's epicenter was only about 140 miles away from the largest earthquake ever recorded - a magnitude-9.5 that killed about 1,600 people in Chile in 1960.