Subduction

plate tectonics · earth science · geology

Plates collide and sink. When two of Earth's giant tectonic plates crash into each other, the heavier one, usually made of ocean floor, gets forced down beneath the lighter one. This heavy plate then dives deep into Earth's hot mantle where it melts.

Denser plates go down. Ocean floor is heavier and denser than continental crust, so it always loses the battle at a collision zone. The oceanic plate sinks while the continental plate rides up and over it, kind of like how a heavy stone sinks through water.

Creates mountains and trenches. Subduction zones form dramatic landscapes with deep ocean trenches on one side and volcanic mountain ranges on the other. These arc-trench complexes are some of Earth's most active and exciting geological features.

Recycling Earth's crust. Subduction is how our planet recycles itself. Most of Earth's continental crust was built over billions of years from material that got pushed down into the mantle and then brought back up again through volcanic activity.

Slow but powerful motion. Plates move incredibly slowly, typically sinking at rates between just a few centimeters to about 11 centimeters per year. But over millions of years, this tiny motion reshapes entire continents and oceans.