What is the process called when two crustal plates collide and one is forced under the other?

What is the process called when two crustal plates collide and one is forced under the other?

• A. Collision
• B. Subduction
• C. Convergence
• D. Rifting

Answer: (B)

Subduction is the process described: when two crustal plates collide, the denser plate sinks beneath the less dense one and dives into the mantle at a subduction zone. This happens most often when oceanic crust meets continental crust (or another oceanic plate), because the oceanic slab is denser and thus pulled down by gravity. The surface features a deep trench where the sinking plate begins, and magma generated as the slab melts and interacts with the mantle leads to volcanic arcs on the overriding plate. Earthquakes commonly occur along the dipping subducting slab, forming what’s known as a Wadati-Benioff zone. In contrast, convergence just means plates are moving toward each other, collision is a broader term often used for continental-continental collisions that build mountains, and rifting describes plates pulling apart.

Subduction is the process described: when two crustal plates collide, the denser plate sinks beneath the less dense one and dives into the mantle at a subduction zone. This happens most often when oceanic crust meets continental crust (or another oceanic plate), because the oceanic slab is denser and thus pulled down by gravity. The surface features a deep trench where the sinking plate begins, and magma generated as the slab melts and interacts with the mantle leads to volcanic arcs on the overriding plate. Earthquakes commonly occur along the dipping subducting slab, forming what’s known as a Wadati-Benioff zone. In contrast, convergence just means plates are moving toward each other, collision is a broader term often used for continental-continental collisions that build mountains, and rifting describes plates pulling apart.