Science Olympiad Dynamic Planet Practice Test

What is the process called when one tectonic plate is forced under another?

1. Subduction

2. Extension

3. Collision

4. Rifting

The correct answer is: Subduction

The process in which one tectonic plate is forced under another is known as subduction. This phenomenon occurs at convergent plate boundaries, where two tectonic plates move toward each other. When an oceanic plate meets a continental plate, the denser oceanic plate is subducted beneath the lighter continental plate. This process can lead to the formation of deep ocean trenches and volcanic arcs. During subduction, the nose of the descending plate pushes into the mantle, causing significant geological activity, including earthquakes and the formation of magma that can result in volcanic eruptions. The subducting plate releases water and other materials into the mantle, which lowers the melting point of the surrounding rock, contributing to magma production. Understanding subduction is crucial because it directly influences the geology of an area, shapes the landscape, and plays a significant role in the Earth's tectonic cycle. In contrast, the other terms refer to different geological processes: extension involves the stretching of the Earth's crust, collision refers to two plates pushing against each other without subduction, and rifting signifies the breaking apart of a tectonic plate, typically resulting in the formation of new crust.