What happens when two oceanic plates collide

Subject : Science

Question: What happens when two oceanic plates collide?

Expert Verified Solution:

When two oceanic plates collide, the following geological processes typically occur:

Subduction: One of the oceanic plates will be forced beneath the other in a process called subduction. This happens because oceanic plates are denser than continental plates, and one plate sinks into the Earth’s mantle beneath the other. The plate that is forced down creates a subduction zone.

Formation of Deep Ocean Trenches: The area where the subducting plate bends and sinks into the mantle often forms a deep ocean trench. These trenches are some of the deepest parts of the ocean and can be several miles deep.

Volcanic Activity: As the subducting plate descends into the mantle, it melts due to the high temperatures and pressures. The molten material, or magma, can rise through the overlying plate, leading to the formation of volcanic island arcs. These are chains of volcanic islands that form parallel to the trench.

Earthquake Activity: The collision and subduction process can cause significant seismic activity. Earthquakes are common in subduction zones due to the intense pressure and friction between the colliding plates.

Oceanic Crust Recycling: The subduction process results in the recycling of the oceanic crust back into the mantle. This helps balance the creation of new crust at mid-ocean ridges with its destruction at subduction zones.

An example of this process is the collision between the Pacific Plate and the North American Plate, which has created the Aleutian Trench and the Aleutian Islands.