short answer

Question

What is happening in the Pacific Ocean that is causing the ocean to get smaller?

Answer 1

The Pacific Ocean is getting smaller primarily due to the tectonic processes of plate subduction, where the Pacific Plate is being forced underneath surrounding continental and oceanic plates. This results in the ocean floor being consumed at trenches, leading to a gradual reduction in the size of the ocean. Additionally, the movement of tectonic plates can alter the shape and depth of ocean basins.