How is plate tectonics involved in ocean expansion?

At zones of ocean-to-ocean rifting, divergent boundaries form by seafloor spreading, allowing for the formation of new ocean basin. As the ocean plate splits, the ridge forms at the spreading center, the ocean basin expands, and finally, the plate area increases causing many small volcanoes and/or shallow earthquakes.

The movement of tectonic plates, which determines the distribution, size, and depth of ocean basins, influencing how water is distributed around the continents.

Explanation: