Seamount

A seamount is an underwater mountain that rises from the ocean floor but never breaks the surface of the water. The key idea is that it stays entirely submerged — no part of it ever becomes an island or is visible above the sea.

Seamounts are volcanic in origin. They form when volcanic activity pushes magma up from deep within the Earth, building a mountain on the seafloor over time. Because they are built by eruptions, their summits are typically pointed rather than flat.

These mountains can be remarkably tall. The textbook states that seamounts can reach heights of 3,000 to 4,500 metres. To put that in perspective, that is comparable to some of the highest mountain ranges on land, yet the entire structure remains hidden beneath the ocean surface.

A well-known example is the Emperor Seamount. It is an extension of the Hawaiian Islands in the Pacific Ocean. The Hawaiian chain itself is volcanic, and the Emperor Seamount continues that same volcanic ridge underwater, showing how a single volcanic hotspot can produce both islands and submerged mountains over long geological time. …