Volcanic Hot Spots

Some volcanoes form over active hotspots. Scientists have identified about 50 hotspots on Earth.

Hotspots sit directly above a rising column of hot rock called a mantle plume. These mantle plumes continuously push hot rock deep in the mantle toward the crust.

Hotspots can be found in the middle of tectonic plates, creating intraplate volcanoes.

They are much more common beneath oceanic crust because the thinner crust allows the plume to break through more easily.

As tectonic plates move over a hotspot, a chain of volcanoes forms. The Hawaiian Islands were created this way in the middle of the Pacific Plate. Over time, older volcanoes that once formed at the hotspot have eroded below sea level, becoming the Emperor Seamounts.

Hotspots can also be active at plate boundaries, especially at mid-ocean ridges. A hotspot along the Mid-Atlantic Ridge formed Iceland.

Hotspots exist within continents, too, but they are less common because the continental crust is much thicker, requiring a strong mantle plume to break through. Eruptions from these hotspots are rare but massive.