What is a volcanic "hotspot"?


The best example of a hotspot producing a line of volcanic islands is the Hawaiian hot spot. This drawing, from Thurman’s Introduction to Oceanography, illustrates how the Hawaiian chain formed as the Pacific tectonic plate moved over the hot spot.

A hotspot is theorized to form as one of Earth’s outer tectonic plates moves over an unusually hot part of the Earth’s mantle and large amounts of magma rise up, piercing through the plates and producing large volcanic eruptions at the Earth’s surface. Hotspot volcanism would thus be unique because it does not occur at the boundaries of Earth’s tectonic plates, where other volcanism occurs.
Source: Ocean Exploration Facts