hot spots

Most volcanoes form along plate boundaries. But some of the world's largest and most active volcanoes are found far from the plates' edges. These volcanoes form over hot spots, intensely hot zones in the mantle deep below the Earth's crust. When plumes of magma rise up from a hot spot, they burst through the crust to form a volcano.

Image credits: main image, courtesy of NPS; Rosamond Kinzler: AMNH.