Some volcanoes pop up in random
places, often far from the edge of a tectonic plate.
These volcanoes are found over "hot spots."
is an intensely hot area in the mantle
below the Earth's crust. The heat that fuels the
hot spot comes from very deep in the Earth. This
heat causes the mantle in that region to melt. The
molten magma rises up and breaks through
the crust to form a volcano.
While the hot spot stays in one place, rooted to its
deep source of heat, the tectonic plate is slowly
moving above it. As the plate moves, so does the
volcano, and another one forms in its place. The
volcano that moved is no longer active. This is
why a chain of extinct volcanoes is often found
extending from a hot spot.
Hot spots are found around the globe, on land and
in the ocean. The Hawaiian Islands are the
youngest volcanic mountains in a long chain of volcanoes that formed over a hotspot. They are still forming
today. Another hot spot is under
Yellowstone National Park, where the heat causes
boiling mud pools and geysers like Old Faithful.