Hotspots

A hotspot is a concentration of heat in the mantle that produces magma that reaches the Earth's surface. These hotspots can produce intraplate volcanoes. Intraplate volcanoes are those that occur within a tectonic plate and NOT on the plate boundary. The Hawaiian Islands were formed when the Pacific plate moved over a hotspot. The bottom picture is of Mauna Loa volcano in Hawaii. The volcanoes of Hawaii are broad domed-shaped volcanoes known as shield volcanoes.

The top picture is of Old Faithful geyser in Yellowstone National Park. Much of Yellowstone National Park is in a caldera- a large depression in a volcano. Yellowstone is an active geologic feature that lies over another intraplate hotspot. There is much conjecture that the Yellowstone area is due to erupt sometime in the future.