card
251

hot spots

OLogy Series
geology
card
251

hot spots

OLogy Series
geology

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.

Old Faithful
Hot spots create more than volcanoes. When water trickles down from the crust into an area heated by a hot spot, it can trigger amazing features like geysers. Geysers are large fountains of steam and hot water that erupt from the ground. The most famous geyser in the world is Old Faithful at Yellowstone National Park in Wyoming. Like many other geysers, Old Faithful erupts at regular intervals or time periods. About every 66 to 80 minutes, it shoots hot water more than 150 feet in the air. The water is heated by a hot spot under Yellowstone. Long ago, this hot spot caused major volcanic eruptions, including one about 600,000 years ago that covered a huge part of the U.S. with ash and lava. Today, the hot spot fuels hundreds of geysers, as well as thousands of hot springs, steaming "pools" of water heated from below.

A hot spot in the mantle stays in one place while a tectonic plate moves over it. This can create:

a massive volcano above the hot spot that keeps growing and growing

a chain of volcanoes extending from a hot spot

a spiral of volcanoes with the hot spot in the middle

Are you right?

Correct!

Since the plate is moving in one direction, a volcano that forms over a hot spot will move on and slowly become extinct. Then a new volcano will form in its place. Over millions of years, this creates a chain of volcanoes, with the youngest ones over the hot spot.

Rosamond Kinzler, Earth scientist

Hot spots produce the tallest mountains on Earth! The Hawaiian volcano Mauna Loa rises over 30,000 feet from the bottom of the ocean. It's over 1,000 feet taller than Mount Everest.

Hot spots only occur in tropical oceans of the world.

Fact
or
Fiction
?

Fiction

Hot spots are found around the globe, under continents and oceans, from the equator to places like Iceland and Antarctica.

In Antarctica, large towers of ice form from steam rising from a hot spot.

Fact
or
Fiction
?

Fact

These "ice towers" form around the Mt. Erebus volcano. It's so cold that steam erupting from the hot spot freezes into ice.

Definition: an intensely hot zone rising from deep in the mantle under the Earth's crust
Cause: unknown
Effects: volcanoes, volcanic islands, underwater mountain ranges, geysers
Location: often in the middle of plates
Examples: Hawaiian Islands, Galapagos Islands
Cool fact: Iceland, part of the Mid-Atlantic Ridge, has hundreds of volcanoes and geysers caused by a hot spot under the island.

Image credits: courtesy of NPS; Rosamond Kinzler: AMNH.