When a Sleeping Giant Awakes

When a Sleeping Giant Awakes

Past volcanic eruptions that have taken place at Yellowstone National Park have been global disasters. Today, scientists are trying to predict how this ticking time bomb will explode—or fizzle out.


6 - 12+


Earth Science, Geology, Geography, Physical Geography

NGS Resource Carousel Loading Logo
Loading ...
Leveled by
Selected text level

There is a giant volcano in the western United States. It is deep underground. The volcano is so big that scientists call it a "supervolcano." The supervolcano lies beneath Yellowstone National Park in Wyoming.

Scientists have been watching the volcano since 1923. Lately, it has been more active than usual. Some experts wonder if it may erupt soon.

Still, most scientists say there's no need to worry. The Yellowstone volcano is currently dormant. This means it is mostly quiet now.

Scorched Earth

The Yellowstone volcano hasn't always been so quiet. It has had three giant eruptions in the past. These eruptions happened about 600,000 to 800,000 years apart.

The last eruption happened 640,000 years ago. The blast shot ash and gas into the air. The ash was so thick that it blocked out the sun. The inside of the volcano was hot and melted rock into magma. The magma rose out of the volcano and burned the land.

Hopefully Just Some Minor Activity

The United States Geological Survey (USGS) is a government science group. USGS scientists study Earth. They are volcano experts. The USGS agrees that a big eruption is very unlikely.

Instead, they think the volcano may cause smaller events. It could heat water underground. Steam or hot water might shoot from the earth. Slow-moving rivers of lava might ooze from the volcano. These will eventually harden into rock.

For now, the Yellowstone volcano is mostly quiet. Scientists are keeping an eye on it. No one knows how much damage it would cause if it erupts. But most scientists say that's still a long way off.

Fast Fact

Migrating Eruptions
Like all volcanic hot spots, the Yellowstone hot spot has remained stable for millions of years, while the North American continent has drifted southwest. The oldest eruptions associated with the Yellowstone hot spot occurred in what is today the southeastern part of Oregon. The most recent eruptions have been in the northeast corner of Wyoming.

Fast Fact

Hot Water
Yellowstone's current geologic activity is limited to hot springs and geysers. Old Faithful, the park's most famous geyser, spews more than 14,000 liters (3,700 gallons) of boiling water more than 30 meters (100 feet) in the air every 91 minutes.

Fast Fact

Supervolcanoes are loosely described as volcanoes that produce more than 1,000 cubic kilometers (240 cubic miles) of gas, ash, magma, and rock. Those that erupted less than 100,000 years ago include:

  • Lake Toba, Indonesia
  • Yellowstone, United States (Idaho and Wyoming)
  • Lake Taupo, New Zealand
Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Alyssa Samson
National Geographic Society
Last Updated

October 19, 2023

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.


If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.


Text on this page is printable and can be used according to our Terms of Service.


Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources