What type of eruption will Yellowstone have if it erupts again?

The most likely explosive event to occur at Yellowstone is actually a hydrothermal explosion—a rock-hurling geyser eruption—or a lava flow. Hydrothermal explosions are very small; they occur in Yellowstone National Park every few years and form a crater a few meters across. Every few thousand years, a hydrothermal explosion will form a crater as much as a few hundred meters across.

Though the worst-case scenario for a giant Yellowstone eruption is indeed bad and could have global implications, most past eruptions at Yellowstone were not highly explosive. Of the past 50 or so eruptions, almost all were simple lava flows. If they occurred tomorrow or next year, they would have minimal direct effect outside Yellowstone National Park.

As for the worst-case scenario, even previous Yellowstone supereruptions did not cause extinctions, and ash fallout on the other side of the continent was minimal.

Yellowstone is routinely monitored for signs of volcanic activity. These methods include using seismographs to detect earthquakes and using GPS (Global Positioning System) to detect ground motion. The USGS has not detected any signs of activity that suggest an eruption is imminent.

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What is a supervolcano? What is a supereruption?

The term "supervolcano" implies a volcanic center that has had an eruption of magnitude 8 on the Volcano Explosivity Index (VEI), meaning that at one point in time it erupted more than 1,000 cubic kilometers (240 cubic miles) of material. In the early 2000s, the term “supereruption” began being used as a catchy way to describe VEI 8 eruptions...

What would happen if a "supervolcano" eruption occurred again at Yellowstone?

If another large, caldera-forming eruption were to occur at Yellowstone, its effects would be worldwide. Such a giant eruption would have regional effects such as falling ash and short-term (years to decades) changes to global climate. Those parts of the surrounding states of Montana, Idaho, and Wyoming that are closest to Yellowstone would be...

When was the last time Yellowstone erupted?

The most recent volcanic activity at Yellowstone consisted of rhyolitic lava flows that erupted approximately 70,000 years ago. The largest of these flows formed the Pitchstone Plateau in southwestern Yellowstone National Park. Learn more: Yellowstone Eruption History The evolution of the Yellowstone Plateau Volcani Field: Past, present, and...

How do scientists know what’s going on beneath the ground at Yellowstone? Is Yellowstone monitored for volcanic activity?

Yellowstone Volcano is monitored for signs of volcanic activity. The Yellowstone Volcano Observatory (YVO), is a partnership between the U.S. Geological Survey (USGS), Yellowstone National Park, the University of Utah, the University of Wyoming, UNAVCO, the Montana Bureau of Mines and Geology, the Idaho Geological Survey, and the Wyoming State...

How much volcanic activity has there been at Yellowstone since the most recent giant eruption?

Since the most recent giant ( caldera-forming ) eruption 631,000 years ago, approximately 80 relatively nonexplosive eruptions have occurred. Of these eruptions, at least 27 were rhyolite lava flows in the caldera, 13 were rhyolite lava flows outside the caldera, and 40 were basalt vents outside the caldera. The most recent volcanic eruption at...

How far in advance could scientists predict an eruption of the Yellowstone volcano?

The science of forecasting a volcanic eruption has significantly advanced over the past 25 years. Most scientists think that the buildup preceding a catastrophic eruption would be detectable for weeks and perhaps months to years. Precursors to volcanic eruptions include strong earthquake swarms and rapid ground deformation and typically take place...

Can we drill into Yellowstone to stop it from erupting?

In some cases, limited scientific drilling for research can help us understand magmatic and hydrothermal (hot water) systems; however, drilling to mitigate a volcanic threat is a much different subject with unknown consequences, high costs, and severe environmental impacts. In addition to the enormous expense and technological difficulties in...

Could a large Yellowstone eruption significantly change the climate?

If another catastrophic, caldera-forming Yellowstone eruption were to occur, it would probably alter global weather patterns and have enormous impacts on human activity (especially agricultural production) for many years. At this time, however, scientists do not have the ability to predict specific consequences or durations of possible global...
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Date published: May 17, 2017

EarthWord–Phreatic Eruption

This EarthWord is straight up steampunk...

Date published: May 10, 2017

The Complex Dynamics of Geyser Eruptions

Despite two centuries of scientific study, basic questions persist about geysers—why do they exist? What determines their behavior?

Date published: August 22, 2016


Look! In the sky! It’s a bird, it’s a plane! Wait, run, it’s this week’s EarthWord!

Date published: October 5, 2015

EarthWord: Fumarole

Fumaroles are openings in the earth’s surface that emit steam and volcanic gases, such as sulfur dioxide and carbon dioxide. They can occur as holes, cracks, or fissures near active volcanoes or in areas where magma has risen into the earth’s crust without erupting. A fumarole can vent for centuries or quickly go extinct, depending on the longevity of its heat source.

Date published: May 30, 2008

What Makes an Old Geyser Faithful?

New research suggests that how often Old Faithful and other Yellowstone geysers erupt may depend on annual rainfall patterns.

Filter Total Items: 13
May 26, 2016

Forecasting Ashfall Impacts from a Yellowstone Supereruption

  • Yellowstone is one of a few dozen volcanoes on earth capable of "supereruptions" that expel more than 1,000 cubic km of ash and debris.
  • The plumes from such eruptions can rise 30 to 50 km into the atmosphere, three to five times as high as most jets fly.
  • Yellowstone has produced three supereruptions in the past 2.1 million years. The most recent was
Attribution: Yellowstone
January 22, 2014

The Yellowstone Volcano: Past, Present and Future

Public Lecture on Yellowstone Volcano by Jake Lowenstern at Menlo Park, CA on January 23, 2014. The Q&A at the end of the talk can be found on the original source video (Source URL).

video thumbnail: Volcano Hazards
July 30, 2012

Volcano Hazards

The United States has 169 active volcanoes. More than half of them could erupt explosively, sending ash up to 20,000 or 30,000 feet where commercial air traffic flies. USGS scientists are working to improve our understanding of volcano hazards to help protect communities and reduce the risks.

Video Sections:

  • Volcanoes: Monitoring Volcanoes
Image: Lava flow breakout
April 8, 2010

Lava flow breakout

Lava flow breakout

Hydrothermal explosion at Biscuit Basin in Yellowstone National Par...
May 29, 2009

Hydrothermal explosion at Biscuit Basin in YNP. These types of even...

Hydrothermal explosion at Biscuit Basin in Yellowstone National Park. These types of events are the most likely explosive hazard from the Yellowstone Volcano.

video thumbnail: Yes! Yellowstone is a Volcano (Part 1 of 3)
January 29, 2009

Yes! Yellowstone is a Volcano (Part 1 of 3)

USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers
the following questions to explain volcanic features at Yellowstone: "How do we know Yellowstone is a
volcano?", "What is a Supervolcano?", "What is a Caldera?","Why are there geysers at Yellowstone?",
and "What are the other geologic hazards in Yellowstone?"


Attribution: Yellowstone
video thumbnail: Yellowstone Eruptions (Part 3 of 3)
January 29, 2009

Yellowstone Eruptions (Part 3 of 3)

USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers
the following questions to explain volcanic eruptions at Yellowstone: When was the last supereruption at
Yellowstone?", "Have any eruptions occurred since the last supereruption?", "Is Yellowstone overdue for
an eruption?", "What does the magma below indicate about a

Attribution: Yellowstone
video thumbnail: Yellowstone Volcano Observatory (Part 2 of 3)
January 29, 2009

Yellowstone Volcano Observatory (Part 2 of 3)

USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers
the following questions to provide a tour of the Yellowstone Volcano Observatory: "What is YVO?", "How
do you monitor volcanic activity at Yellowstone?", "How are satellites used to study deformation?", "Do
you monitor geysers or any other aspect of the Park?", "Are

Attribution: Yellowstone
Excelsior Geyser erupting as a violent hydrothermal explosion. The ...

Excelsior Geyser erupting as a violent hydrothermal explosion. The ...

Excelsior Geyser erupted in a series of violent hydrothermal explosions in the 1880s and early 1890s; one of these eruptions is shown in this colorized postcard made from a photograph. These were the largest such events to occur in the Yellowstone region in historical times. (Original photograph by F. Jay Haynes, 1888; date on postcard is incorrect.)

Yellowstone Lake bathymmetry with zoom on hydrothermal craters...

Yellowstone Lake bathymmetry with zoom on hydrothermal craters

High-resolution bathymetric map of Yellowstone Lake (left) showing the location of hydrothermal vents (black dots) on the lake floor. Zoomed area at right is an ultra-high-resolution (25 cm) bathymetric map of an area known as "Deep Hole," which is a site of special focus for the HD-YLAKE project. The data for Deep Hole were collected by the Woods Hole Oceanographic