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 affected by pyroclastic flows, while other places in the United States would be impacted by falling ash (the amount of ash would decrease with distance from the eruption site). Such eruptions usually form calderas, broad volcanic depressions created as the ground surface collapses as a result of withdrawal of partially molten rock (magma) below. Fortunately, the chances of this sort of eruption at Yellowstone are exceedingly small in the next few thousands of years.

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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...

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 Volcano Observatory

Why are there so many earthquakes at Yellowstone?

Almost all earthquakes at Yellowstone are brittle-failure events caused when rocks break due to crustal stresses. Though we've been looking at Yellowstone for years, no one has yet identified "long-period (LP) events" commonly attributed to magma movement. If LP events are observed, that will NOT mean Yellowstone is getting ready to erupt. LP...

How far would ash travel if Yellowstone had a large explosive eruption?

Knowledge about past eruptions of Yellowstone combined with mathematical models of volcanic ash dispersion help scientists determine where and how much ashfall will occur in possible future eruptions. During the three caldera-forming eruptions that occurred between 2.1 million and 640,000 years ago, tiny particles of volcanic ash covered much of...

How big is the magma chamber under Yellowstone?

Yellowstone is underlain by two magma bodies . The shallower one is composed of rhyolite (a high-silica rock type) and stretches from 5 km to about 17 km (3 to 10 mi) beneath the surface and is about 90 km (55 mi) long and about 40 km (25 mi) wide. The chamber is mostly solid, with only about 5-15% melt. The deeper reservoir is composed of basalt...

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...

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...

What is the difference between "magma" and "lava"?

Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth's surface.

What are some examples of supervolcanoes?

Volcanoes that have produced exceedingly voluminous pyroclastic eruptions and formed large calderas in the past 2 million years include Yellowstone, Long Valley in eastern California, Toba in Indonesia, and Taupo in New Zealand. Other 'supervolcanoes' would likely include the large caldera volcanoes of Japan, Indonesia, Alaska (e.g. Aniakchak,...
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Date published: May 6, 2019

The National Volcano Early Warning System (NVEWS) will help USGS better monitor nation’s most dangerous volcanoes

In September 2004, USGS scientists detected sudden, but unmistakable, signs that Mount St. Helens was waking up. Volcano monitors had picked up the occurrence of hundreds of small earthquakes and other signals that the volcano’s crater floor had begun to rise. Within a week, several eruptions blasted clouds of ash into the atmosphere, and soon after, a new lava dome emerged in the crater.

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Aerial view of the caldera of Mt Tambora, island of Sumbawa, Indonesia.
January 18, 2017

Aerial View of Mt. Tambora Caldera

Aerial view of the caldera of Mt. Tambora, island of Sumbawa, Indonesia.  

Eruption of Mt. Pinatubo
July 29, 2016

Eruption of Mt. Pinatubo

The cataclysmic eruption of Mt. Pinatubo in the Philippines on June 15, 1991 was the second largest eruption of the 20th century. Photograph Credit: Chris Newhall, USGS

Image shows gray ash covering cars and a house
July 18, 2016

Ash Coating from Rabaul Volcanic Eruption

Ash buries cars and buildings after the 1984 eruption of Rabaul, Papua New Guinea. Credit: USGS

July 18, 2016

Inside USGS, No. 6, Ken Pierce, Heavy Breathing of Yellowstone Caldera

Dr. Kenneth Pierce studied the geology and geomorphology of the greater Yellowstone area for nearly his entire career with the U.S. Geological Survey. From 1965 to present, Dr. Pierce has mapped glacial deposits, pioneered Quaternary dating techniques, conducted research on the Yellowstone Hot Spot, studied the geothermal areas, explored the geology of archaeological sites

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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
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Attribution: Yellowstone
Image: Footprints in Ash from 1790 Kilauea Volcano Eruption
March 14, 2016

Footprints in Ash from 1790 Kilauea Volcano Eruption

Footprints made in muddy ash during Kilauea's 1790 eruption are reminders that people experienced the largest explosive eruption in Hawai‘i in 1,000 years. More than 80, and possibly several hundred, people were killed by the eruption soon after the footprints were made.

Satellite image of eruption cloud from Pavlof Volcano in November 2014
November 15, 2014

Satellite image of eruption cloud from Pavlof Volcano in November 2014

Satellite image from the USGS/NASA Landsat-8 satellite showing the eruption cloud at Pavlof Volcano on November 15 at 12:46 pm AKST (21:46 UTC). This is just a portion of the eruption cloud, which extended for more than 250 miles to the northwest at the time this image was collected. In this image, the distance from the erupting vent to the upper left corner of the image

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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).

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).

September 28, 2010

Caldera Demonstration Model

A caldera is a large, usually circular volcanic depression formed when magma is withdrawn or erupted from a shallow underground magma reservoir. It is often difficult to visualize how calderas form. This simple experiment using flour, a balloon, tubing, and a bicycle pump, provides a helpful visualization for caldera formation.

Attribution: Yellowstone
Image: Examining 2008 Eruption of Okmok Volcano in Alaska
July 24, 2010

Examining 2008 Eruption of Okmok Volcano in Alaska

Professor Michael Ort (Northern Arizona University) and graduate student Joel Unema examine deposits from the 2008 eruption of Okmok volcano in Alaska as part of their research to reconstruct the complex history of the eruption.  Dr. Ort has an ARRA-funded cooperative agreement with the USGS through the Volcano Hazards Program.  Photo taken on July 24, 2010 by Dr. Jessica

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Ash is resuspended from Redoubt Volcano eruption
March 28, 2009

Ash is resuspended from Redoubt Volcano eruption

Ash is resuspended from Redoubt Volcano eruption