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

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?

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. Eruptions of that size generally create a circular collapse feature called a caldera . The largest eruption at...

When was the last time there was volcanism at Yellowstone?

The most recent volcanic activity 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 about the eruptive history of Yellowstone at our Yellowstone Volcano Observatory website .

Are earthquakes at Yellowstone related to volcanism?

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...

What was the extent of ash deposition from the largest Yellowstone eruptions?

During the three giant, caldera-forming eruptions that occurred between 2.1 million and 640,000 years ago, tiny particles of volcanic debris (volcanic ash) covered much of the western half of North America. That ash was likely a third of a meter deep several hundred kilometers from Yellowstone and several centimeters thick farther away ( see this...

How large is the magma chamber that is currently 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 beneath the surface and is about 90 km long and about 40 km wide. The chamber is mostly solid, with only about 5-15% melt. The deeper reservoir is composed of basalt (a low-silica rick type) and...

What type of eruption will occur if Yellowstone 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 take place 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...

Can you release some of the pressure at Yellowstone by drilling into the volcano?

Scientists agree that drilling into a volcano would be of questionable usefulness. In addition to the enormous expense and technological difficulties in drilling through hot, mushy rock, drilling is unlikely to have much effect. At near magmatic temperatures and pressures, any hole would rapidly become sealed by minerals crystallizing from the...

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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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

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
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

Attribution: Natural Hazards, Alaska
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.

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

Attribution: Natural Hazards
Ash is resuspended from Redoubt Volcano eruption
March 28, 2009

Ash is resuspended from Redoubt Volcano eruption

Ash is resuspended from Redoubt Volcano eruption

Attribution: Natural Hazards, Alaska