- 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.
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.
Related
What is a supervolcano? What is a supereruption?
What would happen if a "supervolcano" eruption occurred again at Yellowstone?
When was the last time Yellowstone erupted?
How do scientists know what’s going on beneath the ground at Yellowstone? Is Yellowstone monitored for volcanic activity?
Can we drill into Yellowstone to stop it from erupting?
Could a large Yellowstone eruption significantly change the climate?
How much volcanic activity has there been at Yellowstone since the most recent giant eruption?
How far in advance could scientists predict an eruption of the Yellowstone volcano?

- 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.

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).
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).
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:
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:

Hydrothermal explosion at Biscuit Basin in Yellowstone National Park. These types of events are the most likely explosive hazard from the Yellowstone Volcano.
Hydrothermal explosion at Biscuit Basin in Yellowstone National Park. These types of events are the most likely explosive hazard from the Yellowstone Volcano.
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 earthquakes and
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 earthquakes and
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 possible erupt
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 possible erupt
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?"
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?"
Geologic field-trip guide to the volcanic and hydrothermal landscape of the Yellowstone Plateau
Hydrogeology of the Old Faithful area, Yellowstone National Park, Wyoming, and its relevance to natural resources and infrastructure
Protocols for geologic hazards response by the Yellowstone Volcano Observatory
Geologic hazards at volcanoes
Steam explosions, earthquakes, and volcanic eruptions -- what's in Yellowstone's future?
Tracking changes in Yellowstone's restless volcanic system
Living with volcanoes
Related
What is a supervolcano? What is a supereruption?
What would happen if a "supervolcano" eruption occurred again at Yellowstone?
When was the last time Yellowstone erupted?
How do scientists know what’s going on beneath the ground at Yellowstone? Is Yellowstone monitored for volcanic activity?
Can we drill into Yellowstone to stop it from erupting?
Could a large Yellowstone eruption significantly change the climate?
How much volcanic activity has there been at Yellowstone since the most recent giant eruption?
How far in advance could scientists predict an eruption of the Yellowstone volcano?

- 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 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.

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).
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).
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:
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:

Hydrothermal explosion at Biscuit Basin in Yellowstone National Park. These types of events are the most likely explosive hazard from the Yellowstone Volcano.
Hydrothermal explosion at Biscuit Basin in Yellowstone National Park. These types of events are the most likely explosive hazard from the Yellowstone Volcano.
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 earthquakes and
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 earthquakes and
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 possible erupt
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 possible erupt
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?"
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?"