Sapphire Pool, in Biscuit Basin, steams on a stormy morning. A few “biscuits” remain along the pool’s southern edge (center right of photo) – violent geyser eruptions destroyed hundreds of the features when the pool’s plumbing system changed after being jarred by the 1959 Hebgen Lake earthquake. National Park Service photo by Jacob W. Frank, July 20, 2020.
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 (a low-silica rock type) and extends from 20 to 50 km (12 to 30 mi) beneath the surface. Even though the deeper chamber is about 4.5 times larger than the shallow chamber, it contains only about 2% melt.
The method that scientists use to discern this information is similar to medical CT scans that bounce X-rays through the human body to make three-dimensional pictures of internal tissue. In an analogous manner, a method called seismic tomography uses hundreds to thousands of earthquakes recorded by dozens of stations to measure the speed of seismic waves through the Earth--data that allow geophysicists to make three-dimensional pictures of structures beneath the surface. Scientists compare these seismic velocities and infer the composition by comparing them with average, thermally undisturbed values.
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Related
What is the difference between "magma" and "lava"?
Can an eruption at one volcano trigger an eruption at another volcano?
How can we tell when a volcano will erupt?
Can earthquakes trigger volcanic eruptions?
Can we use the heat from Yellowstone for energy?
Can we drill into Yellowstone to stop it from erupting?
How far in advance could scientists predict an eruption of the Yellowstone volcano?
How do scientists know what’s going on beneath the ground at Yellowstone? Is Yellowstone monitored for volcanic activity?
What type of eruption will Yellowstone have if it erupts again?
Sapphire Pool, in Biscuit Basin, steams on a stormy morning. A few “biscuits” remain along the pool’s southern edge (center right of photo) – violent geyser eruptions destroyed hundreds of the features when the pool’s plumbing system changed after being jarred by the 1959 Hebgen Lake earthquake. National Park Service photo by Jacob W. Frank, July 20, 2020.

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.
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.

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).
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.
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.
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?"
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 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
Geologic field-trip guide to the volcanic and hydrothermal landscape of the Yellowstone Plateau
Steam explosions, earthquakes, and volcanic eruptions -- what's in Yellowstone's future?
Tracking changes in Yellowstone's restless volcanic system
The Quaternary and Pliocene Yellowstone Plateau volcanic field of Wyoming, Idaho, and Montana
Teleseismic studies indicate existence of deep magma chamber below Yellowstone National Park
Related
What is the difference between "magma" and "lava"?
Can an eruption at one volcano trigger an eruption at another volcano?
How can we tell when a volcano will erupt?
Can earthquakes trigger volcanic eruptions?
Can we use the heat from Yellowstone for energy?
Can we drill into Yellowstone to stop it from erupting?
How far in advance could scientists predict an eruption of the Yellowstone volcano?
How do scientists know what’s going on beneath the ground at Yellowstone? Is Yellowstone monitored for volcanic activity?
What type of eruption will Yellowstone have if it erupts again?
Sapphire Pool, in Biscuit Basin, steams on a stormy morning. A few “biscuits” remain along the pool’s southern edge (center right of photo) – violent geyser eruptions destroyed hundreds of the features when the pool’s plumbing system changed after being jarred by the 1959 Hebgen Lake earthquake. National Park Service photo by Jacob W. Frank, July 20, 2020.
Sapphire Pool, in Biscuit Basin, steams on a stormy morning. A few “biscuits” remain along the pool’s southern edge (center right of photo) – violent geyser eruptions destroyed hundreds of the features when the pool’s plumbing system changed after being jarred by the 1959 Hebgen Lake earthquake. National Park Service photo by Jacob W. Frank, July 20, 2020.

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.
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.

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).
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.
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.
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?"
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 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