Yellowstone: The National Park and the Supervolcano

The total amount of heat generated around Yellowstone is 5,500 MW, which is more than a big nuclear power station can produce.

Every year, around 5 million tourists from all around the world go to Yellowstone National Park. One of the most visited places in the United States due to its abundance of geysers, hot springs, and boiling mud pots in the midst of a picturesque environment. Very few tourists, however, are aware that they are literally standing on a giant liquid time bomb. One of the most devastating and mysterious natural occurrences on Earth is hiding far below the surface: a supervolcano.

There are just a few of them, but when they do erupt, the results will be unlike anything witnessed in volcanic history. The earth will tremble and quake as a result of an explosion whose roar may be heard from every corner of the planet. The clouds will become dark, black rain will descend on Earth, and a volcanic winter will set up throughout the globe.

National Park of Yellowstone

A picture-perfect Rocky Mountain retreat

rocky mountains yellowstone
Yellowstone Falls, Yellowstone National Park, Montana. (Credit: dszc/Getty Images)

Established on March 1, 1872, Yellowstone National Park is the biggest national park in the United States and the oldest in the world. Millions of people from all over the world visit Yellowstone each year because of its picturesque location on a high plateau in the Rocky Mountains in the US state of Wyoming.

The government has known since 1872 that this special area has to be preserved for future generations. Yellowstone Lake, which sits at an astoundingly high altitude of between 6,900 ft and 8,200 ft (2,100 m and 2,500 m), is surrounded by verdant coniferous trees and a plethora of smaller lakes, all of which provide a stunning background. Streams teeming with trout may be seen winding their way through canyons, valleys, and up and down plateaus.

Wildlife in Yellowstone National Park is quite varied. Bison, elk, wapitis, pronghorn, bighorn sheep, grizzly and black bears, coyotes, cougars, and lynx all have a safe place to roam free and breed in this nature preserve. Large avian species, including bald eagles and Canadian cranes, find a safe haven in the Yellowstone Park. This refuge is home to every species, and some of them even spend the winter here.

Yellowstone Geyser
Castle Geyser in Yellowstone National Park. Image: Peng Zhuang/Dreamstime.

When the Yellowstone National Park was first established in 1872, coniferous woods occupied the majority of the land. The trees in the forest were so close together that they were really suffocating one another. Several years of drought have contributed to the forest’s overage and dryness. A third of the park’s woodland was lost to out-of-control fires in 1988.

The Yellowstone Park no longer looks the same because of these fires. Where the fires once raged, a thriving new forest is taking root. However, due to its high elevation (the elevation of the Yellowstone Caldera is 9,203 ft or 2,805 m) and long, snowy winters, the park will likely take another 30 years or more to reclaim its previous beauty.

However, Yellowstone’s thermal features are the park’s largest draw. The region is a natural wonder due to the concentration of geysers, hot springs, fumaroles (openings from which volcanic gases erupt), and boiling mud pots that is unmatched anywhere else in the world.

A sinister truth lies behind the park’s seemingly perfect surface. Thermal activity is caused by a massive magma chamber underneath the structure. The area where the nature reserve now stands lies atop what was once a supervolcano that has, throughout Earth’s history, erupted on a regular basis and is now overdue for another eruption.

Yellowstone Caldera

The current status

Yellowstones Midway Geyser Basin
Yellowstone’s Midway Geyser Basin with Grand Prismatic Spring and Excelsior Geyser Crater and nearby Firehole River. Image: US Geological Survey.

As natural disasters go, supervolcanoes are up there with the worst of them. In contrast to the typical volcanoes whose explosions humans have seen, these are something entirely new.

Volcanoes are often created when a column of magma rises from deep inside the Earth and erupts at the surface. As it flows away from the vent, the lava cools and solidifies on its sides. This causes the cone to take on the standard form of a volcano. Whenever additional material is deposited on the mountain slopes, the volcano expands.

A supervolcano is born when magma emerges from the Earth’s mantle and builds up in the planet’s crust. More rock melts as a result of the heat from these magma masses, creating a regular chamber under the surface of the Earth that is filled with lava.

Due to the chamber’s growth caused by the continuously replenishing magma masses, the internal pressure is always increasing. There are also highly pressurized gases trapped in the rock pulp, which amplify the phenomenon. Therefore, the whole magma chamber looks like a big pressure cooker that has been set on high heat.

The magma currents deep inside the Earth cause the chamber to expand and compress with periodicity. Long-term changes in the surface elevation of the Earth are observable as a result of these tectonic shifts. Small earthquakes often jolt this area, making the lid more porous and fragile.

The magma eventually rises to the surface of the planet, passing through the top limit of the chamber. Liquid rock masses continue to pour in as it reaches the surface, the surface layer ruptures in several places, and the supervolcano continues to push inexorably toward its eruption.

Yellowstone Supervolcano

Lava and ash fall like rain from hell

yellowstone supervolcano infographic
National Geographic Infographics on Yellowstone Caldera evolution since 18 million years.

The thin, porous top layer of the magma cauldron can no longer resist the strain of the magma surging higher and the many earthquakes. The volcano explodes once the magma reaches the surface.

When the surface of the Earth bulges as far as it can under the pressure of the rising magma, fractures suddenly form in several locations at the same time, concentric around the base of the magma cauldron, like a cake whose crust rips in a ring pattern around the edge as it bakes.

The magma chamber is penetrated by fractures and fissures in the Yellowstone Caldera. And when they eventually burst through the chamber’s roof, the Earth will suffer the most devastating volcanic explosion in recorded history. Massive volumes of molten rock, ash, and hot gases will be released in a concentric lava flow as the supervolcano erupts in an explosion that can be heard around the globe, just like it happened before.

The last Yellowstone Supervolcano eruption

The volcano underneath Yellowstone Park last erupted 630,000 years ago, releasing 235 cubic miles (983 cubic kilometers) of volcanic debris into the atmosphere. A sheet of lava 5 inches (13 centimeters) thick could cover the whole United States with this volume of lava. The 1980 eruption of Mount Saint Helens would be dwarfed by the strength of this explosion.

In the terrible rain of lava, blazing rock, and ash, tens of thousands of people would die. Thousands of square miles of land would be covered in molten lava, about 1500 degrees Fahrenheit (800°C), rushing out from the circular fissure in a matter of minutes, wiping out all life. When a supervolcano like the Yellowstone Caldera erupts, it releases energy on par with that of an asteroid strike.

After everything has been brought to the surface, the subsurface magma chamber of the Yellowstone Supervolcano empties, and the pressure drops. Since there is nothing holding up the floor anymore, the empty chamber becomes unstable, and the weight of the lava that has been ejected into the cavity causes the ceiling to increase in mass. The top layer eventually collapses entirely, moving in tandem with the ring fracture. The resulting Yellowstone Caldera today is a massive, bowl-shaped valley.

You’ll have a tough time finding this Yellowstone Caldera on the ground. However, the caldera’s length is 45 miles (70 kilometers) and its width is 30 miles (50 kilometers), making it so enormous that its full size can only be appreciated from a bird’s-eye view or through satellite imagery. However, molten rock continued to flow to the surface when the magma cauldron collapsed, filling the crater again to a lesser degree with the rock masses on which the modern Yellowstone National Park is situated.

Consequences of the Yellowstone Supervolcano eruption

Mass extinction and a volcanic winter on a global scale

yellowstone supervolcano eruption 1
Hawaii’s Kilauea volcano erupting in 2018. Image: USGS/Planet Pix/Zuma Press

An eruption of such a Yellowstone Supervolcano in the present day would have catastrophic results. A worldwide volcanic winter, the likes of which contemporary mankind has never seen.

About 50 small volcanoes throughout the world go off every year, but only a few of them ever cause widespread damage. Scientists have determined that the global average temperature dropped by 0.5 degrees Celsius (0.9 degrees Fahrenheit) after the 1991 eruption of Pinatubo in the Philippines. When Tambora erupted in Indonesia in 1815, the repercussions were even more severe.

As a consequence, temperatures throughout the planet plummeted, with Europe seeing a decrease of around 4.5 degrees Fahrenheit (2.5 degrees Celsius) on average. This temperature shift brought summer snow to the United States the next year, and the years leading up to 1819 are now remembered as the coldest on record for the northern hemisphere.

Ash and sulfur gases are blasted into the stratosphere during a volcanic eruption, where they combine with atmospheric water vapor to generate sulfuric acid aerosols. This ash smog has the potential to travel across the world, altering weather patterns everywhere. The atmosphere is well shielded from the sun by a layer of ash and sulfur compounds. The surface of the planet cools as a result. A nuclear winter is a comparable situation that will occur following a nuclear war.

After extensive research, scientists have determined that the last time a supervolcano erupted was 74,000 years ago. Caldera dimensions of 60 mi (100 km) in length and 37 mi (60) km in width were left after the eruption of Toba in Sumatra. Modern-day Lake Toba has covered this area.

An estimated three thousand cubic kilometers (720 cubic miles) of lava and ash were released at that time. Ashes in the atmosphere have likely lowered global temperatures by 9 degrees Fahrenheit (5 degrees Celsius). If temperatures were continued to drop so far, Western Europe, where the Gulf Stream has kept things relatively warm, would have a climate more akin to Siberia.

It’s probable that the Toba disaster almost wiped out that era’s human population. Volcanic eruptions and meteorite strikes cause dramatic shifts in the global climate, which in turn cause mass extinctions. Based on genetic research, scientists have shown that our ancestors were almost wiped out by a catastrophic event at least once in our species’ past.

The Toba disaster and the great human extinction both started in the same period, between 70,000 and 80,000 years ago. Five thousand to ten thousand people were all that was left of humanity at the time. There is a possibility that the Toba volcano eruption was the cause of this, although this cannot be proven without more research.

Similar outcomes are possible if Yellowstone Supervolcano were to explode. Ash would blanket the area like snow for thousands of miles. Grain stored in the world’s huge granaries wouldn’t ripen if the climatic zones shifted drastically. This might lead to crop failure and global hunger for many years. Therefore, millions, if not billions, of people throughout the globe might perish as a direct consequence of the Yellowstone Supervolcano’s eruption.

Once every 600,000 years, a catastrophe occurs

The past biggest Yellowstone eruptions

yellowstone eruptions locations

There is a little outward indication of Yellowstone National Park’s volcanic nature. Geysers, hot springs, and fumaroles are the only signs that everything is not as peaceful below the Yellowstone as it seems above ground.

When it comes to the Earth’s mantle, Yellowstone is located in a confined melting zone, or hotspot. Most volcanic activity on Earth occurs near plate borders. However, there are a few locations where eruptions occur on both plates at once. Scientists have discovered that they sit above stationary magma pools. As the magma breaks through the earth’s crust, it triggers volcanic eruptions at roughly regular intervals.

Volcanic eruptions often follow one another in a chain because the magma chambers in the Earth’s crust are immobile but the continental plates move over them. Magma flows erode the Earth’s crust at regular intervals, like placing a sheet of paper over a burning flame and scorching a hole in it. For instance, this is how the volcanic islands of Hawaii came to be, arranged so beautifully like a string of pearls across the Pacific.

The area around the Yellowstone National Park has remnants of previous super-eruptions. Layers of ancient, brittle volcanic ash measuring feet in thickness attest to eruptions from epochs long since gone. The geologic dating of these lava layers has led scientists to conclude that the magma chamber under Yellowstone has brought unfathomable quantities of liquid rock to the surface of the planet on at least three separate occasions in the past:

Three main eruptions

It has been estimated that the first Yellowstone eruption occurred about 2,000,000 years ago. The second time the volcano erupted was 1,300,000 years ago in prehistoric times, and the third and final eruption was 630,000 years ago, creating the caldera in which most of modern-day Yellowstone National Park is situated.

In fact, three separate calderas are found around the Yellowstone, further substantiating these results. In fact, the caldera that makes up the majority of Yellowstone as we know it today is all that’s left behind from the most recent eruption. There are a total of two more calderas in close proximity to the current crater.

The Snake River Plain to the west has six other calderas, with ages that increase from southwest to northeast. Calderas in Yellowstone connect to these in a continuous manner. These findings provide solid evidence for how the continental plate has been moving over the Yellowstone hotspot.

There is a regular cycle of roughly 600,000 years due to the supervolcano’s three eruptions. Scientists studying Earth believe that this pattern will continue and that another eruption will occur 600,000 years after the previous one. As a result, it’s safe to assume that the next eruption is long overdue and will cause a disaster of unprecedented proportions.

Historical eruptions in Yellowstone National Park

Earthquakes and volcanism

Late 19th-century fieldwork led to the first scientific reports of Yellowstone’s volcanism and earthquakes. Numerous mild-to-moderate earthquakes have already led geologists to conclude that the Yellowstone area was at the epicenter of a massive volcanic system.

The 1959 Hebgen Lake earthquake sparked a surge in scientific interest in the area, which resulted in a slew of subsequent geological research. It was the strongest earthquake ever recorded in this area, with a magnitude of 7.5. Because of this tremor, scientists learned that Yellowstone’s volcanism is both frequent and very powerful.

Of particular note were three catastrophic eruptions that released about 1,150 cubic miles (4,800 cubic kilometers) of volcanic material into the atmosphere. After the first caldera was buried by subsequent lava flows, the Huckleberry Ridge Tuff was created. The second caldera, Henry’s Fork, occurred only in the Island Park region southwest of the Yellowstone Plateau. Since the most recent caldera formed 630,000 years ago, there have been more than 30 more volcanic eruptions on the Yellowstone Plateau, again filling the calderas with fresh layers of rock.

The Yellowstone Plateau’s current mountainous, wooded landscape is the result of a series of eruptions that happened after the last caldera formed. Sour Creek Dome, in the northeast of the caldera, erupted after the major eruption, while Mallard Lake Dome, in the south of the caldera, developed 150,000 years ago as a result of the outpouring of magma there.

Both of these features are considered to be active volcanic regions since they were created by magma outflow. The explosive eruption caused the Yellowstone Caldera to collapse several hundred feet before being refilled by lava flows and silt.

When will the next Yellowstone eruption occur?

GPS measurements in the Yellowstone

According to volcanologists, the supervolcano under Yellowstone Park is predicted to erupt at some time. When will it finally erupt? The next Yellowstone eruption might happen next year, in 100 years, or not for 1,000 years, due to the volcano’s very long cycle of 600,000 years.

Consequently, scientists have been monitoring the area for quite some time. The park is equipped with seismographic stations that record any and all earthquakes. According to the data collected, hundreds of earthquakes are recorded every year beneath Yellowstone Park. However, the vast majority of them are extremely small, making detection impossible without specially designed instruments.

However, stronger earthquakes do sometimes disturb the wildlife reserve. As an example, a 7.5-magnitude earthquake rocked the neighborhood in and surrounding the park in 1959. However, it’s clear that the subsoil is incredibly active and boiling under the surface, as shown by the frequent earthquakes and tremors.

By examining the sound waves of these earthquakes as they travel through the crust, geologists may learn a lot about the size and composition of the magma chamber underneath the earth’s crust. The velocity of seismic waves varies with the medium through which they travel. This information led them to the conclusion that the reservoir must be quite large. The chamber is around 25–30 miles (40–50 km) in length, 12–18 miles (20–30 km) in width, and 6–9 miles (10–15 km) in depth.

Additionally, GPS stations can be found at various locations across the park. Scientists believe that changes in ground elevation can be detected if the pressure in the magma chamber fluctuated over time. The earth underneath Yellowstone Park seems to be breathing since these elevation shifts were identified using GPS. The land rose by 30 inches (74 cm) between 1923 and 1985, then dropped somewhat until 1995, and has once again been arching upwards since then. Today in 2022, an injection of magma under Norris Geyser Basin is the reason why the region is 5 inches (13 cm) higher now than it was 22 years ago. These shifts can only be explained by the presence of a massive, volcanically active magma chamber under the surface.

These studies back up the idea that Yellowstone is a very geologically active place. Since this is a ticking time bomb, the only question is when Yellowstone will go off, plunging the world into an unimaginable tragedy.

Geysers in Yellowstone National Park

Wild, gushing jets of steam

yellowstone giant geyser 2
Yellowstone’s Giant Geyser. Image: Janet Jones,

Yellowstone National Park has more than 200 geysers, more than any other park in the world. They are the primary draw for visitors to the national park and one of the most breathtaking sights in the world. The literal translation of their Icelandic name means “gusher.” The biggest geysers really show their stuff when they erupt with huge streams of boiling water and vapor.

Typically found in the vicinity of active volcanoes or relatively new volcanic rock formations, geysers are a kind of groundwater phenomenon. They are sections of massive groundwater networks that go deep underground. There are several forks in the channels, and the water has to force its way through many narrow passages and over many barriers on its ascent. This is what sets geysers apart from naturally heated springs, where the water may rise to the top without any obstructions.

Deeper water warms up when it comes into contact with heated rock, like in Yellowstone’s subsurface magma chamber. Water at enormous depths is heated to temperatures considerably beyond the point at which it would boil if brought to the surface under normal pressure. However, it does not boil because the water column above it exerts pressure on it, raising the boiling point. This results in water that is still liquid despite being between 300 and 340 degrees Fahrenheit (150 and 170 degrees Celsius) in temperature.

But hot water is less dense than cold water. The heated water steadily rises to the surface as a result. Rising water boils because its pressure drops as it moves higher in the water column. Water rushes out of the geyser hole at the surface as the boiling water expands, relieving pressure in the water column. All of the water in the geyser boils at once, and the geyser erupts in a cloud of steam and scalding water.

The length of the heating phase and the rate of water input determine the interval between eruptions. Some geysers only slumber for a few minutes, while others might go dormant for months or even years before erupting on an unsuspecting populace.

The greatest geyser in Yellowstone Park and the second largest active geyser in the world, the Giant Geyser blasted a record 48 times in 2019 and then came to a sudden end in 2022. While other Yellowstone geysers can be timed to the minute. Old Faithful, the most well-known geyser in the Yellowstone Park, erupts with a water column 105 feet (32 meters) high on average every 80 minutes.

The height of the steam fountain varies considerably. While most geysers only shoot water a few inches high, the Giant’s fountain is over 200 feet (60 meters high) and can be seen from miles away. Waimangu, in New Zealand, is the biggest geyser ever recorded. During its most explosive period, it sent 1,480 feet (450-meter) high streams of steam, murky water, and shards of rock into the air.

There aren’t many places in the world where you can see geysers like in Yellowstone National Park. But the highest concentration of geysers are found in the mountains of Iceland, New Zealand, Chile, Indonesia, and Kamchatka.

Fumaroles and other forms of thermal activity in Yellowstone

Sulfur-emitting fissures and boiling mud

boilin mud yellowstone 1
Sulphur Caldron, Yellowstone National Park.

The Yellowstone geysers are the most impressive examples of post volcanic phenomena. However, there is growing evidence that the underground was formed by volcanoes. The geological diversity of the park is further attested to by features such as sulfur-emitting fumaroles, hot springs, and boiling mud pits.

Hot spring water is warmed by deep circulation and by the rock underneath it. This kind of formation occurs when water is allowed to ascend without being stopped. In contrast to geysers, this one has no obstructions to overcome before reaching the top. Instead of erupting violently, the hot water springs slowly out of the ground.

Yellowstone is home to springs ranging in size from only a few millimeters to over 15 meters in circumference. Some are “cool,” with temperatures of between 120 and 145 degrees Fahrenheit (50 and 60 degrees Celsius), while in others, water boils. The “Grand Prismatic Spring” in Yellowstone is the biggest hot spring in the park, with a diameter of 165 feet (50 meters) and a flow rate of 2,000 liters per minute.

Sulfuric acid is produced by reacting water with any sulfur compounds that are released in the spring, most notably hydrogen sulfide. Minerals on the spring’s rim and in its funnel are dissolved by this, in addition to the spring’s high temperature. As a result, the water becomes muddy and rainbow-hued, forming a mud volcano. These holes may radiate in any number of hues, depending on the make up of the surrounding chemical components.


Instead of steaming hot water, volcanic gases escape via vents known as fumaroles. When there is a lack of deep water, fumaroles develop. A whole transformation to gas occurs in the water as a result of the absence of pressure. The gases they emit and their temperatures are used to categorize them. These temperatures might be as low as 210°F (100 °C) or as high as 1830°F (1000 °C).

Water vapor is the primary component of the gas released by all fumaroles. However, fumaroles also bring sulfur compounds like hydrogen sulfide to the surface. This causes the yellow coloration of the vents to be instantly recognizable. Carbon dioxide is abundant in fumaroles with temperatures below the boiling point of water. Depending on the local topography, the gas may collect in low spots and form a fatal trap for wildlife and people around the Yellowstone National Park.

A fresh volcanic eruption is typically signaled by a rise in the fumaroles’ temperatures or an abrupt shift in the gas composition. In contrast, a dormant volcano’s absence of fumarolic activity does not rule out its eventual revival. However, there is not enough information about these connections for this knowledge to be used as a predictor of future volcanic eruptions.

The post volcanic thermal phenomena of Yellowstone National Park—including its iconic geysers, hot springs, mud pots, and fumaroles—have attracted visitors from all over the globe.

The total amount of heat generated by these structures around Yellowstone is 5,500 MW, which is more than a big nuclear power station can produce. However, this geothermal energy can’t be used in Yellowstone since the area is protected as a national park.

By Bertie Atkinson

Bertie Atkinson is a history writer at Malevus. He writes about diverse subjects in history, from ancient civilizations to world wars. In his free time, he enjoys reading, watching Netflix, and playing chess.