The Ground Over Yellowstone Is Rising

Yellowstone National Park is renowned for its powerful geysers and hot springs, a testament to the giant super volcano lying beneath it. This super volcano's existence is due to an enormous magma chamber below the park. In 2015, researchers from the University of Utah discovered that this chamber was much larger than previously thought. They even found an additional reservoir of magma beneath the top one. The size of these magma chambers is significant because larger chambers can contain more magma. Together, these two reservoirs hold enough magma to fill the Grand Canyon 11 times over.

One concerning aspect of these magma chambers is their tendency to push against the ground above them, causing Yellowstone's land to rise about 1 to 2 inches each year. Yellowstone is classified as an active volcano, with a volcanic explosivity index (VEI) of 8 out of 8. This rating implies that an eruption would be catastrophic. To put this into perspective, the eruption of Mount Pinatubo in the Philippines in 1991, which was the most powerful eruption in living memory, had a VEI of 6.

In March 2023, the University of Utah Seismograph Stations recorded 354 earthquakes in the Yellowstone region. While this number might seem high, the most significant event was a minor earthquake of magnitude 3.7, part of a swarm of 106 earthquakes that began on March 29 and continued until the end of the month. Earthquake swarms are not unusual for Yellowstone, and although the seismic activity is slightly higher than usual, it is not considered alarming.

Michael Poland, a geophysicist at the Yellowstone Volcano Observatory, reassures that the volcano is not expected to erupt anytime soon. For an eruption to occur, there must be sufficient magma beneath the surface and enough pressure to cause it to rise, neither of which are present today. However, Poland and his team continuously monitor various indicators of potential eruptions, such as earthquake frequency, ground deformation, changes in geyser activity, and thermal emissions.

Despite sensational media claims that Yellowstone is overdue for an eruption since the last one occurred 70,000 years ago, experts clarify that volcanoes do not operate on predictable timelines. If a super eruption were to happen, the most devastating consequence would not be the lava flows or the accompanying earthquakes, but the ashfall. Historical eruptions of Yellowstone have shown that the ash and dust released can cover vast areas and cause significant environmental and climatic effects.

The most powerful eruption in Yellowstone's history was 2,500 times more destructive than the 1980 eruption of Mount St. Helens. The most recent major eruption, the Lava Creek eruption, formed the Yellowstone Caldera and expelled an enormous amount of volcanic material into the atmosphere. Scientists have also discovered two other significant eruptions that occurred around 9 and 8.7 million years ago, with the younger one being the largest recorded event in the Snake River-Yellowstone volcanic province.

Millions of years ago, the signs of an impending eruption at Yellowstone were apparent long before the actual event. Heat from within the Earth melted rock beneath the crust, creating large magma chambers filled with pressurized molten rock, water vapor, and gases like carbon dioxide. As more magma accumulated, the land above these chambers gradually rose. Minor earthquakes became more frequent, and the ground temperature increased, causing surface lakes and groundwater to warm. Steam began to rise, and the ground around the volcano lifted, creating a dome-shaped uplift.

Narrow cracks formed along the edges of this uplift, releasing pressure from the magma chamber. This process is comparable to shaking a bottle of soda and then opening it, with the magma rising toward the surface. The roof of the magma chamber eventually gave way, leading to a massive eruption. The eruption spewed lava, ash, and volcanic gases into the air, creating a pyroclastic flow—a deadly mixture of hot lava, ash, and gases moving at hurricane speeds. The ashfall from the eruption covered vast areas, causing temperatures to drop globally due to sulfur blocking sunlight. The aftermath included a "volcanic winter," with no summer for several years, leading to widespread food and water shortages.

If such an eruption occurred today, it would devastate large regions of the United States, covering states like Colorado, Utah, and Wyoming with up to three feet of ash. The ash cloud would cause darkness, destroy crops, contaminate water supplies, and damage infrastructure. Fortunately, such a disaster is not expected to happen anytime soon, allowing us to focus on other challenges.