While visitors flock to see popular features like Old Faithful and captivating hot springs, it's the vast underground network of hydrothermal activity responsible for these sights that truly defines the park’s wonder. 

Over the past 2.1 million years, Yellowstone has experienced three massive eruptions–about 2 million, 1.3 million, and 631,000 years ago. Together, they released enough ash to fill the Grand Canyon. Satellites can now spot plumes of ash and gas from volcanic eruptions, and these ancient blasts would have been just as visible from space.

And even today, the park is still very active, but far from a doomsday eruption. Beneath Yellowstone’s surface lies a complex system of magma chambers, fault lines, and hot water that fuels more than 10,000 thermal features–the highest concentration on Earth.

While the park's natural wonders are known and experienced by millions from around the world, it’s still the supervolcano that often captures the public imagination, especially the idea that it’s “overdue” for a catastrophic eruption. But despite the dramatic headlines, scientists say that narrative is misleading. “It’s not overdue, and it can’t erupt without warning,” says Dr. Mike Poland, a geophysicist with the United States Geological Survey (USGS) and Scientist-in-Charge at the Yellowstone Volcano Observatory.

In reality, the most immediate hazard at Yellowstone isn’t a massive volcanic eruption, it’s something far more sudden and unpredictable. Before a volcano erupts, magma moves upward, cracking rock, triggering earthquakes, and releasing gases like carbon dioxide and sulfur dioxide. A potential hazard to the over 4.5 million people that visit Yellowstone every year.

These signs emerge long before any eruption, which is why monitoring them is crucial. Currently, Yellowstone’s magma chamber is nearly too “frozen” to erupt meaning the molten rock is dense and mostly solid, limiting its mobility.

For Poland and the team in charge of monitoring Yellowstone, no two days are the same. Some mornings begin with hauling gear to install GPS stations that track the ground’s tiniest movements. Other days involve collecting microgravity readings to detect shifts in magma or underground fluids. Poland’s team also maintains seismometers across the park to record constant earthquake activity.

In September 2025 alone, 87 minor earthquakes were recorded at Yellowstone, which is normal. In a typical year, 1,500-2,500 earthquakes are located throughout the area, but 99% are magnitude 2 or less and never felt.  

Satellites orbiting overhead add another layer of observation. Radar satellites using InSAR (Interferometric Synthetic Aperture Radar) detect even millimeter-scale rises or sags in the ground, showing how magma and hydrothermal fluids accumulate and drain beneath the surface. 

High-resolution visible imagery provides views of Yellowstone’s surface features from the vantage point of space, helping scientists spot subtle changes in geysers, hot springs, and vegetation patterns. Thermal imaging adds yet another dimension and reveals heat anomalies invisible to the naked eye. In 2018, thermal satellites uncovered a hotspot that had developed in Yellowstone in the early 2000s in Yellowstone, a reminder that even well-studied areas can hide new surprises. This data is available for anyone to access and download.

Some of the tools being used to monitor Yellowstone verge on science fiction. Infrasound detectors, for example, can “hear” explosions miles away, even in remote corners of the park where no one is around to witness them. This means that when a hot spring suddenly bursts into a geyser-like eruption or a hydrothermal explosion rips through the ground, scientists don’t have to rely on chance to catch it because they already have the signal. “Our goal is to install more of that sort of sensor around Yellowstone, and our hope is that we will be able to hear some explosions in the backcountry or that occur at weird times that you wouldn’t otherwise know about, and that will help us better characterize the hazard,” Poland says. 

Together, these technologies create one of the most advanced volcano monitoring networks on Earth, giving scientists a front-row seat to Yellowstone’s dynamic underground world. While many imagine Yellowstone’s biggest threat as a catastrophic super-eruption, scientists like Poland are far more concerned with smaller, sudden hazards—like hydrothermal explosions—that can happen without warning. 

Poland recalls July 23rd, 2024, when an unexpected alert landed in his inbox: a hydrothermal explosion had just rocked Biscuit Basin. In an instant, superheated water and rocks blasted 400–600 feet into the air, scattering debris and tearing apart the nearby boardwalk. The event struck without warning, a reminder that Yellowstone’s most immediate hazards are often sudden and unpredictable. Fortunately, no one was injured.

Imagine a pot of water on a stove with the lid sealed tight. As the water heats, it turns to steam, pushing on the lid. Now imagine that underground, where water seeps into hot rock. Trapped steam builds pressure until it suddenly escapes—BOOM!—blasting through the ground.

Another risk scientists keep a close eye on are earthquakes, which are not related to the Yellowstone volcano, but rather all of the tectonic faults in the region. In Yellowstone, the most serious concern would be a magnitude 7 event, powerful enough to cause widespread damage. Unlike volcanic activity, there’s currently no way to forecast major earthquakes in advance. Still, the USGS is pushing forward with an earthquake early warning system, which is technology that can send out alerts to people and devices seconds before shaking arrives, giving communities just enough time to take protective action.

In 1959, a magnitude 7.3 earthquake occurred just west of Yellowstone. To this day, it is still the largest earthquake ever recorded in the intermountain west. 

By combining fieldwork, satellite data, and continuous monitoring, the nine state and federal agencies that make up the Yellowstone Volcano Observatory work together to detect changes in the area’s geological system.  

Yellowstone is a dynamic, closely watched system that helps scientists better understand how our planet works. It’s this integration of new technology and boots-on-the-ground science that keeps the millions of visitors who flock there each year, safe. The ground may rumble and the geysers will roar, but the real story of Yellowstone is vigilance, discovery, and the remarkable science happening just beneath our feet. 

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Emily Furfaro is the co-founder and Executive Director of Dark Sky Creative Agency where she helps mission-driven teams tell big, bold stories. Before that, she led digital strategy and storytelling at NASA, shaping how the agency shares its science with the world. She’s worked on Emmy and Webby Award–winning projects, helped NASA’s eclipse coverage go global, and guided digital campaigns that reached hundreds of millions. Emily’s background spans creative direction, change management, and executive comms—and she’s all about making complex ideas feel human. She got her start in agency life and public service, with stops at Pace Communications and the White House Office of Communications. She holds a B.S. in Public Relations from Appalachian State University.