More ground uplift at Yellowstone

Over the last 10 years or so, I’ve featured numerous articles about the Yellowstone supervolcano. We know that it is located practically in our backyard and any changes related to hydrothermal or ground movement will attract some media attention.

The Yellowstone Caldera in northwestern Wyoming and measures a rather big 34 by 45 miles. It is one of the most closely monitored volcanic systems in the world. Beneath its dramatic geysers, hot springs and steaming vents lies a vast and complex magma system. One of the most fascinating features of this system is a phenomenon known as volcanic uplift. Yellowstone uplift refers to the gradual rising of the Earth’s surface caused by underground movement of magma, hot fluids and tectonic forces. It has recently grabbed some public attention and can spark concern, but uplift is a normal and ongoing part of Yellowstone’s geologic behavior.

According to a recent feature from Popular Science, since last July, there has been a bulge of about an inch across approximately 19 square miles at the northern rim of the Yellowstone Caldera. The news of this recent event has led to some concern that the supervolcano may be getting ready for a new eruption. However, scientists do not seem to be too concerned, as there have been many past instances of ground deformation. For example, between the 1920s and the early 1980s, parts of the caldera rose approximately 28 inches. Another rapid period of uplift occurred between 2004 and 2010, when some areas rose about 10 inches.

Yellowstone sits above a powerful mantle plume called the Yellowstone hotspot. This hotspot supplies heat to the region, melting portions of the crust and creating large reservoirs of partially molten rock beneath the surface. When magma moves into these underground chambers, it can push the overlying ground upward. This process is relatively slow and can occur over months or years. The rising ground may lift only a few inches annually, but over decades or longer, the total change can be significant.

In addition to magma intrusion, hydrothermal activity plays an important role in ground uplift. Yellowstone’s famous geysers and hot springs depend on a vast network of underground water heated by magma. When hot water and gases accumulate in confined spaces, pressure builds. This pressure can cause sections of the ground to swell temporarily. By contrast, when fluids drain away or pressure decreases, the ground may sink, a process known as subsidence. The cycle of uplift and subsidence is common within the caldera and reflects the dynamic nature of the hydrothermal system.

Scientists measure uplift at Yellowstone Caldera using a combination of advanced instruments that detect extremely small changes in the Earth’s surface. Because the ground may rise only a fraction of an inch per year, highly precise technology is required to track these movements accurately.

One of the primary tools is a network of permanent GPS stations placed throughout the Yellowstone caldera. These stations communicate with orbiting satellites to calculate their exact position. By comparing position data over time, scientists can determine whether the ground is rising, sinking or shifting sideways. GPS instruments at Yellowstone can detect vertical changes as small as hundredths of an inch, allowing researchers to monitor even subtle uplift events.

Another important method is satellite radar imaging, known as InSAR (Interferometric Synthetic Aperture Radar). Radar satellites pass over Yellowstone and send signals toward the surface. When the satellite returns on a later date, scientists compare the new radar image to earlier ones. Even tiny changes in elevation create measurable differences in the radar signals. InSAR is especially useful because it covers large areas at once, providing a clear picture of how the entire caldera is deforming.

Seismographs also play a key role. These instruments record earthquakes, including small earthquake swarms that sometimes accompany magma or hot water movement underground. Although seismographs do not directly measure uplift, they help scientists understand what may be causing the ground to rise.

Yellowstone has been infamous for swarms of small earthquakes. On average, there are approximately 2,000 small earthquakes per year. In 2025, there were slightly more than 1,100, according to data from the USGS.

In terms of our local weather, the weather pattern in the Far West has changed as colder air is finally moving southward into the region. Combined with some moisture from the Pacific Ocean, the chances for measurable snowfall in the lower elevations are higher, especially later this week. The long-range computer models are also indicating that the upper-level winds will likely bring occasional snowfall to the Spokane and Coeur d’Alene region through the end of the month, perhaps into early March. As I mentioned last week, the western part of the country is in the middle of a snow drought. So far, about 15 inches of snow has fallen in the Coeur d’Alene region. Cliff Harris and I believe that Coeur d’Alene could end up with seasonal snowfall totals between 30 and 40 inches by April. Stay tuned.

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Contact Randy Mann at [email protected].