Instruments from the US Geological Survey (USGS) have detected ground uplift of 1.5-2 centimeters along the northern edge of the caldera of the Yellowstone supervolcano in the historic National Park in the United States. The anomaly was recorded in July 2025 and confirmed by radar and GPS detections, but only recently did the USGS release the statement. The question therefore arises spontaneously: should we worry?
Dr. Michael Poland, USGS geophysicist and head of the Yellowstone Volcano Observatory, underlined that this deformation is part of the normal behavior of the caldera, which over the last hundred years has alternated rising and falling ground. The movements can be caused by magmatic activity, fault shifts, or changes in underground hydrothermal fluids.
A history of deformations already known
The affected area is located just south of the Norris Geyser Basin, one of the most active and hottest areas of the supervolcano. Here, between 1996 and 2004, an uplift of 12 centimeters occurred, called the “Norris Uplift Anomaly” (NUA), due to the accumulation of magma at about 14 kilometers of depth. After 2004, the ground subsided and then remained stable until 2013, when it began to show alternating phases of uplift and subsidence due to water released from the magma.
Thanks to modern instruments such as interferometric synthetic aperture radar (InSAR) and GPS stations, the new 2-centimeter lift was intercepted precisely. Although accompanied by a slight increase in seismic activity, there were fewer earthquakes than usual in 2025, with a maximum of magnitude 2.7 recorded in November.
No imminent alarm
Geophysicist Poland reassures that, at the moment, there are no signs of an imminent eruption. Yellowstone remains an active giant, with geysers, fumaroles and earthquakes, but current deformation is modest compared to other volcanic systems. Any catastrophic eruption would require a drastic acceleration of deformation rates, monitorable in real time by GPS networks.
The risks of a supervolcano
The real danger of supervolcanoes such as Yellowstone, Toba or Campi Flegrei is not only the eruption itself, but the global impact it can have. Ash and gases released into the atmosphere can obscure sunlight, causing a “volcanic winter” with plummeting temperatures, effects on photosynthesis and serious consequences for the biosphere and humanity. Yellowstone’s last effusive eruption was 70,000 years ago, while the most violent eruptions occurred between 2.1 million and 630,000 years ago.
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