There Yellowstone volcano caldera, in Wyoming (United States) it rose 2 cm in its northern edge. The United States Geological Survey (USGS) reported this anomaly, thanks to radar and GPS surveys. The lift was recorded between July and September 2025 and, although it is not remarkable, it must be monitored carefully since Yellowstone (journalistically defined as a “supervolcano”) is one of the most dangerous active volcanoes in the worldwhich it has caused in the past very violent eruptions. The current ground deformation, however, is within the normal behavior of the caldera.
The uplift of the Yellowstone caldera
The uplift was recorded in one of the hottest areas of the caldera, just south of the Norris Geyser Basinwhich has already been subject to deformations in the past. Here between 1996 and 2004 there was a rise of well 12cm. This deformation, which was called “Norris Lift Anomaly” or NUA, at the time was attributed to the accumulation of magma at a depth of about 14 km. After 2004, the area sank by about 7 cm, and then showed an alternation of lifting and lowering between 2013 and 2020 due to the release of water from the magma. Over the following years no particular changes were noted, but a July 2025 GPS stations reported a lifting. This change was confirmed by the radar images of satellites: the comparison between images acquired over the same area at different times provided a precise measurement of ground deformations. Between September and December 2025 the area was also affected by a increase in earthquakeswhich could be a response to lifting.
Why is there no danger of an imminent eruption in Yellowstone?
Recent studies have located beneath the Yellowstone caldera seven magma reservoirs at depths between 4 and 47 km, containing approximately 400km3 of magma. It was also discovered that the magma with the composition most suitable for triggering explosive eruptions, the most dangerous, accumulated above all in the northeastern area of the caldera. Studies so far have determined that Yellowstone’s most violent eruptions occur at approximately every 700,000-900,000 years (according to the most recent research even up to 1.5 million years). Whereas the last violent eruption occurred approximately 640,000 years agoeven if the quantity of magma present under the caldera is currently notable, it should not however constitute a cause for alarm. This does not mean that they could take place in the meantime more modest eruptionsof an effusive type. However, the recent deformation, caused by mechanisms such as the accumulation of magma or fluids of magmatic origin, does not raise concerns since it is small entity. It only highlights that Yellowstone is an active and dynamic system, as evidenced by its intensities hydrothermal manifestationssuch as geysers and hot springs. Through these phenomena, the fluid pressure circulating underground decreases and with it also the probability of an explosive volcanic eruption occurring. The mechanism that keeps the caldera “under control” is linked to the presence, at 3.8 km depth in the north-eastern area, of a particularly porous and partially molten layer which acts as a “plug” of the magmatic reservoir but also as a relief valve, allowing the release of gases.
