Newest Volcano Notice Including Yellowstone

Summary

Yellowstone Caldera activity remains at background levels, with 79 located earthquakes in December (largest = M2.7). Deformation measurements indicate subtle uplift along the north caldera rim that appears to have started in July.

Recent Work and News

At least three small eruptions occurred at Black Diamond Pool in Biscuit Basin, site of a hydrothermal explosion in 2024. The eruptions were captured by camera views and infrasound (acoustic) monitoring on December 8, 18, and 20. An eruption of Steamboat Geyser in Norris Geyser Basin occurred on December 31 just after 10 p.m. MST—its third eruption of 2025.

The Yellowstone Volcano Observatory would like to wish everyone a happy and healthy 2026!

Seismicity

During December 2025, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 79 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 2.7 located about 16 miles west-northwest of Lake in Yellowstone National Park on December 31 at 1:44 p.m. MST.

There were no swarms identified during December.

Earthquake activity in Yellowstone is at background levels.

Ground Deformation

Continuous and semipermanent GPS stations, along with satellite interferometric synthetic aperture radar (InSAR), indicate uplift of 2–3 cm (about 1 inch) centered on the north caldera rim to the south of Norris Geyser Basin.  The deformation, which started in July but could only recently be distinguished from seasonal signals, is similar to that which occurred during 1996–2004.  In Yellowstone Caldera, the interruption of long-term subsidence by seasonal summertime uplift, which usually ends in the fall, continued through the end of the year.  In places, uplift since May has reached about 2 cm (less than an inch).  Whether this is an unusually long-lasting seasonal signal or a transition from overall subsidence to uplift is not clear.  The most recent phase of caldera subsidence began in 2015, but prior to that there were periods of uplift during 2004–2009 and 2014–2015.

An example of GPS data can be found at http://www.unavco.org/instrumentation/networks/status/pbo/data/NRWY (click on Static Plots / Cleaned)