USGS Volcano Notice - DOI-USGS-YVO-2025-09-02T20:00:45+00:00

Summary

Yellowstone Caldera activity remains at background levels, with 94 located earthquakes in August (largest = M3.7). Deformation measurements indicate that the annual summertime pause in long-term caldera subsidence started in late May.  A small eruption of Black Diamond Pool in Biscuit Basin was recorded by a webcam and other monitoring equipment on August 12.

Recent Work and News

Minor eruptions of Steamboat Geyser in Norris Geyser Basin remain muted, indicating that a major eruption is unlikely anytime soon.  There have only been 2 major eruptions of the geyser so far during 2025, and the period of frequent activity that started in 2018 is probably ending.

The new webcam at Biscuit Basin, installed in mid-May 2025 to track activity at Black Diamond Pool (where a hydrothermal explosion occurred on July 23, 2024), continues to send static images to https://www.usgs.gov/media/webcams/biscuit-basin-webcam.  During August, the webcam captured a small eruption from the pool on August 12 at 8:27 p.m. MDT.  The eruption only threw muddy water about 3 feet (1 meter) into the air, but it was well recorded by the new seismic and acoustic sensors that were established in the area in late July.

During the past month, field engineers from the University of Utah Seismograph Stations performed maintenance and upgrades on several seismic stations in the park.  In September, additional work is planned to repair malfunctioning GPS sites, to recover temporary GPS deployments, to upgrade additional seismic stations, and to hopefully install a new webcam with a view of Yellowstone Lake.

Seismicity

During August 2025, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 94 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 3.7 located about 15 miles northeast of West Yellowstone, Montana, on August 19 at 11:14 a.m. MDT. This event was preceded by 4 foreshocks and followed by 31 aftershocks in August.

August seismicity in Yellowstone was marked by one swarm of 10 earthquakes that occurred August 30–31 approximately 9 miles north-northeast of Old Faithful in Yellowstone National Park. The largest earthquake in the sequence was a magnitude 2.0 on August 30 at 10:39 a.m. MDT.

Yellowstone earthquake activity remains at background levels.

Ground Deformation

Continuous GPS stations in Yellowstone Caldera continue to record the annual summertime pause in subsidence or transition to slight uplift, which is caused by seasonal changes related to snowmelt and groundwater conditions.  Since late May, the caldera has risen by about 1 cm (less than half an inch), which is superimposed on the overall trend of subsidence that has been ongoing since 2015–2016.  Deformation in the area of Norris Geyser Basin also recorded the seasonal uplift, but with no overall changes over the past several years.

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