Hazard Notification System (HANS) for Volcanoes


U.S. Geological Survey
Sunday, January 1, 2023, 10:26 AM MST (Sunday, January 1, 2023, 17:26 UTC)

44°25'48" N 110°40'12" W, Summit Elevation 9203 ft (2805 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Recent Work and News

Steamboat Geyser had one major water eruption during the past month, on December 6, bringing the total number of eruptions in 2022 to 11.  This is significantly less than the numbers of eruptions in 2021 (20), 2020 (48), 2019 (48), and 2018 (32), suggesting that the geyser’s episode of frequent eruptions may be approaching an end.  But minor activity at the geyser picked up on December 18, so we might see another major water eruption in early 2023.

Overall, 2022 was an average year in terms of seismicity in the Yellowstone region, with slightly less than 2500 located earthquakes, the largest being an M4.2 event on May 11.  Just over 1000 of these earthquakes occurred as part of a swarm near Grizzly Lake, between Norris Geyser Basin and Mammoth Hot Springs, that began in the summer and waxed and waned throughout the year, peaking in September.  No significant changes in deformation occurred during the year, with typical caldera subsidence of a few centimeters (about an inch) interrupted during the summer months by a pause or slight uplift due to groundwater recharge.  This pattern of subsidence with a summer interruption has been ongoing since 2015–2016.

The Yellowstone Volcano Observatory wishes everyone a happy and healthy 2023!


During December 2022, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located about 70 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 2.5 located about 14 miles south-southwest of Mammoth Hot Springs in Yellowstone National Park on December 1 at 5:41 PM MST.  This event was part of ongoing seismicity that began in the area on July 29.  In December, approximately 28 earthquakes were added to the sequence, and seismicity continued through the end of the month.  Earthquake sequences like these are common and account for roughly 50% of the total seismicity in the Yellowstone region.

Yellowstone earthquake activity is currently at background levels.

Ground Deformation

Continuous GPS stations in Yellowstone Caldera recorded gradual subsidence at a rate of 2–3 centimeters (1 inch) per year, which has been ongoing since 2015.  This subsidence was interrupted during the summer months as groundwater recharge from snowmelt caused the ground to swell slightly, but the subsidence resumed in late October.  A similar pattern of ground deformation was measured in the area of Norris Geyser Basin.  In early-mid December, snow and ice accumulation on GPS antennas due to a winter storm that impacted the region caused apparent subsidence of 1-2 cm (less than an inch). This signal reversed itself within a few days as the storm passed and snow/ice cover on the antennas diminished.

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

The Yellowstone Volcano Observatory (YVO) provides long-term monitoring of volcanic and earthquake activity in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.

YVO Member agencies: USGS, Yellowstone National Park, University of Utah, University of Wyoming, Montana State University, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey


Michael Poland, Scientist-in-Charge