Volcano Updates

Summary

Yellowstone Caldera activity remains at background levels, with 46 located earthquakes in April (largest = M1.8). Deformation measurements indicate a small amount of caldera subsidence since early October.

Recent Work and News

Steamboat Geyser erupted for the second time of 2025 on April 14.  Since then, the geyser has been quiet, but minor activity will probably resume in early May if the geyser starts to build to a new major eruption in the weeks to come.

May means the start of the field season in Yellowstone National Park!  Geologists are currently in the park collecting geophysical and geochemical data from the Mud Volcano area and will also be deploying semi-permanent GPS stations in the region to track surface deformation.  These stations are set up every spring to densify the continuous GPS network, and they are recovered in the fall before they are buried by snow.  Additional work later in May will include maintenance of monitoring stations and scouting locations for a new monitoring station in the Biscuit Basin area, where a hydrothermal explosion occurred on July 23, 2024.

Seismicity

During April 2025, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 46 earthquakes in the Yellowstone National Park region. The largest event of the month was a micro earthquake of magnitude 1.8 located about 13 miles north-northeast of Pahaska Tepee, Wyoming, on April 27 at 11:10 AM MDT.

There were no swarms identified during the month of April.

Yellowstone earthquake activity remains at background levels.

Ground Deformation

Continuous GPS stations in Yellowstone Caldera recorded a small amount (about 3 centimeters, or 1.2 inches) of subsidence since October.  This pattern and rate of subsidence continues a trend that started in 2015–2016.  Minor subsidence (about 1 centimeter, or about half an inch) was also measured by a continuous GPS station near Norris Geyser Basin since the end of last summer.

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