USGS Volcano Notice - DOI-USGS-YVO-2023-03-01T08:24:16-08:00

Recent Work and News

There were no recorded eruptions of Steamboat Geyser during the month of February, and the total number of eruptions for the year remains at two. The Norris temperature monitoring network and seismic station YNM have been inaccessible since mid to late February due to a local power failure—the Norris Museum is difficult to access during winter months—but the streamgage on Tantalus Creek, through which all water from Norris Geyser Basin drains, did not record obvious spikes that would be associated with Steamboat eruptions.

Seismicity

During February 2023, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 168 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 2.9 located about 11 miles northeast of West Yellowstone, Montana, on February 7 at 8:44 PM MST.  This event was part of a swarm of 76 earthquakes that occurred in the area during February 4–11. 

In addition, 48 earthquakes were added to the ongoing seismicity that began last summer about 14 miles south-southwest of Mammoth Hot Springs in Yellowstone National Park. The largest earthquake of the month in this sequence, a magnitude 2.4 event, occurred on February 14 at 3:03 AM MST.

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 continued to record gradual subsidence at a rate of several centimeters (about 1 inch) per year, which has been ongoing since 2015.  No significant deformation has been recorded in the area of Norris Geyser Basin since the end of last summer.  Snow and ice accumulation on GPS antennas due to winter storms cause occasional apparent subsidence of 1–3 centimeters, but this does not represent real ground motion and recovers itself quickly once the antennas are free of snow/ice.

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