Monthly update of activity at Yellowstone Volcano for October 1, 2022

Mike Poland, scientist-in-charge of the Yellowstone Volcano Observatory, describes activity at Yellowstone in this monthly update for October 1, 2022. 

The update comes to you from Artist Paintpots in Yellowstone National Park. The paintpots are acid sulfate springs, one of three different types of thermal features in Yellowstone. 

The features start as snowmelt and rainwater percolate deep into the earth. The water is heated by the magma chamber that's cooling well beneath the surface. As the water starts to rise, it picks up gases emitted by the cooling magma body. As the water gets closer to the surface, it might begin to boil. The water will go off and form one of the neutral chloride features like Grand Prismatic Spring or Old Faithful. The gas separates from the water, and because it contains carbon dioxide, it will be slightly acidic. As is moves upward, the gas can start to dissolve some of the rock, turning it into a white, chalky clay. The clay mixes with subsurface water to form the paintpots. 

During the month of September, earthquake activity was slightly elevated in the Yellowstone region. The University of Utah Seismograph Stations located 678 earthquakes; 510 were part of the Grizzly Lake swarm. The largest earthquake of the month was a magnitude 3.9 that occurred as part of the swarm. The Grizzly Lake swarm and several other smaller swarms that occurred in September are a result of water interacting with pre-existing faults. 

The trends in ground deformation continue. Vertical deformation at the White Lake and the Old Faithful GPS stations show subsidence of about two to three centimeters or about one inch every year, interrupted in summer months by a pause in the subsidence or even a slight amount of uplift, caused by groundwater. The water is mostly snowmelt that percolates down into the subsurface where it is soaked up like a sponge. At Norris, the same is true, although Norris hasn't seen as much subsidence as the caldera. 

Steamboat Geyser had one water eruption on September 18, the ninth major eruption of 2022. The number of water eruptions is decreasing so perhaps the geyser is heading back into slumber. 

Yellowstone Volcano remains at normal, background levels of activity. For questions, email yvowebteam@usgs.gov.