Mike Poland, scientistincharge of the Yellowstone Volcano Observatory, describes activity at Yellowstone volcano in this monthly update for September 1, 2022.

The update comes to you from beautiful Sapphire Pool in Yellowstone National Park’s Biscuit Basin. This and other features like Grand Prismatic Spring and Old Faithful, form from water, snow melt, and rainwater that circulates down in the earth and becomes heated by the cooling magma body beneath Yellowstone. The water picks up some of the gases from that magma body and because it's warm, it starts dissolving some of the rock beneath the surface that's very high in silica. The warm water buoyantly rises, moving through colder groundwater, and when it reaches the surface, it deposits a lot of the silica that it had dissolved from the rock below. This process is what creates the beautiful terrace features and also some of the cones that make up geysers like Old Faithful, Castle, and Giant.

These neutral chloride features are some of the most iconic features in Yellowstone National Park. In next month’s update, we will discuss acidic thermal features in Yellowstone.

During the month of August, there were 290 located earthquakes in the Yellowstone region (maximum magnitude M3.1). Seasonal summer uplift detected by the GPS network continues due to groundwater accumulation. The last water eruption of Steamboat Geyser was on June 20, and minor activity is ongoing. Yellowstone remains at normal, background levels of activity.

For questions, email [email protected].

USGS video: https://www.usgs.gov/media/videos/mon...