Images

A garter snake along Violet Creek near the Mary Mountain Trail in Hayden Valley, Yellowstone National Park. This snake used the geothermally warmed creek to thermoregulate during near-freezing overnight conditions. USGS photo by Stanley Mordensky, June 2023.

Thermal feature UNNG-GHG-17a, not far from Sponge Geyser on Geyser Hill in Upper Geyser Basin, Yellowstone National Park.  The feature formed during a period of thermal unrest that began in May 2023 and threw debris and hot water onto the adjacent boardwalk, which was closed for safety.  National Park Service photo by Kiernan Folz-Donahue, May 31, 2023.

Distribution of hydrothermal features in Yellowstone as a function of their pH (modified and updated from Nordstrom et al., 2009). There are two distinct groupings: one is more acidic, and the other neutral to basic.

Borehole station B945, near Panther Meadow between Mammoth Hot Springs and Norris Geyser Basin in Yellowstone National Park.  Left (“before”) panel shows old VSAT satellite communication network, with a large, round antenna (photo by Scott Johnson, EarthScope Consortium, on May 13, 2022).  Right (“after”) panel shows the station with a new Starlink antenna

Front cover of the Yellowstone Volcano Observatory 2022 annual report, which includes a summary of earthquake, deformation, and geyser activity, as well as research investigations and other information.

Soil carbon dioxide concentration and temperature measured at a new thermal area near Tern Lake in Yellowstone National Park on the east side of Yellowstone Caldera. A, Map of soil carbon dioxide flux simulated based on measurements made at the black dots in September 2022. B, Map of soil temperature at a depth of 20 centimeters (8 inches).

Simplified geologic map of the Timber Hill basalt and underlying geology in the Sweetwater Hills. The Sweetwater Road is shown by red. Note the basalt flow generally rests on poorly cemented sediments of the Sixmile Creek Formation shown in orange.  Map by Jesse Mosolof (Montana Bureau of Mines and Geology).

Simplified map of the Wyoming Province—a craton composed of Archean-age continental crust. Archean- and Proterozoic-age rocks outcrop in many places within the Wyoming Province and are shown as dark grey blobs. The yellow blob highlights the location of the Hellroaring and Crevice plutons, a small portion of which are exposed in northern Yellowstone National Park.

Map of the northwestern U.S., showing the approximate locations of the Yellowstone hotspot volcanic fields (orange) and Columbia River Basalts (gray).  Boundary of Yellowstone National Park is shown in yellow.  Inset shows physiographic map of southwest Montana and central Idaho.

USGS scientists work to recover sediment cores from Henrys Lake, Idaho. (Left): geologists traverse frozen Henrys Lake with coring supplies. USGS photo by Sylvia Nicovich, March 30, 2023.  (Right) Geologists lower the corer into the lake through a hole augured through the ice. USGS photo by Chris DuRoss, March 31, 2023.

Frying Pan Lake (also called Waimangu Cauldron), in New Zealand, sits within Echo Crater, which formed during the 1886 eruption of Tarawera.  A hydrothermal explosion from the crater in 1917 resulted in the formation of the hot spring "lake" by 1918.

Map of the distribution of pH for thermal pools within Norris Geyser Basin, Yellowstone National Park.  Cool colors are acidic, and warm colors are neutral to slightly basic.  These data were collected and organized using Geographic Information System (GIS) tools. Map by Jefferson Hungerford and Kiernan Folz-Donahue, Yellowstone National Park.

Volcanic deposits associated with the Absaroka volcanic province along the eastern and northern boundaries of Yellowstone National Park. The left panel shows the spread of the Absaroka Volcanic Supergroup (AVS) throughout Wyoming and Montana.

Isotopic composition of the primary volcanic groups of the Absaroka volcanic province (the Washburn, Sunlight, and Thorofare groups) and two volcaniclastic units, the Sepulcher formation and the Daly formation.

Landsat 8 nighttime thermal infrared image of Yellowstone National Park from January 31, 2023. Satellite-based thermal infrared data show areas on the surface that are warmer versus cooler, and they can be used to estimate surface temperature and the geothermal radiative heat output from the Yellowstone magmatic and hydrothermal system.

An example of the repeating seiche—a long-period oscillatory wave that can be present on a lake—measured over the course of a day by the lake-level sensor at the Grant Village boat dock on the West Thumb of Yellowstone Lake. The plot shows a cyclic variation of about 2 centimeters that occurs numerous times during June 13, 2021.

Geology of the unconformity on Mount Everts in Yellowstone National Park.  Sketch at the top was made by geologist William Henry Holmes in 1878 and correctly identifies Cretaceous sediments overlain by much younger rhyolite rocks, including fine ash deposits (“tufa”).  The photo at the bottom shows the same outcrop as viewed from Mammoth Hot Springs (USGS

Pie diagram showing the chloride flux, in kilotons per year (kt/yr), measured in 2022, with percentages for the four major rivers (Madison, Yellowstone, Snake, and Falls rivers) that drain Yellowstone National Park. Figure developed by Baine McCleskey.

Images of an unnamed thermal feature in the Three River Junction thermal area in southwest Yellowstone National Park. A, WorldView-3 satellite image from September 2014. B, National Park Service (NPS) aerial photograph from 2017. Images A and B were acquired before the feature went largely dry in late 2019 or 2020. C, WorldView-3 satellite image from June 2020.

Map of Yellowstone National Park lakes, rivers, and streams, with colors indicating the amount of arsenic in the water.  The Maximum Contaminant Level (MCL) defined by the Environmental Protection Agency for arsenic in drinking water is 10 micrograms per liter (µg/L).  In the vicinity of major geyser basins, especially on the Firehole and Madison Rivers, a

Map of seismicity (red circles) in the Yellowstone region during 2022. Gray lines are roads, black dashed line shows the caldera boundary, Yellowstone National Park is outlined by black dot-dashed line, and gray dashed lines denote state boundaries.