Images

Photo of the Madison Museum, built in 1930 and designed by Herbert Maier. This structure exemplifies the National Park Rustic style, using natural materials and artisan craftmanship that are intended to blend buildings into the surrounding environment, “suggesting the smallness of man in relation to nature” (Herbert Maier).

Bob Fournier measuring the gas-to-water ratio (gas/steam) at drill site Y2, near Hot Lake on Firehole Lake Drive in Lower Geyser Basin, Yellowstone National Park, in the late 1960s.  USGS Photo.

Yellowstone caldera viewed from Mount Washburn.  The caldera is the low-lying area extending from the foothills of Mount Washburn in the foreground to the rugged mountains on the horizon.  The incised valley of the Yellowstone River stretches from left to right in the middle distance.  Steep valley walls are illuminated by sunlight in the center.&nbsp

Schematic illustration of waterfall formation in which a hard rock that is more resistant to erosion is atop a softer rock that is less resistant to erosion. Source: Wikimedia (https://commons.wikimedia.org/wiki/File:WaterfallCreationDiagram.svg).

The water at Terrace Springs, northeast of Madison Junction in Yellowstone National Park, is relatively cold (about 60 °C or 140 °F), but the water is still saturated with CO₂-rich bubbles. Photo by Shaul Hurwitz in September 2008.

A sulfur flow over acid-sulfate ground at Brimstone Basin near the eastern shore of Yellowstone Lake. The flows formed when native sulfur deposits were ignited during a forest fire. Photo by Shaul Hurwitz, September 2008.

Roadcut in light pink ash-flow deposits of the Lava Creek Tuff on Grand Loop Road near Tuff Cliff.  The color and closely spaced jointing are characteristic of the Lava Creek Tuff map unit.  The steep faces and dense nature of the roadcut exposures indicate that a moderate degree of welding occurred and has not been subsequently modified by hydrothermal al

Lower Falls and Grand Canyon of the Yellowstone River.  The river here is eroding young, post-caldera rhyolite that was softened by hydrothermal alteration.  The V shape of the canyon indicates that the river is actively eroding in response to regional uplift.  Photo by Richard Tollo, George Washington University, August 12, 2008.

GPS station P714, located in Panther Meadow south of Mammoth Hot Springs in Yellowstone National Park. Photo by EarthScope Consortium, June 2008.

Left hand plot shows a focal mechanism from an earthquake where the fault is horizontal (red line), and the motion is right-lateral strike skip.  The initial direction of wave motion (either back toward the source or away from the source is shown by the arrows.  Right hand plot shows the associated beachball diagram, with compressional (“C”) and tensional

Southern tip of the Lemhi Range on the northeastern margin of the eastern Snake River Plain showing the caldera wall of the 6.27 million year old Blue Creek caldera, in the Heise volcanic field.  Also shown are other units from the Heise volcanic field including the Kilgore Tuff and the Blacktail Creek Tuff.  In the foreground is the much thicker sequence

An eruption of Daisy Geyser in the Upper Geyser Basin of Yellowstone National Park. The geyser erupts boiling water at about 93 °C (200 °F). Photo by Shaul Hurwitz on April 12, 2007.

Hydrothermal deposits on Mars. (A) This image was acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera on November 22, 2006.  It shows a bright plateau of layered rocks about 90 meters (98 yards) across called, “Home Plate.”  NASA image: PSP_001513_1655_red; Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

Monitoring station VALT was installed on the crater floor of Mount St. Helens in 2006. It was called VALT because a vault-like structure about the size of a large doghouse was built into the rocky deposits to protect the state-of-the-art (at that time) broadband seismometer from environmental variables such as temperature and humidity.

National Agriculture Imagery Program natural-color image from September 9, 2006, showing newly mapped thermal areas (outlined in yellow) on the north side of the Mallard Lake resurgent dome.

Aerial (balloon) view of Norris Geyser Basin, Yellowstone National Park, looking northwest from the south.  USGS Photo by Brita Graham Wall, 2005.

Grand Prismatic Spring, Midway Geyser Basin, Yellowstone National Park.  Grand Prismatic is the largest hot spring in Yellowstone and the third largest in the world. Photograph by Robert Fournier.

A comparison of black cinders from Cinder Pool, in Norris Geyser Basin (left), with yellow cinders from an unnamed pool in the West Nymph Creek thermal area (right).  The Cinder Pool cinders are black due to finely dispersed pyrite, whereas the yellow color of cinders from the West Nymph Creek pool is due to the lack of pyrite.

Heise cliffs, the type location for the 4.45–7.0 million year old Heise Group from the Heise volcanic field, which preceded the Yellowstone Plateau volcanic field.  Most of the cliffs exposed here are rhyolitic, densely welded, rhyolitic pyroclastic density flow deposits.  USGS Photo by L. A. Morgan (May 2005).

Map showing earthquake focal mechanisms in the Yellowstone region.

Densely welded rhyolites from the central Snake River Plain.  USGS Photo by L. A. Morgan (May 2004).