Images

Lower Falls of the Yellowstone River and the Grand Canyon of the Yellowstone, photographed during a helicopter flyover on August 19, 2019.

Old Faithful Geyser, as well as Old Faithful Inn and the Yellowstone National Park visitor center, as viewed from the lookout on Observation Point trail.

Old Faithful geyser visitor center, and visitor facilities as viewed from Observation point on August 18, 2019.

Map of Yellowstone National Park showing locations of thermal basins that host hot springs, geysers, and mudpots.  Dark green areas host alkaline-chloride fluids.  Yellowstone Caldera margin shown as bold dashed line.

View of the Cirque of the Towers in the Wind River Range, with Pingora Peak in the center. The Bull Lake and Pinedale glaciations carved this valley by steepening and smoothing its granite walls. Image captured while descending from Texas Pass. Image view is toward the southwest. USGS photo by Stanley Mordensky, August 2019.

A closeup of the head and mouthparts of the wetsalts tiger beetle, a voracious predator in Yellowstone. Photo by Robert K. D. Peterson, 2019.

Example of how the same rock type can look very different due to hydrothermal alteration. Left image is of the Lava Creek Tuff, which erupted during the formation of Yellowstone caldera 631,000 years ago, near Tower Junction.

Closeup of a wall of the Grand Canyon of the Yellowstone showing red, orange, and yellow mineral alternation, as well as white veins of silica, in the subsurface alteration zone of a former thermal basin.

Alteration associated with mud pots in Yellowstone National Park. Left image is an overview of Artist Paint Pots. Note the white kaolinite alteration in the lower right and the red/pink mud pots near the boardwalk. Right image is charcoal-gray mud from Mud Volcano consisting of kaolinite with fine-grained pyrite and other iron sulfide minerals.

Steamboat Geyser erupts in the golden light of sunrise on July 18th, 2019. The water-dominated part of a Steamboat eruption usually lasts anywhere from 3 to 90 minutes. Afterwards, a steam-dominated phase continues for many hours.

Dead lodgepole pine trees near the parking lot of Fountain Paint Pots in the Lower Geyser Basin. The trees look as if they are wearing white socks; hence, the name, “bobby socks trees.” The dead trees soak up the silica-rich water, turning the lower portion of the trees white.

Schematic model showing a cross section of Old Faithful's plumbing system as determined from seismic studies. The red circles (t0-t3) show the location of the tremor source over time, and how the tremor source migrates upward prior to an Old Faithful eruption. Times between red circles are based on a 93-minute eruption interval.

Images of snow algae and snow cyanobacteria on snow fields in the Beartooth Mountains near the Beartooth Pass Summit (elevation 10,947 ft/3,368 m) on Highway 212. Top left shows a typical pink snow algae bloom on a patch of snow, and top right shows the snow algae bloom scraped off the snow surface with a rock hammer.

Schematic diagram of Yellowstone's current magmatic system. A silicic crystal-mush (gray region with white crystals) is thought to underlie the caldera at a depth of ~5 km to 15 km, with more mafic basalt (in black) underneath.

Sections of a zircon crystal, only 100 micrometers across, showing stages of the crystal's growth. Upper panel shows the outer surface of the crystal, which is 131,000 years old based on 238U-230Th dating. This is when the crystal stopped growing. Lower panel shows the interior of the same zircon crystal.

Computer model of Lone Star Geyser constructed from multiple overlapping and scaled photographs and looking down into the geyser vent. This is a perspective that is only possible with images collected specifically to build a 3D model. Only the inner portion is obscured because in all the images, this area is continuously blanketed in opaque vapor.

This huge boulder was dropped by a retreating glacier on the north rim of the Grand Canyon of the Yellowstone in Yellowstone National Park, and it is a testament to Yellowstone's icy past.

USGS scientists Rebecca Kramer and Dan Dzurisin install a solar panel and GPS antenna (green square) at a semipermanent GPS station in the southern part of Yellowstone National Park. The work first required digging through 4 feet of snow!

Porcelain Basin in Norris Geyser Basin on May 18, 2019.

Photographs of Cistern Spring showing the draining behavior that occurs after major water eruptions of Steamboat Geyser. Left: about 2.5 hours after the onset of a major Steamboat eruption. Right: about 19.5 hours after that eruption.

Map of thermal areas in Yellowstone National Park. Most of Yellowstone's more than 10,000 thermal features are clustered together into about 120 distinct thermal areas (shown in red). Lakes are blue. The Yellowstone Caldera is solid black and the resurgent domes are dotted black. Roads are yellow.