Images

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).

Exposure of rhyolite volcanic rocks in the central Snake River Plain showing a thick sequence of 10-12 million-year-old, densely welded, pyroclastic density flow units (darker units from middle of photo to top of hill) overlying a thick sequence of white, friable, ash fall deposits.  USGS Photo by L. A. Morgan (May 2004).

Simplified geologic map detailing locations of volcanics at Sepulcher Mountain and igneous intrusion at Electric Peak and surrounding area. This map is Fig. 2.

(Top) 1996–2000 interferogram draped over a 30-m DEM and showing uplift centered a few kilometers (miles) west of South Sister volcano. (Bottom) Geochemical data on top of the 1996–2000 interferogram. The columns show chloride (Cl) and sulfate (SO4) concentrations at sampled springs.

Criteria for estimation of the Volcanic Explosivity Index (VEI).  Modified from: Newhall, C.G., and Self, S., 1982, The volcanic explosivity index (VEI): An estimate of explosive magnitude for historical volcanism. Journal of Geophysical Research, v. 87, no. C2, p.

Benchmark T366, was installed in 1987 a few miles north of Canyon Junction in Yellowstone National Park. Rather than being a brass or aluminum disk, the benchmark is a rod that was driven into the ground until it would not sink any lower.  The precise elevation of the top of the rod was established by surveying methods, and an access cover flush with the g

Geologic map of the Yellowstone Plateau Volcanic field generated by Bob Christiansen and published in 2001.  Available from https://pubs.usgs.gov/pp/pp729g/plate1.pdf.

Geological Map of the area around Monument Geyser Basin and Beryl Spring, taken from the Geological Map of the Yellowstone Plateau Area (Christiansen, 2001)

Left: Map of Yellowstone showing the extent of mapped Lava Creek Tuff members A and B, which erupted during the formation of Yellowstone Caldera about 631,000 years ago. Right: Geologic map of Madison Junction (1:125,000).

Interpretive reconstruction of the Yellowstone Plateau region before initial plateau volcanism (a little before 2 million years ago). The region was entirely an elevated and faulted mountainous terrain with no basin in the present plateau area.

Landsat-7 satellite image of Jemez Mountains and Valles Caldera, New Mexico.  The Valles and Toledo Caldera margins are approximated by dashed yellow lines, and the resurgent dome and lava domes are labeled.  The Banco Bonito lava flow is the youngest in the region at 68,000 years old.  The town of Los Alamos is located just east of the caldera. 

Mount Epomeo on the island of Ischia. The visible western slope of the resurgent block consists of 55,000 year old rocks that formed one of the most widespread Late Quaternary pyroclastic deposits in the Mediterranean region.  INGV photo (https://www.ingv.it/en/Ischia).