Images

Photograph of north and eastern rim of the 9400-year-old Turbid Lake explosion crater showing the primary explosion ejecta rim with a secondary explosion ejecta rim inside the lake-occupied explosion crater.  Many, if not most, larger explosion craters have multiple explosion histories and are long-lived hydrothermal systems. 

Beartooth Mountains looking west northwest from near Beartooth Pass, Wyoming. Photo by Jeff Havig, University of Minnesota, July 20, 2016.

A Ehmania walcotti trilobite from Yellowstone National Park. Scale is in millimeters.  Specimen located at the Smithsonian National Museum of Natural History.

A Ptychopariid trilobite from Yellowstone National Park. Scale is in millimeters.  Specimen located at the Smithsonian National Museum of Natural History.

Map of the Heart Mountain slide block. From Mitchell et al., 2015 ("Catastrophic emplacement of giant landslides aided by thermal decomposition: Heart Mountain, Wyoming." Earth and Planetary Science Letters 411: 199-207), modified from Anders et al. (2010).

Data from GPS station AB53 near the peak of a mountain on Mitkof Island, Alaska, including measured snow depth down at the base of the mountain. Notice how the North (top), east (second from the top), and vertical (third from the top) positions are impacted by the presence of snow. This is an extreme example of the influence of snow on GPS data.

Eruptions between 1064 and 1067 AD produced three lava flows that covered 8 km² (3 mi²) and a field of scoria and spatter that covers 2300 km² (890 mi²). Archeological evidence shows that there were communities of people living in the area who were impacted by the eruption.

(Left) Sample of the Pitchstone Plateau rhyolite flow, which erupted about 72,000 years ago, making it is the youngest rhyolite at Yellowstone. The blocky white crystals in this sample are the mineral sanidine, whereas the rounded crystals are quartz.

Big Southern Butte, Idaho.  The butte is among the largest rhyolite domes in the world and is located in the eastern Snake River Plain. Photo by James Neeley, BLM (https://flic.kr/p/CsA4TV).

Lidar coverage of the Hebgen and Red Canyon faults collected in 2014. Magenta lines show fault scarps mapped by USGS geologists shortly after the 1959 earthquake. Yellow lines show fault scarps interpreted from lidar data 55 years after the earthquake.

Lava Mountain, Wyoming.  (A) View from Dubois, WY, in the Wind River basin looking northwest ~30 km toward Lava Mountain.

Frosted trees in the Fairy Falls area of Yellowstone National Park near the Firehole River.  National Park Service photo by Annie Carlson, 2014.

Schematic cross section of the magmatic and hydrothermal systems underlying Yellowstone Caldera, showing magmatic volatiles emitted during crystallization of the rhyolitic magma and/or from basalt intrusions or convection, and the hypothesized relation with earthquake swarms on the caldera margins.  The exsolved fluids accumulate at lithostatic pressures in the

The contact (red arrow) between Huckleberry Ridge Tuff ignimbrite members A and B is marked by a time break of probably weeks to a month or so.

Titanium tubed used to collect gas from a fumarole near Lassen Peak, California.

Example model output of possible ash distribution from a month-long Yellowstone supereruption. Results vary depending on wind and eruption conditions. Historical winds for January 2001 used here.

Beryl Spring's strongly boiling blue pool is about 8 m (25 ft) wide and contains high-chloride liquid water with a near-neutral pH. Immediately behind the pool is a loud, hissing fumarole producing a white cloud of steam. USGS Photo by Pat Shanks, 2002.

Seismograms of the magnitude 4.8 earthquake that occurred in Yellowstone on March 30, 2014, as recorded by seismometers at station YNR near Norris Geyser Basin.  Top: Seismogram recorded on the accelerometer, which stayed on scale during the shaking.  Bottom: “Clipped” seismogram recorded on the broadband seismometer, which went off scale during the shakin

Telemetry system of the Yellowstone Seismic Network operated by the University of Utah Seismograph Stations.  Black arrows show analog telemetry and pink arrows show digital telemetry.  The green line is the boundary of Yellowstone National Park.

3-component seismograms from station YHB for the M4.8 earthquake that occurred near Norris Geyser Basin on March 30, 2014, and showing the P-wave arrival pick (red) and the S-wave arrival pick (green) as determined by UUSS analysts.  The vertical blue dashed line represents the origin time of the earthquake at 12:34:39.16 UTC.

Station map showing seismograph stations used in the location of the M4.8 earthquake that occurred near Norris Geyser Basin on March 30, 2014.  The yellow star shows the earthquake epicenter.  Red triangles represent seismograph stations with a P-wave arrival pick.  Green triangles represent seismograph stations with both a P-wave and a S-wave arrival