Images

Map of seismicity (white circles) in the Yellowstone region during 2018. Yellow lines are roads, red line shows the caldera boundary, Yellowstone National Park is outlined in black, and dashed lines denote state boundaries.

Geologic time scale showing the geologic eons, eras, periods, epochs, and associated ages in millions of years ago (MYA). The time scale also shows major evolutionary and tectonic events in North America.

Coring platform assembled on the shore of Goose Lake, in Lower Geyser Basin, Yellowstone National Park, in 2018. Today, the nearest thermal features are 400 meters (about 1300 feet) away from Goose Lake, but thousands of years ago Goose Lake itself showed indications of being thermally active!. Steam from Midway Geyser Basin can be seen in the distance.

Hydrothermal sediment deposits from the Goose Lake sediment core, Lower Geyser Basin, Yellowstone National Park. The orange sediment (left, scale in cm) consists mostly of fluorite, a common mineral in some hydrothermal deposits, but not usually found in lake sediments.

Map showing the northwestern corner of the Sour Creek Dome. The red lines mark the area where the map will be changing to become more accurate. Figure adapted from Wilson et al. 2018 (Bulletin of Volcanology, v. 80, article 53; doi:10.1007/s00445-018-1229-x).

A section of the Porcelain Basin Loop boardwalk in the Norris Geyser Basin was removed because the ground below sections of the boardwalk became too hot and made charcoal of the wood footings that support the structure. Luckily enough in this case, the boardwalk was shifted about 3 feet to avoid the new hot ground.

Vertical motion at GPS station P350, in Idaho, together with nearby snowpack measurements (given as snow water equivalent). The GPS station moves downward as snowpack grows, and moves upward after it melts away. Taken from Knappe, et al., 2018 (https://doi.org/10.1029/2018WR023289).

Vertical ground motion (red line) measured at GPS site P350, in central Idaho, and snow depth (expressed as Snow Water Equivalent, or SWE; blue line) measured at a nearby SNOTEL site, during 2010-2016. The GPS station moved downward due to the increasing load of the accumulating snow during winter months, and then upward when the snow melted during summer months.

Map depicting instruments deployed around Yellowstone Lake in 2018.

GPS time series from station NRWY, near Norris Geyser Basin in Yellowstone National Park. The three plots show how the station is moving in a north-south direction (top), east-west direction (middle), and up-down direction (bottom).

View of one of the geothermal seeps that flows into the Yellowstone River south of LaDuke Hot Spring.

View of a clear blue hot spring pool of alkaline chloride fluid with silica sinter apron around it at Biscuit Basin.  This pool is generally close to the boiling temperature (200℉, 93℃) at this altitude (7200 ft, 2195 m).

Alkaline-chloride waters from an eruption of Old Faithful flow over the edge of the white silica sinter terrace into the Firehole River.  The orange coloration on the sinter terrace is due to thermophilic (high temperature) bacteria living in the warm fluids.  Old Faithful Inn is in the background, with the wooded Summit Lake rhyolitic lava flow behind.&nb

New thermal feature beneath the boardwalk on Geyser Hill, Upper Geyser Basin. Boards removed for better observation. Pump Geyser is mound at end of boardwalk. Old Faithful Inn in distance.

An unnamed but charismatic thermal feature alongside Ferris Fork, near the Bechler River. The center of the pool is roiling with gas bubbles, but not boiling! The pool is only about 180 degrees F (81 degrees C), and all the gas is bubbling up from underground.

Mules loaded with sampling equipment and supplies for a mission to collect gas and thermal water samples from the Bechler River area in the southwest part of Yellowstone National Park. 

Ear Spring photographed on September 16, 2018. Rocks and other debris on the ground surrounding the spring were ejected during the September 15 water eruption. The spring is dry in this photo.

Left: steel pipe with small temperature sensors placed every few inches. Right: temperature pipe installed in the streambed.

Montana Bureau of Mines and Geology and Montana Tech scientists preparing for a UAV flight on the west side of the Yellowstone River adjacent from LaDuke Hot Springs.

View of one of the geothermal seeps that flows into the Yellowstone River south of LaDuke Hot Spring.

Serapeum, a Roman Marketplace in Pozzuoli, Italy, records deformation of Campi Flegrei caldera over two millennia.