Michael Poland

Map of Norris Geyser Basin showing the locations of major subbasins, roads and trails, and Nuphar Lake.

High-resolution satellite images of the Porcelain Basin and Nuphar Lake areas of Norris Geyser Basin acquired by Quickbird-2 on September 11, 2006 and WorldView-3 on March 30, 2022.  Note the change in color of Nuphar lake, from deep green to light blue, over time, as well as the increased evidence of flow from thermal features on the east side of Porcelain Bas

Earthquake Lake, which formed when the Madison River was blocked by a landslide that occurred as a consequence of the Hebgen Lake earthquake in 1959.  The lake inundated existing forest, now marked by standing dead trees in the lake water. The landslide scar is visible on the side of the mountain at the far end of the lake.

Map of continuous Global Positioning System (GPS), semipermanent GPS, borehole strainmeters, and borehole tiltmeters that provide surface deformation monitoring capability in and around Yellowstone National Park. Red line denotes boundary of Yellowstone Caldera.

Front cover of the Yellowstone Volcano Observatory 2022 annual report, which includes a summary of earthquake, deformation, and geyser activity, as well as research investigations and other information.

Soil carbon dioxide concentration and temperature measured at a new thermal area near Tern Lake in Yellowstone National Park on the east side of Yellowstone Caldera. A, Map of soil carbon dioxide flux simulated based on measurements made at the black dots in September 2022. B, Map of soil temperature at a depth of 20 centimeters (8 inches).

Distribution of hydrothermal features in Yellowstone as a function of their pH (modified and updated from Nordstrom et al., 2009). There are two distinct groupings: one is more acidic, and the other neutral to basic.

Frying Pan Lake (also called Waimangu Cauldron), in New Zealand, sits within Echo Crater, which formed during the 1886 eruption of Tarawera.  A hydrothermal explosion from the crater in 1917 resulted in the formation of the hot spring "lake" by 1918.

Geology of the unconformity on Mount Everts in Yellowstone National Park.  Sketch at the top was made by geologist William Henry Holmes in 1878 and correctly identifies Cretaceous sediments overlain by much younger rhyolite rocks, including fine ash deposits (“tufa”).  The photo at the bottom shows the same outcrop as viewed from Mammoth Hot Springs (USGS

Map of seismicity (red circles) in the Yellowstone region during 2022. Gray lines are roads, black dashed line shows the caldera boundary, Yellowstone National Park is outlined by black dot-dashed line, and gray dashed lines denote state boundaries.

Google Earth image of the north part of Lower Geyser Basin showing the site of the Fountain Hotel and nearby Leather Pool, which was tapped to provide a source of hot water for the hotel.