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Northwestern Wyoming

"Known today as the Thumb Paint Pots, the Hayden Expedition of 1871 originally named these fanciful features the 'Mud Puffs'. Picture a field of minature mud volcanoes that are 3-4 feet high with steam curling from delicate mud chimneys in various shades of red. Surrounding the cones, the mud appears to be stirred and mixed to the smoothest, most satiny consistency by some unseen hand. Sometimes the mud was thrown 25 feet. Beginning in the early 1970s, the Paint Pots became less active. Activity had increased again."

"Mudpots differ from most hot springs their water is much more acidic and dissolves the underground geological 'plumbing system' into wet clay mud. Also, mudpots vary with precipitation and ground water levels. Sometimes they look like muddy water; other times they look as if you could build pottery with their mud."

This is Seismograph and Bluebell Pools.

"These pools used to be known as 'Blue Pools'. After the 1959 Hebgen Lake earthquake, which measured 7.5 on the Richter scale, the pools were renamed. At West Thumb, no one recorded the nature of the changes caused by the quake, but perhaps someone thought Seismograph Pool somehow 'registered' with earthquakes. These days, Seismograph is sometimes muddy - but not from earthquakes. The mud comes from the runoff of nearby mudpots."

Panorama of Yellowstone Lake's West Thumb.

Lakeside Spring.

This is Lakeshore Geyser.

"Accounts from the 1920s and 1930s tell of Lakeshore Geyser erupting up to 50 feet. The smaller of the two geyser vents is generally not exposed until mid to late August. Although the Lakeshore Geyser boils vigorously and almost continuously, and often erupts a few feet, its last know major eruption was in 1970. One day, however, earthquake activity or other processes may cause the geyser to gain energy and begin erupting more forcefully once again."