Doublet Pool
United States
Doublet Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park, Wyoming. Doublet Pool is 8 feet (2.4 m) deep and its temperature is approximately 194.4 °F (90.2 °C). Its scalloped edge is made of geyserite. Eruptions can occur in Doublet Pool, but only last up to 8 minutes. The pool on the right pulses over the vents about every two hours. Occasionally there will be vibrations, surface wave motion, and thumping; these effects are caused by collapsing gas and steam bubbles deep underground.
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