Located on Lake Yellowstone, West Thumb Basin is a concentration of paint pots, springs/pools/ and geysers. Paint pots have a temperature of 187-199.8F with dimensions of 30 feet diameter. They were originally names Mud Puffs by the 1878 Hayden Survey. Springs have a temperature of 172-193F depending on the spring. Geysers have temperatures up to 201F. Black Pool is 40x75 feet and was a temperature of 132F when it was black caused by the transparent blue water and the orange algae lining the pool. The pool had frequent boiling eruptions on August 15th, 1991, with water doming to 3 feet causing heavy runoff. The temperature increase killed the bacteria allowing Black Pool to now be blue.
Seismograph Pool is located in West Thumb Geyser Basin. Currently has a temperature of 167F. Previously known as the 'Blue Pool'. Renamed to Seismograph pool after the 1959 Hebgen Lake earthquake, which measured 7.5 on the Richter Scale.