Echinus Geyser

Echinus Geyser, in Yellowstone National Park’s Norris Geyser Basin, is the world’s largest acid-water geyser. Named in the late 1870s or early 1880s for the spiny cone that suggested a sea urchin, it is now notable for unpredictable eruptions. When active, it can send water 40 to 60 feet high for about four minutes, though earlier major eruptions lasted as long as 118 minutes. Before 1998, it erupted much more regularly, about every 35 to 75 minutes, but that pattern changed, possibly after a secondary underground water source was cut off. Its highly acidic water has a pH of 3.3 to 3.6 and a measured temperature of 80.3 °C.

Wyoming · United States