Looking at Echinus Geyser today, you may question why it warrants the name of “geyser.”
A fair, crusty pool, Echinus Geyser offers scant evidence of its prior eruption history—that is, unless you read up on its history, or look at photographic evidence. Then you’ll see that, once upon a time, Echinus was a star performer.
Lee H. Whittlesey, writing in Yellowstone Place Names, attributes the origins of Echinus’ name to Hayden Geological Survey mineralogist Albert C. Peale. Ferdinand Vandeveer Hayden wrote of Echinus Geyser in one of his annual reports for the United States Geological and Geographical Survey of the Territories:
This was so named because the pebbles around the basin have some resemblance to the spine-covered sea urchin. The basin is about 40 feet in diameter, and throws a mass of water 15 to 20 feet into the air at intervals the length of which we were unable to determine, on account of our short stay in the basin. The border of the spring is gray and red or reddish brown, coated with black and bluish gray spinous-like processes. The coating of geyserite is thin, and the underlying rocks are exposed at places, as though this were a comparatively new geyser. Below the basin deep red and maroon colored terraces spread for some distance from the geyser, and it is probable that the geyser has at times eruptions on a grand scale (129).
Although Echinus Geyser was noted early on for its resemblance to a genus of sea urchins, there are a few other facets that made Echinus’ fame, besides its echinal appearance.
There has been a little disagreement over how high Echinus Geyser can erupt. The National Park Service entry on Echinus states it generally erupted 40-60 feet in height. Whittlesey, however, estimates it can erupt up to 80 feet.
For a time, especially during the 1970s and 80s, Echinus Geyser was a remarkably reliable geyser, erupting every 35 to 75 minutes. It could be reasonably predicted, since it overflowed around 20 minutes before an eruption. Finally, Echinus is very close to the boardwalk, which allows visitors to get very close to the feature. This made it popular with visitors to the Norris Geyser Basin.
Further, the waters in Echinus Geyser are acidic (verging on a pH of 3.3 to 3.6, on par with orange juice and soda, making it more acidic even than acid rain), which is an extreme rarity in the world of erupting thermal features.
Alas, since the late 1990s, Echinus Geyser has gone from regular performer to irregular spouter. Most of the time, its waters stand idle. Of course, this could always change—you never know what will reawake or go to sleep in Yellowstone National Park.