After the Show: Yellowstone National Park, September 2003 Echinus Geyser after an eruption. Prior to 1998, this geyser erupted at frequent intervals and was the only predicted geyser in Norris Geyser Basin. Now it erupts less frequently and more erratically reaching at most 60 feet in height. Echinus is the largest frequently active acid geyser in the world. Most of the thermal features at Norris Geyser Basin are acidic in nature, unlike the majority of geysers in Yellowstone, which are alkaline in nature.