Norris Geyser Basin is the hottest, oldest, and most dynamic of Yellowstone's thermal areas. Norris shows evidence of having had thermal features for at least , years.
The features in the basin change daily, with frequent disturbances from seismic activity and water fluctuations. The vast majority of the waters at Norris are acidic, including acid geysers which are very rare. Steamboat Geyser, the tallest geyser in the world at β feet 91β m and Echinus Geyser pH 3.
The basin consists of two areas: Porcelain Basin and the Back Basin. Back Basin is more heavily wooded with features scattered throughout the area.
The area was named after Philetus W. Norris, the second superintendent of Yellowstone, who provided the first detailed information about the thermal features. Norris Geyser Basin sits on the intersection of major faults. This fault experienced an earthquake in that measured 7. These two faults intersect with a ring fracture that resulted from the Yellowstone Caldera of , years ago.
These faults are the primary reason that Norris Geyser Basin is so hot and dynamic. The Ragged Hills around parts of Back Basin and are thermally altered glacial moraines. As glaciers receded, the underlying thermal features began to express themselves once again, melting remnants of the ice and causing masses of debris to be dumped. These debris piles were then altered by steam and hot water flowing through them.
