Norris Geyser Basin is the hottest geyser basin in the park and is located near the northwest edge of Yellowstone Caldera near Norris Junction and on the intersection of three major faults. The Norris-Mammoth Corridor is a fault that runs from Norris north through Mammoth to the Gardiner, Montana, area. The Hebgen Lake fault runs from northwest of West Yellowstone, Montana, to Norris. This fault experienced an earthquake in 1959 that measured 7.4 on the Richter scale (sources vary on exact magnitude between 7.1 and 7.8; see 1959 Yellowstone earthquake). Norris Geyser Basin is so hot and dynamic due to the fact that these two faults intersect with the ring fracture zone that resulted from the creation of the Yellowstone Caldera of 640,000 years ago.

The Basin consists of three main areas: Porcelain Basin, Back Basin, and One Hundred Springs Plain. Unlike most of other geyser basins in the park, the waters from Norris are acidic rather than alkaline (for example, Echinus Geyser has a pH of ~3.5). The difference in pH allows for a different class of bacterial thermophiles to live at Norris, creating different color patterns in and around the Norris Basin waters.

The Ragged Hills that lie between Back Basin and One Hundred Springs Plain are thermally altered glacial kames. 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. Madison lies within the eroded stream channels cut through lava flows formed after the caldera eruption. The Gibbon Falls lies on the caldera boundary as does Virginia Cascades.

The tallest active geyser in the world is Steamboat Geyser and it is located in Norris Basin. Unlike the slightly smaller but much more famous Old Faithful Geyser located in Upper Geyser Basin, Steamboat has an erratic and lengthy timetable between major eruptions. During major eruptions, which may be separated by intervals of more than a year (the longest span between major eruptions was 50 years), Steamboat erupts over 300 feet (90 m) into the air. However, Steamboat does not lie dormant between eruptions, instead displaying minor eruptions of approximately 40 feet (12 m).

Periodically, Norris Geyser Basin undergoes a large-scale basin-wide thermal disturbance lasting a few weeks. Water levels fluctuate, and temperatures, pH, colors, and eruptive patterns change throughout the basin. During a disturbance in 1985, Porkchop Geyser continually jetted steam and water; in 1989, the same geyser apparently clogged with silica and blew up, throwing rocks more than 200 feet (61 m). In 2003, a park ranger observed it bubbling heavily, the first such activity seen since 1991. Activity increased dramatically in mid-2003. Because of high ground temperatures and new features beside the trail, much of Back Basin was closed until October. In 2004, the boardwalk was routed around the dangerous area and now leads behind Porkchop Geyser.

North of Norris, Roaring Mountain is a large, acidic hydrothermal area (solfatara) with many fumaroles. In the late 19th and early 20th centuries, the number, size, and power of the fumaroles were much greater than today. The fumaroles are most easily seen in the cooler, low-light conditions of morning and evening. Artists' Paintpots is a small hydrothermal area south of Norris Junction that includes colorful hot springs and two large mudpots.

Monument Geyser Basin has no active geysers, but its 'monuments' are siliceous sinter deposits similar to the siliceous spires discovered on the floor of Yellowstone Lake. Scientists hypothesize that this basin's structures formed from a hot water system in a glacially dammed lake during the waning stages of the Pinedale Glaciation. The basin is on a ridge reached by a very steep one-mile (1.6 km) trail south of Artists' Paint Pots.

Geysers in the Norris Geyser Basin

 

Echinus Geyser: Echinus Geyser was a crowd pleaser for a number of years and then in 1997 it started to visibly slow down. As of February 1999, it was being described as fairly weak and erratic. Echinus has long been the only predicted geyser at Norris, it is unclear if it will keep this status. Predictions have been posted at the Norris Museum, check there for up to date information. In February 1999, eruptions started from an overflowing pool and lasted only about four minutes. Intervals between eruptions were around 90 minutes and the maximum height seen was about 30 to 40 feet.

Whirligig Geyser: This is a fun, if small geyser. The fun part is the chugging sounds the back vent makes during the eruptions.

Cistern Spring: Cistern is connected to Steamboat Geyser. After an eruption of Steamboat, Cistern drains. Cistern has formed some pretty terraces which can be seen on the north side of the pool.

Constant Geyser: In the past few years has been a relatively frequent performer, sometimes erupting every half hour or so in a quick, few seconds, burst. Constant is located just behind and to the right of Whirligig Geyser.

Porcelain Basin: There are numerous small geysers in Porcelain Basin. The activity here is vigorous but often short lived. Geysers can come and go in days and even the larger more stable geysers change from year to year and some times from day to day.

Veteran Geyser: Veteran is often a very active geyser with water being erupted almost continuously. At times though, it does go through cycles that ultimately build to a major eruptions that can throw water about 40 feet at an angle. After these major eruptions, it then rests for a while before starting to build again.

Porkchop Geyser: Porkchop exploded in 1989. For a period before that, Porkchop erupted continuously to 30 feet. Then on September 5, 1989, the steam pressure became too great and it exploded in a steam explosion. The blast blew rocks up to 220 feet away. You can still see the rocks it upended around its crater. Porkchop is now a gently boiling pool.

Emerald Spring: Emerald Spring is a 27 foot deep, green colored, pool of water which usuaaly stays a few degrees below boiling. The bubbles you see are caused by carbon dioxide, steam and other gasses. The water is about as acidic as tomato juice. The green color is due to the combination of the blue of the deep water and the yellow of sulfur that lines the pool's walls. Emerald has been known to act as a geyser in the past sometimes reaching as much as 80 feet tall but this hasn't been seen since the early 1930s.