Glossary

Cone-Type Geyser:

A geyser whose eruption is jetted as a steady column of water and steam from a vent with little or no surface pool. It is not necessary that the vent be at the top of a cone formation. Old Faithful Geyser is a cone-type geyser.

Cyclic:

A geyser that has a series of eruption at relatively short intervals separated from the next series by a relatively long quiet period.

Disturbance:

When applied to Norris Geyser Basin, describes a basin wide or partial basin change in not only geyser and pool behavior but also water temperatures and chemistry. When a disturbance occurs, many dramatic changes can take place. Many previously quiet geysers and pools start erupting. Other pools become murky or change color. And many geysers erupt much more vigorously. Not all geysers are affected positively though. The possibility of a major Steamboat eruption seems to be quenched by the onset of a disturbance for instance. What causes the disturbance? Well, one theory holds that the disturbance is the manifestation of a second hot water reservoir interacting with the surface features. This theory is supported by the change in water chemistry. Disturbances were first noted occurring in the Fall and covering the entire basin but have since been recognized in other seasons and sometimes only affecting small portions of the basin at a time.

Dormant:

When a geyser is not active, it is dormant.

Duration:

The period of time from the start of an eruption to the end of that eruption.

 

Fountain-Type Geyser:

A geyser whose eruptions occur in a series of separate burst, usually through a pool of water over the vent. Grand Geyser is a fountain-type geyser.

Fumarole:

A steam vent. A fumarole is related to a hot spring but the temperature is so high and the water supply so limited that all water is emitted as steam and no pool is able to form.

 

Geyser Gazer:

A geyser aficionado.

 

Geyser Hill Wave:

A theory proposed by T. Scott Bryan that attempts tie together some of the activity seen on Geyser Hill. The geyser hill wave can be thought of as a wave of energy propagating across geyser hill from southeast to northwest. The cycle of the wave can be anywhere from 4 to 12 days. The cycle is easiest to see on the southeast side of Geyser Hill, particularly in Silver Spring, Bronze Spring and Little Squirt Geyser. The water level in Silver and Bronze fluctuates but at its lowest sits below overflow, up to 2 inches below overflow for Bronze and 4 inches below overflow for Silver. At the time of SMax, south maximum, Silver and Bronze rise to overflow or near overflow. Usually, It is only at this time that Little Squirt can erupt. The theory is that SMax is a manifestation of the Geyser Hill Wave. As the Geyser Hill Wave propagates out from the Little Squirt area, there is evidence that it affects other geysers on Geyser Hill. Dome Geyser appears to like to erupt shortly after SMax. Beehive Geyser has been known to dramatically shorten its interval near the time of SMax and then return to its pre-SMax interval within a day or two. Plume Geyser has at times shown a response to the Geyser Hill Wave. Giantess Geyser may prefer to erupt shortly after SMax. Evidence of the Geyser Hill Wave is harder to see on the north and west sides of Geyser Hill. It is possible that a weaker, time delayed affect is being seen on that side of Geyser Hill. For instance, a rising in the water level of Exclamation Point and Beach Springs may be due to the Geyser Hill Wave. Also, there may be some evidence the Aurum Geyser's intervals show a Geyser Hill Wave type of fluctuation.

 

Intermittent Spring:

Intermittent Springs are are hot springs that exhibit occasional overflow, often at predictable intervals.

 

Interval:

There are two definitions for Interval in common usage.

 

The first, often used in general conversations in Yellowstone and on these pages is: The period of time from the START of one eruption to the START of the next eruption. Some scientific publications refer to this as IBE, Interval Between Eruptions.

The second, often used in publications and outside Yellowstone (New Zealand for instance) is: The period of time from the END of one eruption to the START of the next eruption.

Major/Minor:

For geysers with two types of eruptions distinguished by size and/or duration, the larger is called a major and the smaller is called a minor. Lion Geyser, Castle Geyser and North Goggles Geyser are examples of geysers that have major and minor eruptions.

Perpetual Spouter:

A spouting spring that looks like a geyser but does not stop. While related to geysers, there are functional differences in how they erupt.

Preplay:

The activity by a geyser prior to the eruptions. Such activity can be as little as light overflow and bubbling to heavy overflow, splashing and surging. The preplay is often watched to determine if a geyser is ready to erupt.

 

Series:

An active period wherein the geyser erupts repeatedly. A series is over when the geyser takes a long break. Such a geyser can also be called a cyclic geyser. Lion Geyser is a good example of a geyser that erupts in series.

 

Siliceous Sinter:

The deposit of noncrystaline silica that is formed by most hot springs and geysers.

 

Sinter:

Any form of of hot spring deposit regardless of chemical composition. See also siliceous sinter. Sinter deposits form the characteristic gray rock formations seen in the geyser basins.

 

Steam Phase:

The part of an eruption (typically occurring after the water phase) that is mostly steam. The transition from water to steam is usually gradual. A major eruption of Castle Geyser is an example of a geyser with a steam phase.

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