Old Faithful is a cone

geyser A geyser (, ) is a spring characterized by an intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only ...

Yellowstone National Park Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is border ...

in Wyoming, United States. It was named in 1870 during the

Washburn–Langford–Doane Expedition The Washburn Expedition of 1870 explored the region of northwestern Wyoming that two years later became Yellowstone National Park. Led by Henry D. Washburn and Nathaniel P. Langford, and with a U.S. Army escort headed by Lt. Gustavus C. Doane ...

and was the first geyser in the park to be named. It is a highly predictable geothermal feature and has erupted every 44 minutes to two hours since 2000. The geyser and the nearby Old Faithful Inn are part of the Old Faithful Historic District.

History

In the afternoon of September 18, 1870, the members of the Washburn-Langford-Doane Expedition traveled down the

Firehole River The Firehole River is located in northwestern Wyoming, and is one of the two major tributaries of the Madison River. It flows north approximately from its source in Madison Lake on the Continental Divide to join the Gibbon River at Madison Ju ...

from the Kepler Cascades and entered the

Upper Geyser Basin The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles. The number of thermal features in Yellowstone is estimated at ...

. The first geyser that they saw was Old Faithful. Nathaniel P. Langford wrote in his 1871 Scribner's account of the expedition: In the early days of the park, Old Faithful was often used as a laundry:

Eruptions

More than 1,000,000 eruptions have been recorded. Harry Woodward first described a mathematical relationship between the duration and intervals of the eruptions in 1938. Old Faithful is not the tallest or largest geyser in the park; those titles belong to the less predictable Steamboat Geyser. The reliability of Old Faithful can be attributed to the fact that it is not connected to any other thermal features of the

. Eruptions can shoot of boiling water to a height of lasting from to 5 minutes. The average height of an eruption is . Intervals between eruptions can range from 60 to 110 minutes, averaging 66.5 minutes in 1939, slowly increasing to an average of 90 minutes apart today, which may be the result of

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...

s affecting subterranean water levels. The disruptions have made earlier mathematical relationships inaccurate, but have actually made Old Faithful more predictable in terms of its next eruption. After the Borah Peak earthquake in central

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and W ...

in October 1983, the eruption intervals of Old Faithful were noticeably lengthened. Old Faithful eruptions graph

The time between eruptions has a

bimodal distribution In statistics, a multimodal distribution is a probability distribution with more than one mode. These appear as distinct peaks (local maxima) in the probability density function, as shown in Figures 1 and 2. Categorical, continuous, and dis ...

, with the mean interval being either 65 or 91 minutes, and is dependent on the length of the prior eruption. Within a margin of error of ±10 minutes, Old Faithful will erupt either 65 minutes after an eruption lasting less than minutes, or 91 minutes after an eruption lasting more than minutes.

Measurement

Between 1983 and 1994, four probes containing temperature and pressure measurement devices and video equipment were lowered into Old Faithful. The probes were lowered as deep as . Temperature measurements of the water at this depth were , the same as was measured in 1942. The video probes were lowered to a maximum depth of to observe the conduit formation and the processes that took place in the conduit. Some of the processes observed include fog formation from the interaction of cool air from above mixing with heated air from below, the recharge processes of water entering into the conduit and expanding from below, and entry of superheated steam measuring as high as into the conduit.

Images

References

External links