Old Faithful (geyser)
Old Faithful is a renowned cone geyser located in Yellowstone National Park, Wyoming, celebrated for its frequent eruptions of superheated water and steam. First highlighted to the public in 1870, it earned its name due to the regularity of its eruptions, though they do not follow a precise schedule. On average, Old Faithful erupts approximately every 74 minutes, with variations between 60 and 110 minutes, and each eruption can last from 1.5 to 5 minutes. The geyser reaches heights of 130 to 140 feet (39 to 42 meters) and can release between 3,700 and 8,400 gallons of water per eruption.
Yellowstone National Park, established in 1872 as the first national park in the United States, is home to more than 500 active geysers, making it a unique geothermal area. The park sits atop the Yellowstone Caldera, a massive volcanic structure that contributes to its diverse hydrothermal features. While Old Faithful's activity has been consistently observed, geological changes and events, such as earthquakes, have the potential to alter its eruption patterns over time, raising concerns about its long-term viability. Visitors to the park are drawn to Old Faithful for its remarkable display of nature's power, reflecting the region's rich geological history and cultural significance.
On this Page
Old Faithful (geyser)
Old Faithful is the name given to a well-known geyser in Yellowstone National Park in Wyoming. A geyser is a geothermal feature that emits a fountain of superheated water and steam into the air on an intermittent basis. Old Faithful was first brought to public attention in 1870 and named for its frequent and regular eruptions. Contrary to some belief, the geyser does not follow a precise pattern; however, it does erupt several times a day and can be predicted to within a reasonable degree of accuracy. Old Faithful is an example of a cone geyser, a type noted for the cone of rock sediment that forms around its vent. It is one of many geysers at Yellowstone and has erupted more than one million times since the area became a national park in 1872.
Background
By the mid-nineteenth century, the population of the United States was on the rise and Americans began a push to migrate westward, seeking land and opportunities beyond the Mississippi River. Both private and government-sponsored expeditions were dispatched to explore and document these western lands. The Yellowstone region had long been noted by the native people of the region, but it came to the attention of most Americans when a private expedition explored the area in 1869. A year later, a group known as the Washburn-Langford-Doane Expedition visited the region and returned with a recommendation the area be kept free of private development. In 1872, President Ulysses Grant signed legislation formally declaring Yellowstone a protected area and creating the nation's first national park.
Yellowstone National Park covers 3,472 square miles (8,992 square kilometers) over three US states; 96 percent of the park is located in Wyoming, 3 percent in Montana, and 1 percent in Idaho. It was named for the Yellowstone River, which runs through the area before joining the Missouri River in North Dakota. Yellowstone sits over an active volcano called the Yellowstone Caldera. The caldera is a large volcanic crater about 30 by 45 miles (48 by 72 kilometers) wide; it is often referred to as a supervolcano because it has the capability of producing a massive and devastating eruption. The Yellowstone Caldera last erupted about 174,000 years ago, and scientists do not expect another eruption for at least the next few thousand years.
Overview
The Yellowstone Caldera is responsible for the park's more than ten thousand hydrothermal features, including more than five hundred active geysers—more than half of the total number in the world. A geyser occurs only under rare conditions when water from the surface permeates down into the earth. If the water meets a heat source in a confined space, such as a rock chamber heated from below by magma, it can become superheated to beyond the boiling point. When the water temperature reaches a high enough threshold or the surrounding pressure is reduced, the water explodes through the rock and shoots out of a vent into the air.
While an eruption of Old Faithful was first observed by non–Native Americans about 1864, it was not until 1870 that the geyser was officially named by the Washburn-Langford-Doane Expedition. Legend holds that when the expedition members first saw the geyser, it was in mid-eruption, spewing out a towering plume of water. Amazed by the sight, they also noticed it repeated its activity several times in the day. and half of them remained in the area. Expedition member Nathaniel Langford, who named many of the geysers to "best illustrate their peculiarities," called the geyser Old Faithful in honor of its frequent eruptions.
Old Faithful is not the largest geyser at Yellowstone—that honor belongs to Steamboat Geyser, which can reach heights of 300 feet (91 meters) and emit about a million gallons of water. Steamboat's pattern, however, is unpredictable, often going years between eruptions. Other geysers at the park erupt more frequently than Old Faithful, averaging an eruption every 10 to 20 minutes. Old Faithful's fame is a combination of its size and its frequency.
Reports of Old Faithful's activity spawned a misconception among the public that the geyser's eruptions followed a clockwork-like pattern. While the time of Old Faithful's eruptions can be estimated, they do not occur at fixed intervals. The average time between eruptions is 74 minutes, but that period can fluctuate between 60 and 110 minutes. Park rangers are able to estimate the geyser's next eruption by timing its length from first emission to final splash. On average, if the duration is less than 4 minutes, the next eruption should occur between 40 and 60 minutes; if the eruption is longer than 4 minutes, the next activity should fall within 75 to 100 minutes. Most eruptions last between 1 minute 30 seconds and 5 minutes. Using this formula, park staff can predict the next eruption within a 10-minute window with 90 percent accuracy.
The plume of water emitted by Old Faithful averages about 130 to 140 feet (39 to 42 meters) but can range from 100 to 180 feet (30 to 54 meters). The water temperature at the geyser's vent can reach 204 degrees Fahrenheit (96 degrees Celsius), with steam temperatures topping off at more than 350 degrees Fahrenheit (177 degrees Celsius). Depending on the duration of the eruption, an estimated 3,700 to 8,400 gallons of water can be released. Geologists have discovered the rock chamber that collects the water for the eruptions is located about 50 feet (15 meters) underground. The chamber is estimated to be about 50 feet tall by 60 feet (18 meters) wide and sits just southwest of Old Faithful's vent. The chamber is connected to the vent by a channel that runs at about a 24-degree angle.
Because the area around Yellowstone is geologically active, Old Faithful's eruption patterns are subject to changing forces deep in the earth. On August 17, 1959, a 7.3 magnitude earthquake struck the region, killing twenty-eight people. After the earthquake, the geyser's average daily eruptions fell from 21 to 20—a significant drop for a geothermal feature. At some point in the future, continuing geological activity may alter the unique conditions that allow Old Faithful to remain a geyser. As a result, it may one day cease its eruptions and become extinct.
Bibliography
"About Old Faithful—The Most Famous Geyser in the World." YellowstonePark.com, 22 June 2023, www.yellowstonepark.com/about-old-faithful/. Accessed 21 Nov. 2024.
Bryan, T. Scott. The Geysers of Yellowstone. 4th ed., UP of Colorado, 2008.
Dunn, Dr. N. Genean, and Thomas D. Dunn. Geyser Basins of Yellowstone. Arcadia Publishing, 2014.
"Expeditions Explore Yellowstone." National Park Service, 17 Sept. 2019, www.nps.gov/yell/learn/historyculture/expeditions.htm. Accessed 21 Nov. 2024.
Harris, Ann G., et al. "Yellowstone National Park." Geology of National Parks. 6th ed., Kendall/Hunt Publishing, 2004, pp. 619–33.
King, Hobart. "What Is a Geyser?" Geology.com, geology.com/articles/geyser.shtml. Accessed 21 Nov. 2024.
"Old Faithful Geyser—Upper Geyser Basin." YellowstoneNationalPark.com, www.yellowstonenationalpark.com/uppergeyser.htm. Accessed 21 Nov. 2024.
Oskin, Becky. "Old Faithful's Underground Cavern Discovered." Live Science, 12 Apr. 2013, www.livescience.com/28699-old-faithful-hidden-cavern.html. Accessed 21 Nov. 2024.