Old Faithful, located in the Upper Geyser Basin of Yellowstone National Park, is arguably the world’s most famous geyser. Named by the Washburn Expedition in 1870 for its consistent performance, this natural spectacle draws millions of visitors annually. While not the largest or most regular geyser in the park, its frequent and predictable eruptions make it a celebrated geological feature.
The Typical Eruption Height Range
The column of superheated water and steam from Old Faithful does not reach a fixed altitude; the height varies significantly with every eruption. Eruptions typically propel water to a height ranging between 106 and 184 feet (32 to 56 meters). The average height is approximately 130 to 145 feet. A single eruption can expel between 3,700 and 8,400 gallons of boiling water. The variability in height and volume depends on how much water is superheated and pressurized in the underground conduits before the eruption begins.
The Relationship Between Height and Eruption Interval
A direct correlation exists between the height of an eruption and the length of time until the next one occurs. A taller eruption indicates a greater volume of water was discharged, requiring a longer recharge time. Conversely, a shorter eruption height requires a shorter interval before the geyser can erupt again.
This dynamic is explained by the geyser’s underground plumbing system, a network of narrow conduits and chambers. A longer interval allows more groundwater to seep into the system and be heated by the underlying magma. This extended heating and pressure buildup results in a more powerful, taller eruption that expels a larger amount of water and steam. For example, a shorter eruption duration is followed by an interval of approximately 60 minutes, while a longer duration eruption leads to an interval closer to 90 minutes.
How Old Faithful’s Height is Measured
The measurement of Old Faithful’s eruption height combines traditional observation and modern technology. Historically, park rangers used fixed reference points, such as nearby trees or buildings, to visually estimate the peak of the water column.
Today, scientists utilize more precise tools to collect data on the geyser’s performance. Advanced methods, including laser rangefinders, are employed to determine the height of the water column with greater accuracy. This technology allows researchers to bounce a laser beam off the peak of the water jet, providing a precise distance measurement. These measurements, combined with data from seismographs and temperature sensors, help park staff monitor the geyser’s current behavior and reliably predict its next display.