Water volumes, heat flow, and solute discharge from Old Faithful Geyser eruptions, Yellowstone National Park, USA

Journal of Volcanology and Geothermal Research
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Abstract

The iconic Old Faithful Geyser in Yellowstone National Park, USA, has attracted a significant amount of research because of the relative regularity and impressive size of its eruptions. Numerous studies have included observations, measurements, and analyses that informed models of geyser eruptions. However, fundamental quantities, including the associated mass and heat discharged, remain poorly constrained. In April 2025 we measured the volume of water from 45 Old Faithful Geyser eruptions using a portable flume in an outflow channel and specific conductance measurements in the Firehole River. We used high-speed video to perform velocimetry, measured changes in water chemistry to calculate the volume of water evaporated along the outflow channels, and used thermodynamic calculations to estimate the volume of water erupted as steam and to quantify the geyser's heat output. The calculated average volume of water discharged by Old Faithful Geyser in each eruption is 27.9 ± 9.4 m3, with no relation between eruption volume and the length of the preceding eruption interval. Video analysis of the eruption's liquid-dominated phase yields similar volumes of 21–30 m3. The calculated heat flow from the geyser is 2.2–2.4 MW and the average annual discharge of chloride, fluoride, and arsenic are 63 tons, 3.9 tons, and 241 kg, respectively. Average annual silica deposition rate on the geyser cone and along the outflow channels is 7 tons. This study provides a methodology for future studies at geysers worldwide and a baseline for monitoring future activity changes at Old Faithful.

Suggested Citation

Hurwitz, S., McCleskey, R., Rudolph, M.L., Peek, S., Roth, D.A., Schott-Atkins, M., Manga, M., Folz Donahue, K.F., Reed, M.H., and Hungerford, J.D., 2026, Water volumes, heat flow, and solute discharge from Old Faithful Geyser eruptions, Yellowstone National Park, USA: Journal of Volcanology and Geothermal Research, v. 474, 108624, 13 p., https://doi.org/10.1016/j.jvolgeores.2026.108624.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Water volumes, heat flow, and solute discharge from Old Faithful Geyser eruptions, Yellowstone National Park, USA
Series title Journal of Volcanology and Geothermal Research
DOI 10.1016/j.jvolgeores.2026.108624
Volume 474
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) Volcano Science Center
Description 108624, 13 p.
Country United States
State Wyoming
Other Geospatial Old Faithful Geyser, Yellowstone National Park
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