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Hydrothermal Monitoring in Yellowstone National Park

Yellowstone was established as the world’s first national park primarily because of its extraordinary geysers, hot springs, mudpots and steam vents, as well as other geologic features. YVO scientists monitor these hydrothermal features as part of an effort to research and preserve them.

Steamboat Geyser in eruption Norris Geyser Basin, 1964. National Pa...
Steamboat Geyser in eruption Norris Geyser Basin, 1964. National Park Service photo. (Public domain.)

Heat and volcanic gases rise from the Yellowstone magma storage region and warm the salty water that occupies fractured rocks above it. That brine, in turn, transfers its heat to overlying fresh groundwater, which is recharged by rainfall and snowmelt from the surface. This superheated water can flash to steam, propelling both steam and hot water to the surface as a geyser. The hot water also creates mudpots, hot springs, and steam vents. 

The cornerstone of Yellowstone's hydrothermal monitoring program is to collect temperature data from hydrothermal areas using both ground-based and airborne methods. Temperature measurements recorded at 30- to 60-second intervals are made with thermal sensors placed in geysers runoff channels in the Upper Geyser Basin, Lower Geyser Basin, and Norris Geyser Basin. When temperatures exceed a certain baseline for a certain duration, a geyser eruption is implied. This method allows us to continually record the activity of specific geysers and thereby gain insight into the dynamics of the underlying hydrothermal system.

The monitoring program also gathers 1 meter (3.3 ft) resolution and 1 °C (34 °F) accuracy thermal infrared imagery from helicopter and satellite images to see large-scale changes in Yellowstone’s hydrothermal features. Objects on Earth's surface—such as hydrothermal features—emit energy related to their temperature. Although hydrothermal features are not hot enough to emit visible light, they do emit thermal infrared light that can be detected by specific sensors. This method allows us to detect changes in heat flow from hydrothermal areas over time.

Near-real time temperature measurements can be viewed online for thermal features in Norris Geyser Basin.

Satellite thermal infrared temperature map of Yellowstone National Park's thermal areas. Maps like this can be used to assess changes in thermal areas over time, and also estimate the heat output from Yellowstone. Lakes and rivers are blue. The Yellowstone Caldera is black. Roads are yellow. (Credit: Vaughn, Greg. Public domain.)

Satellite-based thermal remote sensing provides a view of Yellowstone’s heat over a large area.

Satellite-based thermal infrared remote sensing provides a view of nearly all the thermal areas in the Park at once, but there are challenges and limitations. For example, the temperature of Yellowstone's thermal areas is often not much higher than the temperature of the surroundings during the day, because the Sun heats the Earth's surface. Using thermal infrared images that are acquired at night minimizes the influence of the Sun, allowing us to estimate just the geothermal component of the temperature. These night time images are especially useful for measuring areas in the park that are not easily accessible.

Overall, research in thermal infrared remote sensing of Yellowstone has helped assess and update maps of the Park's thermal areas, created new thermal anomaly maps, estimated the geothermal heat output, and established background thermal patterns. Examination of how these maps change over time will provide important evidence for how both natural and human-induced processes affect some of Yellowstone's most iconic features.

For more information on mapping Yellowstone's thermal areas from space, check out Scientific Investigations Report 2014-5137.