Vibrating water surface in Double Pools in Yellowstone National Park. Credit: Jimmy Farrell/University of Utah
It is famous for Yellowstone National Park Old Believers, geysers with periodic and somewhat predictable volcanic eruptions that delight visiting tourists. But it’s also home to many others geothermal features Criticism Double pool, a pair of hot springs connected to a small neck with geothermal energy equivalent to a pulse. The pool “hits” every 20-30 minutes, causing the water to vibrate and the floor to vibrate. Researchers at the University of Utah measured the massive cycle with a seismometer to learn more about how it changes over time. Among other findings, they found that the periods of silence between attacks correlated with the amount of heat flowing into the pool new leaf Published in Geophysics Research Letters.
“We know Doublet Pool appears every 20-30 minutes,” said co-author Fan Zhi Lin, a geophysicist at the University of Utah. “But there isn’t much prior knowledge about what controls variance. In fact, I don’t think a lot of people really realize that mega-intervals vary. People pay more attention to heaters.”
The hydrothermal system that developed at Yellowstone was the result of the interaction of shallow groundwater with heat from a hot magma chamber. The system features approximately 10,000 geothermal features, including steam vents (fumaroles), clay pots and limestone terraces (white limestone), as well as geysers and hot springs.
In the case of geysers, the high pressure prevents the water in it from boiling. But as the hot water rises, the pressure drops and steam bubbles form, which expand until they are too large to pass through the geyser’s narrow channels near the surface. Eventually the bubbles reach a critical threshold and the heater starts flowing. The pressure drops sharply and the water boils, creating massive amounts of steam that forces jets of hot water out of the vent in one of the most satisfying volcanic eruptions. Then the cycle starts again.
In contrast, most hot springs maintain a fairly stable hydrodynamic balance. The superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below, so the water never reaches the desired temperature for an eruption to occur. However, some hot springs, such as Doublet Pools and Iodine Pools in New Zealand, have fuzzy periodic outcrops that resemble the pattern of periodic geyser eruptions: When bubbles of hot water vapor reach the top of a cooler channel, they suddenly collapse with a kick. . .
By studying the Doublet Pool, Lin and his authors hope to learn more about dynamic hydrothermal processes at Yellowstone. They specifically wanted to explore what controls the differences that occur during a hot spring’s burst or hot spring’s beating cycle, so they decided to focus on measuring the quiescent period between attacks. From fall 2015 to November 2021, they ran several sampling experiments with geophones installed near the Doublet Pool. They also collected temperature data in November 2021 and pressure data to monitor changes in water levels over four days in April 2022.
flexible et al. He found that periods of silence varied not only from year to year but also from hour to hour or day to day. For example, the interval was around 30 minutes in November 2016 but only 13 minutes in September 2018, and increased to about 20 minutes in November 2021. It happened exactly on September 15, 2018, around ear spring It erupted for the first time since 1957, and after that the water boiled in a double ball. According to the authors, all that heat and pressure eases up in 2021, so Doublet Pool’s quiet periods are starting to return to their normal 30-minute duration.
For daily and hourly differences, the authors suggest there may be a correlation with wind speed. Higher wind speeds appear to be linked to longer periods of stillness, meaning the wind somehow dissipates heat energy from the water, like blowing over a hot cup of coffee. “Right now, we treat the pool as a complete system, which means that the energy drawn from the surface makes it difficult for the system to accumulate enough energy to crash into it.” said Lynn. “One possibility is that the pond is transported convectively, so near-surface cooling could affect the pond bottom on a relatively short time scale.”
The authors were also able to calculate the heating rate and amount of heat needed to power the strokes in the Doublet Pool: about 3 to 7 megawatts of power, equivalent to the power output of 100 household stoves. This, in turn, allows them to use the period of silence as a thermometer, to measure how much heat is getting into the pool. (More heat means shorter periods.)
DOI: Geophysics Research Letter, 2023. 10.1029 / 2022GL101175 (about DOIs).
Include image by WikiBunny11 / CCPI-SA
