These Yellowstone Hot Springs Look Peaceful Until They Start Thumping

In Yellowstone National Park, some hot springs emit a thumping sound that appears peaceful at first glance. Michael Poland, a geophysicist and scientist-in-charge of the Yellowstone Volcano Observatory, captured a photograph of Black Sand Pool, which displays blue water and rising steam near Old Faithful. However, the photograph does not capture the thud caused by the collapsing steam bubbles within the pool. This phenomenon can be heard and felt by visitors at several locations in the park.

Researchers studying Doublet Pool found that the timing of the thumps can change over time, reflecting how heat enters and leaves the pool. During measurements between 2015 and 2021, the pauses between thumping episodes varied from around 20 minutes to approximately 13 minutes. These fluctuations are influenced by factors such as wind, which can carry heat away from the surface, delaying the next round of thumping. When there is more heat stored in the system, the thumping occurs sooner.

By monitoring the thumping patterns in Doublet Pool, scientists can track changes in the area's hydrothermal system. A shorter interval between thumps doesn't necessarily indicate the cause, but it may prompt researchers to investigate nearby springs and geysers for related changes. Each thump provides valuable clues about the underlying heat variations, while visitors can experience the audible and tactile effects of these natural phenomena.