A UC Berkeley earth sciences professor named Michael Manga reported on their findings regarding Old Faithful’s geyser in the February issue of the Journal of Volcanology and Geothermal Research. The short version for why the geyser has such stunning regularity turns out to be related to the plumbing. Any kinks or twists in the pipes cause pressure to build up along the way, resulting in a schedule that tourists can plan their day against.
“Most geysers appear to have a bubble trap accumulating the steam injected from below, and the release of the steam from the trap gets the geyser ready to erupt,” Manga said in a statement. “You can see the water column warming up and warming up until enough water reaches the boiling point that, once the top layer begins to boil, the boiling becomes self-perpetuating.”
Manga came to this realization by studying geysers in both Yellowstone National Park and Chile. They also built an artificial geyser out of glass and tubing in order to test their hypothesis in a lab setting.
“At many geysers it looks like there is some cavity that is stuck off on the side where steam is accumulating,” Manga explained. “So we said, ‘Let’s put in a cavity and watch how the bubble trap generates eruptions.’ It allows us to get both small eruptions and big eruptions in the lab.”
Over the long term, Manga hopes these studies may be applied to volcanic eruptions due to their similarities. It’s certainly easier to drop instruments into boiling water and steam rather than the molten earth produced by a volcano. But that does not mean the existence of geysers like Old Faithful are not interesting in and of themselves.
“One of our goals is to figure out why geysers exist – why don’t you just get a hot spring – and what is it that controls how a geyser erupts, including weather and earthquakes,” he said.
Berkeley has released the Old Faithful video which explains why geysers erupt in the first place. Check it out to see how their do their research in action.