Yellowstone National Park has more geysers than anywhere else on the planet. While some of them erupt regularly enough to be called 'Old Faithful', others are not as consistent.
Scientists don't know why Steamboat Geyser erupts when it does or why it spews so much water. In a new study, researchers at the University of California Berkeley explored the answers to these questions.
UC Berkeley geoscience professor Michael Manga said Steamboat Geyser is chaotic.
"What's special about Steamboat Geyser is it's the world's tallest geyser right now," he said. "It's also famous for being episodically active. It will be quiet for decades and all of the sudden it will erupt, and then may erupt many times, and then go quiet again."
UC Berkeley geoscience researcher Mara Reed said Steamboat has been in an active period since 2018. That isn't usually the case. "This is a geyser that can have eruption intervals, the time between eruption starts, between three days and 50 years," she said.
But when Steamboat does erupt, it's something you don't want to miss, said Reed. "Steamboat is really unparalleled when it comes to geysers," she said.. "Its major eruptions can shoot water 380 feet into the air. It's just this massive water column going up when it actually erupts."
Reed said Steamboat is also unique because there's a lot of data on it. People are around to monitor the eruptions and scientists have equipment in place to measure them.
"That's [the data] really neat because that's actually compiled by geyser enthusiasts. That was a crowdsourced effort," she said. "It's really an example of citizen science in action."
Reed and Manga used this data to try to answer a simple question: why did Steamboat start erupting more frequently in 2018?
The most dramatic answer is the idea that the Yellowstone Volcano may be about to erupt.
"We have geysers in Yellowstone because Yellowstone is a volcano," said Manga. "There's magma and molten rock underground that's heating up groundwater and that's the water that erupts at geysers. So, you might think if fresh magma was injected underground, that it releases fluids that could then create new geysers or make Steamboat become active again."
The team measured the temperature of the water in Cistern Spring, which is connected to Steamboat. A warmer temperature might indicate that Yellowstone Volcano is becoming more active.
"Looking at the chemistry of that water and what's kind of dissolved in the water, we can tell roughly what the temperature of the geothermal reservoir supplying water to that spring is," Reed said. "Since 2000, we haven't really found any change, any significant change, in that data."
The fact that there's no change in temperature means that Yellowstone Volcano is not likely to explode.
To make sure of that, they also looked at neighboring dormant geysers. Manga said no other dormant geysers came to life at the same time as Steamboat. He said they also didn't find any unusual earthquake activity.
But they did find one change. They used satellites to look in the infrared (light that is redder than human eyes can see) and measure how much heat the Yellowstone area was emitting into space. That can act as another measure of volcano activity. That value did increase over time, but only slightly.
Manga said this isn't strong evidence for a Yellowstone Volcano eruption in the near future, but they can't completely rule it out.
That doesn't explain why Steamboat's eruption schedule is so erratic. They found more frequent eruptions in the summer than the winter. Manga said that's because there's more water available in the summer. But he said more frequent eruptions do not mean smaller eruptions.
"One thing we did not find is a relationship between how much water erupts and how long you have to wait between eruptions," said Manga. "That was unexpected. We would have guessed that if you have a really big eruption—a lot of water erupts—then you have to wait longer for the next eruption. And we don't see that relationship."
Manga said Steamboat might be so irregular because it's underground pathways are changing. "The water that's erupting at geysers is always dissolving and re-precipitating minerals underground and that can change the plumbing system," he said. "If you change the pathways through which water is moving, you're also changing the way the geyser can behave."
Reed and Manga said they still aren't really sure what set off the current period of activity, but their research has given them other ideas to explore in the future.
