In March 2018, one of Yellowstone National Park’s 10,000 thermal features suddenly sprang back into action. After 34 years of sporadic activity, the world’s tallest active geyser reawakened. Since then, Steamboat Geyser has delighted visitors with almost weekly eruptions. Although the reason for reawakening isn’t known, a recent paper in the Proceedings of the National Academy of Science (PNAS) reassuringly reports that it does not signal an imminent volcanic eruption.
World’s Tallest Active Geyser Wakes Up
After only sporadic activity for 34 years, Steamboat Geyser in the Norris Basin of Yellowstone National Park woke up in March 2018. The National Park Service records of geyser activity since then show more than 100 instances at a median interval of just around 7 days, with all activity falling at intervals of roughly 3 to 35 days between events.
Driven by magma activity deep underground, geysers expel superheated water through fissures in the overlying rock layers. Steamboat’s eruptions blast from two vents and last between 3 and 40 minutes. This is followed by steam venting, which NPR likens to standing next to a jet engine, and this can last from several hours to several days
What Woke Steamboat Up?
Because Steamboat Geyser sits on top of the massive Yellowstone supervolcano, the researchers wanted to find out why the activity had begun again. With it being only sporadically active historically, and with a gap of around 50 years recorded prior to a cluster of eruptions in the 1960s, finding out what pokes it into life is tricky.
Despite Yellowstone having a wealth of hydrothermal features, getting equipment into the precise location for continual data collection is difficult. However, recording techniques are becoming increasingly more sophisticated. The research team was able to access many different sources for their recent report, including GPS data and seismic data reaching back to 2003, according to Science News.
Even with all the data available, there was still no clear answer to what woke the geyser. GPS data showed the area did experience uplift from magma intrusion, which is what makes the Norris Basin rise and fall. Sensors also showed an increase in regional seismic activity with elevated radiant temperature from heated underground water reservoirs and rock spilling into the surrounding air. However, because none of the other geysers became more active during this period, the scientists discounted these as triggers. Likewise, as Smithsonian Magazine reports, the activity is not the precursor to a Yellowstone eruption.
What Controls Steamboat, and Why Is It the World’s Tallest Geyser?
Scientists didn’t find the trigger, but they did learn more about what might control the intervals between eruptions. Although precipitation and snowmelt didn’t appear to trigger activity, data showed that the eruption cycles were longer in the summer. This suggests that groundwater accumulation might influence the geyser. It’s also possible that the trigger for the uptick in activity is a change in local hydrothermal system conditions. As NPR notes, the ingredients for a geyser include water, heat and a structure that creates pressure by restricting flow. For example, rock porosity and permeability can affect the way that the superheated water escapes from the vents.
Steamboat isn’t the oldest geyser in Yellowstone. Old Faithful has been venting for thousands of years, whereas Steamboat only let rip in 1878, according to PNAS. However, during their analysis, the research team discovered an interesting fact that could explain why it is the world’s tallest. Steamboat’s water reserves lie deeper under the surface. This means that not only is the water hotter because it’s closer to the underlying magma, but it’s also at a greater pressure.
Geysers as Simplified Volcanoes
Analysis of the data hasn’t answered all the questions, but understanding more about geysers and how they are triggered could help volcanologists understand magmatic volcanoes. As The New York Times notes, geysers are simplified volcanoes. Better forecasting could help to predict volcanic and hydrothermal activity.
Regardless of the lack of conclusion, the scientists behind the PNAS paper describe the results as “a window into multiphase hydrothermal systems.” They note that further studies could provide insight into this kind of activity here on Earth as well as in off-world situations, such as those seen on Saturn’s moon, Enceladus.
Meanwhile, a quick glance at the data from Geyser Times is enough to show that Steamboat Geyser is still wide awake.