Yellowstone Caldera Chronicles is a weekly column written by scientists and collaborators of the Yellowstone Volcano Observatory. This week's contribution is from Jamie Farrell, assistant research professor with the University of Utah Seismograph Stations and chief seismologist of the Yellowstone Volcano Observatory.
There's been a lot of talk about Steamboat Geyser recently, and rightly so — major eruptions over the past several weeks have been occurring with surprising regularity (every six to eight days), and the nine eruptions in 2018 ended a period of quiet that lasted 3.5 years. Most of the 2018 eruptions occurred at night or during times when the area was closed to visitors. On June 4, however, the geyser put on a show starting at about 9 a.m. And YVO scientists were on site to witness the spectacle. I was one of those scientists.
Given the increased activity of Steamboat Geyser in 2018, the University of Utah, in conjunction with Yellowstone National Park, installed an array of 28 seismic stations around the geyser in early May. These seismometers, known as nodals, are small, self-contained instruments that spike into the ground and can record ground movement in all three directions (vertical, north-south and east-west) for about 30 days before their batteries run out.
The goals of this experiment were two-fold:
- Record all signals related to the build-up, eruption (water-phase and steam-phase) and post-eruption to learn how Steamboat Geyser works and see if there are any precursory signals leading up to an eruption.
- Create an image of the subsurface around Steamboat Geyser to better understand its plumbing system and how/if it is connected to nearby thermal features.
The instruments were removed after recording for 30 days — a time period that spanned four major eruptions of Steamboat Geyser. In addition, instruments were placed close to nearby features that are known to have subsurface connections to Steamboat, like Cistern Spring (which drains in response to Steamboat eruptions) or that are hypothesized to have some connectivity (like Echinus Geyser and Emerald Pool).
While at Norris Geyser Basin to remove the instruments on June 4, we were lucky enough to witness the major eruption of Steamboat that began at around 9:04 a.m. The eruption began with what is called the water phase. On this particular day, the water phase lasted for around 30 minutes. Hot, silica-rich water erupted to heights beyond 200 feet.
If there was one thing to remember about the Steamboat eruption, it was the noise. The "roar" was just as impressive as the visual spectacle. Every once in a while rocks, some baseball sized, were ejected with the water to astonishing heights.
After 30 minutes, Steamboat entered into what is called the steam phase. Here, the eruption is dominated by the high-speed ejection of steam with a sound that reminds one of a jet engine. This phase can last for hours to days.
The eighth Steamboat eruption of 2018 will definitely be a memory that I will not soon forget — and it was witnessed by a large number of visitors (and also their vehicles, some of which were caked with silica-rich water ejected by the geyser). It was refreshing to see so many people excited about this geologic feature.
If you want to witness a major eruption of Steamboat yourself, it has been erupting every six to eight days over the past several weeks. Do the math, and check it out for yourself. Maybe you'll be as fortunate as I was and get to take home an exceptional memory of the tallest currently active geyser in the world in full eruption.
Note: Just as this article was finished, Steamboat erupted for a ninth time in 2018 — at about 1:06 a.m. on June 11. The pattern continues.