A normally docile hot pool in Yellowstone National Park took a dramatic turn over the weekend, spewing water and other debris in the biggest eruption since 1957. Ear Spring, located on Geyser Hill in the park’s Upper Geyser Basin, erupted water that reached 7 to 10 meters (20 to 30 feet) high on Saturday, ejecting rocks and other things that had fallen into the geyser over the last few years, including coins, old cans, and other human debris, reports the US Geological Survey (USGS).
Geyser Hill is located across the Firehole River (seriously, who had the job of naming these features?) from the park’s most famous thermal feature, Old Faithful. The area hosts dozens of other hot springs, geysers, and fumaroles – a vent in the Earth’s surface where gases and steams emitted. According to the USGS, hydrothermal activity at several of these features has changed since last weekend’s eruption while other thermal features appear to be more active than usual.
Most interestingly, another feature has formed overnight on September 18 that is now located directly under the Ear Spring, forcing the park to close off parts of it. This new feature is “pulsing water,” and a 2.5-meter-wide (8-foot) area of ground surrounding the new hole is “breathing,” rising and falling by about 15 centimeters (6 inches) every 10 minutes.
But don’t go hitting the Yellowstone Caldera Panic Button just yet. Though it sounds like a scene straight out of Dante’s Peak, the hydrothermal activity is in no sense signaling that the supervolcano is about to erupt. Changes in hydrothermal features are common. Shifts in the hydrothermal systems happen just a few hundred feet below the Earth’s crust and they’re not directly related to magma, which moves around several kilometers deep.
“There are no signs of impending volcanic activity,” wrote the USGS. “There has been no significant increase in seismicity nor broad-scale variations in ground movement.”
What happens next is still uncertain, but most likely one of two things will occur. Either this thermally heated ground continues to expand and cause changes in thermal activity for the next few years – just like what happened in the Norris Geyser Basin in 2003 – or a small hydrothermal explosion happens, creating a crater a few feet across and ejecting rocks and hot water hundreds of feet in the air – like what happened in 1989 at the Porkchop Geyser.
Chances are, the crowd’s favorite geyser, Old Faithful, will probably stay the same as it is. Geyser Hill and the beloved geyser have separate hydrothermal plumbing systems and behave independently of each other.