BILLINGS, Mont. — A surprise eruption The amount of steam in a geyser basin in Yellowstone National Park, which sent people scrambling for safety as large boulders were thrown into the air, highlighted a little-known danger that scientists hope they can someday predict.
Tuesday’s hydrothermal explosion in Biscuit Basin caused no injuries as dozens of people fled across the boardwalk before the wooden walkway was destroyed. The explosion sent steam, water, rocks and dark-colored dirt about 100 feet into the air.
It emerged in a park filled with geysers, hot springs and other hydrothermal features that attract millions of tourists annually. Some, like the famous Old Faithful, explode like clockwork and are well understood by scientists who monitor the park’s seismic activity.
But the type of explosion that happened this week is less common and understood, and potentially more dangerous, as it happens without warning.
“This makes it clear that even small events — and this one in the scheme of things was relatively small, although dramatic — can be really dangerous,” said Michael Poland, chief scientist at the Yellowstone Volcano Observatory. “We have gotten very good at understanding the signs that a volcano is awakening and may erupt. We don’t have that knowledge base for hydrothermal systems like Yellowstone.”
Poland and other scientists are trying to change that with a nascent monitoring system that was recently installed in another geyser basin in Yellowstone. It measures seismic activity, deformations in the Earth’s surface and low-frequency acoustic energy that could signal an eruption.
The day before the Biscuit Basin explosion, the U.S. Geological Survey published a paper by scientists at the observatory about a minor hydrothermal explosion in April in Yellowstone’s Norris Geyser Basin. It was the first time such an event was recognized based on monitoring data, which was closely examined after geologists found a small crater in the basin in May.
Both explosions are believed to result from blocked passages in the extensive natural plumbing network beneath Yellowstone, Poland said. A clog can cause heated, pressurized water to instantly turn to steam and explode.
Tuesday’s explosion came with little warning. Witness Vlada March told the Associated Press that steam began rising in the Biscoito Basin “and within seconds, it became this huge thing… It just exploded and became like a black cloud that covered the sun.”
March captured widely circulated video of the explosion, which sent debris flying into the air as tourists fled in fear.
“I think our tour guide said, ‘Run!’ And I started running and yelling at the kids, ‘Run, run, run!’” she added.
Scientists don’t know if they will be able to find a way to predict the explosions, Poland said.
Yellowstone encompasses the caldera of a massive, dormant volcano that shows no signs of erupting anytime soon, but provides the heat for the national park’s famous geysers, hot springs, mud pots, and several other hydrothermal features. Although much less common than geyser eruptions, hydrothermal explosions happen frequently enough in Yellowstone to be studied — and they are a safety concern.
For a geologist, seeing one in person is a payday. That’s what happened in 2009, when Montana Tech geology professor Mike Stickney and several other geologists were nearby when one happened near the site of Tuesday’s explosion in Biscuit Basin.
“It was very sudden and without any detectable warning, just sitting on the boardwalk there. It was just a ‘whoosh’ and that was it. No one saw this coming,” Stickney said.
Although it did not register on a sensitive seismometer at Old Faithful, 2 miles away, he estimated the recent explosion was 10 times larger.
In May, after scientists found a crater a few feet (1-2 meters) wide in the Norris Geyser Basin, 18 miles (29 kilometers) north of Biscuit Basin, they consulted acoustic and seismic data from the new Geyser Basin monitoring system. basin to determine that this The explosion happened at 2:56 pm on April 15, just days before the roads opened for the spring tourist season.
However, the data did not include obvious precursors that could potentially be used to develop a warning system someday.
The long-term study of where hydrothermal explosions and other ground disturbances might occur in Yellowstone is the focus of University of Wyoming geology professor Ken Sims, who has used ground-penetrating radar and other techniques to identify problem areas.
The information is critical to building roads and bridges in Yellowstone, he said.
“Whenever you create a super active system like this, you have to pay attention to what’s going on,” Sims said.
A detection system takes time and money to develop, with monitoring stations costing around $30,000 each.
However, even if explosions like the recent one in Yellowstone could be predicted, there is no viable way to prevent them, Poland said.
“One of the things people ask me occasionally is, ‘How do you stop a volcano from erupting?’ You don’t get out of the way,” Poland said. “For any of these activities, you don’t want to be there when it happens.”
___
Hanson reported from Helena, Montana, and Gruver from Cheyenne, Wyoming.
This story originally appeared on ABCNews.go.com read the full story
