Yellowstone's Gurgles Nothing to Fear

August 17, 2003
By NICK GEVOCK Chronicle Staff Writer

YELLOWSTONE NATIONAL PARK -- If a recently discovered bulging mound in the bottom of Yellowstone Lake starts spewing toxic gases, tourist Paul Hartloff said, it could be a good news-bad news proposition.

"It will be hard on the fish, but it will take care of the lake trout, that's for sure," the Santa Barbara, Calif., resident joked, referring to the pesky invasive fish wreaking havoc on the lake.

With the curious bulge below the lake and new boiling features welling up in the Norris Geyser Basin, something out of the ordinary is going on in Yellowstone's bizarre underground plumbing.

Searing ground temperatures, bursts of steam and flows of hot water near the trail prompted park officials to close most of the Norris Basin recently.

But this is, after all, Yellowstone -- a geologic freak show of boiling mud, steaming holes and geysers.

If there's one constant at Yellowstone, it's the fact that it's always changing, scientists say.

"This is just part of the change that goes on in Yellowstone," said park geologist Hank Heasler. "I won't say it's normal, because we don't know what 'normal' is."

Whatever is going on underneath Yellowstone is unclear, but all the activity certainly creates an excellent opportunity to learn, said Jacob Lowenstern, a researcher at the U.S. Geological Survey in Menlo Park, Calif.

Measuring the changes

Thus far, it doesn't look like Livingston and Bozeman will be evacuated anytime soon to protect locals from a cataclysmic disaster.

Scientists say there's no evidence that Yellowstone is poised for a powerful eruption, such as the one roughly 600,000 years ago that spewed massive amounts of lava and ash.

If the park were ready to blow, there would be several signs that magma was moving toward the surface.

Earthquakes would be more frequent and stronger.

The ground, while often rising and falling in Yellowstone, would most likely gradually rise.

And the chemistry of many geysers would change.

All of those things are constantly monitored by scientists involved with the Yellowstone Volcanic Observatory, or YVO, a long-running study of the park's volcanology.

If the park was poised for a major eruption, the precursors wouldn't be subtle, Heasler said.

"I doubt you'd need seismographs to know that changes were happening in Yellowstone," he said.

Early signs of an impending outburst would be similar to the 1980 eruption of Mount St. Helens in Washington state. Scientists knew something big was brewing under that peak months ahead of time, although they couldn't predict exactly how big or when the eruption was coming.

The current geologic activity in Yellowstone appears to be much closer to the surface than would be exhibited by magma flows. At such shallow depths, water heated by the earth is driving the changes.

"We're not searching for magmatic fluids," said Bob Smith, a geologist at the University of Utah who has studied the park for three decades. "We think this is a very shallow system."

A deeper peek

Norris is the most dynamic of the park's geyser basins and Lowenstern said it always experiences a flare-up of activity in summer.

But this year is exceptional, with a new mud pot welling up, 200 degree temperatures on the ground and geysers that haven't erupted in years spouting off.

And unlike years past, dramatic improvements in equipment are allowing scientists to peek deeper underneath the park and more precisely record changes in the upper plumbing. They are using precision seismometers and satellite-mapping systems to record the changes.

"Let's say we're doctors and Norris Geyser Basin is our patient," explained Heasler. "Before, we had the ability to take its pulse and temperature. Now we have a stethoscope and an X-ray machine, and we can look inside of it."

The YVO has for years had two-dozen seismographs spread throughout the park. They log earthquakes, which shake the park daily, and also keep track of long-term changes, such as rises or drops in the ground level.

Scientists involved with the YVO have had two seismographs at Norris for a long time. Since the activity swelled up this summer, however, they've brought in five more, and added Global Positioning System satellite mapping equipment.

The precise logs collected by the equipment will show whether anything preceded a major eruption of a geyser, such as another feature draining or boiling over, Lowenstern said.

"We'll be able to look at very subtle things that are going on within the geyser basin," he said. "We can look at fluids actually moving through the subsurface in cracks."

The researchers are also recording the temperature in some of the thermal features, often using long poles to drop a thermometer into a bubbling pool. And they're taking water samples from features, looking for changes in chemistry that might give clues to what's going on.

Hot working conditions

While the science is fascinating, the work to gather the data is hot and sweaty for the handful of researchers let in the basin every day.

Heasler said they wear standard park service uniforms, but add gaiters over pant legs to keep scalding water out of their boots if something boils over. The ground feels like a hot pad.

The smell of pines being roasted by the ground permeates the air.

"It's very heavy and overpowering, not like a light, pine-fresh smell," Heasler said. "You smell a heavy odor that's almost sickeningly sweet."

An occasional cloud of steam that often stinks like rotten eggs drifts by. The scientists keep an eye on each other to make sure no one gets dehydrated or dizzy from the fumes.

The risk from the toxic fumes, however, is minimal because there's so much fresh air in the park, Lowenstern said.

"Any of these gases, if they're concentrated, can be toxic, but in general, the air is well mixed around these geyser basins," he said. "If you're sitting in a crevice with very little circulation, then you might have a problem."

Tourists intrigued

Despite signs blocking the trail and news accounts of the geologic grumbling, tourists aren't spooked at all. In fact, the robust activity at Norris was adding to the already spectacular show in the portion of the basin that remains open.

Echinus Geyser has begun erupting more often and shooting water higher than normal, interpretive ranger Elise Horman said. Just after she finished a walking tour Thursday, the geyser put on a spectacle, spewing water 40 feet in the air.

The threat of Yellowstone blowing up is akin to tornadoes in the Midwest or earthquakes on the West Coast, said Californian Felicie Hartloff, who with her husband Paul spends summers in West Yellowstone.

The geysers are the most active she's seen in 15 years of visiting the park and she's been lucky enough to witness a bunch of eruptions.

But she's not losing sleep over fears of a mushroom cloud of ash, toxic gases or massive flows of lava if the park bursts.

"It's like living in California, you can't worry about the earthquakes," Hartloff joked. "If Yellowstone does blow and we make it, at least we could say we were here."

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