Bulging Earth Under Yellowstone Lake Raises Fears

YELLOWSTONE NATIONAL PARK, Wyo. -- Below the blue waters of Yellowstone Lake, a mysterious dome 2,100 feet across and 100 feet high is causing concern among scientists and citizens who don’t know whether it’s a harmless curiosity or a hazard on the verge of exploding.

The dome, also called a bulge, is less than a mile from shore and was recently explored by researchers with the U.S. Geological Survey, using unmanned submarines and sonar.

"It could be the precursor to a hydrothermal explosion," said Lisa Morgan, a geologist leading the team.

Hydrothermal blasts occur when super-heated water, often under extreme pressure, rapidly flashes to steam, hurling rocks and sometimes gouging out huge craters.

News of the dome comes at a time of increased activity beneath Yellowstone, which experienced a magnitude 4.4 earthquake in August.

In July, the park shut down part of a popular trail near the Norris Geyser Basin because the ground heated up to 200 degrees.

The events have sparked Internet chatter and fear from some that a catastrophe is at hand. But scientists and park officials have cautioned against panic, saying that Yellowstone is intensely monitored for any changes.

Morgan said while the dome may explode, it might just as easily collapse or simply do nothing.
Still, she and park officials are drawing up a hazard-assessment plan just in case.

"A hydrothermal explosion is an extreme event and a rare event but they have happened," Morgan said.

Mary Bay, an area of the lake near the dome, was created by a hydrothermal blast more than 13,000 years ago that scientists consider to be one of the biggest explosions in geologic history.
There are at least five other craters in Yellowstone Lake caused by enormous eruptions.

Exactly what damage an explosion would cause today is being investigated. Morgan said it could eject rocks and poisonous gas and cause waves as high as 20 feet. Whether the damage would spread beyond the park depends on the force of the blast.

"No one has ever witnessed a large hydrothermal explosion. It’s a steam explosion, which can be as powerful as TNT," park geologist Hank Heasler said.

Heasler keeps tabs on the rising temperatures in the park through a network of sensors.

The park, which draws 3 million visitors a year, sits atop one of the most active volcanoes on Earth, a deep caldera 45 miles long and 30 miles across, with more than 10,000 vents, geysers and bubbling pools of hot water.

Scientists compare the place to a piecrust expanding with steam then subsiding as heat escapes through the crust.

Geologists estimate that the last big eruption happened 640,000 years ago, when the volcano sent ash as far south as Texas.
Scientists say it was 1,000 times more powerful than the Mount Saint Helens cataclysm in 1980. There have been 30 eruptions since.

The lake floor remained largely a mystery until researchers using cameras on robot submarines began exploring it.

Down among the shadows, the team saw more than 250 thermal vents, fissures, geyser basins and columns of silica soaring 30 feet high.

"Everyone is paying attention to the bulge, but it’s only one feature," said Morgan, who has studied the lake for five years. "We found extensive fault systems and landslides. When you think of all the seismic energy that could be released, it could be extreme."

A Web site claims Yellowstone "will blow its cork" in the next six months, causing "the three days of darkness spoken of in the Bible."

Such talk confounds park officials and scientists.

"We say the park is safe," said Yellowstone spokeswoman Cheryl Matthews.

Source: The LA Times/The Salt Lake Tribune http://www.sltrib.com/2003/Nov/11252003/nation_w/114284.asp

Very interesting. I remember hearing something about this, but not as detailed as this article. Thanks for posting it!
Susan

This does not surprise me at all, and I find it amazing that as many people are as surprised as they are.

I have been to Yellowstone many times, mostly in the 1970's.  When I was younger, I was a real rockhound, and did a lot of research on Plate Tectonic theory, vulcanism and earthquakes.

I clearly remember going to Mammoth Terraces Hot Springs there in around 1972, and seeing that the terraces were "dying".  From what my grandparents told me, the flow was much lower then it was 5 years before, and the colours were much dimmer then they used to be.

We went there again in 1976, and Mammoth was almost dead.  But around the corner was the beginning of a new terrace.  The colours were bright, and the water was flowing from it very rapidly.  A geologist was there studying it, and told me that it was moving.  He pointed out to me an old terrace further down the trail that was dead with plants growing on it.  He pointed out to me how it was moving in a line, and would eventually move to the other side of the hill (in a few thousand years).

On the same trip we bought a Super 8mm movie (remember those?) that was shot in the 1960's.  It showed Mammoth as a very active and vibrant terrace.  In the 15 or so years since that film was shot, it had changed dramatically.  I would love to go there now 27 years later and see how much more it has changed.

Most people only see Yellowstone as a park with geyser and buffalo.  I see it as a very geologically active area, which is still changing and growing.  I remember going into the back areas on foot, and seeing small geysers forming and some hot pools growing while others died.

The Pacific-Northwest is covered with volcanos, guysers, and hot springs.  There is even a section of Boise that has it's homes heated by natural hot springs, and has been doing that for over 100 years.

And Mt. Saint Hellens proves this fact.  Just driving through Idaho, Oregon, Washington, Montana, and Wyoming will prove how geologically dynamic that area is.  That the area has gone so long (over 150 years) without more visible evidence is a surprise to me.  While I hope this volcano does not happen, that it someday will is unevitable.  But I would not buy into the hype of the "end of the world" types.

But it will make me try and catch Yellowstone in the next few years.  I would love to see how much has changed since I have been there last.