Sunday, March 05, 2006



Yellowstone National Park is one of my favorite places. You might have read about renewed geothermal activity at the park. The March issue of Nature has an article about how a large blob of the earth within Yellowstone Park has risen over the past five years.

The LA Times reported on March 4th that "The bulge, about 25 miles across, rose 5 inches from 1997 to 2003 and may have triggered some thermal unrest at Norris Geyser Basin, including a sudden rise in temperatures, new steam vents and the awakening of Steamboat geyser, the team reported in the current issue of the journal Nature. It is presumed to be caused by the movement of molten rock."

The Great Falls Tribune reported "Steamboat geyser erupted in May 2000 after nine years of dormancy and then erupted five more times between 2002 and 2003. Porkchop geyser also sprang to life after 14 years of dormancy.

Ground temperatures at Norris, the hottest and most unstable geyser area in the park, rose so high in 2003 that Yellowstone officials closed some boardwalks.

And just north of Norris near Nymph Lake, a series of steam vents churned and emitted white clouds of gas.

Scientists studying the shore of Yellowstone Lake found that the caldera has been rising and falling for at least 15,000 years, sometimes swinging more than 10 feet."

All of this is very exciting, since I studied the various geyser basins before and during my Yellowstone visit, and am very interested in going back again.

Here's a photo of one of my favorite terraces in the park. I remember walking beside the very large and intensely detailed structures and thinking how it looked like it was made from dried egg whites and sugar.

Here's a map of the various calderas in the park. The volcano is one of the largest on the planet, and is 40,000 years past due for an eruption. The last major eruption was 640,000 years ago and was of global significance.

Here's another groovy map of the main caldera. This gives an idea of the size of the volcano. Compare this to the size of Mt. St. Helens.

Image above and text below from

"The Yellowstone Caldera. The best estimate of the caldera rim is shown salmon. White arrows show interpreted magma migration paths. The red symbols mark volcanic centers that erupted after the caldera formed 640,000 years ago. The areas of known past or present thermal activity are colored yellow. Credit: R.L. Christiansen/USGS"

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