Saturday, May 21, 2011
Yellowstone getting ready to blow? I hope it holds off until after my visit in August...
The nation's oldest park is also one of the most studied. The interest is not just in it's amazing vistas and wildlife, but in the volcanic beast below the park.
Yellowstone sits atop one of the world's biggest, active volcanoes, one capable of laying waste to much of north America.
Scientists keep an eye on it using a network of seismic and GPS sensors.
Professor Emeritus Robert Smith of the University of Utah is one of those scientists. A geophysicist, Smith a leading expert on the Yellowstone super volcano. "We monitor it in real time for earthquake swarms and ground deformation."
He says the park is in constant motion. Visitors can't see it, but the ground at their feet is moving up and down as magma pushes against the thin crust and powers the park's many geysers.
The changes are most evident at the Norris Geyser Basin. Henry Heasler, the Yellowstone Park geologist said, "It changes daily. Sometimes it's hard to keep up with the change near boardwalks because that impacts visitor and employee safety."
"Why are all the hydrothermal features here?" Heasler continued, "The geysers? The mud pots? The steam vents? The hot springs? It's because of the heat beneath our feet."
The heat from the volcano.
And beginning in 2004, volcanic pressure caused an amazing rise at the park: Three-inches a year for five-years.
Professor Smith said, "That's a lot of uplift and it's over an area that's over the entire Yellowstone caldera -- 50-miles long of uplift."
"If you went under a rubber sheet," Heasler said describing the uplift, "And pushed your thumb up, it's not just sticking up where your thumb is, there's like a slope to it."
In fact, as the land has bulged, Yellowstone lake has tilted enough that its water has flooded out trees on the south arms.
And now, the ground is sinking.
And the drop has brought up a whole new set of questions for scientists. "Why haven't the trees emerged again?" asked Heasler. "We don't know." They are watching the data as well as the geothermal features of the park for clues.
At times, those geologists see themselves are doctors monitoring a patient. In this case, the patient took a deep breath (between 2004-09) and now it is letting it out. That much is clear from the observations.
The unanswered question is, "why?"