“The eruption of super-volcanoes dwarfs the eruptions of recent volcanoes and can trigger planetary climate change by inducing Ice Ages,” says this article in the Daily Mail.
“One such event was the Huckleberry Ridge eruption of present-day Yellowstone Park about two million years ago, which was more than 2,000 times larger than the 1980 eruption of Mount St. Helens in Washington.”
What allows those volcanoes to grow so large?
Scientists at Oregon State University (OSU) think they have found the answer.
“The creation of a ‘halo’ of rock around the magma chamber allows the pressure to build over tens of thousands of years, resulting in extensive uplifting in the roof above the magma chamber,” says Patricia Gregg, lead author of an OSU modeling study.
Repeated intrusions of magma from below heat the surrounding rock and make it malleable.
That increase in ductility* allows the chamber to grow without erupting, whereas when magma chambers are smaller, they may relieve the pressure through frequent small eruptions.
‘You can compare it to cracks forming on the top of baking bread as it expands,’ says Gregg.
Eventually, however, the cracks grow in size and propagate downward toward the magma chamber and trigger a collapse – and then eruption.
“Gregg said that despite its explosive history, it doesn’t appear that Yellowstone is primed for another super-eruption anytime soon.
‘The uplift of the surface at Yellowstone right now is on the order of millimeters,’ she explained.
‘When the Huckleberry Ridge eruption took place, the uplift of the whole Yellowstone region would have been hundreds of meters high, and perhaps as much as a kilometer.’
“Other super-volcano sites include Lake Toba in Sumatra, the central Andes Mountains, New Zealand and Japan.”
See entire article, including photos:
Thanks to Linda Binutti for this link
* Ductility: A solid material’s ability to deform under tensile stress.