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Question: Will the super volcano in Yellowstone Park blow in the next 100 years?
This is a great question, and one that a lot of people living in Wyoming, Montana, and Idaho would love to have answered. Yellowstone has had 3 super eruptions in the last 2.1 million years, that were between 700 and 6,000 times as big as the 1980 Mt St. Helens event, which devastated much of SW Washington State.
Making an accurate long-term prediction based on only three previous events is almost impossible. If the events were completely random, and there was on average a super eruption every 700,000 years, we could predict that there was a 1 in 7000 chance that there would be an eruption in any 100-year period. There have been 80 smaller eruptions at Yellowstone since the last super eruption 640,000 years ago, which would suggest that we should expect a smaller eruption every 8000 years. The last small eruption at Yellowstone, however, was 70,000 years ago, so either we are really overdue for one, or the volcanic system has entered a quiet phase.
The U S Geological Survey has a volcano monitoring program at Yellowstone that watches for any unusual activity that might indicate that an eruption is likely. Yellowstone is a very active place with lots of small earthquakes, minor uplift events, and changes to the hot springs and geysers occurring every year. In fact, there was a small earthquake swarm with over 2350 earthquakes occurring beneath Yellowstone Park between January 15 and February 7 of 2010. Analysis of earthquake data suggests that there is magma (molten rock) only a few kilometers below the surface, but fortunately, this magma appears to have partly solidified to the point where it is very unlikely to erupt.
Before we have a new eruption, scientists expect that the Yellowstone magma chamber will have to get a new pulse of fresh magma from depth. How much warning would we get if an eruption was going to occur? That is hard to say, but with the extensive monitoring program that is currently in place, we are likely to have days to months of notice before a small eruption, and likely to have months to years of warning before a super eruption. So back to your original question: There is no current activity at Yellowstone that would suggest that a super eruption is likely to occur anytime in the near future, and it is very unlikely that we will have any big eruptions from Yellowstone in the next 100 years. We have learned a lot about volcanoes since Mt St. Helens erupted 30 years ago, but volcanic prediction is still an inexact science, so I hope that my prediction here is correct.
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