(Sound effect: fuse) Short fuse. (Sound effect: volcanic eruption)
I'm Bob Karson with the discovery files--new advances in science and engineering from the National Science Foundation.
(Sound effect: volcanic rumblings) Volcanic eruptions like Mt. St. Helens are serious events but there's a category of eruption 100 times that size--the "super-eruption." When earth saw one of these 74,000 years ago in what is now Indonesia, it nearly choked off the whole human race. A massive cloud of super-heated gas, rock and ash covered whole continents. Geologists generally believe super-eruptions are produced by (Sound effect: volcanic pool bubbling) giant pools of magma that form below the surface, then simmer for 100 to 200-thousand years before erupting. But a new Vanderbilt University-directed study says that, once they form, these magma pools can only exist for a few thousand, perhaps only a few hundred years, before erupting.
(Sound effect: light digging, scraping) The team took samples from the site of an earlier super-eruption--Bishop Tuff in east-central California. Four independent lines of evidence showed that the magma pool most likely formed just 500 to 3000 years before the eruption. The researchers say this time scale means geologists need to regularly monitor sites like Yellowstone, where super-eruptions are likely to occur. (Sound effect: eruption) There's nothing known to present science that can stop one of these, but understanding the mechanisms could help us get better prepared.
"The discovery files" covers projects funded by the government's national science foundation. Federally sponsored research--brought to you, by you! Learn more at nsf.gov or on our podcast.