A recent study published in the June 2012 issue of the
Quaternary Geochronology, conducted by a joint research team from Washington State University and the Scottish Universities Environmental Research Center, indicates that the largest Yellowstone eruption on record, Huckleberry Ridge (forming the Island Park Caldera), was actually three seperate eruptions at least 6,000 years apart. The last significant explosive eruption of Yellowstone, Lava Creek, was 640,000 years ago.
The study employs an improved dating methodology, using potassium 40 and argon 40 isotopes (
40Ar/39Ar), which reduces the error margin. Darren Mark, study co-author at the Scottish research center, helped fine tune the dating technique to improve it by 1.2 percent, to a precision of 0.2%, an exponential improvement in accuracy.[
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According to the study, the three members of the Huckleberry Ridge eruption (A, B, and C) are 2.135 ± 0.006 Ma, 2.131 ± 0.008 Ma, and 2.113 ± 0.004 Ma, respectively, with eruption volumes of 820, 1340, and 290 km
3, respectively.
While the study indicates that the ejected volume of the largest Yellowstone eruption, Huckleberry Ridge, is "reduced by 12% from previous estimates", it also indicates that, "explosive eruptions from the Yellowstone volcanic field
occurred more frequently, producing
more homogeneous magma than was previously believed" (from the paper's abstract). That magma consistency, its "homogeneity", has bearing on the likelihood of an explosive eruption.
“This research suggests explosive volcanism from Yellowstone is
more frequent than previously thoughtâ€, indicated study co-author Ben Ellis of Washington State University.[
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Also, while that Huckleberry Ridge eruption volume is reduced by 12%, it should be noted that Huckleberry Ridge is still 2.2 times the eruption volume of the second largest Yellowstone eruption, Lava Creek -- 640,000 years ago, which is still a VEI of 8. Lava Creek had 1,000 times the eruption volume of Mt St Helens.