Tag Archives: pyroclastic flows

Supervolcanic Ash Can Turn To Lava Miles From Eruption, MU Scientists Find

“Viscous heating” can reheat volcanic ash enough to convert it to lava

COLUMBIA, Mo. ­— Supervolcanoes, such as the one sitting dormant under Yellowstone National Park, are capable of producing eruptions thousands of times more powerful than normal volcanic eruptions. While they only happen every several thousand years, these eruptions have the potential to kill millions of people and animals due to the massive amount of heat and ash they release into the atmosphere. Now, researchers at the University of Missouri have shown that the ash produced by supervolcanoes can be so hot that it has the ability to turn back into lava once it hits the ground tens of miles away from the original eruption.

Following a volcanic eruption, lava typically flows directly from the site of the eruption until it cools enough that it hardens in place. However, researchers found evidence of an ancient lava flow tens of miles away from a supervolcano eruption near Yellowstone that occurred around 8 million years ago. Previously, Graham Andrews, an assistant professor at California State University Bakersfield, found that this lava flow was made of ash ejected during the eruption. Following Andrew’s discovery, Alan Whittington, an associate professor in the University of Missouri department of geological sciences in the College of Arts and Science, along with lead author Genevieve Robert and Jiyang Ye, both doctoral students in the geological sciences department, determined how this was possible. (more…)

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Before the Explosion – Volcano’s Warning Tremors Explained

No matter their size or shape, explosive volcanoes produce tremors at similar frequencies for minutes, days or weeks before they erupt. In the Feb. 24 issue of the journal Nature, researchers at Yale University and the University of British Columbia describe a model that explains this strange phenomenon — and may help forecast deadly eruptions.

When such volcanoes erupt they can shoot hot ash up to 40 kilometers into the atmosphere and cause devastating destruction when the ash column collapses and spreads as “pyroclastic flows”. Prior to most of these explosive eruptions the volcanoes shake slightly but measurably, and the shaking becomes more dramatic during the eruption itself.  This tremor is one of the primary precursors and warnings used by volcanologists for forecasting an eruption. (more…)

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