Supervolcanic ash can turn to lava miles from eruption, scientists find

Aug 27, 2013
Evidence of flowing lava hardened into rock found in Idaho several miles away from the site of an eight million year old supervolcano eruption at Yellowstone. Credit: Graham Andrews, assistant professor at California State University Bakersfield

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 , 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.

"During a supervolcano eruption, pyroclastic flows, which are giant clouds of very hot ash and rock, travel away from the volcano at typically a hundred miles an hour," Robert said. "We determined the ash must have been exceptionally hot so that it could actually turn into lava and flow before it eventually cooled."

Evidence of flowing lava hardened into rock found in Idaho several miles away from the site of an eight million year old supervolcano eruption at Yellowstone. Credit: Graham Andrews, assistant professor at California State University Bakersfield

Because the ash should have cooled too much in the air to turn into lava right as it landed, the researchers believe the phenomenon was made possible by a process known as "viscous heating." Viscosity is the degree to which a liquid resists flow. The higher the viscosity, the less the substance can flow. For example, water has a very low viscosity, so it flows very easily, while molasses has a higher and flows much slower. Whittington likens the process of viscous heating to stirring a pot of molasses.

"It is very hard to stir a pot of molasses and you have to use a lot of energy and strength to move your spoon around the pot," Whittington said. "However, once you get the pot stirring, the energy you are using to move the spoon is transferred into the molasses, which actually heats up a little bit. This is viscous heating. So when you think about how fast the hot ash is traveling after a massive supervolcano eruption, once it hits the ground that energy is turned into heat, much like the energy from the spoon heating up the molasses. This extra heat created by viscous heating is enough to cause the ash to weld together and actually begin flowing as lava."

Evidence of flowing lava hardened into rock found in Idaho several miles away from the site of an eight million year old supervolcano eruption at Yellowstone. Credit: Graham Andrews, assistant professor at California State University Bakersfield

The volcanic ash from this eruption has to be at least 1,500 degrees Fahrenheit to turn into lava; however, since the ash should have lost some of that heat in the air, the researchers believe viscous heating accounted for 200 to 400 degrees Fahrenheit of additional heating to turn the into .

Explore further: Volcanic eruption coats Japanese city with ash

More information: Robert, Andrews, Ye, and Whittington's paper was published in Geology.

Related Stories

Volcanic eruption coats Japanese city with ash

Aug 19, 2013

Residents in a southern Japanese city accustomed to frequent eruptions from a nearby volcano were busy washing ash off the streets Monday after the mountain spewed a record-high smoke plume into the sky.

Alaska volcano shoots ash 15,000 feet into the air

May 18, 2013

(AP)—One of Alaska's most restless volcanoes has shot an ash cloud 15,000 feet into the air in an ongoing eruption that has drawn attention from a nearby community but isn't expected to threaten air traffic.

Improving forecasts of volcanic ash concentrations

Feb 14, 2012

Volcanic ash can severely damage airplanes, and eruptions such as the 2010 Eyjafjallajokull eruption may result in major disruption to air travel. Improved forecasting of ash cloud locations and concentrations could benefit ...

Online tool boosts ash cloud forecasts

Aug 16, 2013

A new online tool for predicting the amount of ash pumped into the atmosphere during a volcanic eruption has been made openly available to scientists around the world.

Satellite looks down the eye of erupting Nabro Volcano

Jun 28, 2011

Wow! What an amazing and detailed top-down view of an active volcano! This is the Nabro Volcano, which has been erupting since June 12, 2011. It sits in an isolated region on the border between Eritrea and ...

Recommended for you

Image: Grand Canyon geology lessons on view

5 hours ago

The Grand Canyon in northern Arizona is a favorite for astronauts shooting photos from the International Space Station, as well as one of the best-known tourist attractions in the world. The steep walls of ...

First radar vision for Copernicus

5 hours ago

Launched on 3 April, ESA's Sentinel-1A satellite has already delivered its first radar images of Earth. They offer a tantalising glimpse of the kind of operational imagery that this new mission will provide ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

jsdarkdestruction
3.3 / 5 (3) Aug 27, 2013
"While they only happen every several thousand years, "
tens of thousands of years to hundreds of thousand years is more accurate.
Q-Star
2.6 / 5 (5) Aug 27, 2013
Silly geologists,,,, that's not ash turning into lava, it's plasma filaments shaping the universe just as Alfven predicted.
Gmr
3.6 / 5 (5) Aug 27, 2013
In b4 Aether Wave Theory

Heck, we should make up "phys.org tinfoil hat bingo" - print up sheets with the usual screedmeisters marked, in columns for subject matter across the top, and post-order along the side.

More news stories

Tiny power plants hold promise for nuclear energy

Small underground nuclear power plants that could be cheaper to build than their behemoth counterparts may herald the future for an energy industry under intense scrutiny since the Fukushima disaster, the ...

Hand out money with my mobile? I think I'm ready

A service is soon to launch in the UK that will enable us to transfer money to other people using just their name and mobile number. Paym is being hailed as a revolution in banking because you can pay peopl ...