Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Traveling Through a Volcano

24.07.2012
How much ash will be injected into the atmosphere during Earth’s next volcanic eruption?

Recent eruptions have demonstrated our continued vulnerability to ash dispersal, which can disrupt the aviation industry and cause billions of dollars in economic loss. Scientists widely believe that volcanic particle size is determined by the initial fragmentation process, when bubbly magma deep in the volcano changes into gas-particle flows.

But new Georgia Tech research indicates a more dynamic process where the amount and size of volcanic ash actually depend on what happens afterward, as the particles race toward the surface. Their initial size and source depth, as well as the collisions they endure within the conduit, are the differences between palm-sized pumice that hit the ground and dense ash plumes that jet into the atmosphere and can halt aviation. The findings are published in the current edition of Nature Geoscience.

Assistant Professor Josef Dufek used lab experiments and computer simulations to study particle break-up, known as granular disruption, in volcanic eruptions. His team, which included the University of California, Berkeley’s Michael Manga and Ameeta Patel, determined that shallow (approximately 500 meters below the surface) fragmentation levels likely cause abundant, large pumice that are often seen in large volcanic eruptions. If the fragmentation begins a few kilometers underground, the volcano is more likely to emit fine-grained ash.

“The longer these particles stay in the conduit, the more often they collide with each other,” said Dufek, a faculty member in Georgia Tech’s School of Earth and Atmospheric Sciences. “These high-energy collisions break the volcanic particles into fractions of their original size. That’s why deeper fragmentations produce small particles. Particles that begin closer to the surface with less energy don’t have time for as many collisions before they exit the volcano. They stay more intact, are larger and often contained in pyroclastic flows.”

The team collected volcanic rock from California’s Medicine Lake volcanic deposit for collision experiments. They also used glass spheres because, like glass, pumice is heated and hardens before crystals are able to form. Using a pumice gun that propels volcanic fragments using compressed gases, Dufek and his team determined that particles must collide at a minimum of 30 meters per second to break into larger pieces.

Using numerical simulations, the researchers concluded that large pumice particles (greater than fist size) will not likely remain intact unless the fragmentation is very shallow. Abundant large pumice rocks in a deposit provide an indication of the depth of fragmentation, which may vary over the course of the eruption. Due to the depth and violent nature of the process, scientists have had little record of the depth of the fragmentation process, even though much of the eruptive dynamics and subsequent hazards are determined in this process.

Dufek and his team will next use the research to better understand the dynamics of one of the most rare natural disasters: super volcanoes, which produced the features in Yellowstone National Park.

“We know very little about the eruption processes during super eruptions,” said Dufek. “Indications of their fragmentation levels will provide important clues to their eruptive dynamics, allowing us to study them in new ways.”

This project is supported by the National Science Foundation (NSF) (Award Numbers 0809321 and 0809564). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of the NSF.

Jason Maderer | Newswise Science News
Further information:
http://www.gatech.edu

More articles from Earth Sciences:

nachricht Research icebreaker Polarstern begins the Antarctic season
09.11.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Far fewer lakes below the East Antarctic Ice Sheet than previously believed
08.11.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

Im Focus: Nanorobots propel through the eye

Scientists developed specially coated nanometer-sized vehicles that can be actively moved through dense tissue like the vitreous of the eye. So far, the transport of nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. The work was published in the journal Science Advances and constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.

Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

In focus: Peptides, the “little brothers and sisters” of proteins

12.11.2018 | Life Sciences

Materials scientist creates fabric alternative to batteries for wearable devices

12.11.2018 | Materials Sciences

A two-atom quantum duet

12.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>