Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Decompression-driven crystallization warms pathway for volcanic eruptions

11.09.2006
Mount St. Helens data will improve volcanic monitoring worldwide

The reason may be counter-intuitive, but the more magma crystallizes, the hotter it gets and the more likely a volcano will erupt, according to a team of scientists that includes a University of Oregon geologist. The knowledge likely will aid monitoring of conditions at Mount St. Helens and other volcanic hot spots around the world.

Reporting in the Sept. 7 issue of the journal Nature, the researchers show that rapid crystallization of magma within one to two kilometers of the surface (about one-half to one mile) causes magma to heat up to as much as 100 degrees Celsius (212 degrees Fahrenheit).

"While this sort of heating has been expected in theory, we are the first to show that we can measure it," said Katharine Cashman, a professor of geologic sciences at the University of Oregon. "These results have important consequences for models of magma ascent beneath volcanoes, as increasing the melt temperatures causes the melt viscosity to decrease so that it can flow more easily, like heating up a jar of honey to allow the honey to flow out of the jar."

Explosive volcanic eruptions are fueled by the escape of volcanic gases from magma stored in underground reservoirs and pipes several kilometers below the surface. Predicting such eruptions requires a real-time knowledge of just where the magma is at any one time and what it is doing.

"This work is now being used to gauge the direction of the volcanic activity currently happening at Mount St. Helens and could be applied to any active volcano for which monitoring and petrological records are available," said Jon Blundy, professor of earth sciences at the University of Bristol (United Kingdom), in a news release.

Cashman and Blundy have now collaborated since 1998, when Blundy took a sabbatical at the University of Oregon, on four published studies on Mount St. Helens, located 53 miles northeast of Portland, Ore. Cashman has studied the volcano and similar ones elsewhere for more than a decade.

The latest study was a follow-up to one Blundy and Cashman published in Geology last year (October 2005), in which they used small pockets of melt that get trapped in crystals as they expand to demonstrate that the crystals grow by decompression as magma rises toward the surface. That paper also showed that these crystals grow rapidly, in months rather than years. The new study refined their conclusions in Geology by using experimental calibrations to show the rapid heating as magma nears the surface.

"This may sound counter-intuitive, but think about the need to add heat to something to melt it," Cashman said.

In this follow-up study to last year's report, the researchers were able to reconstruct changes in pressure, temperature and crystallization that occur in magma before an eruption. They showed that as pressure decreases, crystallinity increases; the more magma crystallizes, the hotter it gets.

The finding that a drop in pressure rather than a loss of heat to surrounding rocks, as previously thought, means that there are more possibilities for eruption dynamics, the researchers concluded.

If ascending magma is able to heat itself up simply by crystallizing, they report, it may provide an important trigger for eruption without the need to invoke an extraneous heat source such as a shot of hotter magma from deep below the surface. The new findings also suggest the possibility that volcanic crystals grow in response to decompression by heating on an unexpectedly short timescale of several years, a period during which volcanoes can be more effectively monitored.

Jim Barlow | EurekAlert!
Further information:
http://www.uoregon.edu

More articles from Earth Sciences:

nachricht Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University

nachricht NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>