Study provides fresh insight on volcanic eruptions

October 14, 2004

EUGENE, Ore. -- New tools for monitoring volcanoes may be developed with help from a study on Mount St. Helens published this week (Oct. 14) in Science Express by an international team of geoscientists, including University of Oregon volcanologist Katharine Cashman.

The study on geochemical precursors to volcanic activity leading to the cataclysmic eruption of the southwestern Washington mountain in 1980 yields new insight about volcano behavior.

"We're looking at chemical signatures--chemistry that's related to volatile, or gas, phases in the eruptive cycle," says Cashman, a professor of geological sciences.

"We've learned that the magma that erupted on May 18, 1980, had probably begun degassing for a minimum of five years before the eruption," she explains. "Then, throughout the summer of 1980, what we see is evidence that gas from the deeper magma storage system had been interacting with the magma at a shallower level."

The study provides a detailed picture of magma and gas movement during 1980. The data shows that ascending magma stalled and was stored at a depth of three to four kilometers beneath the surface.

Cashman's in-depth knowledge of Mount St. Helens began when she served as the U.S. Geological Survey spokesperson before, during and after the 1980 eruption. Since then, she's become an authority on volcanoes from Hawaii to Italy, where she had intended to spend the current academic year working with Italian volcanologists to compare eruptive styles at Etna, Stromboli and Vesuvius with those of the Cascades. She flew back from Italy last weekend to rejoin colleagues at Mount St. Helens where her role is to "be eyes and corporate memory from the '80s so we can make comparisons between then and now."

This week's ScienceExpress publication follows on the heels of a Geology magazine article (February 2004) by Cashman and Richard Hoblitt of the Hawaiian Volcano Observatory which reported that the ash Mount St. Helens spewed during the months before its huge 1980 eruption contains tiny crystals that show an explosive eruption was likely.

Cashman, whose research interests include volcanology, igneous petrology and crystallization kinetics, joined the UO faculty in 1991. Her work is funded by the National Science Foundation.
-end-
Notes to Editors: This research appears online in the journal ScienceExpress, www.sciencexpress.org.

Co-authors of the ScienceExpress paper are: First author Kim Berlo, Department of Earth and Planetary Sciences, University of Bristol, United Kingdom; Jon Blundy, Department of Earth and Planetary Sciences, Macquarie University, Sydney, Australia; Chris Hawkesworth, Department of Earth and Planetary Sciences, University of Bristol, United Kingdom; and Stuart Black, Department of Archaeology, University of Reading, United Kingdom.

Cashman prefers that reporters contact her by e-mail.

Contact: Melody Ward Leslie, 541-346-2060, mleslie@uoregon.edu

Source: Cashman, cashman@oregon.uoregon.edu

Link: http://darkwing.uoregon.edu/~cashman/

University of Oregon

Related Magma Articles from Brightsurf:

Magma 'conveyor belt' fuelled world's longest erupting supervolcanoes
International research led by geologists from Curtin University has found that a volcanic province in the Indian Ocean was the world's most continuously active -- erupting for 30 million years -- fuelled by a constantly moving 'conveyor belt' of magma.

Deep magma facilitates the movement of tectonic plates
A small amount of molten rock located under tectonic plates encourages them to move.

3D magnetotelluric imaging reveals magma recharging beneath Weishan volcano
Researches have succeeded in obtaining a high-resolution 3D resistivity model of approximately 20 km depth beneath the Weishan volcano in the Wudalianchi volcanic field (WVF) for the first time.

Study proves that magma chambers can be totally molten
The paper shows that basaltic magma chambers may develop as large bodies of crystal-free melts in the Earth's crust.

New study takes the pulse of a sleeping supervolcano
Under the volcanoes in the Andes where Chile, Argentina and Bolivia meet, there is a gigantic reservoir of molten magma.

How and when was carbon distributed in the Earth?
A magma ocean existing during the core formation is thought to have been highly depleted in carbon due to its high-siderophile (iron loving) behavior.

Research shows why there's a 'sweet spot' depth for underground magma chambers
Computer models show why eruptive magma chambers tend to reside between six and 10 kilometers underground.

'Crystal clocks' used to time magma storage before volcanic eruptions
The molten rock that feeds volcanoes can be stored in the Earth's crust for as long as a thousand years, a result which may help with volcanic hazard management and better forecasting of when eruptions might occur.

Magma is the key to the moon's makeup
For more than a century, scientists have squabbled over how the Earth's moon formed.

'Amazing snapshots' plumb volcanic depths
Research shedding light on the internal 'plumbing' of volcanoes may help scientists better understand volcanic eruptions and unrest.

Read More: Magma News and Magma Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.