. Earth Science News .
SHAKE AND BLOW
Months Of Geologic Unrest Signaled Reawakening Of Icelandic Volcano

By the time the volcano began to erupt on March 20, the volcano's flanks had expanded by more than six inches as magma flowed from deep within the Earth into shallow chambers underneath the mountain. File image courtesy AFP.
by Staff Writers
Madison WI (SPX) Nov 18, 2010
Months of volcanic restlessness preceded the eruptions this spring of Icelandic volcano Eyjafjallajokull, providing insight into what roused it from centuries of slumber.

An international team of researchers analyzed geophysical changes in the long-dormant volcano leading up to its eruptions in March and April 2010 that suggest that magma flowing beneath the volcano may have triggered its reawakening. Their study is published in the Nov. 18 issue of the journal Nature.

"Several months of unrest preceded the eruptions, with magma moving around downstairs in the plumbing and making noise in the form of earthquakes," says study co-author Kurt Feigl, a professor of geosciences at the University of Wisconsin-Madison. "By monitoring volcanoes, we can understand the processes that drive them to erupt."

With funding from a RAPID grant from the U.S. National Science Foundation, Feigl and collaborators from Iceland, Sweden, and the Netherlands used a combination of satellite imaging and GPS surveying to watch the volcano's edifice as it deformed. They found that the volcano swelled for 11 weeks before it began to erupt in March 2010 from one flank.

"If you watch a volcano for decades, you can tell when it's getting restless," Feigl says.

In late summer 2009, a subtle shift at a GPS station on Eyjafjallajokull's flank prompted the study's lead author, Freysteinn Sigmundsson, and his colleagues to begin monitoring the mountain more closely. Then, in early January 2010, the rate of deformation and the number of earthquakes began to increase.

As the deformation and seismic unrest continued, the researchers installed more GPS stations near the mountain. Just a few weeks later, the instruments detected more rapid inflation, indicating that magma was moving upwards through the "plumbing" inside the volcano.

By the time the volcano began to erupt on March 20, the volcano's flanks had expanded by more than six inches as magma flowed from deep within the Earth into shallow chambers underneath the mountain.

Surprisingly, the rapid deformation stopped as soon as the eruption began. In many cases, volcanoes deflate as magma flows out of shallow chambers during an eruption. Eyjafjallajokull, however, maintained basically the same inflated shape through mid-April, when the first eruption ended.

After a two-day pause, the volcano began to erupt again on April 22. This time, the lava broke out through a new conduit under the ice on the summit of the mountain, causing an explosive reaction as water flashed to steam and gas escaped from bubbles in the magma. The resulting "ash" plume rose high into the atmosphere, disrupting air traffic over Europe for weeks and stranding millions of travelers.

Why did Eyjafjallajokull erupt when it did? The geologic processes that trigger an actual eruption are not yet well understood, says Feigl. "We're still trying to figure out what wakes up a volcano."

To begin to answer this question, the scientists suggest that a magmatic intrusion deep within the volcano may have triggered the eruption, but this hypothesis remains to be tested at other volcanoes.

They are also studying the structures inside the volcano, such as magma chambers and intrusive conduits, by extracting information from the sensors installed around Eyjafjallajokull.

"The explosiveness of the eruption depends on the type of magma, and the type of magma depends on the depth of its source," Feigl says. "We're a long way from being able to predict eruptions, but if we can visualize the magma as it moves upward inside the volcano, then we'll improve our understanding of the processes driving volcanic activity."

Satellite radar images were obtained from TerraSAR-X, a satellite operated by the German Space Agency (DLR). Funding was provided by the National Science Foundation, Icelandic Research Fund, University of Iceland, and the Icelandic government.



Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
University of Wisconsin-Madison
Bringing Order To A World Of Disasters
When the Earth Quakes
A world of storm and tempest



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


SHAKE AND BLOW
Icelandic volcano: Scientists map anatomy of an eruption
Paris (AFP) Nov 17, 2010
The eruption of Eyjafjoell, the Icelandic volcano which grounded flights across Europe this year, followed a long, threatening warm-up in which the mountain growled and its icy flanks bulged, scientists said on Wednesday. Vulcanologists from the United States, Iceland, Sweden and the Netherlands used satellite images and data from Global Positioning System (GPS) movement monitors to build a ... read more







SHAKE AND BLOW
New Sensor Allows On-Site, Faster Testing For Scour Assessment

China says over 81 million disaster-hit people need aid

Italy ill-prepared for natural disasters: experts

Minneapolis Disaster Spawning New Concepts In Bridge Research, Testing And Safety

SHAKE AND BLOW
Sonar System Inspired By Dolphins

New Technology Gives On-Site Assessments In Archaeology

Thales announces venture for Chinese in-flight systems

Laser camera 'sees' around corners

SHAKE AND BLOW
EU, Japan sketch battle lines in bluefin tuna meet

Caspian states may impose sturgeon fishing ban: Moscow

Scientists Question Indicator Of Fisheries Health

China defends Brahmaputra dam project amid Indian concern

SHAKE AND BLOW
Delayed ice threatening Canada polar bears

As Arctic Temperatures Rise, Tundra Fires Increase

Drumlin Field Provides Answers About Glaciation And Climate

Report warns of dangers of Arctic drilling

SHAKE AND BLOW
Chips bags too noisy for US, but a hit in Canada

Pelletized Manure Reduces Toxic Runoff

New Revelations In Ammonia Synthesis

Detroit's Urban Farms Could Provide A Majority Of Produce For Local Residents

SHAKE AND BLOW
Panama Canal said at earthquake risk

Months Of Geologic Unrest Signaled Reawakening Of Icelandic Volcano

Indonesia volcano death toll rises to 273

Toll from La Nina-fuelled rains in Colombia climbs to 136

SHAKE AND BLOW
Swazi life expectancy halved by AIDS, TB: health charity

Madagascar general says power take-over bid unchanged

UN negotiating Sudan peacekeepers increase: Ban

Rebel troops claim Madagascar government suspended

SHAKE AND BLOW
Human Children Outpaced Neanderthals By Slowing Down

Paraguay nixes British expedition to remote tribal region

Origin Of Cells Associated With Nerve Repair Discovered

The Brains Of Neanderthals And Modern Humans Developed Differently


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement