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Volcanoes


Bizarro Earth

Supervolcano may be brewing beneath Mount St Helens

David Shiga
New Scientist
Wed, 10 Jun 2009 17:48 UTC
Image
© MAI / Rex Features
The US volcano may be connected to a semi-molten magma chamber that could fuel a giant eruption.
Is a supervolcano brewing beneath Mount St Helens? Peering under the volcano has revealed what may be an extraordinarily large zone of semi-molten rock, which would be capable of feeding a giant eruption.

Magma can be detected with a technique called magnetotellurics, which builds up a picture of what lies underground by measuring fluctuations in electric and magnetic fields at the surface. The fields fluctuate in response to electric currents travelling below the surface, induced by lightning storms and other phenomena. The currents are stronger when magma is present, since it is a better conductor than solid rock.

Graham Hill of GNS Science, an earth and nuclear science institute in Wellington, New Zealand, led a team that set up magnetotelluric sensors around Mount St Helens in Washington state, which erupted with force in 1980. The measurements revealed a column of conductive material that extends downward from the volcano. About 15 kilometres below the surface, the relatively narrow column appears to connect to a much bigger zone of conductive material.
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Cloud Lightning

Kilauea Volcanic Lightning


Space Weather
Sat, 06 Jun 2009 14:15 UTC
Image
© Stephen O'Meara
On May 19th, adventure photographer Stephen O'Meara was monitoring an eruption of the Rabaul volcano in Papua, New Guinea, when something happened that, he says, "I'll remember for a very long time. A storm cloud approached the volcano's 2 km plume, and lightning began to arc between the two." He set up his camera in a secure location and recorded the "awesome and blinding" spectacle.

This isn't the first time lightning has been observed around a volcano. Recent examples include Alaska's Mt. Redoubt, Chile's Chaitin volcano and Kilauea in Hawaii. Clouds of water vapor shoot out of these volcanoes in a dusty mixture likened to a "dirty thunderstorm," and lightning emerges from within the turbulent plume.
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Bizarro Earth

Rotation is Key to Understanding Volcanic Plumes


PhysOrg
Wed, 25 Mar 2009 18:44 UTC
Rotation
© UPI/Landov
In 2008, the Mount Chaiten eruption in southern Chile showed what appeared to be a volcanic plume wrapped in a sheath of lightning.
A 200-year-old report by a sea captain and a stunning photograph of the 2008 eruption of Mount Chaiten are helping scientists at the University of Illinois better understand strong volcanic plumes.

in a paper to appear in the March 26 issue of the journal Nature, the scientists show that the spontaneous formation of a "volcanic mesocyclone" - a cyclonically rotating columnar vortex - causes the volcanic plume to rotate about its axis. The rotation, in turn, triggers a sheath of lightning and creates waterspouts or dust devils. The origins of these volcanic phenomena were previously unexplained.

"Rotation is an essential element of a strong volcanic plume," said Pinaki Chakraborty, a postdoctoral researcher and the paper's lead author. "By taking into account the rotation, we can better predict the effects of volcanic eruptions."
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Bizarro Earth

New rumbling from Chilean volcano worries experts

Monica Vargas
News Daily
Fri, 16 May 2008 12:46 UTC
Santiago - Chile's Chaiten volcano groaned, rumbled and shuddered on Thursday, raising new concerns among authorities, as lightning bolts pierced the huge clouds of hot ash hovering ominously above its crater.

Chile's National Emergency Office, ONEMI, said heavy ash kept shooting from the volcano in southern Chile as it generated small tremors.

On the ground, heavy flooding hit the area around Chaiten as falling ash swelled rivers, overflowing their banks.

"There's been additional volcanic activity that we're really worried about," regional governor Sergio Galilea told reporters.

The Chaiten volcano, 760 miles south of the capital Santiago, started erupting on May 2 for the first time in thousands of years, spewing ash, gas and molten rock into the air.
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Cloud Lightning

Chile: Dirty thunderstorm shoots lightning from volcano

Paul Simons
The Times
Thu, 08 May 2008 14:01 UTC
Recent pictures of the Chaiten volcano in Chile showing lighting bursting out show a marvellous phenomenon known as volcanic lightning.

The photo of lightning bursting out during a volcanic eruption in Chile, above, was a truly awesome sight. Although the picture seemed to show a thunderstorm colliding with the cloud of volcanic ash, it actually showed a marvellous phenomenon known as volcanic lightning.

Usually, lightning is sparked off by countless tiny pieces of ice inside a turbulent thundercloud banging into one another. Each collision generates static electricity, rather like a balloon rubbed on a jumper.



Image
©Unknown

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Cloud Lightning

Scientists find that lightning is good indicator of volcanic activity


EurekAlert
Thu, 29 Mar 2007 08:16 UTC
Although it's been more than a year since Mount Augustine had its memorable eruption, work continues for University of Alaska Fairbanks researchers. The work of Alaska Volcano Observatory employees from UAF's Geophysical Institute will be appearing in the upcoming issue of the journal Science.

The article, which came out on Feb. 23, documents electrical activity that occurred during the January 2006 eruption of Mount Augustine. While it has long been known that volcanic eruptions can produce vigorous lightning, there are few direct observations of the phenomena, states the article. Following the initial eruptions of Jan. 11 and 13, 2006, two of which produced lightning, two electromagnetic lightning detectors were set up in Homer about 60 miles from Augustine. A couple of days later, the volcano erupted again, with the first of four eruptions producing a "spectacular lightning sequence."
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