Earth Science News  





.
SHAKE AND BLOW
Eruptive Characteristics Of Oregon's Mount Hood Analyzed

New research at Oregon State University has outlined the mechanisms that may lead to the next eruption of Mount Hood, the tallest mountain in Oregon. (Photo courtesy of Oregon State University)
by Staff Writers
Corvallis OR (SPX) Aug 04, 2010
A new study has found that a mixing of two different types of magma is the key to the historic eruptions of Mount Hood, Oregon's tallest mountain, and that eruptions often happen in a relatively short time - weeks or months - after this mixing occurs.

This behavior is somewhat different than that of most other Cascade Range volcanoes, researchers said, including Mount Hood's nearby, more explosive neighbor, Mount St. Helens.

The research is being reported this week in Nature Geoscience by geologists from Oregon State University and the University of California at Davis, in work supported by the National Science Foundation.

It will help scientists better understand the nature of Mount Hood's past and future eruptions, as well as other volcanoes that erupt by similar mechanisms. This includes a large number of the world's active volcanoes.

"These data will help give us a better road map to what a future eruption on Mount Hood will look like, and what will take place before it occurs," said Adam Kent, an OSU associate professor of geosciences. "It should also help us understand the nature of future eruptions and what risks they will entail."

Mount Hood, at 11,249 feet tall, is the highest mountain in Oregon and fourth highest in the Cascade Range. The last major eruption was in the late 1780's, and the effects of this eruption where viewed by members of the Lewis and Clark Expedition in 1805. It is considered potentially active and the Oregon volcano most likely to erupt, although the chances of that are still small.

Geologists are already able to use things like gas emissions, the chemistry of hot springs, ground deformation, local earthquakes and other data to help predict when a volcanic eruption is imminent, Kent said, and the new findings will add even more data toward that goal.

Two types of magma, or molten underground rock, are often involved in volcanic processes - mafic magma, which has less silica and is more fluid; and felsic magma, which has a higher silica content and a thicker consistency, like toothpaste. A third type of magma, called andesite, named after the Andes Mountains where it is often found, is composed of a mixture of both felsic and mafic magma.

Andesite is common in volcanoes that form at subduction zones - regions where one tectonic plate is sinking below another - and include those that form around the well-known Pacific Ocean "rim of fire".

The rocks around Mount Hood, scientists say, are almost exclusively formed from andesitic magma. And research suggests that the recharge of mafic magma to mix with its thicker felsic counterpart often occurs just prior to an actual eruption.

"The intense mixing of these two types of magma causes an increase in pressure and other effects, and is usually the trigger for an eruption," Kent said. "But this process doesn't happen in all volcanic events. In the Cascade Range, Mount Hood appears to be one volcano where andesitic magma and recharge-driven eruptions are dominant."

That may be because of local crustal conditions, Kent said. Even though the Cascade Range is linked to melting rock from the Cascadia Subduction Zone, some parts of the crust are more difficult than others for magma to move through. Mount Hood appears to be in a region where it takes the extra pressure of magma mixing to cause an eruption.

Kent said that researchers study these processes not only to improve their ability to predict eruptions, and to recognize precursors to eruption, but also to assess possible ore deposits associated with volcanic activity, and learn more about the fundamental dynamics of volcanic processes.




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



Related Links
Oregon State University
Bringing Order To A World Of Disasters
When the Earth Quakes
A world of storm and tempest



Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
SHAKE AND BLOW
Stiff penalties for Philippine volcano tourism
Manila (AFP) June 13, 2010
The tourist trade faces strict penalties for allowing visitors onto a volcano island near the Philippine capital after it began to show signs that it might erupt, the coastguard said on Sunday. Resort and boat operators who violate the ban by bringing tourists to Taal may have their vessels confiscated and their resorts closed, said Captain Frankelino Phaeton. "They (the tourists) are cu ... read more

.
Get Our Free Newsletters Via Email
  


SHAKE AND BLOW
Japanese rescue-bot can sniff out disaster survivors

Flood-triggered landslide in China leaves 21 missing

Haiti's homeless on the move again as hurricanes loom

Wildfire Prevention Pays Big Dividends In Florida

SHAKE AND BLOW
China Leads In Outer Space Pollution

MetOp-B Module Passes Crucial Vacuum Test

Safe And Efficient De-Orbit Of Space Junk Without Making The Problem Worse

RIM unleashes BlackBerry Torch to take on iPhone

SHAKE AND BLOW
Well kill doesn't mask grim reality for Gulf fishermen

Workers in China rush to restore water to 330,000 people

Pacific islands want louder voice on climate

Biodiversity: Mediterranean most threatened sea on Earth

SHAKE AND BLOW
Ice drilling could foretell climate

Ice-Free Arctic Ocean May Not Be Of Much Use In Soaking Up Carbon Dioxide

Best Hope For Saving Arctic Sea Ice Is Cutting Soot Emissions

Cutting Into Arctic Sea Ice

SHAKE AND BLOW
Pakistan farmers see livelihoods wiped out by floods

Bee 'pastures' could help agriculture

Argentine farmers, leaders locked in feud

More Russians tuck into Uruguayan beef

SHAKE AND BLOW
Eruptive Characteristics Of Oregon's Mount Hood Analyzed

Desperate Pakistan flood survivors clamour for aid

Relief critical for flood-ravaged Pakistan

Pakistan survivors claw at debris of flooded homes

SHAKE AND BLOW
Mozambican-U.S. joint military exercise

More Somalis arrive from Saudi Arabia

GBissau records veterans in demobilisation drive

Uganda's rebels seen behind border killing

SHAKE AND BLOW
Walker's World: Sarkozy gets tough

Massive Gains For Women's Employment In India

Divers Plumb The Mysteries Of Sacred Maya Pools

Scientists use noses to help disabled write, surf, move


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