July 1, 2009

Alaska’s Mount Redoubt Seems To Have Cooled Off

Alaska's Mount Redoubt has gradually slowed down in activity since the last eruption three months ago.

The Alaska Volcano Observatory said on Tuesday that seismic activity has calmed down and the eruptions may have stopped. The observatory has dropped the alert levels for the areas around the mountain.

Several eruptions starting in March interrupted air traffic and covered Anchorage, the Kenai Peninsula and Wasilla with ash. Due to prior events, geologists felt that the eruptions would be prolonged for several months, but Redoubt's last noteworthy eruption was April 4.

In the last three months, volcanic action was sustained as a lava dome with enough magma to fill 16 Louisiana Superdomes grew inside it, geologist Ryan Bierma said. The bubble is 3,300 feet long, 1,500 feet wide and 656 feet tall, filling a crater from a prior eruption.

The dome grew in size due to lava oozing from of the mountain, Bierma said, but the growth of it has slowed.

"There hasn't been much change noted since early June," he said.

The volcano began erupting on March 22 and the last big eruption happened on April 4, when Redoubt shot an ash plume 50,000 feet skyward.

The eruption caused Alaska residents to use dust masks and air filters to save their lungs.

The troublesome ash from Redoubt once sent ash 150 miles away towards a KLM jet with 231 passengers on Dec. 15, 1989. The engines flamed out and the jet fell 2 miles before the crew restarted the engines and the plane made it safely to Anchorage.

Geologists have been watching the mountain and seismic activity has almost stopped. There has also been less gas coming from the dome itself.

The scientists used infrared cameras to look at where cracks were happening and if magma was getting closer to the surface, Bierma said. A glacier that was on top of the crater has melted, but areas of the dome are cool and new snow has stuck and not melted.

Scientists note that the dome could be unstable and may erupt with hardly any warning, resulting in ash and mudflows in the Drift River Valley.

Image Courtesy Heather Bleick, AVO/USGS


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