Still steaming: Redoubt's seismic activity declining
After weeks of hiding behind clouds, Mount Redoubt made an appearance on Friday, and was surprisingly still giving off a plume of steam.
"The steam doesn't mean anything is in the works, though. Seismic activity has been the same for weeks -- gradually declining," said Chris Waythomas, a geologist with the U. S. Geological Service at the Alaska Volcano Observatory in Anchorage.
Instead of seismic activity, Waythomas said the cause of the steam was something visible even from this side of Cook Inlet, as much of the volcano was draped under a thick, white blanket of freshly fallen snow.
"That's the cause of the steam, there's snowfall at 8,000 feet and above, and the lava dome is still really hot. As snow comes into contact with it, the snow and water is just boiling off, and the calm, clear conditions allowed it to be visible," he said.
Waythomas said this is not an uncommon phenomenon on cool, clear days.
"Iliamna and Augustine give off steam plumes like this too occasionally, when the conditions are similar," he said.
As to how hot Redoubt's dome is, Waythomas couldn't say for certain at this time, but he said researchers should know soon.
"We're hoping to be over there next week with an infrared camera, which can be used to determine the surface temps," he said.
Redoubt's dome growth -- formed in the volcano's summit crater -- began in early April, following several explosive events, and the protracted growth lasted into May. The volcano's last episode in 1989 and '90 built up a dome that would collapse on an almost weekly basis, before rebuilding again. This went on for an extended period of time.
As such, researchers suspected the same would occur during this series of eruptions. However, as time ticks by, it is starting to appear the this may not be the case.
The volcano has been in a "code yellow" status since it was downgraded by the AVO on June 30, after volcanic activity had decreased significantly, but it was still exhibiting signs of elevated unrest above known background levels.
"It's headed toward background activity, though. I wouldn't be surprised if it was downgraded to green next month," Waythomas said.
For more information on Redoubt and its current status, visit the AVO Web site at http://www.avo.alaska.edu/activity/Redoubt.php.
Joseph Robertia can be reached at joseph.robertia@peninsulaclarion.com.