Posted on 07/29/2008 11:35:48 AM PDT by cogitator
Alaska's Okmok volcano started erupting on July 12 and is still going. The most recent update from yesterday indicated an ash plume could be at 35,000 feet. This has a definite current events aspect because a lot of planes flying to China (Olympics) will fly near this event. Aircraft jet engines do not do well on an ash-rich diet.
Okmok has always been one of my favorite Aleutian volcanoes because it has an incredible 10-km wide circular caldera, almost like a "Lost World" setting. So after my two-week hiatus, I'll provide a picture of the current eruption, and a couple of caldera pictures, from altitude and on the ground inside.
Eruption cloud on July 20: picture credited to photographer Phil Walgren on an Alaska Airlines flight
Caldera from an Alaska Airlines plane (this is a real picture, not a model!) click for full size; credited to Cyrus Read on Alaska Airlines 
Inside the caldera (AVO/USGS - Christina Neal) 
Inside the caldera II (Celso Reyes) 
Were it not that for most of the year the caldera is socked in with clouds, it could be the Haleakala of the North.
** ping! **
The plume is up to 10,000 feet today, eruption continuous and could pick up steam at any time.
Not to mention ash. (chuckle)
gnip...
Big increase in particulates in the air means cooler temps in the near future.
Thanks for the post. Always love the pictures!
Astonishing pictures.
Thanks
I would hate to have to buy the carbon credits from Al Gore on this one!
What is the expected VEI strength rated at? That looks very significant. What effects is expected to have on the northern hemisphere?
Our daughter and I went to Japan in 2005 to visit some friends, and the flight took us over Alaska. What an awesome sight! The mountains looked SO close to us, and the glaciers looked like service roads around the mountains.
I doubt it. You can tell from the other pictures that Okmok has several subsidiary cones inside the caldera, and I would think one of them is the source; it could also be a new vent, too. As for the VEI, you'd have to ask the AVO. The sulfur cloud spread pretty good, according to NASA (I really cut down the size of this one; click for full):
Given the obvious dissipation, probably no notable effects at distance. But I'd ask my pilot to China to check the flight plan.
I found this blog (I'll have to bookmark it), with news about Okmok. They peg it at VEI 4 from a new vent. It's got a great shot of the current eruption.
Today the scientists said the nature of the eruption has changed, it is erupting through a new vent, and they cannot any longer predict future behavior based on past behavior. They don’t know what it will do now.
I guess I'd say that because massive caldera forming eruptions are pretty rare, another one from Okmok can't be ruled out but isn't likely. So I'd expect (in the pattern of other Aleutian volcanoes) an ongoing eruption for several months, which means intervals of days to weeks between significant ash-emitting eruptions. The item on the blog I just linked to also indicated possible lava; they called it a low-level thermal anomaly so it could also be a hot plug in the vent, which could have been coughed out by the more recent eruption.
Thank you for all the information cogitator.
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