OKMOK, CLEVELAND: She and Coast Guard air crew saw both erupting at once. By BETH BRAGGPublished: July 23rd, 2008 12:21 AM
Geologist Tina Neal and the crew of a U.S. Coast Guard C-130 got more than they bargained for Monday when they took to the air for a look at the erupting Okmok Volcano. Mount Cleveland -- another Aleutian Island volcano about 100 miles west of Okmok -- had burst into action too. "I've never been in the air looking at one eruption and seeing the plume from another," said Neal, an Alaska Volcano Observatory scientist who has spent 25 years working with the U.S. Geological Survey in volcano-rich Alaska and Hawaii.
"When we took off from Kodiak all we knew about was Okmok. It was while we were at Okmok and looking down and photographing it that the pilot noticed a dark cloud ahead of us to the west. We realized it couldn't be Okmok because the wind was blowing in the other direction.
"Within 20 minutes we got a call from base saying Cleveland had erupted. Inadvertently we were in the air over Okmok while Cleveland ash was traveling toward us. That's a first in my career."
What Neal and the Coast Guard crew saw was a volcanopalooza, the first double burst in Alaska in more than 30 years. The last time two Alaska volcanoes erupted at the same time was 1974, maybe earlier, according to Cheryl Cameron, a Fairbanks geologist who works for the state Department of Natural Resources.
"Trident Volcano had a big, long, intermittent eruption from 1953 to 1974, and during those 21 years we had dozens of other eruptions," Cameron said.
Even without the double whammy, Neal said, her experience Monday was unprecedented. She has often flown over a lava-producing eruption -- but never over an ash-producing one.
"It was the most violent eruption I've ever seen," she said. "Ash was just boiling out of the ground."
The Coast Guard flight was unable to check out Cleveland on Monday because of fuel limitations, Neal said. Both volcanoes continued to erupt Tuesday and were color-coded orange, one level below red, the highest aviation alert level.
Satellite images indicate that lava is flowing at Cleveland, a busy 5,676-foot volcano that erupts with frequency on uninhabited Chuginadak Island.
No lava has been reported at Okmok, a 3,500-foot volcano on Umnak Island that last erupted in 1997. Ten people were on the island when Okmok first blew July 12 and were evacuated safely.
Neal said she could barely see Okmok's caldera floor because so much ash has filled it. A caldera is the broad crater-like basin formed when a volcanic peak collapses after an explosive eruption.
Okmok's continuous ash plume is pulsing in response to the varying intensity of the eruption, Neal said, rising from 15,000 feet to 20,000 or even 25,000 feet in a matter of minutes, then going back down to 15,000 feet. "In the 20 minutes we were there, we saw it go up and down twice," she said. Cleveland's plume consists of steam and some ash and is between 10,000 and 20,000 feet high, observatory reports said.
There have been no reports of significant ash fall in Dutch Harbor, about 60 miles from Umnak Island and about 150 miles from Chuginadak Island, since Okmok's initial eruption.