Update: 12/21 at 3:15 p.m.
A volcano in the eastern Aleutians erupted suddenly Dec. 20 prompting the Alaska Volcano Observatory (AVO) to issue its highest alert level for aviation. The alert has since been downgraded.
Bogoslof volcano is on an uninhabited island 60 miles northwest of Unalaska.
AVO scientist Michelle Coombs said several pilots reported seeing an ash cloud at about 34,000 ft in altitude — about the same height as the cruising altitude for large jet planes.
She said satellite data show a short-lived explosion occurred around 4 p.m., but the activity has since died down.
Coombs said the volcano seems to have erupted because it was “gassy.”
“It looked like it had a lot of gas in it — a lot of sulfur gas and probably water gas,” Coombs said. “[The eruption] might have been the opening event in possible the eruptive sequence.”
It’s an eruptive sequence that might include new land forming.
The area is very dynamic. Coombs said over the years the shape, height and number of islands have changed. Since the 1700’s, Bogoslof has erupted 8 times and Coombs said it’s hard to know how long this eruption will last.
Eruptions are like personalities.
“Some volcanoes tend to erupt have a big explosive eruption and then go back to sleep,” Coombs said. “A lot of volcanoes have more longer-lasting, low-level activity.”
She said long eruptions — lasting weeks or months — are common in Alaska.
Because there is no ground-based monitoring equipment on Bogoslof volcano, the AVO cannot predict future eruptive activity. Instead, it is monitoring from afar — using satellite images and other data for indications of significant seismic activity.
If this eruption continues it could impact aviators, mariners and drop ash on nearby communities.
Prior to this, the last recorded eruption of Bogoslof was in 1992 and lasted nearly a month.
ORIGINAL STORY:
A volcano in the eastern Aleutians erupted suddenly Tuesday afternoon. The Alaska Volcano Observatory (AVO) said several pilots reported seeing an ash cloud about 34,000 feet above Bogoslof volcano.
Bogoslof volcano is on an uninhabited island 60 miles northwest of Unalaska.
The observatory said a short-lived explosion occurred at 4pm Tuesday, but the activity has died down. For now, the AVO and U.S. Geological Survey (USGS) has raised the aviation code to “red” and the alert level to “warning.”
Because there is no-ground based monitoring equipment on Bogoslof volcano, the AVO cannot predict future eruptive activity. Instead, it will monitor from afar — using satellite images and other data for indications of significant seismic activity.
Prior to this, the last recorded eruption of Bogoslof was in 1992.