December 30, 2011

Ash Cloud Cause For Potential Airline Angst

Satellite imagery is showing Alaska´s Cleveland Volcano spewing ash 15,000 feet into the air from uninhabited Chuginadak Island about 940 miles southwest of Anchorage, USA Today is reporting. “It´s not expected to cause a disruption to big international air carriers,” U.S. Geological Survey (USGS) scientist-in-charge John Power said, who went on to call the event a “small explosion”.

Air carriers in the region are showing a bit more concern, “any time you put an ash cloud up into the atmosphere, the airlines, the air carriers, air freight companies – it´s a major concern,” Power said.

Last summer, satellite images revealed lava building and forming a dome-shaped accumulation. Chris Waythomas of the USGS said in September that lava domes form a lid on a volcano´s “plumbing,” including the chamber holding the magma.

When they grow big enough, lava domes can become unstable and will sometimes collapse. When the magma chamber decompresses it can lead to an explosion as the conduit inside the volcano suddenly becomes unsealed and gases escape. Radar images earlier this month showed the dome had cracked and subsided, Power explained.

The Federal Aviation Administration (FAA) becomes concerned for trans-Pacific flights when an ash cloud has the potential to exceed 20,000-foot, as Cleveland Volcano has done in the past.

The last major eruption of Cleveland Volcano´s was in 2001 and has seen bursts of activity nearly every year since then. The latest ash cloud is not uncommon.

“It´s not unexpected for a volcano like Cleveland to do things like this,” Power said.

“Unfortunately, Cleveland is one of those that is so remote, we have no on-ground monitoring or instrumentation there, so it´s hard for us to pinpoint things any more accurately than we can do with satellite imagery.”

The observatory Thursday morning had no satellite images of the crater after the eruption.


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