After more than 40 years of quiet, the Great Sitkin Volcano has grown restless.
The Alaska Volcano Observatory (AVO) raised its alert level last week after Adak residents reported a steam plume rising 1,000 feet above the summit.
AVO Geophysicist Dave Schneider said the plume is just the latest sign of life at Great Sitkin, which has shown increasing seismic activity since the summer of 2016. That’s why the AVO upgraded its alert level from “normal” to “advisory.”
“The earthquake activity has been consistent, it’s on a slight upward trend, [and] it’s continuing," said Schneider. "That’s the kind of signal you look for in the earliest stage of volcanic eruptions.”
Still, it’s too soon to say whether Great Sitkin will actually explode.
Schneider said magma has collected beneath the volcano, but it’s impossible to predict if it’ll push its way to the surface or just cool off and solidify into rock.
“There is no single silver bullet in volcano monitoring," he said. "There is a possibility that it will erupt, but we can’t really provide any short-term forecast on that at this time.”
If the volcano does blow, Schneider said ash could affect flights to and from Adak, which is located about 25 miles west of Great Sitkin.