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Tremors Die Down at Semisopochnoi

NASA Earth Observatory

A major Alaska volcano is quieting down, but equipment trouble may make it difficult to collect long-term data.  KDLG’s Chase Cavanaugh has more. 

The Alaska Volcano Observatory reports that Semisopochnoi, a peak in the western Aleutian Islands, has ended a several month period of seismic activity.  When the tremors were still active, the volcano’s aviation color code was yellow.  Normally, it would be downgraded to green, but Coordinating Scientist Jeff Freymueller says the Observatory has been having equipment problems.  Specifically, a telemetry link at Amchitka, which transmits the mountain’s seismic data, has been unreliable.

“It’s actually been working mostly fine since it was repaired at the end of May, but we don’t really have a lot of confidence that it’s going to stay up for months and months at a time. If it does, we’ll be very happy with that, but we’re not sure we can rely on it.”

Despite the malfunctions, Freymueller says AVO is quite confident about the decrease in seismic activity.

“This seismic swarm started just a few days actually after, maybe a week and a half, after we repaired the telemetry link on Amchitka. It’s been dying off over the last couple of months and is essentially over at this point. We’re quite confident that the level of activity on Semisopochnoi has gone back down to pretty much a background level. We list it as unassigned because we’re not yet confident about the longer-term reliability of the telemetry link for the data.”

The ideal fix would be a dome surrounding the link’s satellite dish, but AVO lacks the funds to construct it.  Freymueller says that Amchitka is a very expensive area to access, and if it wasn’t for interagency cooperation, they wouldn’t have been able to fix the telemetry link in the first place.

“We actually managed to get people onto Amchitka twice this year, which is really the first time in about two years that we were able to do anything there. That was actually thanks to a partnership with the Department of Energy and their interest in Amchitka has to do with the fact that it had been used previously as a nuclear testing site.”

At this point, AVO hopes that the smaller dish they’ve installed will not be as buffeted by the wind and be able to remain operation through the winter.   More information on Semisopochnoi and other Alaskan volcanoes is available at