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(Update) Iliamna volcano: 'Seismic swarm', but eruption not likely

  • Author: Craig Medred
  • Updated: September 27, 2016
  • Published May 5, 2012

Correction: The activity shown on the webicorder was really just "noise" and Iliamna did not exhibit any increase in activity, according to an email from Stephanie Prejean, a research geophysicist at the Alaska Volcano Observatory. We regret the error.

Update: The Alaska Volcano Observatory's latest status report, from Saturday afternoon, does not indicate a change in status for Iliamna despite the new activity: "Seismic activity at Iliamna Volcano remains slightly above background. Nothing unusual was observed in web camera and mostly cloudy satellite images over the past 24 hours. The current activity at Iliamna does not indicate an imminent or certain eruption." The original report follows below.

Iliamna Volcano, located 140 miles southwest of Anchorage and 70 miles northwest of Homer, experienced increased seismic activity early Saturday morning, causing consternation among some Cook Inlet area residents. But according to the Alaska Volcano Observatory, an eruption is still considered not imminent or certain.

The most recent status update from the AVO, from Noon Friday, says that the volcano was exhibiting activity above background, but that the seismic activity wasn't enough to indicate an eruption or change in status.

The observatory said Friday that a similar seismic swarm at Iliamna in 1996-1997 was not followed by an eruption, and further that historically the mountain hasn't exhibited volcanic activity.

But according to the "webicorder" streaming seismic data from a monitoring station about 2 miles from Iliamna's summit, a band of new seismic activity began Saturday a little before 3:30 a.m. Saturday, and ended by 10:30 a.m.

As of Saturday at Noon, there hasn't been a new status update issued for Iliamna, and the aviation color code and volcano alert status has not changed from Yellow/Advisory.

We will update this news brief as soon as new information becomes available.

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