The Alaska Volcano Observatory changed the Aviation Color Code of Iliamna Volcano to Yellow on Friday, March 9.
Over the past three months the earthquake rate at the volcano has steadily increased and now exceeds normal background levels. Although it is not certain that this sustained increase in earthquake activity represents the movement of magma at depth, it is a significant change and AVO has increased the Alert Level to Advisory and the Aviation Color Code to Yellow.
The current activity does not mean an eruption is imminent or certain. A similarly energetic episode of seismic unrest from September 1996 to February 1997 was likely related to the intrusion of new magma at depth, but an eruption did not occur.
AVO will continue to observe Iliamna closely, will conduct additional investigations and report on them as warranted.
For more details, visit https://www.avo.alaska.edu/activity/Iliamna.php.