USGS Volcano Notice for Aviation - DOI-USGS-AVO-2023-08-25T09:29:33-07:00

A decrease in seismic activity at Mount Cleveland over the past few weeks to background levels has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to GREEN/NORMAL.

An increase in the number of small earthquakes near Mount Cleveland in mid-July 2023 prompted raising the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on July 19. This activity  continued for the next several weeks but has since declined. Slightly elevated surface temperatures and weak gas emissions from the summit crater continue to be observed occasionally, but this is not unusual for Mount Cleveland.

The last eruptive activity at Mount Cleveland was a short-lived explosion during the evening (local time) of June 1, 2020. Despite the current pause, the eruptive period at Mount Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These have occurred without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Mount Cleveland is currently monitored with a five-station real-time seismic network. We now have enough stations at the volcano to locate volcanic earthquakes thanks to a partnership between AVO and the AVERT (Anticipating Volcanic Eruptions in Real-Time) project at Columbia University. Based on past events, explosive eruptions of Cleveland may occur with little or no warning. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.