USGS Volcano Hazards Program Volcano Update

AVO update page and observatory web site

Cleveland Volcano appears to have entered a renewed phase of elevated unrest and AVO detected three explosions and minor ash plumes during the past week. This level of activity prompted AVO to change the Aviation Color Code and Alert Level from Yellow/Advisory to ORANGE/WATCH on Jan. 2. Three brief explosions were detected on Dec. 28, Dec. 30 and Jan. 2 and minor ash plumes were observed in satellite data following events on Dec. 30 and Jan. 2 UTC.

Analysis of satellite, wind, and ash dispersion data indicates that the Dec. 30 and Jan. 2 plumes probably did not reach more than 15,000 feet above sea level.

At the present level of unrest, it is possible for brief, sudden explosions of blocks and ash from the summit vent of Cleveland Volcano to occur with little to no warning. These explosions may produce drifting ash clouds and local fallout of ash over the surrounding ocean, on the flanks of Cleveland Volcano, and on parts of Chuginadak Island. It is possible that more energetic explosions will occur that may produce more significant ash clouds.

If a large ash-producing event occurs, nearby seismic, infrasound, or volcanic lightning networks should alert AVO staff quickly. However, for some events, a delay of several hours or more is possible. Cleveland volcano does not have a local seismic network and is monitored using only distant seismic and infrasound instruments and satellite data.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. The last minor ash emission following an explosion was on Jan. 2, 2014.

Update in Common Alerting Protocol (CAP) format