AVO reported that during 20-24 September nothing significant was observed in satellite images and web camera views of Cleveland, and nothing noteworthy was detected in seismic or infrasound data. Minor steaming was noted during 22-24 September. A three-minute-long explosion that began at 1747 on 25 September was detected by seismic and infrasound sensors. Satellite data 30 minutes later suggested that a volcanic cloud likely containing ash rose to 4.6 km (15,000 ft) a.s.l. and drifted S. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Geological Summary. The beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano. Joined to the rest of Chuginadak Island by a low isthmus, Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano. Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998). In 1944 it produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.

Source: US Geological Survey Alaska Volcano Observatory (AVO)