AVO reported that during 6-12 December no thermal anomalies were visible in mostly clear satellite images, and no activity was detected by seismic or infrasound sensors. AVO noted that lava effusion may have paused or stopped; a satellite image acquired on 26 November showed that the lava dome had the appearance of rubble in the bottom of the shallow crater. On 12 December AVO lowered the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory, though an explosion the next day prompted a return to Orange and Watch, respectively. That explosion on 13 December was detected at 0420, and produced an eruption cloud identified in satellite data rising to an altitude of 6.1 km (20,000 ft) a.s.l. and drifting E.

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)