On 28 April, Thomas Madsen (president, Aleutian Air Ltd.) observed an eruption plume emerging from the summit of Mt. Cleveland. He first saw the grayish-white plume at about 1220, from 190 km to the E, estimating that it reached ~2,900 m altitude . . . and extended SW. The plume had definite dark streaks and swirls of ash. Passengers on a Peninsula Airways flight . . . at about 1900 reported that the eruptive activity had declined to minor steam emission.

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.

Information Contacts: J. Reeder, ADGGS.