Chuginadak is part of an island chain called Islands of Four Mountains. The name derived from the Russian Четырехсопочные Острова (Ostrava Chetyre Soposhnye) which was given to the chain by Russian explorers that noticed four prominent mountains in 1826. The Islands of Four Mountains also include Amukta, Chagulak (a 3km wide island with a steep 1142m high volcano), Yunaska (the largest island), Herbert (a circular island with a 2km wide caldera), Carlisle (containing a 1610m high stratovolcano), Uliaga (the northernmost and smallest which in the 80s was ravaged by a shipwreck leaking oil) and the Kagamil Islands. Thus, it appears there are more than four mountains, although Cleveland, Chagulak, Herbert and Carlisle were probably the most ‘prominent’. These volcanoes have an unknown eruptive history.
The eastern part of Chuginadak Island, which contains the heavily eroded Tana volcanic complex, is connected to Cleveland volcano by a narrow isthmus. Aleut oral history mentions that Cleveland and the eastern part of Chuginadak Island were separate islands in the past.
Since 1893, Cleveland had approximately 15 eruptions which are characterized by explosive ash emission (eruption columns can be up to 12 km high), lava flows and lava fountaining. VEI (Volcanic Explosivity Index: seehttp://volcanoes.usgs.gov/
From the end of January until the beginning of February 2013 a lava dome in the crater grew to a diameter of 200m. Since then, the few clear days that have occurred did not show any changes of growth of the summit dome. Currently, Cleveland is under volcano alert level yellow (see more information on volcano alert color codes see: http://volcanoes.usgs.gov/
Image: Cyrus Read (USGS). The image shows Cleveland volcano in the back with Carlisle volcano on the foreground.
References and further reading
Webcam monitoring Cleveland from the Alaska Volcano Observatory: http://www.avo.alaska.edu/