February 20, 2012 – ALASKA – The remote Kanaga stratovolcano in the Aleutian Islands might have begun erupting, the Alaska Volcano Observatory (AVO) reports. A possible ash cloud about 39 km (24 mi) NE of the volcano, likely from weak explosive activity, was detected on satellite imagery, and volcanic tremor was detected under the volcano from 15:23-15:27 UTC (6:23 AM AKST) on 18 February, followed by numerous small events for about an hour at Kanaga Volcano. AVO has placed the volcano at Aviation Color Code YELLOW. “This new unrest indicates a possibility for sudden explosions of ash to occur at any time, and ash clouds exceeding 20,000 feet above sea level may develop. If a large, explosive, ash-producing event occurs, the local seismic network, satellite ash alarms, infrasound, and volcanic lightning will alert AVO to the new activity.” Kanaga Volcano occupies the northern corner of Kanaga Island, one of the most southerly members of the central Aleutian chain. It is a symmetric composite cone 1307 m high and 4.8 km in diameter at sea level, built of interbedded basaltic and andesitic lava flows, scoria layers, and pyroclastic rocks. Kanaga Volcano last erupted 1994-1995 when observed eruptive plumes were relatively dilute, rising to altitudes of less than 3 km (9,840 ft) and dropping ash onto the flanks of the volcano. At least two significant ash plumes were recorded over the course of this eruption: the first, to ~7.5 km (24,600 ft) occurred on February 21, 1995 and the second on August 18, 1995, when an eruption cloud reached ~4.5 km (14,760 ft). A light dusting of ash fell on the community of Adak and air traffic was disrupted due to continuing low-level activity and cloudy conditions which prevented visual approaches to the Adak air field.

Source:  http://theextinctionprotocol.wordpress.com/2012/02/20/aleutian-islands-kanaga-volcano-awakens-first-eruption-in-17-years/