Wednesday, Mar 07, 2012
After no further signs of restlessness had been detected at Kanaga during the past week, AVO lowered the alert level back to normal (green). [more]
Tuesday, Feb 28, 2012
No unusual activity was observed in seismic data or mostly cloudy satellite images of Kanaga volcano in the past 24 hours. ... [more]
Kanaga volcanoKanaga volcano is an active symmetrical stratovolcano rising 1300 m on the northern part of Kanaga Island in the western Aleutians, Alaska. It is one of the most southerly volcanoes of the central Aleutian chain.
The volcano has a small 200 m wide and 60 m deep circular summit crater with fumaroles inside the crater and around its rims. Historical eruptions have been recorded since 1763, but not in much detail due to the remoteness of the volcano. A new eruption might have started on 18 February 2012.
Background:Symmetrical Kanaga stratovolcano is situated within the Kanaton caldera at the northern tip of Kanaga Island. It is composed of interbedded basaltic and andesitic lava flows, scoria layers, and pyroclastic rocks.
The rim of Kanaton caldera forms a 760-m-high arcuate ridge south and east of Kanaga; a lake occupies part of the SE caldera floor. The volume of subaerial dacitic tuff is smaller than would typically be associated with caldera collapse, and deposits of a massive submarine debris avalanche associated with edifice collapse extend nearly 30 km to the NNW. Several fresh lava flows from historical or late prehistorical time descend the flanks of Kanaga, in some cases to the sea.
Kanaga is also noted petrologically for ultramafic inclusions within an outcrop of alkaline basalt SW of the volcano. Fumarolic activity occurs in a circular, 200-m-wide, 60-m-deep summit crater and produces vapor plumes sometimes seen on clear days from Adak, 50 km to the east.
(Smithsonian / GVP volcano information)
Prior to 2012, the last eruption of Kanaga was in 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. Larger ash emissions reaching up to 7.5 km occurred on 21 February 1995. ...more
Kanaga was seen in eruption 1906 a hunter reported. The eruption was accompanied by earthquakes and lava flows were reported on the east and west side of the steep volcano's cone.
Not much is known about the eruption of Kanaga volcano in 1904. Historic documents suggest a lava flow on the upper southern flank.