Report on Kanaga (United States) — May 1994
Bulletin of the Global Volcanism Network, vol. 19, no. 5 (May 1994)
Managing Editor: Richard Wunderman.
Kanaga (United States) Low-level steam-and-ash emissions continue
Please cite this report as:
Global Volcanism Program, 1994. Report on Kanaga (United States) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 19:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199405-311110.
51.923°N, 177.168°W; summit elev. 1307 m
All times are local (unless otherwise noted)
Low-level steam and ash emissions continued through late May and the first half of June, although poor weather frequently prevented observations. On several occasions in late May a vigorous steam plume was observed rising through scattered clouds above the volcano. Observers in Adak . . . saw a steam plume over the volcano on 31 May and a gray plume rising 1,000-1,200 m on 9 June. Aerial photographs of the summit area taken by U.S. Navy personnel in late January show that the vent system extends beyond the summit onto the upper W flank, corroborating reports by ground observers during the last several months.
Geologic Background. Symmetrical Kanaga stratovolcano is situated within the Kanaton caldera at the northern tip of Kanaga Island. The caldera rim 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. Historical eruptions, most of which are poorly documented, have been recorded since 1763. 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.
Information Contacts: AVO.