Report on Korovin (United States) — 22 February-28 February 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 February-28 February 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Korovin (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 22 February-28 February 2006. Smithsonian Institution and US Geological Survey.
52.381°N, 174.166°W; summit elev. 1518 m
All times are local (unless otherwise noted)
AVO reported that the Concern Color Code at Korovin volcano was raised from Green to Yellow on 22 February due to an increase in seismicity at the volcano. Distinct seismic signals indicating unrest were recorded on 4 days between 17 and 22 January, with a sustained 11-minute-long seismic signal on 22 February. After 22 February, seismicity decreased and distinct seismic signals like those recorded earlier were not detected. Clouds obscured satellite views of the volcano after 22 February. A pilot report on the 22nd indicated that the summit area was obscured by clouds, and there were no signs of ashfall on the flanks and no steam plume above the volcano. No obvious signs of activity were seen on 23 February by observers in the village of Atka. AVO received no reports of volcanic activity and there were no indications that an eruption was imminent.
Geologic Background. Korovin, the most frequently active volcano of the large volcanic complex at the NE tip of Atka Island, contains a 1533-m-high double summit with two craters located along a NW-SE line. The NW summit has a small crater, but the 1-km-wide crater of the SE cone has an unusual, open cylindrical vent of widely variable depth that sometimes contains a crater lake or a high magma column. A fresh-looking cinder cone lies on the flank of partially dissected Konia volcano, located on the SE flank. The volcano is dominantly basaltic in composition, although some late-stage dacitic lava flows are present on both Korovin and Konia.