Increased seismicity and recent satellite detections of significant sulfur dioxide emissions forced the Alaska Volcano Observatory (AVO) to increase alert levels for Korovin volcano on October 28, 2020. The Aviation Color Code was raised to Yellow and Alert Level to Advisory.
Discrete earthquakes have been detected at the volcano over the past two weeks and sulfur dioxide degassing has been detected four times in satellite data on October 15, 20 and 26. Clear satellite views show no other signs of activity at this time.
Korovin is monitored by local seismic and infrasound sensors, satellite data, and regional lightning detection instruments.
The last eruption at this volcano took place in 2007. Its strongest known eruption took place in 1998 (VEI 3).
A WorldView-1 satellite image taken on October 26, 2020 shows the typical minor steam plume from the crater lake at the summit of Korovin Volcano. Imagery is panchromatic grayscale. Image credit: Hannah Dietterich
Korovin, the most frequently active volcano of the large volcanic complex at the NE tip of Atka Island, contains a 1 533 m (5 029 feet) high double summit with two craters located along a NW-SE line.
The NW summit has a small crater, but the 1 km (0.6 miles) 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.
This volcano is located within the Aleutian Islands, a UNESCO Biosphere Reserve property.
Featured image: Janet Schaefer, USGS/AVO