KVERT reported that during 5 and 9-10 December seismic activity at Karymsky was at background levels; possible explosions may have generated ash-and-gas plumes to an altitude of 2.8 km (9,200 ft) a.s.l. Volcanologists occasionally saw ash plumes rise to altitudes of 2 km (6,600 ft) a.s.l. and drift E. Ash deposits on the E flank were more than 5 km long. Analysis of satellite imagery revealed a thermal anomaly in the crater on 8 December and an ash plume that drifted ESE. The Level of Concern Color Code remained at Orange.

Geological Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)