KVERT reported that seismic activity at Karymsky was above background levels on 1 and 5 January, suggesting that possible ash plumes rose to an altitude of 3.8 km (12,500 ft) a.s.l. Seismic activity did not exceed background levels on the other days during 31 December-7 January. A thermal anomaly was detected daily in satellite imagery. An ash plume drifting 140 km SE was also seen in imagery on 2 January. Based on a pilot observation, the Tokyo VAAC reported that on 5 January an ash plume rose to an altitude of 4.6 km (15,000 ft) a.s.l.

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.

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)