KVERT reported on 30 December that a new 60- to 80-m diameter cone formed at Karymsky's summit. A small lava dome that was 20-30 m in diameter was noted in the crater of the cone. During 23-30 December, many weak, shallow earthquakes were recorded at the volcano. Interpretations of seismic data suggested that seven ash plumes rose 2.5-4 km (8,200-13,100 ft) a.s.l. during 24 and 26-27 December. Ash plumes extended mainly E, SE, and occasionally SW of the volcano. KVERT reported that ash emissions could affect low-flying aircraft in the vicinity of the volcano. Karymsky remained at Concern Color Code 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)