KVERT reported that weak-to-moderate seismic activity at Karymsky was detected during 14-21 December. Seismic data indicated that ash plumes possibly rose to an altitude of 3 km (9,800 ft) a.s.l. during 13-15 December. Volcanologists observed weak gas-and-steam activity on 18 December. Satellite imagery showed a thermal anomaly on the volcano on 20 December. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Geological Summary. Karymsky is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the S side of the Pleistocene Dvor volcano and is located outside the N 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 enclosing caldera formed about 7,600-7,700 radiocarbon years ago; construction of the stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300 years of quiescence. Much of the cone is covered by lava flows less than 200 years old. Recorded eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater.