High seismic activity at Karymsky continued during 6-13 May. The number of local shallow events was 150-500 per day during the week. According to seismic data, possible ash-and-gas plumes rose up to the 1,000 m above the crater on 5, 8, and 9 May. According to satellite data, a thermal anomaly was registered on 6 and 8 May. Gas-and-steam plumes containing some ash extended ~40 km E on 6 May and ~30 km S on 9 May. Clouds obscured the volcano at other times. A larger eruption to 3 km altitude (10,000 feet) was reported on 18 May. 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.

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