KVERT reported that during 26 August-1 September moderate seismic activity continued at Karymsky, indicating that possible ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Gas-and-steam plumes containing ash drifted 40 km E on 26 and 29 August. A thermal anomaly on the volcano was detected by satellite during 26 and 29-30 August. The Aviation Color Code remained at Orange.

Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 2 September an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted NE. Ash plumes rose to an altitude of 2.1 km (7,000 ft) a.s.l. during 5-6 September and drifted SE and SW.

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)