KVERT reported on 15 September that the Concern Color Code level at Karymsky was raised from Yellow to Orange. Approximately 50-100 shallow earthquakes occurred daily during 9-15 September. During 8-10 and 12 September, a thermal anomaly was detected in the crater. An ash plume was visible on satellite imagery extending ~140 km SE on 13 September. On 17 and 19 September, eruption plumes rose to altitudes of 2.7 km (9,000 ft) a.s.l. and drifted SE.

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), Tokyo Volcanic Ash Advisory Center (VAAC)