The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that thermal anomalies over Karymsky were identified in satellite images during 24 and 28-30 April and on 1 May. Explosive activity began on 29 April and ash plumes generated during 29-30 April and on 1 May drifted 120 km SE, E, and NE. KVERT issued a Volcano Observatory Notice for Aviation (VONA) noting that explosions occurred at 1320 and 1830 on 30 April; the ash plume from the second explosion rose 3.5-4 km (11,500-13,100 ft) a.s.l. Dates are based on UTC times; specific events are in local time where noted.

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)