During 6-13 September, seismicity at Karymsky remained above background levels, with 200-250 local shallow events occurring per day. The character of the seismicity indicated that ash-and-gas explosions rose to ~1 km above the volcano and gas blow-outs possibly occurred. Observations of Karymsky on 8 September revealed three new small lava flows on the volcano's S and SE slopes. A thermal anomaly was visible on satellite imagery, but ash was not. Karymsky remained at Concern Color Code Yellow.

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)