KVERT reported that technical problems prevented seismic data collection at Karymsky during 26 July-2 August. A thermal anomaly over the volcano was detected in satellite images during 29-31 July and 1 August; weather conditions prevented views on the other days.

On 6 August at 1035 a plume was observed by helicopter pilots (and confirmed by volcanologists at Tolbachik) rising 6 km (19,700 ft) a.s.l. and drifting 30 km E. An explosion at 1145 generated an ash cloud observed in satellite images that rose to an altitude of 4 km (13,100 ft) and drifted 45 km ESE. The ash cloud was 9 x 14 km. Ash plumes that were observed in satellite images at 1332 and 1512 rose to altitudes of 4.2 km (13,800 ft) and drifted 30 km ESE, and 4 km (13,100 ft) and drifted 80 km ESE, respectively. The Aviation Color Code remained at 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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)