Based on satellite data KVERT reported that an eruption at Karymsky began at about 0630 on 4 December and generated an ash cloud that rose to an altitude of km (9,000 ft) a.s.l. An ash cloud 16 x 12 km in dimension was identified in satellite images about three hours later, 92 km E of the volcano. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Geological Summary. Karymsky is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the S side of the Pleistocene Dvor volcano and is located outside the N 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 enclosing caldera formed about 7,600-7,700 radiocarbon years ago; construction of the stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300 years of quiescence. Much of the cone is covered by lava flows less than 200 years old. Recorded eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater.