During 27 April-3 May, Karymsky's seismicity remained above background levels and its character suggested that weak ash-and-gas explosions, gas blow-outs, and debris avalanches occurred. On 28 April at about 1630 an ash explosion produced a cloud to 500 m a.s.l. and deposited ash predominately to the W and to a lesser extent to the E. A new cone was visible inside the crater. Thermal anomalies were visible on AVHRR satellite imagery, but ash was not. The volcano remained at Concern Color Code Yellow ("volcano is restless").

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)