KVERT reported that during 12-19 August seismicity from Kizimen was above background levels and weak volcanic tremor continued to be detected. Video images showed an occasional steam plume that rose to an altitude of 3 km (9,800 ft) a.s.l. and fumarolic activity on 14 August. A lava flow on the E flank was active. Satellite images showed a large bright thermal anomaly on the volcano all week and a gas-and-steam plume that drifted 57 km NNE on 15 August. The Aviation Color Code remained at Orange.

Based on analyses of satellite imagery, the Tokyo VAAC reported that a possible eruption on 20 August produced a plume that rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted E. Subsequent images that day showed that continuing ash emissions had later dissipated.

Geological Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to St. Helens prior to its 1980 eruption. The summit consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2334-m-high edifice was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2000-3500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of long-term lava dome growth have occurred. The latest eruptive cycle began about 3000 years ago with a large explosion and was followed by intermittent lava dome growth lasting about 1000 years. An explosive eruption about 1100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. Prior to 2010, only a single explosive eruption, during 1927-28, had been recorded in historical time.

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)