The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that the eruption at Krasheninnikov continued during 18-25 September. A daily large thermal anomaly over the volcano was identified in satellite images. Explosions at Northern Cone produced ash plumes that rose 2.4 km a.s.l., or nearly 600 m above the summit, and drifted 260 km SE and E during 23-25 September. A commercial satellite image on 25 September showed that lava flows had traveled 2.9 km NW, 2.8 km NE, and 3 km ENE. The upper half of the ENE flows were incandescent along with the main vent of Northern Cone. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified.

Geological Summary. The late Pleistocene to Holocene Krasheninnikov volcano is comprised of two overlapping stratovolcanoes within a 9 x 10 km Pleistocene caldera. Young lava flows from summit and flank vents descend both into the caldera and down its outer flanks, and older flows that covered much of the SE caldera rim extended downslope at least 7 km. Tephra deposits from the caldera-forming eruption directly overlie a 39,000 years before present (BP) tephra thought to be associated with the formation of Uzon caldera (Florenskii, 1988). The intra-caldera stratovolcanoes are situated along a NE-SW-trending fissure that has also produced zones of Holocene cinder cones extending 15-20 km beyond the caldera. Construction of the southern edifice began about 11,000 years BP and lasted for about 4,500 years; it has a summit crater about 800-900 m wide. The northern edifice was constructed during a cycle of similar length that began about 6,500 years ago; it has a summit crater about 1.5 km wide, within which is low cone with an 800-m-wide crater containing another small cone. An eruptive cycle during about 600-400 years BP (1350-1550 CE) produced the Pauk lava cone in the crater of the northern cone and the Yuzhny lava flow on SW flank outside the caldera, followed by the Molodoy flow from the upper SW flank (Ponomareva, 1987; Ponomareva and Tsyurupa, 1985; Ponomareva and Braitseva, 1990).

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Copernicus