According to reports KVERT received from the town of Severo-Kurilsk (~70 km NE of the volcano), volcanism that began at Chikurachki on 25 January had decreased by 20 February. Visual observations from a helicopter on 18 February revealed that a small new crater had formed in the SSE part of the volcano's summit crater. A gas-and-steam plume was visible rising 150 m above the crater and extending to the ESE. A stripe of fresh ash was visible on the volcano's E slope. No thermal anomaly or ash plume was visible on satellite imagery. KVERT reported that the possibility of ash explosions occurring remained. According to the Tokyo VAAC, possible eruptions on 21 February at 0325 and 24 February at 1232 may have produced ash clouds that rose to ~6 and 5.8 km, respectively.

Geological Summary. Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is a relatively small cone constructed on a high Pleistocene edifice. Oxidized basaltic-to-andesitic scoria deposits covering the upper part of the young cone give it a distinctive red color. Frequent basaltic Plinian eruptions have occurred during the Holocene. Lava flows have reached the sea and formed capes on the NW coast; several young lava flows are also present on the E flank beneath a scoria deposit. The Tatarinov group of six volcanic centers is located immediately to the south, and the Lomonosov cinder cone group, the source of an early Holocene lava flow that reached the saddle between it and Fuss Peak to the west, lies at the southern end of the N-S-trending Chikurachki-Tatarinov complex. In contrast to the frequently active Chikurachki, the Tatarinov centers are extensively modified by erosion and have a more complex structure. Tephrochronology gives evidence of an eruption around 1690 CE from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959.

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