According to KVERT, the Tokyo VAAC stated that an eruption at Chikurachki began at 1000 on 16 February. A Support to Aviation Control Service (SACS) notice described a large amount of aerosol near the Northern Kuriles Islands at 1322 that same day. Satellite images detected ash plumes that rose to altitudes of 7-7.5 km (23,000-24,600 ft) a.s.l. and drifted 80 km W. The Aviation Color Code was raised to Orange. At 0641, 1328, and 1635 on 17 February satellite images showed ash plumes rising to altitudes of 3-3.5 km (10,000-11,500 ft) a.s.l. and drifting 95-230 km SW.

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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)