Chikurachki began erupting on 18 April 2003 and the eruption was clearly continuing through 25 April. Associated ash plumes were over 100 km long.

During this week, 30 April-6 May, the Tokyo VAAC issued ash advisories on Chikurachki plumes for aviators. Early in the week the critical visual and satellite observations remained ambiguous with respect to the presence of ash in the atmosphere. On 2 May (at 1934 UTC) U.S. Airforce meteorologists detected Chikurachki ash emissions at ~3 km altitude and moving ESE at ~50 km/hour.

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)