Chikurachki stratovolcano, located on Paramushir Island in the Northern Kuriles, began erupting on 18 April 2003. During the next few days observers described the ash falls and substantial plumes with estimated heights up to ~10 km altitude. Observers on Paramushir island saw ash explosions on 18 April; ash fell in Podgorny town and Cape Vasiliev. Satellite data for 18 April revealed that ash plumes moved towards the SSE and traveled a distance of more than 50 km. The Aviation Meteorological Center at Yelizovo airport reported that on 19 April ash plumes rose 2,000 m. Three distinct eruptive events were detected in satellite data on 19 April, in one case ash plumes extended over 50 km SE.

The longest reported plume of the week occurred on 20 April; it reached over 250 km from the volcano towards the SE, later blowing E. Satellite analysts described a variety of plumes on 21 April: a narrow ash plume (visible ~130 km in length and trending SE), a comparatively wide ash plume (~ 25 km wide at a distance of ~50 km from the volcano), and some other ash plumes (over 50-70 km in length moving to the S). One reason why this eruption and its plumes are important is because they lie along a frequently traveled aviation route.

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)