Report on Chikurachki (Russia) — 30 April-6 May 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 April-6 May 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Chikurachki (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 30 April-6 May 2003. Smithsonian Institution and US Geological Survey.
50.324°N, 155.461°E; summit elev. 1781 m
All times are local (unless otherwise noted)
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.
Geologic Background. Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is actually a relatively small cone constructed on a high Pleistocene volcanic 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 from 1781-m-high Chikurachki reached the sea and form capes on the NW coast; several young lava flows also emerge from beneath the scoria blanket on the eastern flank. The Tatarinov group of six volcanic centers is located immediately to the south of Chikurachki, 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 volcanoes are extensively modified by erosion and have a more complex structure. Tephrochronology gives evidence of only one eruption in historical time 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.