Report on Chikurachki (Russia) — 23 March-29 March 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 March-29 March 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Chikurachki (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 23 March-29 March 2005. Smithsonian Institution and US Geological Survey.
50.324°N, 155.461°E; summit elev. 1781 m
All times are local (unless otherwise noted)
On 25 March, KVERT raised the Concern Color Code at Chikurachki from Yellow to Orange. On 23 March, satellite imagery showed a weak ash plume extending ~70 km (~44 mi) E of the volcano. The height of the plume was unknown. The Concern Color Code was originally raised from Green to Yellow on 12 March when explosions were first noted. Chikurachki is not monitored with seismic instruments. KVERT has satellite data and occasional visual observations of the volcano.
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.