Report on Etorofu-Yakeyama [Grozny Group] (Japan - administered by Russia) — 15 August-21 August 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
15 August-21 August 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Etorofu-Yakeyama [Grozny Group] (Japan - administered by Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 15 August-21 August 2012. Smithsonian Institution and US Geological Survey.
Etorofu-Yakeyama [Grozny Group]
Japan - administered by Russia
45.012°N, 147.871°E; summit elev. 1158 m
All times are local (unless otherwise noted)
According to news reports, Ivan Grozny, one of two volcanoes comprising the Grozny Group, erupted on 16 August, after increased gas emissions from the NE flank were observed the day before. An ash plume rose 1.2 km and caused ashfall in Goryachiye Klyuchi (9 km W) and Kurilsk (25 km away). Residents reported a sulfur dioxide odor. By the afternoon ashfall had ceased and the odor subsided.
Geological Summary. The Etorofu-Yakeyama (Ivan Grozny) complex is located in the center of Iturup Island. It has a 3-3.5 km diameter caldera open to the south, where a large extrusive andesitic dome was emplaced. Several other lava domes of Holocene age were constructed to the NE; extrusion of these domes has constricted a former lake in the northern side of the caldera to an extremely sinuous shoreline. Historical eruptions, the first of which took place in 1968, have been from the central Yakeyama (Grozny) dome.