Report on Moyorodake [Medvezhia] (Japan - administered by Russia) — April 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 4 (April 1987)
Managing Editor: Lindsay McClelland.
Moyorodake [Medvezhia] (Japan - administered by Russia) Intense fumarolic activity
Please cite this report as:
Global Volcanism Program, 1987. Report on Moyorodake [Medvezhia] (Japan - administered by Russia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198704-290100
Japan - administered by Russia
45.389°N, 148.838°E; summit elev. 1124 m
All times are local (unless otherwise noted)
Intense activity from a few groups of fumaroles in Kudriavy's summit crater was occurring during a 6 November aerial survey. Sulfur deposits were noted around the fumaroles. East of the crater, on the outer dome slope, very intense gas emission (more active than in the crater) was observed.
Geological Summary. The Moyorodake volcanic complex (also known as Medvezhia) occupies the NE end of Iturup (Etorofu) Island. Two overlapping calderas, 14 x 18 and 10 x 12 km in diameter, were formed during the Pleistocene. The caldera floor contains several lava domes, cinder cones and associated lava fields, and a small lake. Four small closely spaced stratovolcanoes were constructed along an E-W line on the eastern side of the complex. The easternmost and highest, Medvezhii, lies outside the western caldera, along the Pacific coast. Srednii, Tukap, and Kudriavy (Moyorodake) volcanoes lie immediately to the west. Historically active Moyorodake is younger than 2000 years; it and Tukap remain fumarolically active. The westernmost of the post-caldera cones, Menshoi Brat, is a large lava dome with flank scoria cones, one of which has produced a series of young lava flows up to 4.5 km long that reached Slavnoe Lake. Eruptions have been documented since the 18th century, although lava flows from cinder cones on the flanks of Menshoi Brat were also probably erupted within the past few centuries.
Information Contacts: G. Steinberg and B. Piskunov, Yuzhno-Sakhalinsk.