Report on Kuchinoerabujima (Japan) — 27 May-2 June 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 May-2 June 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Kuchinoerabujima (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 May-2 June 2015. Smithsonian Institution and US Geological Survey.
30.443°N, 130.218°E; summit elev. 639 m
All times are local (unless otherwise noted)
JMA reported that at 0959 on 29 May an explosive and phreatomagmatic eruption at Kuchinoerabujima generated an ash plume that rose 9 km above Shindake Crater's rim and drifted ESE. Pyroclastic flows descended the SW flank and reached the coast on the NW flank. Volcanic earthquakes increased after that event, but then decreased around 1300. The Alert Level was raised to 5 (the highest level on a 1-5 scale). According to a news article all residents and visitors (137-141) were safely evacuated by a ferry to neighboring Yakushima Island. Later that day ash plumes rose 200 m and drifted SW. Scientists conducted an overflight and confirmed pyroclastic flow deposits on the NW and NE flanks.
Ash plumes continued to be emitted the next day, rising as high as 1.2 km. A field team observed discolored trees on the SE and SW flanks, and fallen trees near the coast on the NW flank. Cloud cover prevented views of the eruption area, but the team was able to confirm continued fumarolic activity from a crack in the W part of the crater as well as incandescence.
Geologic Background. A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km west of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. The youngest cone, centrally-located Shintake, formed after the NW side of Furutake was breached by an explosion. All historical eruptions have occurred from Shintake, although a lava flow from the S flank of Furutake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shintake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions.