Report on Izu-Torishima (Japan) — 3 July-9 July 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 July-9 July 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Izu-Torishima (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 3 July-9 July 2013. Smithsonian Institution and US Geological Survey.
30.484°N, 140.303°E; summit elev. 394 m
All times are local (unless otherwise noted)
According to the Tokyo VAAC a pilot observed an ash plume from Tori-shima drifting at an altitude of 2.1 km (7,000 ft) a.s.l. on 6 July.
Geologic Background. The circular, 2.7-km-wide island of Izu-Torishima in the southern Izu Islands is capped by an unvegetated summit cone formed during an eruption in 1939. Fresh lava flows from this eruption form part of the northern coastline of the basaltic-to-dacitic edifice. The volcano is referred to as Izu-Torishima to distinguish it from the several other Japanese island volcanoes called Torishima ("Bird Island"). The main cone is truncated by a 1.5-km-wide caldera that contains two central cones, of which 394-m-high Ioyama is the highest. Historical eruptions have also occurred from flank vents near the north coast and offshore submarine vents. A 6-8 km wide submarine caldera lies immediately to the north.