Report on Kirishimayama (Japan) — 28 November-4 December 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 November-4 December 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Kirishimayama (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 November-4 December 2018. Smithsonian Institution and US Geological Survey.
31.934°N, 130.862°E; summit elev. 1700 m
All times are local (unless otherwise noted)
JMA reported that vigorous fumarolic activity on the S side of Iwo-yama (also called Ioyama), on the NW flank of the Karakuni-dake stratovolcano in the Kirishimayama volcano group, continued during 30 November-3 December. Fumarolic plumes rose 100 m above the vent, and hot mud was ejected from the vent. A hot pool of water persisted on the S side of the area. Fumarolic plumes rose 50 m above a vent 500 m W of Iwo-yama. The Alert Level remained at 2 (the second lowest level on a scale of 1-5).
Geologic Background. Kirishimayama is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene dominantly andesitic group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located Karakunidake being the highest. Onamiike and Miike, the two largest maars, are located SW of Karakunidake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Miike to Ohachi, and at Shinmoedake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.