Report on Kirishimayama (Japan) — 2 March-8 March 2022
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 2 March-8 March 2022
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2022. Report on Kirishimayama (Japan) (Sennert, S, ed.). Weekly Volcanic Activity Report, 2 March-8 March 2022. 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 an increase in volcanic earthquakes just below Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group). A total of 17 events were recorded during 1-2 March, prompting JMA to raise the Alert Level to 2 (on a scale of 1-5) on 2 March. No changes were seen at the volcano during a field visit that same day. Volcanic earthquakes persisted, with 5-12 events per day recorded through 7 March. Emissions had risen no higher than 30 m above the crater rim since 1 January, and fumarolic plumes continued to rise no higher than 100 m from a fissure on the W flank. During a field survey conducted on 4 March at the base of the volcano, sulfur dioxide emissions were below the detectable limit and no changes to area hot springs were observed.
Geological Summary. 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.