Editing Kikai Caldera (section)

=== Kikai-Koabiyama eruption ===
The Kikai-Koabiyama (K-Kob) pyroclastic flows are rhyolitic and are distributed across most of Takeshima and the plateau-like area on the northwest side of the caldera rim of Satsuma Iwo-Jima. They consist of numerous thin flow units and fill the basins in the basement, exhibiting significant variation in thickness. In Takeshima, the pyroclastic flows are thick, ranging from {{Convert|20-100|m|ft|abbr=on}}, whereas in Iwo Jima, they are relatively thin, measuring a few to {{Convert|30|m|ft|abbr=on}}.<ref name="gbank" /><ref name=":2" />

The eruption of the K-Kob pyroclastic flows has been dated using [[K–Ar dating|K-Ar dating]] to be {{Val|140000|20000|fmt=commas}} years before present.<ref name="gbank" /> While no distal tephra from this eruption has been reported, a tephra layer with potential geochemical and age correlation has been discovered in [[Lake Suigetsu]].<ref>{{Cite journal |last1=Maruyama |first1=Seiji |last2=Takemura |first2=Keiji |last3=Hirata |first3=Takafumi |last4=Yamashita |first4=Tohru |last5=Danhara |first5=Tohru |date=2019-08-11 |title=Major and trace element abundances in volcanic glass shards in visible tephras in SG93 and SG06 drillcore samples from Lake Suigetsu, central Japan, obtained using femtosecond LA–ICP–MS |journal=Journal of Quaternary Science |volume=35 |issue=1–2 |pages=66–80 |doi=10.1002/jqs.3124 |issn=0267-8179|doi-access=free }}</ref>