Fukutoku-Ohkano-Ba

The August 2021 eruption of the Fukutoku-Oka-no-Ba (FOB) submarine volcano in Japan was remarkable partly because it generated a 16-km water-rich atmospheric plume, new islands, and a large pumice raft. Because the FOB vent lies at a depth of 40 m, this eruption has an associated hydroacoustic record. A central unanswered question is: to what extent did processes beneath the sea surface correlate with the intensity of the atmospheric portion of the 2021 FOB eruption? Here, I compare hydroacoustic data with lightning and plume height/width data (Himawari-8). I also examine the volume flow rate derived from plume observations in relation to hydroacoustic and lightning characteristics. The lightning, hydroacoustic, and plume flux data are highly correlated, suggesting the submarine and subaerial portions of the eruption are coupled (McKee et al., 2026, Volcanica).