After JMA first reported new activity around the Kaitoku Seamount in August, discolored water continued to be periodically visible in Sentinel satellite images through 27 December. Though weather clouds sometimes prevented views of the vent area, and on occasion no activity was visible in clear images, plumes of discolored water drifting away from the vent area appeared to become more frequent in October. Images from 18 October, and 22 and 27 November possibly captured material at the surface or an eruption plume rising above the water. The Japan Coast Guard posted pictures of disturbed water around the vent in November. Recent Sentinel images on 17 and 27 December captured plumes of discolored water drifting as far as 10 km from the vent area.

Geological Summary. A submarine eruption was observed in 1984 from Kaitoku Seamount (Kaitoku Kaizan), a three-peaked submarine volcano 130 km NNW of Kita-Iojima. A submarine eruption had previously been reported in 1543 from a point about 40 km to the SW, which the Japan Meteorological Agency attributes to Kaitoku.

Sources: Sentinel Hub, Japan Coast Guard