Global Volcanism Program | Image GVP-10575
Wave erosion has exposed the spectacular stratigraphy of Sumisujima, a steep-sided pinnacle that is a remnant of the outer southern flank of a submarine caldera 6-9 km wide. Intrusive rocks, dikes, tephra layers, and breccias are visible in this view of the eastern side of the pinnacle. Submarine eruptions have been reported from a number of locations near here, the last of which occurred in 1916. Water discoloration has been frequently observed nearby since the 1970s.
Copyrighted photo by Kenichiro Tani, 2002 (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/).