2 Topography of Izu Oshima Volcano. Distribution of the 1986 eruptive deposits are also shown. 2 Tephra layers exposed outside the caldera of Izu Oshima Volcano. 3 Tephra and loess stratigraphy of Izu Oshima Volcano since the formation of the caldera. While the height of the tephra column shows the eruptive mass of each tephra, the height of the loess column shows the median thickness of each loess layer.
Characters show the tephra names.
R means the rhyolitic ash layer, which was brought by the 838 eruption of Kozushima Volcano and was interbedded within the N3.0 tephra. Star shows the horizon of a flank eruption and appended characters show its location, which is indicated as a direction from the caldera center. 4 Temporal change in cumulative discharge mass of magma. Symbols show the type of eruption.