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Global Volcanism Program | Image GVP-02073

This outcrop at Oshima volcano, in the Izu Islands south of Tokyo, shows more than 100 individual tephra layers. They were produced by eruptions of Oshima at fairly regular intervals over a period of about 10,000 years. The lower layers follow the older preexisting topography. A prominent unconformity in the center of the outcrop is an erosional surface that truncated the earlier eruption deposits. The upper layers mantled this uneven surface. Photo by Richard Fiske, 1961 (Smithsonian Institution).

This outcrop at Oshima volcano, in the Izu Islands south of Tokyo, shows more than 100 individual tephra layers. They were produced by eruptions of Oshima at fairly regular intervals over a period of about 10,000 years. The lower layers follow the older preexisting topography. A prominent unconformity in the center of the outcrop is an erosional surface that truncated the earlier eruption deposits. The upper layers mantled this uneven surface.

Photo by Richard Fiske, 1961 (Smithsonian Institution).

Keywords: outcrop | tephra | volcanic ash | geology | stratigraphy | deposit


Izu-Oshima