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 image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.

Galleries: Volcanic Outcrops | Ash Plumes and Ashfall

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

Izu-Oshima