This entire flat forested plain, known as Aokigahara ("Blue Tree Plain") is underlain by a single massive lava flow from Fuji. A major explosive and effusive eruption began in June 864 CE from Nagaoyama, a vent on the NW flank. Lava flowed into lakes Motosu and Senoumi, destroying lakeshore houses. It divided Lake Senoumi into the two present-day lakes of Shojiko(seen here in the distance against a Tertiary mountain range to the NW) and Saiko. The Aokigahara Marubi lava field covered an area of 32 km².

Photo by Lee Siebert, 1977 (Smithsonian Institution).

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

Keywords: lava flow

Fujisan