Global Volcanism Program | Image GVP-11403
This massive boulder (top photo) was carried down the Biwasawa valley on the east side of Bandai volcano in a lahar during an eruption in 1888. The deposit covers the broad floor of the Nagase valley. In addition to this lahar, the 1888 eruption included a pyroclastic flow on the east side and a catastrophic debris avalanche that swept over villages to the north of the volcano. The bottom photo is taken from the same location a century later.
Top photo by Fukushima Minposha Newspaper, 1888; bottom photo by Lee Siebert, 1988 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.