Usu rises to the SE above the town of Toyako Spa on the shores of Lake Toya on 12 August 1977. O-Usu (left) and Ko-Usu (right) lava domes are within the summit caldera. The first of three major explosive eruptions during 7-9 August originated from vents behind Ko-Usu in this view and stripped trees of vegetation on the upper slopes. Growth of a new lava dome in the area between the two domes later in the eruption greatly changed the morphology of the summit.

Photo by Lee Siebert, 1977 (Smithsonian Institution).

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

Galleries: Lava Domes

Keywords: lava dome | environmental impact

Toya