The massive dacitic lava dome of Lassen Peak rises above Lake Helen on the south side of the volcano. Plugs of dark dacitic lava exposed near the summit are surrounded by vast aprons of lighter-colored talus associated with growth of the lava dome.

Photo by Lee Siebert, 1972 (Smithsonian Institution).

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

Lassen Volcanic Center