Global Volcanism Program | Image GVP-03195
These hills below the north flank of Mount Shasta are hummocks resulting from the massive Shasta Valley debris avalanche deposit, which formed during a major volcanic flank collapse event in the Pleistocene. Individual hummocks, composed of remnants of the ancestral Shasta volcano, are up to 200 m high and some are more than 1 km long.
Photo by Lee Siebert, 1981 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.