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Global Volcanism Program | Image GVP-03216

A roadcut exposes the internal structure of the Shasta Valley debris-avalanche deposit, formed by collapse of Mount Shasta during the Pleistocene.  The deposit contains angular blocks of Mount Shasta rocks surround by crushed matrix of similar material, in sharp contact with blocks and matrix of differing lithologies. Photo by Lee Siebert, 1981 (Smithsonian Institution).

A roadcut exposes the internal structure of the Shasta Valley debris-avalanche deposit, formed by collapse of Mount Shasta during the Pleistocene. The deposit contains angular blocks of Mount Shasta rocks surround by crushed matrix of similar material, in sharp contact with blocks and matrix of differing lithologies.

Photo by Lee Siebert, 1981 (Smithsonian Institution).


Shasta