Sonographs of submarine sediment failure caused by the 1980 earthquake off northern California

M.E. Field; R. K. Hall

doi:10.1007/bf02462754

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Sonographs of submarine sediment failure caused by the 1980 earthquake off northern California

M.E. Field·R. K. Hall

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Abstract

In 1980, a large earthquake caused extensive sediment failure on the shallow continental shelf off the Klamath River in northern California. Side-scan sonography was used to complement detailed geophysical profiling in identifying specific features and resolving modes of failure. The features include a nearly flat failure terrace mantled with sand boils, collapse craters and sediment flows, and bounded on the seaward side by a meandering continuous toe ridge. Seaward of the terrace lies a compression zone delineated by small pressure ridges. Our findings indicate a temporal progression of failure from lique-faction of shallow subsurface sand to lateral spread of intact blocks to sediment collapse and flow. ?? 1982 A. M. Dowden, Inc.

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M.E. Field, R. K. Hall. 1982. Sonographs of submarine sediment failure caused by the 1980 earthquake off northern California. https://doi.org/10.1007/bf02462754

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