Gravitational Failure of Sea Cliffs in Weakly Lithified Sediment

Abstract

Research Article| March 01, 2002 Gravitational Failure of Sea Cliffs in Weakly Lithified Sediment MONTY A. HAMPTON MONTY A. HAMPTON 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025 Search for other works by this author on: GSW Google Scholar Author and Article Information MONTY A. HAMPTON 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025 Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 Copyright © 2002 Geological Society of America Environmental & Engineering Geoscience (2002) 8 (3): 175–191. https://doi.org/10.2113/8.3.175 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation MONTY A. HAMPTON; Gravitational Failure of Sea Cliffs in Weakly Lithified Sediment. Environmental & Engineering Geoscience 2002;; 8 (3): 175–191. doi: https://doi.org/10.2113/8.3.175 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract Gravitational failure of sea cliffs eroded into weakly lithified sediment at several sites in California involves episodic stress-release fracturing and cantilevered block falls. The principal variables that influence the gravitational stability are tensional stresses generated during the release of horizontal confining stress and weakening of the sediment with increased saturation levels. Individual failures typically comprise less than a cubic meter of sediment, but large areas of a cliff face can be affected by sustained instability over a period of several days. Typically, only the outer meter or so of sediment is removed during a failure episode. In-place sediment saturation levels vary over time and space, generally being higher during the rainy season but moderate to high year-round. Laboratory direct-shear tests show that sediment cohesion decreases abruptly with increasing saturation level; the decrease is similar for all tested sediment if the cohesion is normalized by the maximum, dry-sediment cohesion. Large failures that extend over most or all of the height of the sea cliff are uncommon, but a few large wedge-shaped failures sometimes occur, as does separation of large blocks at sea cliff–gully intersections. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.