Rock-fall potential in the Yosemite Valley, California
Open-File Report
99-578
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Abstract
We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.
Suggested Citation
Wieczorek, G.F., Morrissey, M.M., Iovine, G., Godt, J., 1999, Rock-fall potential in the Yosemite Valley, California: U.S. Geological Survey Open-File Report 99-578, Report: 7 p.; 1 Plate: 49.38 x 31.82 inches, https://doi.org/10.3133/ofr99578.
ISSN: 2331-1258 (online)
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Rock-fall potential in the Yosemite Valley, California |
| Series title | Open-File Report |
| Series number | 99-578 |
| DOI | 10.3133/ofr99578 |
| Year Published | 1999 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Contributing office(s) | Geologic Hazards Science Center |
| Description | Report: 7 p.; 1 Plate: 49.38 x 31.82 inches |
| Country | United States |
| State | California |
| Other Geospatial | Yosemite Valley |
| Projection | Lambert Conformal Conic Projection |
| Scale | 12000 |