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Influence of tectonic folding on rockfall susceptibility, American Fork Canyon, Utah, USA

Natural Hazards and Earth System Science

By:
,
DOI: 10.5194/nhess-7-1-2007

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Abstract

We examine rockfall susceptibility of folded strata in the Sevier fold-thrust belt exposed in American Fork Canyon in north-central Utah. Large-scale geologic mapping, talus production data, rock-mass-quality measurements, and historical rockfall data indicate that rockfall susceptibility is correlated with limb dip and curvature of the folded, cliff-forming Mississippian limestones. On fold limbs, rockfall susceptibility increases as dip increases. This relation is controlled by several factors, including an increase in adverse dip conditions and apertures of discontinuities, and shearing by flexural slip during folding that has reduced the friction angles of discontinuities by smoothing surface asperities. Susceptibility is greater in fold hinge zones than on adjacent limbs primarily because there are greater numbers of discontinuities in hinge zones. We speculate that susceptibility increases in hinge zones as fold curvature becomes tighter.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Influence of tectonic folding on rockfall susceptibility, American Fork Canyon, Utah, USA
Series title:
Natural Hazards and Earth System Science
DOI:
10.5194/nhess-7-1-2007
Volume
7
Issue:
1
Year Published:
2007
Language:
English
Publisher:
European Geosciences Union
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1
Last page:
14
Number of Pages:
14