Hillslope evolution by bedrock landslides

Science

Volumn 275, Issue 5298, 1997, Pages 369-372

  Densmore, Alexander L ^a   Anderson, Robert S ^a   McAdoo, Brian G ^a   Ellis, Michael A ^a  

^a NONE

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; DISASTER; EVOLUTION; GEOLOGY; MODEL; PHYSICS; PRIORITY JOURNAL; ROCK; SAND; UNITED STATES;

BASE LEVEL; BEDROCK LANDSLIDE; HILLSLOPE DEVELOPMENT;

EID: 0030620885     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.275.5298.369     Document Type: Article

References (37)

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3. M. L. Stout, Geol. Soc. Am. Abstr. Programs 16, 257 (1984); P. C. Augustinus, Earth Surf. Process. Land. 17, 39 (1992); J. M. Harbor, Geol. Soc. Am. Bull. 104, 1364 (1992); S. W. Nelson, U.S. Geol. Surv. Bull. 2107, 43 (1993); N. Hovius, C. P. Stark, P. A. Allen, Geology, in press.
4. M. L. Stout, Geol. Soc. Am. Abstr. Programs 16, 257 (1984); P. C. Augustinus, Earth Surf. Process. Land. 17, 39 (1992); J. M. Harbor, Geol. Soc. Am. Bull. 104, 1364 (1992); S. W. Nelson, U.S. Geol. Surv. Bull. 2107, 43 (1993); N. Hovius, C. P. Stark, P. A. Allen, Geology, in press.
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22. The model consisted of two parallel, clear acrylic plates, each 51 cm by 38 cm by 0.6 cm thick. The 2.5-cm space separating the plates was filled with a granular material. Baselevel for the hillslope was determined by a sliding acrylic strip that formed one wall of the model (the active boundary), which was lowered at 0.5-cm intervals. Because all material reaching the toe of the hillslope was removed, no buttressing of the hillslope was allowed. The mass of the removed material was measured on a digital balance with a precision of ±0.1 g.
23. See reviews in S. K. Grumbacher, K. M. McEwen, D. A. Halverson, D. T. Jacobs, J. Lindner, Am. J. Phys. 61, 329 (1993); J. M. Carlson and G. H. Swindle, Proc. Natl. Acad. Sci. U.S.A. 92, 6712 (1995).
24. See reviews in S. K. Grumbacher, K. M. McEwen, D. A. Halverson, D. T. Jacobs, J. Lindner, Am. J. Phys. 61, 329 (1993); J. M. Carlson and G. H. Swindle, Proc. Natl. Acad. Sci. U.S.A. 92, 6712 (1995).
25. This lowering could result from fluvial or glacial incision, by sea-or lake-level fall, or by dip-slip motion on a fault.
26. For example, V. Frette et al., Nature 379, 49 (1996).
27. We also evaluated the effect of structural dip on slide behavior [K. Terzaghi in (8); S. R. Hencher, in Slope Stability: Geotechnical Engineering and Geomorphology, M. G. Anderson and K. S. Richards, Eds. (Wiley, Chichester, UK, 1987), pp. 145-186] by creating horizontal stratigraphy and then tilting the entire model, either toward or away from the active boundary. This created either a dip-slope or antidip-slope, respectively.
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32. In contrast, time-predictable behavior would imply the existence of a threshold strength or steep toe height that must be exceeded before failure occurs. We saw no evidence for such a threshold.
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37. We thank D. Stakes of MBARI for access to her workstation and data visualization software; S. Anderson, G. Dick, K. Howard, and J. Repka for helpful discussions; H. Kelsey for observations and advice; and two anonymous reviewers for their comments. Supported by NASA Earth Systems Science graduate fellowship NGT-51220 to A.L.D. and by a grant from the NASA Surface Change Program. SeaBeam data collection and ALVIN dives were supported by Office of Naval Research grant N00014-9301-202.