HILLSLOPES, LANDSLIDES, AND DRY RED KIDNEY BEANS
Our investigation stems from the original analysis of Densmore and others (1997) and from their result that inner gorges, commonly observed in a variety of actively deforming landscapes, can be part of the natural hillslope development process rather than a signal of recent incision or rock uplift. We add to earlier models by testing the rate of base-level fall, lowering the side panel by increments of 0.5 and 1.0 cm/time-steps, the magnitude dictated by the size of the kidney bean (i.e., jointed rock particle).
A relatively low rate of base-level fall resulted in more frequent small bean-slides, the common generation of inner-gorges of up to 4 bean-heights, and in a characteristic pitted morphology of the hillslope. In contrast, a base-level fall of 1 cm/time-step (i.e. slightly larger than the typical kidney bean) resulted in largely slope-clearing bean-slides and inner gorges were only rarely developed. Our results indicate that the morphology of hillslopes generated by climate-driven landslides should reflect the combination of the rate of base-level fall and the characteristic length-scale of the bulk rock strength, a result that may be tested in actively deforming regions with high-resolution topography and bedrock geology.
Refs: Aalto, R. and five others, Science, 277, 1909-1914, 1997; Densmore, A. L. and three others, Science, 275, 369-372, 1997.