Recent theoretical investigations suggest that the rate of river incision into bedrock depends nonlinearly on sediment supply, challenging the common assumption that incision rate is simply proportional to stream power. Our measurements from laboratory abrasion mills support the hypothesis that sediment promotes erosion at low supply rates by providing tools for abrasion, but inhibits erosion a...

[1] The mechanisms that control climate-dependent rockfall from permafrost mountain slopes are currently poorly understood. In this study, we present the results of an extensive rock slope monitoring campaign at the Matterhorn (Switzerland) with a wireless sensor network. A negative dependency of cleft expansion relative to temperature was observed at all clefts for the dominant part of the yea...

, 369 (1997); 275 Science et al. Alexander L. Densmore, Hillslope Evolution by Bedrock Landslides www.sciencemag.org (this information is current as of September 3, 2008 ): The following resources related to this article are available online at http://www.sciencemag.org/cgi/content/full/275/5298/369 version of this article at: including high-resolution figures, can be found in the online Update...

[1] One potential consequence of global climate change and rapid changes in land use is an increased risk of flooding. Proper understanding of floodwater infiltration thus becomes a crucial component of our preparedness to meet the environmental challenges of projected climate change. In this paper, we present the results of a long-term infiltration experiment performed on fractured ash flow tu...

The dynamic responses of the polar ice sheets in Greenland and Antarctica can have substantial impacts on sea level rise. Understanding the mass balance requires accurate assessments of the bedrock and surface layers, but identifying each layer is performed subjectively by time-consuming, dense hand selection. We have developed an approach for semi-automatically estimating bedrock and surface l...

The critical shear stress (τc) at which grains are entrained on a bedrock surface is important for determining how rivers evolve through changes in sediment cover and erosion. difference τc alluvial surfaces also determines whether channel may be susceptible to runaway alluviation. Bedrock beds can have wide variety of morphologies, but we do not fully understand this variation affects τc. Here...

[1] The linear correlation between modern sediment yields and mean drainage-basin elevation suggests that mountainbelt topography is denuded exponentially with a time scale of approximately 50 Myr following the cessation of active uplift. Some Paleozoic orogens, however, still exist as highelevation terrain. Here I explore this paradox within the broader question of what variables control the d...