GEOB 103 Study Guide - Midterm Guide: Alluvium

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List the factors that control soil strength and soil cohesion, and explain how these factors influence rock strength underlying bedrock also influences the stability of soil mantled slopes slopes underlain by rock layers that dip parallel to the slope surface are more prone to instability cohesion: the tendency of the material to stick to itself landslides tend to happen during and after rainstorms because even partially saturated soils are weaker than dry soils slopes fail when they become saturated enough that material strength is less than the shearing stress. Diffusive processes rainsplash: heavy intense rainfall loosens sediment from soil surfaces, allowing transport by moving water produces net downslope sediment transport limited to thinly vegetated areas close to drainage divides sheetwash: overland flow that is not concentrated into discrete channels and spreads across the ground surface does not transport much sediment in humid or temperate environments rare on heavily vegetated areas soil creep: incremental downslope movement of soil and sediment.