Gradual, Incremental Hillslope Transport: Creep 12/6/2018
Schedule Conversion of Rock to Regolith on Hillslopes Soil Transport by Creep on Hillslopes Mass Balance derivation of hillslope profile using Kirkby relation MATLAB numerical example Creep process descriptions Coupled Production and transport 12/6/2018
Convex Hillslopes 12/6/2018
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Terms for discussion 12/6/2018
Lecture done largely on the board using notes from Anderson’s Little Book of Geomorphology. http://instaar.colorado.edu/~andersrs/T he_little_book_010708_print.pdf 12/6/2018
Here are many of the equations from the discussion on the board 12/6/2018
Closure through Kirkby, 1971 Creep: assume m = 0, n = 1 (W is in negative z direction) 12/6/2018
Good questions from Claudio: -we posit that flux should increase with distance, but the kirkby relation assumes that m = 0, effectively making the flux insensitive to distance and only slope, n and k. Is kirkby still the right way to close these equations? -Next time…do I want to get into the new, non-linear flux equns? 12/6/2018
MATLAB Numerical Example Kirkby relation for flux Numerical solution FTFS, FTCS methods Available Variables Initial Conditions Boundary Conditions Some outcomes 12/6/2018
Input Parameters 12/6/2018
Initial Conditions (profile) 12/6/2018
Boundary Condition 1: Constant exit slope. All material carried away. 12/6/2018
Boundary Condition 2: Lowering at constant rate. Like stream incision. 12/6/2018
Boundary Condition 3: No flux across last node Boundary Condition 3: No flux across last node. All material accumulates. 12/6/2018
Initial Conditions: Can vary the initial geometry of the surface. Initial Condition: Linear slope, flat base (moraine or ridgeline) 12/6/2018
Initial Conditions: Can vary the initial geometry of the surface. Initial Condition: Fault Scarp with flat base 12/6/2018
Approach to Equilibrium: Can monitor progress toward balance Y-axis is the ratio of dz/dt (erosion rate at ridgeline) to E (erosion rate at outlet) 12/6/2018
Given more time: 12/6/2018