Metadata-Version: 2.4
Name: wmbe
Version: 0.1.34
Summary: Tools for modeling the weathering-mediated erosion of bedrock, with a focus on environments with no soil or talus accumulation such as steep bedrock channel walls
Author-email: "Colin P. Stark" <cstarkjp@gmail.com>
Project-URL: homepage, https://cstarkjp.github.io/WMBE
Project-URL: repository, https://github.com/cstarkjp/WMBE
Project-URL: documentation, https://cstarkjp.github.io/WMBE
Keywords: geomorphology,erosion,bedrock,weathering
Classifier: Development Status :: 3 - Alpha
Classifier: Framework :: Jupyter
Classifier: Framework :: MkDocs
Classifier: Intended Audience :: Science/Research
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: License :: OSI Approved :: GNU General Public License v3 (GPLv3)
Classifier: Operating System :: MacOS
Classifier: Operating System :: POSIX :: Linux
Classifier: Operating System :: Microsoft :: Windows
Classifier: Topic :: Scientific/Engineering :: Physics
Requires-Python: >=3.14
Description-Content-Type: text/markdown
License-File: LICENSE.md
Requires-Dist: numpy
Requires-Dist: matplotlib
Requires-Dist: sympy
Requires-Dist: scipy
Requires-Dist: pandas
Requires-Dist: jupyter
Requires-Dist: ipython
Requires-Dist: openpyxl
Requires-Dist: tqdm
Dynamic: license-file

# [**Weathering-mediated bedrock erosion**](https://pypi.org/project/wmbe/)


[![](https://github.com/cstarkjp/WMBE/actions/workflows/pypi-publish.yml/badge.svg?style=cache-control=no-cache)](https://github.com/cstarkjp/WMBE/actions/workflows/pypi-publish.yml)


**Summary:**    Tools for modeling the weathering-mediated erosion of bedrock. The focus is on environments with no soil or talus accumulation: for example, on steep bedrock channel walls.

<!-- The current treatment is 1d only, and it assumes an exponentially decaying weakening profile with depth into the rock. -->



<div align="center">

![Non-dimensionalized bedrock erosion rate at steady-state $\nu_{\mathrm{s}}$ vs dimensionless weathering number $\mathcal{W}$](https://raw.githubusercontent.com/cstarkjp/WMBE/main/images/erosionrate_steadystate.png)

</div>

### Abstract

Weathering is an important process in bedrock river channels, but it receives less attention than on rockslopes and soil-mantled hillslopes. Sub-aerial weathering in particular weakens channel rock exposed during stage variation and makes it more susceptible to mechanical erosion. Such erosion modifies the depth-profile of rock weathering, which in turn modifies the process of weakening.
Here we study how these interactions lead to a steady-state erosion rate.

Experiments indicate that rock weakness, defined as its propensity to erosion by flow-driven particle-impact wear, is inversely proportional to tensile strength squared, and that weathering-driven weakening takes place through wetting/drying, freeze/thaw and thermal cycling at rates that diminish in a roughly exponential fashion with depth. 

Such weakening propagates into the rock at a speed ${\lambda} {\eta_0}$, where  ${\eta_0}$ is the weathering rate of fresh rock and ${\lambda}$ is the e-folding depth.
The dimensionless ratio of this weakening speed to the speed of erosion of fresh rock ${u}_0$, which we call the weathering number ${\mathcal{W}}$, fundamentally controls model behavior.

For small ${\mathcal{W}}<0.25$ and slow weathering relative to erosion, the two speeds simply add and the erosion rate is approximately ${\lambda}{\eta_0} + {u_0}$.
However, for  ${\mathcal{W}} \gg 2.5$ and relatively fast weathering, the predicted behavior is counter-intuitive: the erosion rate is asymptotically the geometric mean of the two speeds $\sqrt{ {\lambda} {\eta_0} {u_0} }$.

The rate of weathering alone never limits the rate of erosion, and so the concept of weathering limitation does not apply in the traditional sense.


### Code

The code is provided as a [Python package](https://pypi.org/project/wmbe/) and [Jupyter notebooks](https://github.com/cstarkjp/WMBE/tree/main/notebooks).


### References

 1. [Inoue, T., Yamaguchi, S., and Nelson, J. M., 2017.](https://doi.org/10.1016/j.geomorph.2017.02.018). "The effect of wet-dry weathering on the rate of bedrock river channel erosion by saltating gravel", Geomorphology, 285, 152–161.  

 1. [Li, K., Ma, L., Li, X., and Peng, S., 2016.](https://www.jestr.org/downloads/Volume9Issue3/fulltext10932016.pdf) "Effect of drying-wetting cycles on triaxial compression mechanical properties of sandstone", Journal of Engineering Science and Technology Review, 9, 66–73.

 2. [Stark, C.P., and Stark, G.J., 2022.](https://doi.org/10.5194/esurf-10-383-2022) "The direction of landscape erosion", Earth Surface Dynamics, 10: 383-419.
