## Introduction

The displacement profile of the surface of the earth under crustal loads (i.e. mountain chains), can be fairly reproduced by an "elastic" or "flexural" model. In this model, the uppermost layer of the earth (i.e. the elastic lithosphere) responds to crustal loads as an "elastic" beam, floating in a weaker, fluid-like foundation (i.e. the astenospheric mantle) (Turcotte and Schubert, 1982; Watts, 2001).

This simple, "flexural" model provides insight into how tectonic loads (i.e. mountain chains) and sedimentary basins are linked, and into how the crust and mantle support loads. The use of the flexural model has allowed geologists to understand the regional variations of strength of the lithosphere, and the implication that these variations have for mountain building, sedimentary basin formation, and earthquakes (Watts, 2001).

Flex2D is a program that implements the "elastic", "flexural" model. Crustal loads can be entered and plotted, the profile of deformation produced by these loads can be computed and visualized, and the effect of changes in model parameters can be evaluated.

Geologists often talk about the "flexural" link between tectonic loads and sedimentary basins, but they rarely do the math. Perhaps, because implementing the flexural model is tedious, specially if done in spreadsheets. Flex2D makes flexural modeling an easy task.

Acknowledgements

Plots in Flex2D rely on the SM2DGraphView Framework by Snowmint Creative Solutions:

SM2DGraphView Copyright © 2012 Snowmint Creative Solutions LLC http://www.snowmintcs.com/
This framework is freely available to the Cocoa community.

Formulas and algorithms are from Hetenyi (1946) for the case of an elastic beam of constant thickness, and Bodine (1981) for the case of an elastic beam of variable thickness. I would like to thank German Ojeda (Ecopetrol) for providing me with Matlab scripts for Bodine's solution. A short description of the formulas is given in the formulas section.

License

Flex2D is free for academic, non-profit purposes. If you want to use the program for consulting, please contact me at nestor.cardozo@uis.no.