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NAME

v.flexure - Lithospheric flexure: gridded deflections from scattered point loads

KEYWORDS

vector, geophysics

SYNOPSIS

v.flexure
v.flexure --help
v.flexure input=name [layer=string] column=name[,name,...] te=float te_units=string output=name [raster_output=name] [g=float] [ym=float] [nu=float] [rho_fill=float] [rho_m=float] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog

Parameters:

input=name [required]
Name of input vector map
Vector map of loads (thickness * area * density * g) [N]
layer=string
Layer number or name
Layer containing load values
Default: 1
column=name[,name,...] [required]
Column containing load values [N]
te=float [required]
Elastic thicnkess: scalar; unis chosen in "te_units"
te_units=string [required]
Units for elastic thickness
Options: m, km
output=name [required]
Output vector points map of vertical deflections [m]
raster_output=name
Output raster map of vertical deflections [m]
g=float
gravitational acceleration at surface [m/s^2]
Default: 9.8
ym=float
Young's Modulus [Pa]
Default: 65E9
nu=float
Poisson's ratio
Default: 0.25
rho_fill=float
Density of material that fills flexural depressions [kg/m^3]
Default: 0
rho_m=float
Mantle density [kg/m^3]
Default: 3300

Table of contents

DESCRIPTION

v.flexure computes how the rigid outer shell of a planet deforms elastically in response to surface-normal loads by solving equations for plate bending. This phenomenon is known as "flexural isostasy" and can be useful in cases of glacier/ice-cap/ice-sheet loading, sedimentary basin filling, mountain belt growth, volcano emplacement, sea-level change, and other geologic processes. v.flexure and r.flexure are the GRASS GIS interfaces to the the model gFlex. As both v.flexure and r.flexure are interfaces to gFlex, this must be downloaded and installed. The most recent versions of gFlex are available from https://github.com/awickert/gFlex, and installation instructions are avaliable on that page via the README.md file.

NOTES

input is a vector points file containing the loads in units of force. Typically, this will be a representation of a distributed field of loads as a set of points, so the user will implicitly include the area over which a stress (vertical load) acts into the quantities in the database table of input.

te, written in standard text as Te, is the lithospheric elastic thickness.

output is provided as a grid of vector points corresponding to the GRASS region when this command is invoked. Be sure to use g.region to properly set the input region! raster_output is the same output, except converted to a raster grid at the same resolution as the current computational region. If you have a grid spacing that is much smaller than a flexural wavelength, it is possible to interpolate the vector output to a much finer resolution than this raster output provides.

The Community Surface Dynamics Modeling System, into which gFlex is integrated, is a community-driven effort to build an open-source modeling infrastructure for Earth-surface processes.

SEE ALSO

v.flexure v.surf.bspline

REFERENCES

Wickert, A. D. (2015), Open-source modular solutions for flexural isostasy: gFlex v1.0, Geoscientific Model Development Discussions, 8(6), 4245–4292, doi:10.5194/gmdd-8-4245-2015.

Wickert, A. D., G. E. Tucker, E. W. H. Hutton, B. Yan, and S. D. Peckham (2011), Feedbacks between surface processes and flexural isostasy: a motivation for coupling models, in CSDMS 2011 Meeting: Impact of time and process scales, Student Keynote, Boulder, CO.

van Wees, J. D., and S. Cloetingh (1994), A Finite-Difference Technique to Incorporate Spatial Variations In Rigidity and Planar Faults Into 3-D Models For Lithospheric Flexure, Geophysical Journal International, 117(1), 179–195, doi:10.1111/j.1365-246X.1994.tb03311.x.

AUTHORS

Andrew D. Wickert

Last changed: $Date 2015-11-15 (Sun, 15 Nov 2015)$

SOURCE CODE

Available at: v.flexure source code (history)


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