v.flexure - GRASS GIS manual

NAME

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

KEYWORDS

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

DESCRIPTION
NOTES
SEE ALSO
REFERENCES
AUTHORS

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 T_e, 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.

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

SOURCE CODE

Available at: v.flexure source code (history)