NAME

       gmtflexure - Compute flexural deformation of 2-D loads, forces, bending and moments

SYNOPSIS

       gmtflexure rm/rl[/ri]/rw -ETe[u]|D|file [ [l|r][/args] ] [ pPoisson ] [ yYoung ] [ force ]
       [ args] [  ] [ wfile] [ [level] ] [ wd] [ zm] [ -bi<binary> ] [ -i<flags> ] [ -o<flags> ]

       Note: No space is allowed between the option flag and the associated arguments.

DESCRIPTION

       gmtflexure computes the flexural response to 2-D loads using a  range  of  user-selectable
       options,  such  as  boundary  conditions, pre-existing deformations, variable rigidity and
       restoring  force,  and  more.   The  solutions  are  obtained  using   finite   difference
       approximations to the differential equations.

REQUIRED ARGUMENTS

       -Drm/rl[/ri]/rw
              Sets density for mantle, load, infill (optionally, otherwise it is assumed to equal
              the load density), and water.  If ri is not given then it defaults to rl.

       -ETe[u]|D|file
              Sets the elastic plate thickness (in meter); append  k  for  km.   If  the  elastic
              thickness  exceeds 1e10 it will be interpreted as a flexural rigidity D instead (by
              default D is computed from Te, Young's modulus, and  Poisson's  ratio;  see  -C  to
              change these values).  Alternatively, supply a file with variable plate thicknesses
              or rigidities.  The file must be co-registered with any file given via -Q.

OPTIONAL ARGUMENTS

       -A[l|r]bc[/args]
              Sets the boundary conditions at the left and right boundary.  The bc can be one  of
              four  codes:  0  selects  the  infinity condition, were both the deflection and its
              slope are set to zero.  1 selects the periodic condition where both the  first  and
              third  derivatives  of  the  deflection  are  set  to  zero.  2 selects the clamped
              condition where args (if given) sets  the  deflection  value  [0]  (and  its  first
              derivative  is set to zero), while 3 selects the free condition where args is given
              as moment/force which specify the end  bending  moment  and  vertical  shear  force
              [0/0].  Use SI units for any optional arguments.

       -CpPoisson
              Change the current value of Poisson's ratio [0.25].

       -CyYoung
              Change the current value of Young's modulus [7.0e10 N/m^2].

       -Fforce]
              Set a constant horizontal in-plane force, in Pa m [0]

       -Qn|q|t[args]
              Sets  the  vertical load specification. Choose among these three options: -Qn means
              there is no input load file and that  any  deformation  is  simply  driven  by  the
              boundary  conditions set via -A.  If no rigidity or elastic thickness file is given
              via -E then you must also append min/max/inc to initiate the locations used for the
              calculations.   Append  +  to  inc  to  indicate  the  number  of  points  instead.
              -Qq[loadfile] is a file (or stdin if  not  given)  with  (x,load  in  Pa)  for  all
              equidistant  data  locations.   Finally,  -Qt[topofile]  is a file (or stdin if not
              given) with (x,load in m or km, positive up); see -M for topography unit used [m].

       -S     Compute the curvature along with the deflections and  report  them  via  the  third
              output column [none].

       -Twfile
              Supply a file with pre-existing deformations [undeformed surface].

       -Wwd   Specify  water  depth  in m; append k for km.  Must be positive [0].  Any subaerial
              topography will be scaled via the densities set in -D to compensate for the  larger
              density contrast with air.

       -Zzm   Specify  reference depth to flexed surface in m; append k for km.  Must be positive
              [0].  We add this value to the flexed surface before output.

       -V[level] (more ...)
              Select verbosity level [c].

       -bi[ncols][t] (more ...)
              Select native binary input.

       -icols[l][sscale][ooffset][,...] (more ...)
              Select input columns (0 is first column).

       -ocols[,...] (more ...)
              Select output columns (0 is first column).

       -^ or just -
              Print a short message about the syntax of the command, then exits (NOTE: on Windows
              use just -).

       -+ or just +
              Print  an  extensive  usage  (help)  message,  including  the  explanation  of  any
              module-specific option (but not the GMT common options), then exits.

       -? or no arguments
              Print a complete usage (help) message, including the explanation of  options,  then
              exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

NOTE ON UNITS

       The -M option controls the units used in all input and output files.  However, this option
       does not control values given on the command line to the -E, -W, and  -Z  options.   These
       are assumed to be in meters unless an optional k for km is appended.

PLATE FLEXURE NOTES

       We solve for plate flexure using a finite difference approach. This method can accommodate
       situations such as variable rigidity, restoring force that depends on the deflection being
       positive or negative, pre-existing deformation, and different boundary conditions.

EXAMPLES

       To  compute  elastic plate flexure from the topography load in topo.txt, for a 10 km thick
       plate with typical densities, try

              gmt flexure -Qttopo.txt -E10k -D2700/3300/1035 > flex.txt

REFERENCES

SEE ALSO

       gmt, gravfft grdflexuregrdmath

COPYRIGHT

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe