.. index:: ! gmtflexure ********** gmtflexure ********** .. only:: not man gmtflexure - Compute flexural deformation of 2-D loads, forces, bending and moments Synopsis -------- .. include:: ../../common_SYN_OPTs.rst_ **gmtflexure** |-D|\ *rm*/*rl*\ [/*ri*]\ /*rw* **-E**\ *Te*\ [**u**]\|\ *D*\|\ *file* [ |-A|\ [**l**\|\ **r**][/*args*] ] [ |-C|\ **p**\ *Poisson* ] [ |-C|\ **y**\ *Young* ] [ |-F|\ *force* ] [ |-Q|\ *args*\ ] [ |-S| ] [ |-T|\ *wfile*\ ] [ |SYN_OPT-V| ] [ |-W|\ *wd*] [ |-Z|\ *zm*] [ |SYN_OPT-bi| ] [ |SYN_OPT-d| ] [ |SYN_OPT-e| ] [ |SYN_OPT-h| ] [ |SYN_OPT-i| ] [ |SYN_OPT-o| ] |No-spaces| 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 ------------------ .. _-D: **-D**\ *rm*/*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*. .. _-E: **-E**\ *Te*\ [**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: **-A**\ [**l**\|\ **r**]\ *bc*\ [/*args*] Sets the boundary conditions at the **l**\ eft and **r**\ ight 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. .. _-C: **-Cp**\ *Poisson* Change the current value of Poisson's ratio [0.25]. **-Cy**\ *Young* Change the current value of Young's modulus [7.0e10 N/m^2]. .. _-F: **-F**\ *force*] Set a constant horizontal in-plane force, in Pa m [0] .. _-Q: **-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: **-S** Compute the curvature along with the deflections and report them via the third output column [none]. .. _-T: **-T**\ *wfile* Supply a file with pre-existing deformations [undeformed surface]. .. _-W: **-W**\ *wd* 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. .. _-Z: **-Z**\ *zm* 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: .. |Add_-V| unicode:: 0x20 .. just an invisible code .. include:: ../../explain_-V.rst_ .. |Add_-bi| unicode:: 0x20 .. just an invisible code .. include:: ../../explain_-bi.rst_ .. |Add_-d| unicode:: 0x20 .. just an invisible code .. include:: ../../explain_-d.rst_ .. |Add_-e| unicode:: 0x20 .. just an invisible code .. include:: ../../explain_-e.rst_ .. |Add_-h| unicode:: 0x20 .. just an invisible code .. include:: ../../explain_-h.rst_ .. include:: ../../explain_-icols.rst_ .. include:: ../../explain_-ocols.rst_ .. include:: ../../explain_help.rst_ 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 -------- :doc:`gmt `, :doc:`gravfft `, :doc:`grdflexure `, :doc:`grdmath `