[CIG-SEISMO] specfem2d receivers on surface with an external mesh

[Dimitri Komatitsch]

Dear Giuseppe, dear all,

You are right, option "enreg_surf_same_vertical" in the Par_file 
currently does not work for external meshes because we have no easy way 
of knowing where the topography is in an external mesh (we would need to 
have a list of all element edges that are along the upper surface; could 
be done, but not done yet; not too difficult).

In the meantime the easiest thing to do is probably to zoom on your 
topography in Gmesh (zooming a lot) and then click on the point where 
you want your receiver to be located, and write down the coordinates of 
that point (and then enter that manually in the Par_file).

Best regards,
Dimitri.

On 11/06/2017 01:26 PM, Giuseppe Di Giulio wrote:
> ​​​​​
> profilo_geo.msh.gz 
> <https://drive.google.com/a/ingv.it/file/d/19zHUn9T6deq0q1KeVzeJs0jqAw3uFkaR/view?usp=drive_web>
> ​​​Dear SpecFem developers
> 
> I am using Specfem2D 7.0 with an external mesh (built by gmsh) aimed at 
> investigating the topographic effect.
> 
> My will is to fix the position of the receivers on the topographyc surface.
> 
> My understanding is that the parameter "enreg_surf_same_vertical" in the 
> Par_file cannot be "true" with an external mesh.
> 
> I try to set multiple receiver lines in the Par file where (xdeb,zdeb) 
> are the coordinates of my receivers. The receiver lines (nreceiversets 
> parameter) are fixed to the same number of receivers, and  nrec is equal 
> to 1 for each receiver line (and for this I do not care of xfin and 
> zfin; see the end of message).
> 
> Unfortunately it does not work, the error message after the run of 
> xmeshfem2D is
> 
> "At line 326 of file ../shared/read_value_parameters.f90
> Fortran runtime error: Bad real number in item 1 of list input"
> 
> Any suggestion to place receivers on topographic surface with an 
> external  2D mesh is welcome.
> 
> The Par_file and my mesh are available as attach
> 
> Thanks
> 
> Giuseppe
> 
> 
> # first receiver line
> nrec                            = 1             # number of receivers
> xdeb                            = 10.           # first receiver x in meters
> zdeb                            = 880.          # first receiver z in meters
> xfin                            = 2500.          # last receiver x in 
> meters (ignored if onlyone receiver)
> zfin                            = 870.000427          # last receiver z 
> in meters (ignored if onlyone receiver)
> enreg_surf_same_vertical        = .false.         # receivers inside the 
> medium or at the surface
> 
> # second receiver line
> nrec                            = 1             # number of receivers
> xdeb                            = 1000.           # first receiver x in 
> meters
> zdeb                            = 1000.          # first receiver z in 
> meters
> xfin                            = 2500.          # last receiver x in 
> meters (ignored if onlyone receiver)
> zfin                            = 870.000427          # last receiver z 
> in meters (ignored if onlyone receiver)
> enreg_surf_same_vertical        = .false.         # receivers inside the 
> medium or at the surface
> 
> 
> 
> 
> 
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> 

-- 
Dimitri Komatitsch, CNRS Research Director (DR CNRS)
Laboratory of Mechanics and Acoustics, Marseille, France
http://komatitsch.free.fr