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

[Dimitri Komatitsch]

Dear Giuseppe,

Using a single receiver per set, as in your:

# 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

works fine here though. Are you using a recent version of the code?

Cheers,
Dimitri.

On 11/07/2017 03:59 PM, Dimitri Komatitsch wrote:
> 
> 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
>>
>>
>>
>>
>>
>> _______________________________________________
>> CIG-SEISMO mailing list
>> CIG-SEISMO at geodynamics.org
>> http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-seismo
>>
> 

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