[CIG-SEISMO] specfem2d external mesh

[Dimitri Komatitsch]

Hi Phil,

"enreg_surf_same_vertical" is a parameter in the DATA/Par_file that asks 
the code, if you set a receiver at a given position (x_s,z_s), to record 
at the elevation of topography z(x_s) instead of at z_s.

In other words, the code ignores the value of z_s you gave and replaces 
it with the elevation of topography at this location (hence the name 
"record along the same vertical at the location of topography", which 
for some reason led to "enreg_surf_same_vertical" (surf is for 
"surface", and "enreg(istrer)" is French for "record")

We should probably change that to "record_at_surface_same_vertical"
(I initially developed the code in French, a long time ago :-)

(the length is limited to 31 characters)

That option is useful when one does not know the exact value of 
topography height at that location, the code will then compute it for you.

Best wishes,
Dimitri.

On 09/24/2015 09:52 AM, Phil Cummins wrote:
>
> Hi,
>
> I am running specfem2d version 7.0 under Mac OS 10.9.5. We have been
> running using a mesh generated in gmesh and converted to a specfem2d
> using LibGmsh2Specfem_convert_Gmsh_to_Specfem2D_official.py. It was
> working fine for our mesh but we recently tried to extend it to model an
> earthquake source lying just outside our original mesh. Now when we try
> to run specfem2d it produces the following output when running the mesher:
>
>   running the mesher...
>
>   Reading the parameter file ...
>
>   Title of the simulation
>   Basin Jakarta P-SV
>
>   1 1 2100.d0  500.d0   300.d0 0 0 1000.d0 100.d0 0 0 0 0 0 0
>   2 1 2670.d0 1500.d0  1000.d0 0 0 1500.d0 500.d0 0 0 0 0 0 0
>   3 1 3200.d0 6000.d0  3500.d0 0 0 3000.d0 800.d0 0 0 0 0 0 0
>   4 1 3000.d0 4000.d0  2500.d0 0 0 2000.d0 600.d0 0 0 0 0 0 0
>   5 1 3800.d0 7000.d0  4000.d0 0 0 3500.d0 1000.d0 0 0 0 0 0 0
>
>   Nb of solid, fluid or porous materials =            5
>
>   Material #           1  isotropic
>   rho,cp,cs =    2100.0000000000000        500.00000000000000
> 300.00000000000000        1000.0000000000000        100.00000000000000
>   Material is solid
>
>   Material #           2  isotropic
>   rho,cp,cs =    2670.0000000000000        1500.0000000000000
> 1000.0000000000000        1500.0000000000000        500.00000000000000
>   Material is solid
>
>   Material #           3  isotropic
>   rho,cp,cs =    3200.0000000000000        6000.0000000000000
> 3500.0000000000000        3000.0000000000000        800.00000000000000
>   Material is solid
>
>   Material #           4  isotropic
>   rho,cp,cs =    3000.0000000000000        4000.0000000000000
> 2500.0000000000000        2000.0000000000000        600.00000000000000
>   Material is solid
>
>   Material #           5  isotropic
>   rho,cp,cs =    3800.0000000000000        7000.0000000000000
> 4000.0000000000000        3500.0000000000000        1000.0000000000000
>   Material is solid
>
>
>   Parameter file successfully read...
>
>   Source           1
>   Position xs, zs =    915000.00000000000       -20000.000000000000
>   Frequency, delay =    5.0000000000000000        0.0000000000000000
>   Source type (1=force, 2=explosion):            2
>   Time function type (1=Ricker, 2=First derivative, 3=Gaussian, 4=Dirac,
> 5=Heaviside):            3
>   Angle of the source if force =    0.0000000000000000
>   Mxx of the source if moment tensor =    1.0000000000000000
>   Mzz of the source if moment tensor =    1.0000000000000000
>   Mxz of the source if moment tensor =    1.0000000000000000
>   Multiplying factor =    10000000000.000000
>
>
>   The mesh contains       160167  elements
>
>   Control elements have            4  nodes
>
>
>   Min and max value of X in the grid =    750000.00000000000
> 1000000.0000000000
>   Min and max value of Z in the grid =   -150000.00000000000
> 1474.3499999999999
>
>   nedges_coupled (acoustic/elastic)           0
>   nedges_coupled (acoustic/poroelastic)           0
>   nedges_coupled (poroelastic/elastic)           0
>
>   Position (x,z) of the source =    915000.00000000000
> -20000.000000000000
>
> STOP for now we cannot use both enreg_surf_same_vertical and
> read_external_mesh
>
>    running the solver...
>
> We suspect the "STOP" message is indicating some problem with the mesh,
> but we don't know what "enreg_surf_same_vertical " is referring to. Can
> someone please tell us what this means?
>
> The specfem2d solver tries to run anyway, but eventually hits a floating
> point exception after printing out the total number of receivers.
>
> No doubt we have made some mistake with our external mesh, but it is
> difficult to diagnose the problem. Do you think this
> "enreg_surf_same_vertical " message is telling us what the problem is,
> and if so what does it mean?
>
> Thanks,
>
> - Phil
> ------------------------------------------------------------------------
>
>
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-- 
Dimitri Komatitsch
CNRS Research Director (DR CNRS), Laboratory of Mechanics and Acoustics,
UPR 7051, Marseille, France    http://komatitsch.free.fr