[CIG-SEISMO] single force solution

[Dimitri Komatitsch]

Hi Sevan,

I guess you can keep cc'ing the list because it is an issue Clément, 
Vadim, Paul, Sébastien and I have been facing as well in our coupling 
with external codes, thus we are interested in knowing more about the 
potential problem.

Thanks,
Best wishes,
Dimitri.

On 04/12/2017 11:24 AM, Sevan Adourian wrote:
> Hi Hom Nath,
>
> Thanks for your answer and concern. Since you suggest something that is
> not directly "specfem related", can I send you directly an email so that
> we can discuss it? And then I can post the solution once we'll find it,
> in order to close the topic!
>
> Thanks again,
> Sévan
>
> On Tue, Apr 11, 2017 at 8:46 PM, Hom Nath Gharti <hgharti at princeton.edu
> <mailto:hgharti at princeton.edu>> wrote:
>
>     Hi Sévan,
>
>     Do you also switch the orientations of source and receiver?
>
>     Thanks,
>     Hom Nath
>
>     On Tue, Apr 11, 2017 at 1:39 PM, Sevan Adourian
>     <sevan.adourian at berkeley.edu <mailto:sevan.adourian at berkeley.edu>>
>     wrote:
>
>         Hi cig-seismo community,
>
>         I'm trying to compute Green's functions using Specfem3D-Globe,
>         using a single force point source solution coupled with a source
>         time function that basically represents a filtered Dirac delta.
>         In order to test my implementation, I imposed a source at a
>         point A and looked at the obtained Green's function at a
>         receiver B. Then, I switched the position of the source and the
>         receiver and compared the 2 in order to check the reciprocity of
>         those Green's functions.
>
>         It turned out that I have a perfect reciprocity (in the
>         frequency band that correspond to my filtered Dirac delta) only
>         on the component in which I input the force, while the other
>         components don't quite match.
>
>         I strongly suspected a reference frame rotation issue, so I
>         tried to input the force in the global xyz coordinate system
>         (i.e. adding the force directly in the accel_crust_mantle array
>         in the comp_add_sources subroutine, without multiplying with the
>         nu_source matrix) and looked at the Green's functions in this
>         xyz coordinates system (ie, directly writing in the seismograms
>         structure the values of ux, uy and uz computed in the
>         compute_seismogram subroutine), but I still have this issue.
>         Would anyone have an idea of where this probable rotation issue
>         could come from?
>
>         I'm working on specfem3D-Globe v6.0.0.
>
>         Thanks in advance for your help!
>         Sévan
>
>         --
>         Sevan Adourian
>         Masters Student at Ecole Normale Superieure de Paris
>         sevan.adourian at ens.fr <mailto:sevan.adourian at ens.fr>
>
>
>
>     _______________________________________________
>     CIG-SEISMO mailing list
>     CIG-SEISMO at geodynamics.org <mailto:CIG-SEISMO at geodynamics.org>
>     http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-seismo
>     <http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-seismo>
>
>
>
>
> --
> Sevan Adourian
> Masters Student at Ecole Normale Superieure de Paris
> sevan.adourian at ens.fr <mailto:sevan.adourian at ens.fr>
>
>
> _______________________________________________
> 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