[CIG-SEISMO] single force solution

[Sevan Adourian]

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>
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> 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
>>
>
>
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-- 
Sevan Adourian
Masters Student at Ecole Normale Superieure de Paris
sevan.adourian at ens.fr
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