[CIG-SHORT] Initial stress diagnostic output

[Demian Gomez]

Hi Charles,

Are you suggesting that I should turn off gravity and run my problem with
zero displacements at the fault? This will output the stress field that I
introduced as initial stress without altering anything, right? Didn't think
of that... thanks.

What do you mean by "You should be able to fix this by constraining the
displacements."? My initial stresses are s_xx = s_yy = s_zz = rho*g*depth
and s_xy = s_yz = s_xz = 0, which should be the lithostatic stress in
equilibrium. My model is spherical built in ECEF coordinates so s_zz is not
aligned with g. However, since s_xx = s_yy = s_zz and s_xy = s_yz = s_xz =
0 the initial stress state is independent of the coordinate system. I am
therefore assuming that my problem has to be related to the interpolation
from the spatialdb to the domain or something similar.

Thanks again,
Demián

--
*Dr. Demián D. Gómez*
Postdoctoral Researcher
The Ohio State University - School of Earth Sciences
275 Mendenhall Laboratory
125 South Oval Mall
Columbus, Ohio 43210
Cell: +1 (901) 900-7324
email: gomez.124 at osu.edu


On Tue, Nov 22, 2016 at 12:43 PM, Charles Williams <willic3 at gmail.com>
wrote:

> Dear Demian,
>
> I may be mistaken, but I believe that if you turn off gravity for your
> problem the remaining stresses should be the initial stresses.  The one
> issue is that if the stresses aren’t in equilibrium there will be some
> displacement, which will in turn alter the stresses.  You should be able to
> fix this by constraining the displacements.
>
> Cheers,
> Charles
>
> On 23/11/2016, at 4:44 AM, Demian Gomez <demiang at gmail.com> wrote:
>
> Dear all,
>
> I am still trying to incorporate gravity to my model. After I run my
> quasi-static simulation (with zero displacement at the fault) I'm getting
> ~16 m of displacement with a very suspicious spatial variation. Therefore,
> something is inconsistent but I can't figure out what it is. Is there a way
> to output the initial stress as a diagnostic variable (like density,
> lambda, etc)? I didn't find how to do this in the manual. It would be very
> helpful to see how Pylith is assigning my initial stress spatialdb to the
> domain.
>
> Thanks,
> Demián
>
> --
> *Dr. Demián D. Gómez*
> Postdoctoral Researcher
> The Ohio State University - School of Earth Sciences
> 275 Mendenhall Laboratory
> 125 South Oval Mall
> Columbus, Ohio 43210
> Cell: +1 (901) 900-7324
> email: gomez.124 at osu.edu
>
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