[CIG-SHORT] Initial stress diagnostic output

Tue Nov 22 12:12:52 PST 2016

Hi Demian,

Let us know what happens.  The problem is that with interpolation, etc., your stresses may not be in equilibrium.  You will be able to tell.  If there are no displacements, then you should be in equilibrium.  Otherwise, you will get displacements.

Cheers,
Charles

> On 23/11/2016, at 8:06 AM, Demian Gomez <demiang at gmail.com> wrote:
> 
> 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 <mailto:gomez.124 at osu.edu>
> 
> On Tue, Nov 22, 2016 at 12:43 PM, Charles Williams <willic3 at gmail.com <mailto: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 <mailto: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 <tel:%2B1%20%28901%29%20900-7324>
>> email: gomez.124 at osu.edu <mailto:gomez.124 at osu.edu>
>> _______________________________________________
>> CIG-SHORT mailing list
>> CIG-SHORT at geodynamics.org <mailto:CIG-SHORT at geodynamics.org>
>> http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short <http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short>
> Charles Williams I Geodynamic Modeler
> GNS Science I Te Pῡ Ao
> 1 Fairway Drive, Avalon 5010, PO Box 30368, Lower Hutt 5040, New Zealand
> Ph 0064-4-570-4566 I Mob 0064-22-350-7326 I Fax 0064-4-570-4600
> http://www.gns.cri.nz/ <http://www.gns.cri.nz/> I Email: C.Williams at gns.cri.nz <mailto:your.email at gns.cri.nz>
> 
> _______________________________________________
> CIG-SHORT mailing list
> CIG-SHORT at geodynamics.org <mailto:CIG-SHORT at geodynamics.org>
> http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short <http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short>
> 
> _______________________________________________
> CIG-SHORT mailing list
> CIG-SHORT at geodynamics.org
> http://lists.geodynamics.org/cgi-bin/mailman/listinfo/cig-short

Charles Williams I Geodynamic Modeler
GNS Science I Te Pῡ Ao
1 Fairway Drive, Avalon 5010, PO Box 30368, Lower Hutt 5040, New Zealand
Ph 0064-4-570-4566 I Mob 0064-22-350-7326 I Fax 0064-4-570-4600
http://www.gns.cri.nz/ <http://www.gns.cri.nz/> I Email: C.Williams at gns.cri.nz <mailto:your.email at gns.cri.nz>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.geodynamics.org/pipermail/cig-short/attachments/20161123/afb1d900/attachment.html>