[CIG-SHORT] Fault opening error

[Brad Aagaard]

Birendra,

I ran a few time steps with the tighter tolerances and didn't get an 
error. I am out of the office for another week and don't have time to 
run anything until I return.

There is a curved fault dynamic simulation test in tests/2d/nonplanar.

Regards,
Brad


On 8/5/13 7:11 AM, Birendra jha wrote:
> Hi Brad
>
> I did that. It did not solve the fault opening problem.
>
> Do you have some time to run this case? It should take 1-2 minutes. The main problem is that when slip is non-zero on the curved fault surface, slip vector on one of these nodes is assigned some non zero value in the normal direction during numerical iteration. Since fault is under compression everywhere, it gives an error from FaultCohesiveDyn::integrateResidual. Is it possible that after the iterations have converged, there is no slip component in the normal direction? If so, then this error check in inetgrateResidual is probably too strict?
>
> Do you have a simple case where spontaneous fault slip is modeled on a curved fault surface?
>
> Thanks and best regards
> Birendra
>
>
> --------------------------------------------
> On Sun, 8/4/13, Brad Aagaard <baagaard at usgs.gov> wrote:
>
>   Subject: Re: [CIG-SHORT] Fault opening error
>   To: cig-short at geodynamics.org
>   Date: Sunday, August 4, 2013, 8:23 PM
>
>   Birendra,
>
>   Your solver tolerances need adjustment. The FaultCohesiveDyn
>   object in a
>   quasi-static simulation requires use of absolute tolerances
>   in order to
>   properly detect stick/slip with the iterative solver (see
>   the friction
>   session in the CDM2013 tutorial for details). You should
>   lower the
>   ksp_rtol and snes_rtol tolerances to 1.0e-20 to force use of
>   the
>   absolute tolerances.
>
>   Brad
>
>   On 8/2/13 2:35 PM, Birendra jha wrote:
>   > Hi everyone,
>   >
>   > I am trying to run a model with a fault
>   (FaultCohesiveDyn) in it. The fault surface is not planar
>   but is curved. I am getting fault opening error at some
>   node, which stops the simulation. Why does this happen? What
>   should I do to avoid getting this error?
>   >
>   > Please see the attached files which should run.
>   >
>   > Here is what I have tried so far:
>   > 1. different fault dips
>   > 2. different fault traces (plane to curved)
>   > 3. different fault friction coefficients
>   >
>   > My objective is to get some reverse slip on this curved
>   fault surface. The slip does not have to be on the curved
>   part, it can be on the part that strikes parallel to the
>   y_pos boundary.
>   >
>   > Thank you very much for any help.
>   >
>   > Birendra
>   >
>   >
>   >
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