[CIG-SHORT] Zero initial tractions

[Ge Li, Mr]

Hi all ,

I had some weird stuff and questions about zero initial tractions and fault opening in the output.
1.
All traction values are at t=0.0*s are zero, e.g. benchmark results
of tpv205, point (0.0, 7.5),h-shear-stress, although initial horizontal shear traction prescribed here is 81.6MPa
Static friction is 81.24MPa and dynamic friction is 63MPa. Time step is chosen as 0.05s in this example
and h-shear-stress is 81.10MPa,slightly smaller than 81.24MPa.
So first question is: Why traction value at t=0.0*s is not equal to prescribe initial tractions?
Although it seems that this problem doesn't affect following stress evolution and yield similar results to other codes, e.g. eqsim, I am still curious about it and want to figure out why.

2.
I did some tests by setting time step equal 0.02,0.01,0.005 and 0.002 respectively and found identical patterns
that initial zero followed by a traction jump after one time step. Interestingly, h-shear-stress approaches 81.24MPa as time
step decreases and reaches 81.24 at 0.002*s.
So second question is: It seems that there is a minimum time step above which complete evolution cannot be captured. But how to determine it?

3.
 Under 'open free surface = true' case , I find some points where fault opens with none-zero tractions  These points are selected using Paraview find data function(slip[:,2]>10e-10 & abs(traction[:,2])>10e-10).
This  is a link my .cfg file and output.:

https://www.dropbox.com/sh/8s4m448qy8i8id4/AAACD73Kc8tYSYs___5XOoKEa?dl=0

There is also a screenshot of selected point lists from Paraview.

This phenomenon  should be impossible considering a 'True' case! If there is something about output should be noticed?

Looking forward to your reply! Thanks !

Ge
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